ACI 530-11 Building Code Requirements and Specification for Masonry.pdf
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This document provides an abstract and overview of the Building Code Requirements and Specification for Masonry Structures. The document was developed jointly by the Masonry Standards Joint Committee (MSJC) which is sponsored by The Masonry Society (TMS), the American Concrete Institute (ACI), and the Structural Engineering Institute of the American Society of Civil Engineers (SEI/ASCE). The standards contained in the document provide requirements for designing, constructing, and specifying masonry structures. The document covers topics such as materials, analysis and design, seismic design, and quality assurance for masonry construction. It is intended to be used by individuals competent to evaluate its recommendations and requirements.
![About the MSJC and its Sponsors
Masonry Standards Joint Committee
The Masonry Standards Joint Committee (MSJC) is, as its name suggests, a joint committee sponsored by The
Masonry Society (TMS), the American Concrete Institute (ACI), and the Structural Engineering lnstitute of the
American Society of Civil Engineers (SEl/ASCE). lts mission is to develop and maintain design and
construction standards for masonry for reference by or incorporation into model building codes regulating
masonry construction. In practice, the MSJC is responsible for the maintenance of the Building Code
Requirementsfor Masonry Structures (TMS 402/AC1530/ASCE 5), Specificationfor Masonry Structures (TMS
602/ACI 530.1/ASCE 6) and their companion Commentaries. Committee membership is open to al] qualified
individuals, within the constraints of balance requirements, balloting schedules and particular needs for
technical expertise. Committee meetings are open to the public.
Committee Activities include:
1. Evaluate and ballot proposed changes to existing standards ofthe committee.
2. Develop and ballot new standards for masonry.
3. Resolve Negative votes from ballot items.
4. Provide interpretation ofexisting standards of the Committee.
5. Identify areas of needed research.
6. Sponsor educational seminars and symposia.
7. Monitor intemational standards.
Additional details ofthe Committee, its work, and its meeting schedule are posted at www.masonrysociety.org
and can be obtained from The Masonry Society. A roster ofthe Committee Members during the 2011 Revision
Cycle is shown on the following page.
THE
MASONRY
SOCIETY
Advancing the knowledge of masonry
The Masonry Society (TMS) was founded in 1977 as a not-for-profit professional, technical, and educational
association dedicated to the advancement of knowledge on masonry. Today TMS is an intemational gathering of
people interested in the art and science of masonry, and its members include design engineers, architects, builders,
researchers, educators, building officials, material suppliers, manufacturers, and others who want to contribute to and
benefit from the global pool ofknowledge on masonry.
TMS gathers and disseminates technical information through its committees, publications, codes and standards,
newsletter, refereed joumal, educational programs, workshops, scholarships, disaster investigation team, and
conferences. The work ofTMS is conducted by individual TMS members and through the volunteer committees
composed of both members and non-members. The Masonry Society serves as the lead Society for the support
ofthe MSJC, andas such, meetings ofthe committee are held at TMS meetings and activities ofthe Committee
are managed by TMS.
For more information about TMS, contact The Masonry Society, 3970 Broadway, Suite 201-0, Boulder, CO
80304-11 35, U.S.A; Phone: 303-939-9700; Fax:303-541-9215; E-mail: info@masonrysociety.org; Website:
www.masonrysociety.org](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-4-320.jpg)
![C-26
CODE
1.8.7 Prestressing steel
Modulus of elasticity shall be determined by tests. For
prestressing steels not specifically listed in ASTM
A416/A416M, A421/A421M, or A722/A722M, tensile
strength and relaxation losses shall be determined by tests.
1.9 - Section properties
1.9.1 Stress computations
1.9.1.1 Members shall be designed using
section properties based on the m1mmum net cross-
sectional area of the member under consideration. Section
properties shall be based on specified dimensions.
1.9.1.2 In members designed for composite
action, stresses shall be computed using section properties
based on the mínimum transformed net cross-sectional
area of the composite member. The transformed area
concept for elastic analysis, in which areas of dissimilar
materials are transformed in accordance with relative
elastic moduli ratios, shall apply.
TMS 402-1 1/ACI530-11/ASCE 5-11
COMMENTARY
1.8.7 Prestressing steel
The material and section properties of prestressing
steels may vary with each manufacturer. Most significant
for design are the prestressing tendon's cross section,
modulus of elasticity, tensile strength, and stress-relaxation
properties. Values for these properties for various
manufacturers' wire, strand, and bar systems are given
elsewhere117
. The modulus ofelasticity ofprestressing steel
is often taken egua] to 28,000 ksi (193,000 MPa) for design,
but can vary and should be verified by the manufacturer.
Stress-strain characteristics and stress-relaxation properties
of prestressing steels must be determined by test, because
these properties may vary between different steel forros
(bar, wire, or strand) and types (mild, high strength, or
stainless).
1.9 - Section properties
1.9.1 Stress computations
Mínimum net section is often difficult to establish in
hollow unit masonry. The designer may choose to use the
mínimum thickness of the face shells of the units as the
mínimum net section. The mínimum net section may not
be the same in the vertical and horizontal directions.
For masonry of hollow units, the mínimum cross-
sectional area in both directions may conservatively be
based on the mínimum face-shell thicknessu8
.
Salid clay masonry units are permitted to have coring
up to a maximum of 25 percent of their gross cross-
sectional area. For such units, the net cross-sectional area
may be taken as egua! to the gross cross-sectional area,
except as provided in Section 2.1.5.2.2(c) for masonry
headers. Severa! conditions of net area are shown in Figure
CC-1.9-1.
Sínce the elastic properties of the materials used in
members designed for composite action differ, egua!
strains produce different levels of stresses in the
components. To compute these stresses, a convenient
transformed section with respect to the axis of resistance
is considered. The resulting stresses developed in each
fiber are related to the actual stresses by the ratio E1 1 Ex
between the moduli of elasticíty of the most deformable
material in the member and of the materials in the fiber
considered. Thus, to obtain the transformed section, fibers
of the actual section are conceptually widened by the ratio
ExiE1 • Stresses computed based on the section properties
of the transformed section, with respect to the axis of
resistance considered, are then multiplied by ExiE1 to
obtain actual stresses.](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-39-320.jpg)
![C-28
CODE
1.9.4 lntersecting walls
1.9.4.1 Wall intersections shall meet one of the
following requirements:
(a) Design shall conform to the provisions ofSection 1.9.4.2.
(b) Transfer of shear between walls shall be prevented.
1.9.4.2 Design ofwall intersection
1.9.4.2.1 Masonry shall be in running bond.
1.9.4.2.2 Flanges shall be considered
effective in resisting applied loads.
1.9.4.2.3 The width of fiange considered
effective on each side of the web shall be the smaller
of the actual fiange on either side of the web wall or
the following:
(a) 6 multiplied by the nominal flange thickness for
unreinforced and reinforced masonry, when the
flange is in compression
(b) 6 multiplied by the nominal fiange thickness for
unreinforced masonry, when the fiange is in flexura!
tension
(e) 0.75 multiplied by the fioor-to-floor wall height for
reinforced masonry, when the flange is in flexura!
tension.
The effective fiange width shall not extend past a
movement joint.
1.9.4.2.4 Design for shear, including the
transfer of shear at interfaces, shall conform to the
requirements of Section 2.2.5; or Section 2.3.6; or
Sections 3.1.3 and 3.3.4.1.2; or Sections 3.1.3 and 3.2.4;
or Section 4.6; or Section 8.1.3 and 8.3.4.1.2.
1.9.4.2.5 The connection of intersecting
walls shall conform to one ofthe following requirements:
(a) At least fifty percent of the masonry units at the
interface shall interlock.
(b) Walls shall be anchored by steel connectors grouted
into the wall and meeting the following requirements:
(1) Minimum size: 1
/ 4 in. x 11
/ 2 in. x 28 in.
(6.4 mm x 38.1 mm x 711 mm) including 2-in.
(50.8-mm) long, 90-degree bend at each end to
form a U or Z shape.
(2) Maximum spacing: 48 in. (1219 mm).
(e) lntersecting reinforced bond beams shall be provided
at a maximum spacing of 48 in. (1219 mm) on
center. The area of reinforcement in each bond beam
shall not be less than 0.1 in.2
per ft (2 11 mm2
/m)
multiplied by the vertical spacing ofthe bond beams
in feet (meters). Reinforcement shall be developed
on each side ofthe intersection.
TMS 402-11/ACI530-11/ASCE 5-11
COMMENTARY
1.9.4 lntersecting walls
Connections of webs to flanges of walls may be
accomplished by running bond, metal connectors, or bond
beams. Achieving stress transfer at a T intersection with
running bond only is difficult. A running bond connection
should be as shown in Figure CC-1.9-2 with a "T"
geometry over their intersection.
The alternate method, using metal strap connectors, is
shown in Figure CC-1.9-3. Bond beams, shown in Figure
CC-1.9-4, are the third means of connecting webs to
flanges.
When the flanges are connected at the intersection,
they are required to be included in the design.
The effective width ofthe flange for compression and
unreinforced masonry in flexura] tension is based on
shear-lag effects and is a traditiona1 requirement. The
effective width of the flange for reinforced masonry in
flexura] tension is based on the experimental and
analytical work ofHe and Priest1eyu9
• They showed that
the shear-lag effects are significant for uncracked walls,
but become less severe after cracking. He and Priestleyl.l9
proposed that the effective width of the flange be
determined as:
¡ 11
1,1 = o.75h +0.511
2.5h
11 1h 5, 1.5
1.5 < 11 1h 5, 3.5
11 1h > 3.5
where l.r is the effective flange width, Ir is the width of the
flange, and h is height of the wall. These equations can
result in effective flange widths greater than 1.5 times the
height ofthe wall. However, a limit ofthe effective flange
width of 1.5 times the wall height, or :Y. of the wall height
on either side of the web, is provided in the code. This
limit was chosen since the testing by He and Priestleyu9
was limited to a flange width of 1.4 times the wall height.
Designers are cautioned that longitudinal reinforcement
just outside the effective flange width specified by the
code can affect the ductility and behavior of the wall. Any
participation by the reinforcement in resisting the load can
lead to other, more brittle, failure modes such as shear or
crushing ofthe compression toe.](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-41-320.jpg)
![C-42
CODE
1.14.1.4 Lateral ties - Lateral ties shall
conform to the following:
(a) Vertical reinforcement shall be enclosed by lateral
ties at least 1
/ 4 in. (6.4 mm) in diameter.
(b) Vertical spacing of lateral ties shall not exceed 16
longitudinal bar diameters, 48 lateral tie bar or wire
diameters, or least cross-sectional dirnension of the
member.
(e) Lateral ties shall be arranged so that every comer and
altemate longitudinal bar shall have lateral support
provided by the comer of a lateral tie with an included
angle of not more than 135 degrees. No bar shall be
farther than 6 in. (152 mm) clear on each side along the
lateral tie from such a laterally supported bar. Lateral ties
shall be placed in either a mortarjoint or in grout. Where
longitudinal bars are located around the perimeter of a
circle, a complete circular lateral tie is permitted. Lap
length for circular ties shall be 48 tie diameters.
(d) Lateral ties shall be located vertically not more than
one-half lateral tie spacing above the top of footing or
slab in any story, and shall be spaced not more than
one-half a lateral tie spacing below the lowest horizontal
reinforcement in beam, girder, slab, or drop panel above.
(e) Where beams or brackets frarne into a column from four
directions, lateral ties shall be permitted to be terminated
not more than 3 in. (76.2 mm) below the lowest
reinforcement in the shallowest ofsuch beams or brackets.
1.14.2 Lightly loaded columns
Masonry columns used only to support light frame
roofs of carports, porches, sheds or similar structures
assigned to Seismic Design Category A, B, or e, which are
subject to unfactored gravity loads not exceeding 2,000 lbs
(8,900 N) acting within the cross-sectional dimensions of
the column are permitted to be constructed as follows:
(a) Mínimum side dimension shall be 8 in. (203 mm)
nominal.
(b) Height shall not exceed 12ft (3.66 m).
(e) eross-sectional area of longitudinal reinforcement
shall not be less than 0.2 in.2
(129 mm2
) centered in
the column.
(d) eolumns shall be fully grouted.
TMS 402-11/ACI 530-11/ASCE 5-11
COMMENTARY
1.14.1.4 Lateral ties - Lateral reinforcement
in columns performs two functions. It provides the
required support to prevent buckling of longitudinal
column reinforcing bars acting in compression and
provides resistance to diagonal tension for columns acting
in shear1 38
• Ties may be located in the mortar joint, when
the tie diameter does not exceed Y2 the specified mortar
joint thickness. For example, Y4 in. (6.4 mm) diameter ties
may be placed in Y2 in. (12.7 mm) thick mortarjoints.
The requirements of this eode are modeled on those
for reinforced concrete columns. Except for permitting
4-in. (6.4-mm) ties in Seismic Design eategory A, B, and
e' they reflect the applicable provisions ofthe reinforced
concrete code.
1.14.2 Light/y loaded columns
Masonry columns are often used to support roofs of
carports, porches, sheds or similar light structures. These
columns do not need to meet the detailing requirements of
Section 1.14.1. The axial load limit of 2,000 pounds
(8,900 N) was developed based on the flexura] strength of
a nominal 8 in. (203 mm) by 8 in. (203 mm) by 12ft high
(3.66 m) column with one No. 4 (M#13) reinforcing bar in
the center and.fm of 1350 psi (9.31 MPa). An axial load of
2,000 pounds (8,900 N) at the edge of the member will
result in a moment that is approximately equal to the
nominal flexura! strength ofthis member.](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-55-320.jpg)
![C-44 TMS 402-11/ACI 530-11/ASCE 5-11
COMMENTARY
(a) Single Face
Alternate COIJses
D08:D
Ir:'] r:"ll
lt::J ~·
11, _ _ _ ¿¡
(a) Single Face
Ties Embedded
In Mortar Joints
Brick Pilasters
Ties Embedded
InMarta" Joints
Block Pilasters
000
000
(b) Double Face
Alternale CC~Jses
•1 :.:11:·.1 ~:
1!, _____ _ ::!1
(b) DOlble Faca
Figure CC-1.15-J - Typical pilasters
Table ce 11s 2 P
- - f
hvsical propert1es o stee remforcinQ wire andbars
Designation Diameter, in. Area, in.2
Perimeter, in.
(mm) (mm2
) (mm)
Wire
W1.1 (11 gage) (MW7) 0.121 (3. 1) 0.011 (7.1) 0.380 (9.7)
Wl.7 (9 gage) (MW11) 0.148 (3.8) 0.017 (11.0) 0.465 (11.8)
W2.1 (8 gage) (MW13) 0.162 (4.1) 0.020 (12.9) 0.509 (12.9)
W2.8 (3/16 in. wire) (MW18) 0.187 (4.8) 0.027 (17.4) 0.587 (14.9)
W4.9 (1/4 in. wire) (MW32) 0.250 (6.4) 0.049 (31.6) 0.785 (19.9)
Bars
No. 3 (M#lO) 0.375 (9.5) 0.11 (71.0) 1.178 (29.9)
No. 4 (M#l3) 0.500 (12.7) 0.20 (129) 1.571 (39.9)
No. 5 (M#16) 0.625 (15.9) 0.31 (200) 1.963 (49.9)
No. 6 (M#19) 0.750 (19.1) 0.44 (284) 2.356 (59.8)
No. 7 (M#22) 0.875 (22.2) 0.60 (387) 2.749 (69.8)
No. 8 (M#25) 1.000 (25.4) 0.79 (510) 3.142 (79.8)
No. 9 (M#29) 1.128 (28.7) 1.00 (645) 3.544 (90.0)
No. 1O (M#32) 1.270 (32.3) 1.27 (8 19) 3.990 (101)
No. 11 (M#36) 1.410 (35.8) 1.56 (1006) 4.430 (113)](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-57-320.jpg)
![C-50
1
j
r
l y
X
'·
X =]_ ~ 4(l b ) 2
-1
2
2
COMMENTARY
A111 at Top of Wall for Uplift
'
)
z
z
y= lb - X= lb_]_ ~ 4(l bY -1
2
2
TMS 402-11/ACI530-11/ASCE 5-11
1
J
r
X y l
J
'·
:. AP1 =(2X +Z)t-:t·t f( ~~ -sin B) whereB =2arcsinc::}n degrees
1 1
j 1
J
1
r 1
r
ly ' y l
X Z/2 Zf2 X
]
'· z
'·
:. Apr = (2X+Z)t+tlc~~ -sinO} whereB =2arcsi{t~Z }ndegrees
1 1 1
j 1
J
1
í 1
) í
'y X Z/2 Z/2 X
yl
]
'• z '•
:.AP, =(2X+Z)t+tl("
0
- sine} whereB=2arcsi{t/2)indegrees
IW 4
Figure CC-1.17-5 - Ca/culalion ofAdjusled Values ofAfJ/ (Plan Views)](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-63-320.jpg)
![C-88
CODE
2.1.7.6.1.3 Between the anchored ends,
each bend in the continuous portien ofa transverse U-stirrup
shall enclose a longitudinal bar.
2.1.7.6.1.4 Longitudinal bars bent to
act as shear reinforcement, where extended into a region
of tension, shall be continuous with longitudinal
reinforcement and, where extended into a region of
compression, shall be developed beyond middepth of the
member, d/2.
2.1.7.6.1.5 Pairs of U-stirrups or ties
placed to form a closed unit shall be considered properly
spliced when lepgth of laps are l.7 Id. In grout at least
18 in. (457 mm) deep, such splices with Avh not more
than 9,000 lb (40 032 N) per leg shall be permitted to be
considered adequate if legs extend the full available depth
ofgrout.
2.1.7.6.2 Welded wire reinforcement
2.1.7.6.2.1 For each Ieg of welded
wire reinforcement forming simple U-stirrups, there
shall be either:
(a) Two longitudinal wires at a 2-in. (50.8-mm) spacing
along the member at the top ofthe U, or
(b) One longitudinal wire located not more than d/4 from
the compression face and a second wire closer to the
compression face and spaced not less than 2 in.
(50.8 mm) from the first wire. The second wire shall be
located on the stirrup leg beyond a bend, or on a bend
with an inside diameter ofbend not less than 8db
2.1.7.6.2.2 For each end of a single-leg
stirrup of plain or deformed welded wire reinforcement,
there shall be two longitudinal wires spaced a mínimum of
2 in. (50.8 mm) with the inner wire placed at a distance at
least d/4 or 2 in. (50.8 mm) from middepth ofmember, d/2.
Outer longitudinal wire at tension face shall not be farther
from the face than the portien of primary flexura]
reinforcement closest to the face.
2.1.7.7 Splices ofreinforcement - Lap splices,
welded splices, or mechanical splices are permitted in
accordance with the provisions of this section. Welding
shall conform to AWS D1.4.
2.1.7.7.1 Lap splices
2.1.7.7.1.1 The mínimum length of lap
for bars in tension or compression shall be determined by
Equation 2-12, but not less than 12 in. (305 mm).
2.1.7.7.1.2 Where reinforcement
consisting of No. 3 (M#1O) or larger bars is placed
transversely within the lap, with at least one bar 8 inches
(203 mm) or less from each end of the lap, the mínimum
length of lap for bars in tension or compression
determined by Equation 2-12 shall be permitted to be
reduced by multiplying by the confinement factor, (. The
clear space between the transverse bars and the lapped
bars shall not exceed 1.5 in. (38 mm) and the transverse
TMS 402-11/ACI 530-11/ASCE 5-11
COMMENTARY
2.1.7.6.1.3 and 2.1.7.6.1.5 U-stirrups
that enclose a longitudinal bar obviously have sufficient
resistance in the tension zone ofthe masonry.
2.1.7.6.2 Welded wire reinforcement -
Although not often used in masonry construction, welded
wire reinforcement provides a convenient means of
placing reinforcement in a filled collar joint. See
Reference 2.24 for more information.
2.1.7.7 Splices of reinforcement The
importance ofcontinuity in the reinforcement through proper
splices is emphasized by the different requirements for the
stress level to be transferred in the various types ofsplices2
·
25
•
2.1.7.7.1 Lap splices
2.1.7.7.1.2 An extensive testing
program conducted by the National Concrete Masonry
Association2
·
26
and additional testing done by Washington
State University2 27
show that reinforcement provided
transverse to lapped bars controls longitudinal tensile
splitting of the masonry assembly. These tranverse bars
increase the lap performance significantly, as long as there
is at least one No. 3 {M#lO) transverse reinforcing bar
placed within 8 in. (203 mm) of each end of the splice.](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-101-320.jpg)
![BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-89
CODE
bars shall be fully developed in grouted masonry. The
reduced lap splice length shall not be less than 36db.
Where · ZJA,c < 1O
. d2.5 - .
b
(Equation 2-13)
Ase is the area ofthe transervse bars at each end of the
lap splice and shall not be taken greater than 0.35 in2
(226 mm2
) .
2.1.7.7.1.3 Bars spliced by noncontact
lap splices shall not be spaced transversely farther apart
than one-fifth the required length of lap nor more than
8 in. (203 mm).
2.1.7.7.2 Welded splices - Welded splices
shall have the bars butted and welded to develop in tension at
least 125 percent ofthe specified yield strength ofthe bar.
2.1.7.7.3 Mechanical splices
Mechanical splices shall have the bars connected to
develop in tension or compression, as required, at least
125 percent ofthe specified yield strength ofthe bar.
2.1.7.7.4 End-bearingsplices
2.1.7.7.4.1 In bars required for
compression only, the transmission of compressive stress
by bearing of square cut ends held in concentric contact
by a suitable device is permitted.
2.1.7.7.4.2 Bar ends shall termínate in
flat surfaces within 11
/ 2 degree of a right angle to the axis
of the bars and shall be fitted within 3 degrees of full
bearing after assembly.
2.1.7.7.4.3 End-bearing splices shall be
used only in members containing closed ties, closed
stirrups, or spirals.
COMMENTARY
These bars must be fully developed and have a clear
spacing between the transverse bars and the lapped bars
not exceeding 1.5 in. (38 mm). Testing also indicated that
the lap length must be at least 36db or the effect of the
transverse reinforcement is minimal. As a result, this limit
was applied to the lap length. The testing also showed that
even when more transverse reinforcement area is
provided, it becomes significantly less effective in
quantities above 0.35 in2
(226 mm2
) . Thus, the transervse
reinforcement area at each of the lap, Ase. is limited to
0.35 in? (226 mm
2
), even ifmore is provided.
2.1.7.7.1.3 If individual bars in
noncontact lap splices are too widely spaced, an
unreinforced section is created, which forces a potential
crack to follow a zigzag line. Lap splices may occur with
the bars in adjacent grouted cells if the requirements of
this section are met.
2.1.7.7.2 Welded sp/ices - A full welded
splice is primarily intended for large bars (No. 6 [M#19]
and larger) in main members. The tensile strength
requirement of 125 percent of specified yield strength is
intended to ensure sound welding, adequate also for
compression. It is desirable that splices be capable of
developing the ultimate tensile strength of the bars spliced,
but practica! limitations make this ideal condition difficult
to attain. The maximum reinforcement stress ust:d in design
under this Code is based upon yield strength. To ensure
sufficient strength in splices so that brittle failure can be
avoided, the 25 percent increase above the specified yield
strength was selected as both an adequate mínimum for
safety anda practicable maximum for economy.
2.1.7.7.3 Mechanical splices Full
mechanical splices are also required to develop 125 percent
of the yield strength in tension or compression as required,
for the same reasons discussed for full welded splices.
2.1.7.7.4 End-bearing splices
Experience with end-bearing splices has been almost
exclusively with vertical bars in columns. lf bars are
significantly inclined from the vertical, special attention is
required to ensure that adequate end-bearing contact can
be achieved and maintained. The lateral tie requirements
prevent end-bearing splices from sliding.](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-102-320.jpg)
![C-90
CODE
2.2- Unreinforced masonry
2.2.1 Scope
This section provides requirements for unreinforced
masonry as defmed in Section 1.6, except as otherwise
indicated in Section 2.2.4.
2.2.2 Stresses in reinforcement
The effectofstresses in reinforcement shall be neglected.
2.2.3 Axial compression andjlexure
2.2.3.1 Members subjected to axial compression,
flexure, or to combined axial compression and flexure shall
be designed to satisfy Equation 2-14 and Equation 2-15.
fa+fb::;¡
Fa Fb
(Rquation 2- 14)
(Equation 2-15)
where:
(a) For members having an hlr ratio not greater than 99:
F- 1 , 1- _h_
[ ( )2]
a - Ú{)fm I40r (Equation 2-16)
(b) For members having an h/r ratio greater than 99:
Fa =Ú{)J ~c ~r r (Equation 2-17)
(e) Fb =().{)¡;~ (Equation 2-18)
(Equation 2-19)
TMS 402-11/ACI 530-11/ASCE 5-11
COMMENTARY
2.2- Unreinforced masonry
2.2.1 Scope
This section provides for the design of masonry
members in which tensile stresses, not exceeding allowable
limits, are resisted by the masonry. This has previously
been referred to as unreinforced or plain masonry. Flexura!
tensile stresses may result from bending moments, from
eccentric verticalloads, or from lateralloads.
A fundamental premise is that under the effects of
design loads, masonry remains uncracked. Stresses due to
restraint against differential movement, temperature change,
moisture expansion, and shrinkage combine with the design
load stresses. Stresses due to restraint should be controlled
by joints or other construction techniques to ensure that the
combined stresses do not exceed the allowable.
2.2.2 Stresses in reinforcement
Reinforcement may be placed in masonry walls to
control the effects of movements from temperature
changes or shrinkage.
2.2.3 Axial compression andjlexure
2.2.3.1 For a member solely subjected to axial
load, the resulting compressive stress fa should not exceed
the allowable compressive stress Fa; in other words,fa!Fa
should not exceed l. Similarly, in a member subjected
solely to bending, the resulting compressive stress.lb in the
extreme compression fiber should not exceed the
allowable compressive stress Fb , or again, fb / Fb should
not exceed l.
This Code requires that under combined axial and
flexure loads, the sum of the quotients of the resulting
compression stresses to the allowable (fa iFa+ fb/Fb) does
not exceed l. This unity interaction equation is a simple
portioning ofthe available allowable stresses to the applied
loads, and is used to design masonry for compressive
stresses. The unity formula can be extended when biaxial
bending is present by replacing the bending stress quotients
with the quotients ofthe calculated bending stress over the
allowable bending stress for both axes.
In this interaction equation, secondary bending effects
resulting from the axial load are ignored. A more accurate
equation would include the use of a moment magnifier
applied to the tlexure term,fb /Fb. Although avoidance of a
moment magnifier term can produce unconservative results
in sorne cases, the committee decided not to include this
term in Equation 2-14 for the following reasons:
At larger h/r values, where moment magnification is
more critica!, the allowable axial load on the member
is limited by Code Equation 2-15.
For the practica! range of h/r values, errors induced
by ignoring the moment magnifier is relatively small,
less than 15 percent.
The overall safety factor of 4 included in the
allowable stress equations is sufficiently large to](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-103-320.jpg)
![BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-91
CODE COMMENTARY
allow this simplification in the design procedure.
The requirement of Equation 2-15 that the axial
compressive load P not exceed 1
/4 ofthe buckling load P.
replaces the arbitrary upper lirnits on slenderness used in
ACI 531228
.
The purpose ofEquation 2-15 is to safeguard against a
premature stability failure caused by eccentrically applied
axial load. The equation is not intended to be used to check
adequacy for combined axial compression and flexure.
Therefore, in Equation 2-19, the value ofthe eccentricity "e"
that is to be used to calculate Pe is the actual eccentricity of
the applied compressive load. The value of"e" is not to be
calculated as Mmax divided by P where Mmax is a moment
caused by other than eccentric load.
Equation 2-15 is an essential check because the
allowable compressive stress for members with an h/r
ratio in excess of 99 has been developed assuming only a
nominal eccentricity of the compressive load. Thus, when
the eccentricity of the compressive load exceeds the
mínimum eccentricity of O.lt, Equation 2-17 will
overestimate the allowable compressive stress and
Equation 2-15 may control.
The allowable stress values for Fa presented in
Equations 2-16 and 2-17 are based on an analysis ofthe
results of axial load tests performed on elay and concrete
masonry elements. A fit of an empírica! curve to this test
data, Figure CC-2.2-1, indicates that members having an
hlr ratio not exceeding 99 fail under loads below the Euler
buckling load ata stress leve! equal to:
¡,;J-(h1140r)
2
] (same with SI units)
Thus, for members having an h/r ratio not exceeding 99,
this Code allows axial load stresses not exceeding 1
/ 4 of
the aforementioned failure stress.
Applying the Euler theory of buckling to members
having resistance in compression but not in tension,
References 2.29, 2.30, and 2.31 show that for a solid
section, the critica! compressive load for these members
can be expressed by the formula
P.= (n2
E,,l, 1h2
)(I- 2e / t)3
(same with SI units)
in which
1, uncracked moment ofinertia
e eccentricity of axial compressive load with
respect to the member longitudinal
centroidal axis.
In the derivation of this buckling load equation,
tension cracking is assumed to occur prior to failure.
For hlr values in excess of99, the limited test data is
approximated by the buckling load.](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-104-320.jpg)
![BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-97
CODE
2.3- Reinforced masonry
2.3.1 Scope
This section provides requirements for the design
of structures neglecting the contribution of tensile strength
of masonry, except as provided in Section 2.3.6.
2.3.2 Design assumptions
The following assumptions shall be used in the design
ofreinforced masonry:
(a) Strain compatibility exists between the reinforcement,
grout, and masonry.
(b) Strains in reinforcement and masonry are directly
proportional to the distances from the neutral axis.
(e) Stress is linearly proportional to the strain.
(d) Stresses remain in the elastic range.
(e) Masonry in tension does not contribute to axial and
flexura) strength.
2.3.3 Stee/ reinforcement- Allowab/e stresses
2.3.3.1 Tensile stress in bar reinforcement shall
not exceed the following:
(a) Grade 40 or Grade 50 reinforcement: 20,000 psi
(137.9 MPa)
(b) Grade 60 reinforcement: 32,000 psi (220.7 MPa)
2.3.3.2 Tensile stress in wire j oint
reinforcement shall not exceed 30,000 psi (206.9 MPa).
2.3.3.3 When lateral reinforcement is provided
in compliance with the requirements of Section 1.14.1.4,
the compressive stress in bar reinforcement shall not
exceed the values given in Section 2.3.3.1. Otherwise, the
compressive resistance of steel reinforcement shall be
neglected.
2.3.4 Axial compression andjlexure
2.3.4.1 Members subjected to axial
compression, flexure, or combined axial compression and
flexure shall be designed in compliance with Sections
2.3.4.2 through 2.3.4.4.
2.3.4.2 A//owableforces and stresses
COMMENTARY
2.3 - Reinforced masonry
2.3.1 Scope
The requirements covered in this section pertain to the
design of masonry in which flexura[ tension is assumed to
be resisted by reinforcement alone, and the flexura) tensile
strength of masonry is neglected. Tension still develops in
the masonry, but it is not considered to be effective in
resisting design Joads.
2.3.2 Design assumptions
The design assumptions listed have traditionally been
used for allowable stress design of reinforced masonry
members.
Although tension may develop in the masonry of a
reinforced element, it is not considered effective in
resisting axial and flexura] design loads.
2.3.3 Steel reinforcement - A//owable stresses -
The allowable steel stresses have a sufficiently large
factor ofsafety that second-order effects do not need to be
considered in allowable stress design.
2.3.4 Axial compression andjlexure
See Commentary for 2.2.3.1.
2.3.4.1 No Commentary.
23.4.2 A//owable forces and stresses - This
Code limits the compressive stress in masonry members
based on the type of load acting on the member. The
compressive force at the section resulting from axial loads
or from the axial component of combined loads is
calculated separately, and is limited to the values
permitted in Section 2.3.4.2.1. Equation (2-21) or (2-22)
controls the capacity of columns with large axial Joads.
The coefficient of0.25 provides a factor ofsafety ofabout](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-110-320.jpg)
![C-98
CODE
2.3.4.2.1 The compressive force in
reinforced masonry due to axial load only shall not exceed
that given by Equation 2-21 or Equation (2-22:
(a) For members having an hlr ratio not greater than 99:
P, = (0.25/ ~ A. +0.65A,F,{l-C~, )']
(Equation 2-21)
(b) For members having an hlr ratio greater than 99:
Pa=(0.25/,;,An + 0.65A 51 F 5 {?~r J(Equation 2-22)
2.3.4.2.2 The compressive stress in
masonry due to tlexure or due to flexure in combination
with axial load shall not exceed 0.45!'m provided that the
ca!culated compressive stress due to the axial load
component,fa, does not exceed the allowable stress, Fa,
in Section 2.2.3.1.
TMS 402-11/ACI 530-11/ASCE 5-11
COMMENTARY
4.0 against crushing of masonry. The coefficient of 0.65
was determined from tests of reinforced masonry columns
and is taken from previous masonry codes2
·
28
•
2
·
53
. A
second compressive stress calculation must be performed
considering the combined effects of the axial load
component and flexure at the section and should be
limited to the values permitted in Section 2.3.4.2.2. (See
Commentary for Section 2.2.3.)
2.3.4.2.2 Figure CC-2.3-1 shows the
allowable moment (independent of member size and
material strength) versus the ratio of steel reinforcement
(Grade 60) multiplied by the steel yield stress and divided
by the specified compressive strength of masonry
(modified steel reinforcement ratio) for both clay and
concrete masonry members subjected to pure tlexure.
When the masonry compressive stress controls the design,
there is little increase in moment capacity with increasing
steel reinforcement. This creates a limit on the amount of
reinforcement that is practica! to use in allowable stress
design of masonry. Even when the masonry allowable
compressive stress controls the design, the failure of the
member will still be ductile. For clay masonry, the
masonry stress begins to control the design at 0.39pba1 and
for concrete masonry, the masonry stress begins to control
the design at 0.38pba1, where Pbal is the reinforcement ratio
at which the masonry would crush simultaneously with
yielding ofthe reinforcement. The reinforcement ratio as a
fraction of the balanced reinforcement ratio, Pbal, is also
shown in Figure CC-2.3-1.
The interaction equation used in Section 2.2.3 is not
applicable for reinforced masonry and is therefore not
included in Section 2.3.](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-111-320.jpg)
![BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-99
CODE COMMENTARY
2.3.4.3 Columns 2.3.4.3 Columns
Design axial loads shall be assumed to act at an
eccentricity at least egua! to 0.1 multiplied by each side
dimension. Each axis shall be considered independently.
The mínimum eccentricity of axial load (Figure CC-
2.3-2) results from construction imperfections not
otherwise anticipated by analysis.
0.1
0.09
0.08
0.07
• E
....
"'
0.06
-e
0.05
.Q
~ 0.04
0.03
0.02
0.01
o
In the event that actual eccentricity exceeds the
mínimum eccentricity required by this Code, the actual
eccentricity should be used. This Code requires that
stresses be checked independently about each principal
axis ofthe member (Figure CC-2.3-2).
Additional column design and detailing requirements
are given in Section 1.14.
.•...................•...•....¡.............•........•......¡..............................¡..............................¡..............................;.............................
··· ·························································¡······················ ···· ······ ········· ·· ~ .I~Y. ..J.. ¡
:.:.:...·.::.:..:.::·:·····.:..:..·..·:...·:·:
·:·:
·:·:·:
·:·:·:.:_..,:.,.::·:·:·:·:·:·:
···:·:·:·····:···:·:·:·:·:·:·:·:·:·:·:·:·:·:·'··,::::::::::::::···············;............. ........................................1
.....9..M
.Y.........
············ ····························l··..·..·..·..·:
...
·:·:·:·..·:...·..·..·..·:.:...
..
..................
......
..~.i.,,·:.:..........................
.
.............:. ..
· ..
·:·:·:·:·:
· :·:·:·:·····::
.
;-:=] _: :r::= :c:r==
............................L..........................J...§.~~~.~ ..~~ ..~ ·~ ·~ ·~ ·~ .~~~':~ .~ .~ .~ ...L..........................
l ! ¡ i j
o 0.05 0.1 0.15 0.2 0.25
o 0.125 0.25 0.375 0.50 0.625 0.75 0.825 bal )cMU
Figure CC-2.3-1 Allowable moment vs. modifiedsteel reinforcement ratio
Load =P
Load Acting at Centroid
Figure CC-2.3-2 - Minimum design eccentricity in columns](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-112-320.jpg)
![BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-101
CODE
Equation 2-26 or Equation 2-27, as appropriate.:
F. shall not exceed the following:
(a) Where MI(Vd) :S 0.25:
F.:::; 3..[1:
(b) Where MI( Vd) 2: .1.0
(Equation 2-25)
(Equation 2-26)
(Equation 2-27)
(e) The maximum value ofF. for MI(Vd) between 0.25
and 1.0 shall be permitted to be linearly interpolated.
2.3.6.1.3 The allowable shear stress
resisted by the masonry, Fvm, shall be computed using
Equation 2-28:
Fvm = ~[ ( 4 .0 - 1.75 ( ~ )] ..¡¡: ]+0.25 ~
(Equation 2-28)
MI(Vd) shall always be taken as a positive number and
need not be taken greater than 1.0.
2.3.6.1.4 For special reinforced masonry
shear walls, the allowable shear stress resisted by the
masonry, F,.,, shall be computed using Equation (2-29):
(Equation 2-29)
MI( Vd) shall always be taken as a positive number and
need not be taken greater than 1.0.
2.3.6.1.5 The allowable shear stress
resisted by the steel reinforcement, F,,s, shall be computed
using Equation 2-30:
Fvs =O.j AvFsd)
1 Ans
(Equation 2-30)
2.3.6.2 Shear reinforcement shall be provided
when /v exceeds F,.m . When shear reinforcement is
required, the provisions of Section 2.3.6.2.1 and 2.3.6.2.2
shall apply.
2.3.6.2.1 Shear reinforcement shall be
provided parallel to the direction of applied shear force.
Spacing ofshear reinforcement shall not exceed the lesser
of d/2 or 48 in. (12 19 mm).
COMMENTARY
stress values. The provisions of this Section were
developed through the study of and calibrated to
cantilevered shear walls. The ratio MI( Vd), can be difficult
to interpret or apply consistently for other conditions such
as for a uniformly loaded, simply supported beam.
Concurren! values of M and Vd must be considered at
appropriate locations along shear members, such as
beams, to determine the critica! MI(Vd) ratio. To simplify
the analytical process, designers are permitted to use
MI(Vd) = l. Commentary Section 3.3.4.1.2 provides
additional information.
2.3.6.1.3 Equation 2-28 is based on
strength design provisions with the masonry shear strength
reduced by a factor of safety of 2 and service loads used
instead offactored loads.
2.3.6.1.4 A reduced value is used for the
allowable masonry shear stress in special reinforced
masonry shear walls to account for degradation of
masonry shear strength in plastic hinging regions.
Davis254
proposed a factor with a value of 1.0 for wall
ductility ratios of2.0 or less, and a linear decrease to zero
as the ductility ratio increases from 2.0 to 4.0. The
committee chose a constan! value of 0.5, resulting in the
allowable stress being reduced by a factor of2, for design
convenience.
2.3.6.1.5 Commentary Section 3.3.4.1.2.2
provides additional information.
2.3.6.2.1 The assumed shear crack is at 45
degrees to the longitudinal reinforcement. Thus, a
maximum spacing of d/2 is specified to assure that each
crack is crossed by at least one bar. The 48-in. (1219-mm)
maximum spacing is an arbitrary choice tbat has been in
codes for many years.](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-114-320.jpg)
![BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-119
CODE COMMENTARY
e =
1 A '"'' 11111 y + _ _ Y
_
(
E )[E -E ( J) E ]
S y S Enlll + aEy E mil 2 E mil
By statics, P = Cs + Cm -Ts, where:
P = D + 0.75L + 0.525QE.
The maximum area of reinforcement per unit length
ofwall is determined as:
For a fully grouted member with only concentrated
tension reinforcement, the maximum reinforcement is:
0.64/~,( Enw J-_!_
As Em11 +aEY bd
p= - =
bd / y
··, ~
Strain ~ cmu
Stress
rr...,r-r.,0.8f'm
fy
Steel in
compression
Figure CC-3.3-2 - Prescribed strain distribution and
corresponding stress distribution.
If there is concentrated compression reinforcement
with an area equal to the concentrated tension
reinforcement, As , the maximum reinforcement is:
0.64/ ,;,( Emll )-_!_
As E m11 +aE y bd
p= bd = { . }
/y -min Em11 - : (Em11 +aey),ey Es
where d ' is the distance from the extreme](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-132-320.jpg)
4.43.7.3 In Equation 4-3, the value of J,s
shall be not less thanfse.and not larger than/¡,y.
4.4.3.8 Computa/ion off
psfor shear walls - For
walls with bonded prestressing tendons,f
ps shall be computed
based on strain compatibility or shall be taken equal to /¡,y .
Instead of a more accurate determination, /,., for members
with unbonded prestressing tendons shall be!se.
4.5 -Axial tension
Axial tension shall be resisted by reinforcement,
prestressing tendons, or both.
4.6 -Shear
4.6.1 For walls without bonded mild
reinforcement, nominal shear strength, Vn, shall be
computed in accordance with Sections 3.2.4a, 3.2.4b,
3.2.4c, and 3.2.4e. N, shall include the effective prestress
force, A,slse.
4.6.2 For walls with bonded mild reinforcement,
nominal shear strength, Vn, shall be computed in
accordance with Section 3.3.4.1.2.
4.6.2.1 Nominal masonry shear strength, Vn,,
shall be computed in accordance with Section 3.3.4.1.2.1.
P, shall include the effective prestress force, A,slse.
COMMENTARY
yield strengths between 60 ksi (420 MPa) and 270 ksi
(1865 MPa). As with reinforced masonry designed in
accordance with Chapters 2 and 3, the calculated depth in
compression should be compared to the depth available to
resist compressive stresses. For sections with uniform
width, the value ofthe compression block depth, a, should
be compared to the solid bearing depth available to resist
compressive stresses. For hollow sections that are
ungrouted or partially-grouted, the available depth may be
limited to the face shell thickness of the masonry units,
particularly if the webs are not mortared. The a/d
limitation is intended to ensure significant yielding of the
prestressing tendons prior to masonry compression failure.
In such a situation, the nominal moment strength is
determined by the strength of the prestressing tendon,
which is the basis for a strength-reduction factor equal to
0.8. This ductility lirnit was determined for sections with
bonded tendons, and when more experimental and field
data are available on the ductility of both unbonded and
bonded systems, this limit will again be reviewed.
The calculation ofthis limit assumes that the effective
prestressing stress is equivalent to 0.65 fv. If the
magnitude ofthe initial effective prestress (i.e.,fs.) is less
than 0.65fv, then the strain in the steel at ultimate strength
6s should be compared to the yield strain (i.e., 6v =fv 1E.).
The steel strain at ultimate strength 65 can be
approximated by assuming the strain in the steel is equal
to an initial strain dueto the effective prestressing (es,; =!se
lEs ) plus additional strain due to flexure (ss.flex =
0.003x((d- 1.25a)/1.25a).
4.5 -Axial tension
The axial tensile strength of masonry in a prestressed
masonry wall is to be neglected, which is a conservative
measure. This requirement is consistent with that of
Section 2.3. If axial tension develops, for example dueto
wind uplift on the roofstructure, the axial tension must be
resisted by reinforcement, tendons, or both.
4.6 - Shear
This section applies to both in-plane and out-of-plane
shear.
The shear capacity of prestressed walls is calculated
using the provisions ofthe Chapter 3. Calculation of shear
capacity is dictated by the presence or absence of bonded
mild reinforcement. While the MSJC acknowledges that
prestressed masonry walls are reinforced, for walls
without bonded mild reinforcement, the unreinforced
(plain) masonry shear provisions of Chapter 3 are used to
calculate shear capacity. When bonded mild reinforcement
is provided, then the reinforced masonry shear provisions
ofChapter 3 are used to calculate shear capacity.](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-152-320.jpg)
![C-146 TMS 402-11/ACI530-11/ASCE 5-11
COMMENTARY
1 6' -8" r- 8'-0" 1 6' -8" r- 8'-0" 1 6'-8" 18' - O"
1 6' -8" 1
[U
~----~ r-----_,
IJ ----y---y-J ~
o
1
;,.
o
1
;,.
Three Bay Automotive Garage Plan
12 "{205 mm) Composite Masonry Walls
Wall Height = 12' {3.7 m)
X
~] b b
1 1
;,. (o
~J ~
o
1
;,.
~l
L10·-·· _J ,._
•.•r
1
8'- O" _j 6' - 8" L8' - 0" _j 5' -4"
....,_______________ 50' - 8"
cb
Mínimum Cumulative Shear Wall Length Along Each Plane = 0.2 x Long Dimension
Min. 1=0.2{50.67') =10.13' {3.09 m)
Wallline 1: 1= {24.67 + 7.33) = 32.0' > 10.13· OK
1= {7.52 m+ 2.23 m)= 9.75 m> 3.09 m OK
Wall line 2:1 = {6.0' + 6.0' + 6.0' + 6.0') = 24.0' > 10.13' OK
1={1.83 m + 1.83 m + 1.83 m+ 1.83 m) = 7.32 m > 3.09 m OK
Wallline A: Note, 5'-4"{1.62 m) wall segments not included as they are less than Y. of 12' (3.66 m) wall height
1=(6.67' + 6.67') =13.33' > 10.13' OK
1= (2.03 m + 2.03 m) = 4.06 m > 3.09 m OK
Wallline 8: 1=(6.67' + 6.67' + 6.67' + 6.67') = 26.67' > 10.13· OK
1=(2.03 m+ 2.03 m+ 2.03 m+ 2.03 m)= 8.13 m> 3.09 m OK
Figure CC-5.3-1 - Cumulative length ofshear wal/s
-B
--0](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-159-320.jpg)
![C-180
CODE
(b) Strain in masonry shall be directly proportional to the
distance from the neutral axis.
(e) Flexura! tension in masonry shall be assumed to be
directly proportional to strain.
(d) Flexura! compressive stress in combination with axial
compressive stress in masonry shall be assumed to be
directly proportional to strain. Nominal compressive
strength shall not exceed a stress corresponding to
0.85fA.4c .
(e) The nominal flexura! tensile strength of AAC
masonry shall be deterrnined from Section 8.1.8.3.
8.2.3 Nominal axial strength of unreinforced
(plain) AAC masonry members
Nominal axial strength, Pn , shall be computed using
Equation 8-3 or Equation (8-4.
(a) For members having an hlr ratio not greater than 99:
P" = 0+85A.f~ c [~-c.:,)']}
(Equation 8-3)
(b) For members having an hlr ratio greater than 99:
8.2.4 Axial tension
The tensile strength of unreinforced AAC masonry
shall be neglected in design when the masonry is
subjected to axial tension forces.
8.2.5 Nominal shear strength of unreinforced
(plain) AAC masonry members
The nominal shear strength of AAC masonry, VnAAC ,
shall be the least of the values computed by Sections
8.3.4.1.2.1 through 8.3.4.1.2.3. In evaluating nominal
shear strength by Section 8.3.4.1.2.3, effects of
reinforcement shall be neglected. The provisions of
8.3.4.1.2 shall apply to AAC shear walls not laid in
running bond.
8.2.6 Flexura/ cracking
The flexura( cracking strength shall be computed in
accordance with Section 8.3.6.5.
TMS 402·11/ACI 530·11/ASCE 5-11
COMMENTARY
8.2.4 Axial tension
Commentary Section 2.2.4 provides further information.](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-193-320.jpg)
![BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-181
CODE
8.3 - Reinforced AAC masonry
8.3.1 Scope
The requirements ofthis section are in addition to the
requirements of Chapter 1 and Section 8.1 and govern
AAC masonry design in which reinforcement is used to
resist tensile forces.
8.3.2 Design assumptions
The following assumptions apply to the design of
reinforced AAC masonry:
(a) There is strain compatibility between the
reinforcement, grout, and AAC masonry.
(b) The nominal strength of reinforced AAC masonry
cross sections for combined flexure and axial load
shall be based on applicable conditions of
equilibrium.
(e) The maximum usable strain, &m11 , at the extreme AAC
masonry compression fiber shall be assumed to be
0.003.
(d) Strain in reinforcement and AAC masonry shall be
assumed to be directly proportional to the distance
from the neutral axis.
(e) Tension and compression stresses in reinforcement
shall be calculated as the product of steel modulus of
elasticity, Es, and steel strain, &5 , but shall not be
greater thanfr. Except as permitted in Section 8.3.3.5
for determination of maximum area of flexura!
reinforcement, the compressive stress of steel
reinforcement shall be neglected unless lateral
restraining reinforcement is provided in compliance
with the requirements of Section 1.14.1.4.
(f) The tensile strength of AAC masonry shall be
neglected in calculating axial and flexura] strength.
(g) The relationship between AAC masonry compressive
stress and masonry strain shall be assumed to be defmed
by the following: AAC masonry stress of 0.85f ÁAc
shall be assumed uniformly distributed over an
equivalent compression stress block bounded by edges
of the cross section and a straight line parallel to the
neutral axis and Jocated at a distance a =0.67 e from the
fiber of maximum compressive strain. The distance e
from the fiber of maximum strain to the neutral axis
shall be measured perpendicular to the neutral axis.
8.3.3 Reinforeement requirements and details
8.3.3.1 Reinforcing bar size limitations
Reinforcing bars used in AAC masonry shall not be larger
than No. 9 (M#29). The nominal bar diameter shall not
exceed one-eighth of the nominal member thickness and
shall not exceed one-quarter of the least clear dimension of
COMMENTARY
8.3- Reinforced AAC masonry
Provisions are identical to those of concrete or clay
masonry, with a few exceptions. Only those exceptions
are addressed in this Commentary.
8.3.2 Design assumptions
For AAC, test results indicate that &mu for Class 4
AAC masonry and higher is 0.003 and the value of the
stress in the equivalent rectangular stress block is 0.85
f ÁAc with a = 0.67c. 8
'
2
'
8
·
3
•
8
.4 Additional testing88
has
indicated a E:m11 of0.0012 for Class 2 AAC masonry.
8.3.3 Reinforcement requirements and details
8.3.3.1 Reinforeing bar size limitations
Grout spaces may include, but are not limited to, cores,
bond beams, and collar joints. At sections containing lap
splices, the maximum area of reinforcement specified in](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-194-320.jpg)
![BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-185
CODE
VnAAC =0.661"' ~ ~ ~~ C ]+ ~
2. ~~ AC 1,. t
(Equation 8-13b)
For AAC masonry not laid in running bond, nominal
masonry shear strength as govemed by web-shear cracking,
VnAAC, shall be computed using Equation 8-13c:
VnAAC =0.9 ~ f~ c A11 +0.05Pu (Equation 8-13c)
8.3.4.1.2.2 Nominal shear strength as
governed by crushing of diagonal compressive strut -
For walls with M,/(V11 dv) < 1.5, nominal shear strength,
VnAAC, as governed by crushing of a diagonal strut, shall
be computed as follows:
' h·l
2
VnAAC = 0.17j AAC t 2 3w 2
h +(-;¡ lw)
(Equation 8-14)
For walls with M,/(Vudv) equal to or exceeding 1.5,
capacity as governed by crushing of the diagonal
compressive strut need not be calculated.
8.3.4.1.2.3 Nominal shear strength
provided by shear reinforcement - Nominal shear
Strength prOVided by reinfO
rCement, V11s, Shall be
computed as follows:
Vns = O.s(~v )fydv (Equation 8-15)
Nominal shear strength provided by reinforcement,
Vns, shall inelude only deformed reinforcement embedded
in grout for AAC shear walls.
COMMENTARY
hysteretic behavior was not changed after the formation of
flexure-shear cracks. Thus, flexure-shear cracking does
not constitute a limit state in AAC masonry and design
equations are not provided.
Masonry units not laid in running bond may exhibit
discontinuities at head joints. The nominal masonry shear
strength calculation for AAC masonry not laid in running
bond considers the likelihood ofvertical discontinuities at
head joints and is based on test results for AAC walls
made of vertical panels with open vertical joints between
sorne panels.
8.3.4.1.2.2 Nominal shearstrength as
governed by crushing of diagonal compressive strut -
This mechanism limits the shear strength at large levels of
axial load. It was based on test results8
·
2
, using a diagonal
strut width of0.251,. based on test observations.
8.3.4.1.2.3 Nominal shear strength
provided by shear reinforcement - Equation 8-15 is
based on Equation 3-24. Equation 3-24 was developed
based on results of reversed cyclic load tests on masonry
wall segments with horizontal reinforcement distributed
over their heights. The reason for the 0.5 efficiency factor
is the non-uniform distribution of tensile strain in the
horizontal reinforcement over the height of the element.
The formation of an inclined diagonal compressive strut
from one comer of the wall segment to the diagonally
opposite comer creates a strain field in which the
horizontal shear reinforcement at the top and bottom of
the segment may not yield. For that reason, not all of the
horizontal shear reinforcement in the wall may be fully
effective or efficient in resisting shear forces.
AAC masonry walls differ from concrete masonry
walls and clay masonry walls in that horizontal joint
reinforcement is not used for horizontal shear
reinforcement. For reasons of constructability, AAC walls
are traditionally reinforced horizontally with deformed steel
reinforcing bars in grout-filled bond beams. In addition, the
strength ofthe thin set AAC mortar exceeds the strength of
the AAC masonry units, which would suggest that AAC
walls will behave in a manner similar to reinforced
concrete. Assemblage testing conducted on AAC masonry
walls also suggested that horizontal joint reinforcement
provided in concrete bond beams could be fully effective in
resisting shear. For this reason, earlier additions ofthe Code
presented Equation 8-15 without the 0.5 efficiency factor,
mimicking the reinforced concrete design equation for
strength provided by shear reinforcement.](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-198-320.jpg)
![BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-187
CODE
force on the piers shall not exceed 0.3 Anf ÁAc .
8.3.4.3.2 Longitudinal reinforcement - A
pier subjected to in-plane stress reversals shall be
reinforced symmetrically about the geometric center ofthe
pier. The longitudinal reinforcement of piers shall comply
with the following:
(a) At least one bar shall be provided in each end ce!l.
(b) The mínimum area of longitudinal reinforcement
shall be 0.0007 bd.
8.3.4.3.3 Dimensional limits - Dimensions
shall be in accordance with the following:
(a) The nominal thickness of a pier shall not be less than
6 in. ( 152 mm) and shall not exceed 16 in. (406 mm).
(b) The distance between lateral supports of a pier shall
not exceed 25 multiplied by the nominal thickness of
a pier except as provided for in Section 8.3.4.3.3(c).
(e) When the distance between lateral supports of a pier
exceeds 25 multiplied by the nominal thickness of the
pier, design shall be based on the provisions of
Section 8.3.5.
(d) The nominal length of a pier shall not be less than
three multiplied by its nominal thickness nor greater
than six multiplied by its nominal thickness. The clear
height of a pier shall not exceed five multiplied by its
nominal Iength.
Exception: When the factored axial force at the
location of maximum moment is less than
0.05f '.«c Ag, the length of a pier shall be permitted
to be taken equal to the thickness ofthe pier.
8.3.5 Wall designfor out-ofplane Ioads
8.3.5.1 Scope - The requirements of Section
8.3.5 are for the design ofwalls for out-of-plane loads.
8.3.5.2 Maximum reinforcement The
maximum reinforcement ratio shall be determined by
Section 8.3.3.5.
8.3.5.3 Moment and deflection calculations -
Moment and detlection calculations in Section 8.3.5.4 and
8.3.5.5 are based on simple support conditions top and
bottom. For other support and fixity conditions, moments,
and detlections shall be calculated using established
principies ofmechanics.
COMMENTARY
8.3.5.3 Moment and deflection calculations-
This section only includes design equations based on
walls having simple support conditions at the top and
bottom of the walls. In actual design and construction,
there may be varying support conditions, thus changing
the curvature of the wall under lateral Ioading. Through
proper calculation and using the principies of mechanics,
the points of intlection can be determined and actual
moments and deflection can be calculated under different
support conditions. The designer should examine moment
and deflection conditions to locate the critica] section
using the assumptions outlined in Section 8.3.5.](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-200-320.jpg)
![BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY
t5 = 5M••,h
2
S 48EAACJg
CODE
(b) Where Mcr < Mser< M,.
t5,.= 5Mcrh2 +5(Mser-Mcr)h2
48 EAAc fg 48EAAC]cr
(Equation 8-24)
(Equation 8-25)
The cracking moment of the wall shall be computed
using Equation 8-26, where J,.AAc is given by Section
8.1.8.3:
Mcr =s,.(frAAC + ~) (Equation 8-26)
lf the section of AAC masonry contains a horizontal
leveling bed, the value of J,.AAc shall not exceed 50 psi
(345 kPa).
8.3.6 Wa/1 designfor in-plane loads
8.3.6.1 Scope - The requirements of Section
8.3.6 are for the design ofwalls to resist in-plane loads.
8.3.6.2 Reinforcement - Reinforcement shall
be in accordance with the following:
(a) Reinforcement shall be provided perpendicular to the
shear reinforcement and shall be at least equal to one-third
Av . The reinforcement shall be uniformly distributed and
shall notexceed a spacing of8 ft (2.44 m).
(b) The maximum reinforcement ratio shall be
determined in accordance with Section 8.3.3.5.
8.3.6.3 Flexura/ and axial strength - The
nominal flexura( and axial strength shall be determined in
accordance with Section 8.3.4.1.1.
8.3.6.4 Shear strength - The nominal shear
strength shall be computed in accordance with Section
8.3.4.1.2.
8.3.6.5 Flexura/ cracking strength - The
flexural cracking strength shall be computed in
accordance with Equation 8-27, where J,.AAc is given by
Section 8.1.8.3:
V e r=~~ (frAAC + ~) (Equation 8-27)
If the section of AAC masonry contains a horizontal
leveling bed, the value of J,.AAc shall not exceed 50 psi
(345 kPa).
COMMENTARY
C-189](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-202-320.jpg)
![C-202 TMS 402-11/ACI 530-11/ASCE 5-11
Code Equation No. SI Unit
Units
or Section No. Equivalent Equation
Apv in mml
(2-6) Bab = 0.1 1AP,,.¡;:
Bab in Newtons
Rz in MPa
Bab = 1072VJ~ ,Ab
Bah in Newtons
(2-7)
~ f~A b in Newtons
Bvpry = 2.0Bab = 2.5Apl.¡;:
Ap1in mml
(2-8)
Babin Newtons
Bvpry in Newtons
Rz in MPa
Ahin mm¿
(2-9) B,s = 0.36Abfy Bas in Newtons
fv inMPa
ba in Newtons
(2-10) .!!_g_+ .!2..~ 1 b"in Newtons
Ba Bv Ba in Newtons
Bv in Newtons
2.1.5.2.2(e) 0.108 ~ spec i fie d unit compressive strength of header in MPa
db in mm
(2-11) Id =0.22ddFs Fs in MPa
Id in mm
Av~ 0.4{~: J
Av in mm2
b.., inmm
s in mm
2.1.7.4.1.5(b)
/y inMPa
s~(~J dinmm
8/}b ~ b is dimensionless
dbin mm
2
Rz inMPa
Id=
I.Sdb /yY
(2-12)
Kg /y in MPa
Kin mm
Id in mm
I l.59A,c 11.59A Asein mm2
(2-13) ~ = 1.0- where d 2S se ~ 1.0
d2.5 dbin mm
b b
Fa in MPa
(2-14) fa + fb~ 1 Fbin MPa
Fa Fb la in MPa
Ji, in MPa
(2-15) P ~ (X)P, P in Newtons
P, in Newtons
Fo·(Y.lr+-c.:J]
Fa inMPa
(2-16)
f'm in MPa
h in mm
rinmm
( J
Fa in MPa
_ 1 , 70r f'm in MPa
(2-17) Fa-(X)J m h hin mm
r inmm
(2-1 8) Fb =(X)¡,;,
F bin MPa
f'm in MPa](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-215-320.jpg)
![BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-203
Code Equation No. SI Unit
Units
or Section No. Equivalent Equation
E, in MPa
e in mm
(2-19) P. r/E,,l, ( 1- 0.577::_r hin mm
h2
r / in mm4
Pe in Newtons
r inmm
binmm
VQ fv in MPa
(2-20) /., =-¡¡; 1, in mm4
" Q in mm3
V in Newtons
2.2.5.2(a) 0. 125¡¡;;
R, inMPa
Answer in MPa
A, in mm2
2.2.5.2(c) 255 + 0.45 N.,!A, Nv in Newtons
Answer in k.Pa
A, in mm2
2.2.5.2(d) 255 + 0.45 Nv!A, Nv in Newtons
Answer in k.Pa
A, in mm'
2.2.5.2(e) 414 + 0.45 N.,!A, Nv in Newtons
Answer in k.Pa
A, in mm2
A51 in mm2
Pa = (0.25/~A, + 0.65A s ,F s { l -c:~r r]
Fs in MPa
(2-21) f', in MPa
hin mm
Pa in Newtons
rinmm
A, in mm'
As1 in mm2
Pa=(0.25 ü, . An + 0.65 Ast F s) C~r r Fs in MPa
(2-22) f', in MPa
hin mm
Pain Newtons
r inmm
nf,;, ¡;, in MPa
Pmax =
2/y(n+f~)
f', inMPa
(2-23)
!,,
V
b, in mm
(2-24) f.,=- d., in mm
A,., fv in MPa
V in Newtons
Fv in MPa
(2-25) Fv =F.,,+ F.,, F,., in MPa
F,,5 inMPa](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-216-320.jpg)
![C-204 TMS 402-11/ACI 530-11/ASCE 5-11
Code Equation No. SI Unit
Units
or Section No. Equivalent Equation
d inmm
F,,in MPa
(2-26) Fv ~ 0.25.¡¡:: For MI(Vd) :S 0.25 M in Newton-mm
V in Newtons
.¡¡::: in MPa
dinmm
FvinMPa
(2-27) Fv = 0.18.¡¡:: For MI(Vd) ?. 1.0 M in Newton-mm
V in Newtons
.¡¡::: in MPa
An in mm
2
d inmm
Fvm =0.042[(4.0- 1. 75(~))~]+0.25 ~
F,., in MPa
(2-28) M in Newton-mm
P in Newtons
V in Newtons
.¡¡::: inMPa
An in mm
2
d inmm
F., = 0.02{(4.0-1.75(~))~]+0.25 ~
F,., in MPa
(2-29) M in Newton-mm
P in Newtons
V in Newtons
.¡¡::: inMPa
Anin mm2
Avin mm
2
(2-30) ( AvFsd) dinmm
Fvs= 0.5 - -
F, in MPa
A11
s
Fvs in MPa
s mmm
A . ::<
p1 mmm
(3-1) Banb = 0.33Aptg .¡¡::: inMPa
Banb in Newtons
(3-2) Bans =Ab/y
Abin mm2
/y in MPa
Ban.• in Newtons
A . ~ z
p1 mmm
(3-3) Banb =0.33Aptg .¡¡::: inMPa
Banb in Newtons
f'., in MPa
Banp =1.5/', e6d6 +2.071f(16 +e6 +d6 )d6
eb in mm
(3-4) dbin mm
hin mm
B01,nin Newtons
Abin mm
2
(3-5) Bans =Abfy /y in MPa
Ba"' in Newtons
Apvin mm
2
(3-6) Banb =0.33Apvg .¡¡::: inMPa
Banb in Newtons](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-217-320.jpg)
![BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-205
Code Equation No. SI Unit
Units
or Section No. Equivalent Equation
Abin mm
2
(3-7) Bvnc =3216 Vf'm Ab
Bl'llc in Newtons
f'm in MPa ~ ¡,;,Ab in Newtons
Ap1 in mm"
(3-8) Bvnpry =2.0Banb =0.67Aptg
.¡¡:: in MPa
Banb in Newtons
Bvn>rv in Newtons
Ab in mm
2
(3-9) Bvns =0.6Ab/y ¡;, in MPa
Bvn.r in Newtons
boj bv¡
ba¡in Newtons
(3- 10)
bv¡in Newtons
- - + - -5 1
(J Ban (J BV/1 8011 in Newtons
8 ,11 in Newtons
Pnin Newtons
P. o 0.80{0.80A. J~ [1-c:oJ]) h An in mm2
(3-11) For - 599 f'm in MPa
r hin mm
rmmm
Pnin Newtons
P. o oso(080A.J~C~' n h An in mm
2
(3-12) For ->99 f'm in MPa
r hin mm
rmmm
(3-13) M e= 8M,
Me in N-mm
M, in N-mm
Ó=
1 A11 in mm2
P, f'm in MPa
(3-14) 1-
A/' COrr
P, in Newtons
hin mm
n m h
rinmm
3.2.4(a) 0.33A11
.¡¡:: in N
An in mm
2
f'm in MPa
3.2.4(b) 0.83A11 in N Anin mm
2
3.2.4(c) 0.26A11
+0.45N, in N Anin mm
2
N, in Newtons
3.2.4(d) 0.26A11
+ 0.45N, in N
A11 in mm2
N, in Newtons
3.2.4(e) 0.414A11 +0.45N, in N
A11 in mm2
N,, in Newtons
3.2.4(f) O. l03A11
inN An in mm•
(3-15) '· =13db
l. in mm
dbin mm
dbin mm
2 .¡¡:: in MPa
Id =
l.5db / yY
(3-16)
K.¡¡: ¡;, in MPa
K in mm
ld in mm
e;= 1.0- 11 .59Asc where l l.59Asc O Ase in mm
2
(3-17)
dl.5 dl·5 :$ l. dbin mm](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-218-320.jpg)
![C-206 TMS 402-11/ACI530-11/ASCE 5-1 1
Code Equation No. SI Unit
Units
or Section No. Equivalent Equation
A, in mm2
Ast in mm2
P
. ~ 0.80 [0.80/~ (A. -A., )+f ,A.,l[1- e.:,n f', in MPa
(3-18) /y in MPa
P, in Newtons
hin mm
rin mm
A, in mm2
As1 in mm2
p/1 = 0.80 [o.8o¡,;,(A,- AS/)+ !y As/1
(?~r r f', in MPa
(3-19) /y in MPa
P, in Newtons
hin mm
rmmm
V,., in Newtons
(3-20) V,= v,m +V/IS V,5 in Newtons
V,, in Newtons
Anv in mm
M,, in N-mm
V,, in Newtons
(3-21)
Vn ~ 0 . 5A ,. g For Mu O d. in mm
-- ~ .25.
Vudv V, in Newtons
..JY:: inMPa
A,. in mm
M,, in N-mm
V11 ~ 0.33A,• .¡¡;: M u ~ LOO .
V" in Newtons
(3-22) For d. in mm
Vudv V, in Newtons
..JY:: inMPa
A,. in mm
M11 inN-mm
V,, in Newtons
(3-23) v,m =0.083[4.0- 1.7{ MI/ )]AII.g,+0.25?,, d. in mm
V/IdV P, in Newtons
V,, in Newtons
..JY:: inMPa
A. in mm'
v"s = o.5( ~· )1y d.
/y inMPa
(3-24) d. in mm
s in mm
Vn.• in Newtons
[ ;; )~ 0.20/ ~
P11 in Newtons
(3-25) Agin mm2
f'm in MPa
hin mm
w, in N/mm
w,h
2
p e, p
0
P,1 in Newtons
(3-26) M" e, in mm
=-8
- + •if2+ . 11 11
P, in Newtons
ó,, in mm
M11 in N-mm
P11 in Newtons
(3-27) P,, = puw +pu
f P,1 in Newtons
P,"' in Newtons](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-219-320.jpg)
![C-208 BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES (TMS 402/ACI 530/ASCE 5)
Code Equation No. SIUnit
Units
or Section No. EquivalentEquation
Mn in N-mm
f,, in MPa
A . 2
Mn = (rpsAps + fyAs + Pu{ d ~)
ps mmm
(4-2)
fy in MPa
A , in mm2
Pu in Newtons
dinmm
a mmm
¡;,, in MPa
f.e in MPa
dinmm
(4-3)
F ~ F +{6,900{~ lt'f "" ~"' l IPin mm
ps se 1 bdf J;,u in MPa
p m A . 2
ps mmm
b inmm
f ~, inMP a
f, =0.2 ~ /AAC
/¡'inMPa
(8-1)
~ IAAc in MPa
(8-2) f v =0.15 f~A C
f., in MPa
f ÁAcin MPa
hin mm
P,, ~ oso{oss~ , r.,cH ,~ J])
rinmm
(8-3) An inmm
2
FAAcinMPa
Pn in Newtons
hin mm
P. ~ oso[o•,..., ,AA~ 7
~')']
rinmm
(8-4) An in mm2
fÁAcin MPa
Pn in Newtons
(8-5) le= 13db
l. in mm
dbin mm
Id, in mm
1.5d/ fyy
dbinmm
Id= KAAc inmm
(8-6)
K AAcR
fy in MPa
~ 1g in MPa
hin mm
rinmm
P. = o
.so[o.ss1._.,(A, - A,)+ fA,[1-c~J l A n in mm
2
(8-7) A ,1 in mm2
fy in MPa
fÁAc in MPa
Pn in Newtons
hin mm
rinmm
Anin mm2
(8-8)
~ . {70rr
Ast in mm
2
Pn = 0.80 0.85 fAA c(An- A51 ) + fy A51 h fy in MPa
fÁAcin MPa
Pn in Newtons
Vn in Newtons
(8-9) ~ = ~1AA C + ~ s vnAAc in Newtons
Vns in Newtons](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-221-320.jpg)
![BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES AND COMMENTARY C-219
Report No. 3.1(b)-2: lgarashi, A., Seible, F., and
Hegemier, G., Development of the Generated
Sequential displacement Procedure and the Simulated
Seismic Testing of the TCCMaR Three-Story In-Piane
Walls, June 1993.
Report No. 3.1 (c)-1: Merryman, K., Leiva, G.,
Antrobus, B., and Klingner, R., In-Plane Seismic
Resistance ofTwo-Story Concrete Masonry Coupled
Shear Walls, September 1989, 176 pp.
ReportNo.3.1(c)-2: Leiva, G., and Klingner,
R., In-plane Seismic Resistance of Two-story
Concrete Masonry Shear Walls with Openings,
August 1991,326 pp.
Report No. 3.2(a)-1: Hamid, A., Abboud, B.,
Farah, M., Hatem, K., and Harris, H., Response of
Reinforced Block Masonry Walls to Out-of-Plane
Static Loads, September 1989, 120 pp.
Report No. 3.2(b)-1: Agbabian, M., Adham, S.,
Masri, S., Avanessian, V., and Traína, V., Out-of-
Plane Dynamic Testing ofConcrete Masonry Walls,
V. 1 and 2, July 1989, 220 pp.
Report No. 3.2(b)-2: Blondet, M., and Mayes,
R.L., The Transverse Response of Clay Masonry
Walls Subjected to Strong Motion Earthquakes, V. 1:
General!nformation, April 1991, 172 pp.
Report No. 3.2(b)-2: Blondet, M., and Mayes,
R.L., The Transverse Response of Clay Masonry
Walls Subjected to Strong Motion Earthquakes, V.
2: Walls No. 4 and 6 (Group 1), Aprill991, 267 pp.
Report No. 3.2(b)-2: Blondet, M., and Mayes,
R.L., The Transverse Response of Clay Masonry
Walls Subjected to Strong Motion Earthquakes, V.
3: Walls No. 8, 9, JO and Il (Group 2), April1991 ,
310 pp.
ReportNo. 3.2(b)-2: Blondet, M., and Mayes,
R.L., The Transverse Response ofClay Masonry Walls
Subjected to Strong Motion Earthquakes, V. 4: Walls
No. 3, 5, and 7 (Group 3), Apri11991, 256 pp.
Report No. 4. 1-1 : He, L., and Priestley,
M.J.N., Seismic Behavior ofFlanged Masonry Shear
Walls, May 1988, 119 pp.
Report No. 4. 1-2: He, L., and Priestley,
M.J.N., Seismic Behavior ofFlanged Masonry Shear
Walls -FinalReport, November 1992, 279 pp.
Report No. 4.2-1: Hegemier, G., and
Murakami, H., On the Behavior of Floor-to-Wall
Intersections in Concrete Masonry Construction: Part
1: Experimental.
Report No. 4.2-2: Hegemier, G., and
Murakami, H., On the Behavior of Floor-to-Wall
Intersections in Concrete Masonry Construction:
Part JI: Theoretical.
Report No. 5.1-1: Porter, M., and Sabri, A.,
Plank Diaphragm Characteristics, July 1990, 226 pp.
ReportNo. 5.2-1: Porter, M., Yeomans, F., and
Johns, A., Assembly of Existing Diaphragm Data, July
1990, 142 pp.
Report No. 6.2-1: Scrivener, J., Bond of
Reinforcement in Grouted Hollow Unit Masonry: A
State-of-the-Art, June 1986, 53 pp.
Report No. 6.2-2: Soric, Z., and Tulin, L.,
Bond Splices in Reinforced Masonry, August 1987,
296 pp.
Report No. 7.1-1: Paulson, T., and Abrams, D.,
Measured lnelastic Response of Reinforced Masonry
Building Structures to Earthquake Motions, October
1990,294 pp.
ReportNo. 8.1-1: Hart, G., A Limit State
Design Methodfor ReinforcedMasonry, ]une 1988.
Report No. 8.1-2: Hart, G., Expected Value
Design in the Context of a Limit Sate Design
Methodology, February 1990.
Report No. 8.2-1: Hart, G., and Zorapapel,
G.T., Reliability of Concrete Masonry Wall
Structures, December 1991,229 pp.
Report No. 8.2-2: Hart, G., and Sajjad, N.,
Conjinement in Concrete Masonry, December 1990.
Report No. 8.2-3: Hart, G., and Jang, J.,
Seismic Performance of Masonry Wall Frames,
December 1991.
Report No. 9.1-1: Kariotis, J.C., and
Johnson, A.W., Design of Reinforced Masonry
Research Building, September 1987, 42 pp.
Report No. 9.1-2: Kariotis, J.C., and Waqfi,
O.M., Tria! Designs Made in Accordance with
Tentative Limit States Design Standards for
Reinforced Masonry Buildings, February 1992, 184
pp.
Report No. 9.2-1: Seible, F., Report on
Large Structures Testing Facilities in Japan,
September 1985, 120 pp.
Report No. 9.2-2: Seible, F., Design and
Construction of the Charles Lee Powell Structural
Systems Laboratory, November 1986, 65 pp.
Report No. 9.2-3: Seible, F., The Japanese
Five-story Full Sea/e Reinforced Masonry Building
Test, January 1988, 100 pp.](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-232-320.jpg)
![S-10
SPECIFICATION
1.3- Reference standards (Continued)
AE. ASTM C34-03 Standard Specification for
Structural Clay Load-Bearing Wall Tile
AF. ASTM C55-06el Standard Specification for
Concrete Building Brick
AG. ASTM C56-05 Standard Specification for
Structural Clay Nonloadbearing Tile
AH. ASTM C62-08 Standard Specification for
Building Brick (Solid Masonry Units Made from Clay or
Shale)
Al. ASTM C67-08 Standard Test Methods for
Sampling and Testing Brick and Structural Clay Tile
AJ. ASTM C73-05 Standard Specification for Calcium
Silicate Brick (Sand-Lime Brick)
AK. ASTM C90-08 Standard Specification for
Loadbearing Concrete Masonry Units
AL. ASTM CI09/C I09M-08 Standard Test Method for
Compressive Strength ofHydraulic Cement Mortars (Using
2-in. or [50-mm] Cube Specimens)
AM. ASTM C126-09 Standard Specification for
Ceramic Glazed Structural Clay Facing Tile, Facing Brick,
and Solid Masonry Units
AN. ASTM C129-06 Standard Specification for
Nonloadbearing Concrete Masonry Units
AO. ASTM C143/C143M-08 Standard Test Method for
Slump ofHydraulic-Cement Concrete
AP. ASTM C144-04 Standard Specification for
Aggregate for Masonry Mortar
AQ. ASTM CIS0-07 Standard Specification for Portland
Cement
AR. ASTM C212-00 (2006) Standard Specification
for Structural Clay Facing Tile
AS. ASTM C216-07a Standard Specification for
Facing Brick (Solid Masonry Units Made from Clay or
Shale)
AT. ASTM C270-08 Standard Specification for Mortar
for Unit Masonry
AU. ASTM C476-09 Standard Specification for Grout for
Masonry
AV. ASTM C482-02 (2009) Standard Test Method for
Bond Strength of Ceramic Tite to Portland Cement Paste
AW. ASTM C503-08a Standard Specification for
Marble Dimension Stone
AX. ASTM C568-08 Standard Specification for
Limestone Dimension Stone
TMS 602-11/ACI530.1-11/ASCE 6-11
COMMENTARY](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-253-320.jpg)
![S-12
SPECIFICATION
1.3- Reference standards (Continued)
BT. ASTM D638-08 Standard Test Method for Tensile
Properties ofPlastics
BU. ASTM D994-98 (2003) Standard Specification for
Preforrned Expansion Joint Filler for Concrete (Bituminous
Type)
BV. ASTM Dl056-07 Standard Specification for
Flexible Cellular Materials - Sponge or Expanded Rubber
BW. ASTM Dl187-97 (2002)e1 Standard Specification for
Asphalt-Base Emulsions for Use as Protective Coatings for Metal
BX. ASTM Dl227-95 (2007) Standard Specification for
Emulsified Asphalt Used as a Protective Coating for Roofing
BY. ASTM D2000-08 Standard Classification System
for Rubber Products in Automotive Applications
BZ. ASTM D2265-06 Standard Test Method for
Dropping Point of Lubricating Orease Over Wide
Temperature Range
CA. ASTM D2287-96 (2001) Standard Specification for
Nonrigid Vinyl Chloride Polymer and Copolymer Molding
and Extrusion Compounds
CB. ASTM D4289-03 (2008) Standard Test Method for
Elastomer Compatibility ofLubricating Oreases and Fluids
CC. ASTM E72-05 Standard Test Methods of Conducting
Strength Tests ofPanels for Building Construction
CD. ASTM E328-02 (2008) Standard Test Methods for
Stress Relaxation Tests for Materials and Structures
CE. ASTM E5 18-09 Standard Test Methods for Flexura]
Bond Strength ofMasonry
CF. ASTM E519-07 Standard Test Method for Diagonal
Tension (Shear) in Masonry Assemblages
CG. ASTM F959M-07 Standard Specification for
Compressible-Washer-Type Direct Tension Indicators for
Use with Structural Fasteners [Metric]
American Welding Society
CH. AWS D 1.4-05 Structural Welding Code -
Reinforcing Steel
Federal Test Method Standard
CI. FTMS 791B (1974) Oil Separation from
Lubricating Orease (Static Technique). Federal Test Method
Standard from the U.S. Army General Material and Parts
Center, Petroleum Field Office (East), New Cumberland
Army Depot, New Cumberland, PA 17070
TMS 602-11/ACI530.1-11/ASCE 6-11
COMMENTARY](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-255-320.jpg)
![S-38
SPECJFICATION
2.4 B. Prestressing tendons
l. Provide prestressing tendons that conform to one of
the following standards, except for those permitted
in Articles 2.4 B.2 and 2.4 B.3:
a. Wire .....................................ASTM A42JIA421M
b. Low-relaxation wire .............ASTM A4211A421M
c. Strand ...................................ASTM A416/A4.16M
d. Low-relaxation strand ..........ASTM A4!6/A416M
e. Bar........................................ASTM A722/A722M
2. Wire, strands, and bars not specifically Iisted in
ASTM A416/A416M, A421/A421M, or
A722/A722M are permitted, provided that they
conform to the mínimum requirements in ASTM
A416/A416M, A421/A421M, or A722/A722M and
are approved by the Architect/Engineer.
3.Bars and wires of less than 150 ksi (1034 MPa)
tensile strength and conforming to ASTM
A82/A82M, A510/A510M, A615/A6 15M,
A996/A996M, or A706/A706M are permitted to be
used as prestressed tendons, provided that the stress
relaxation properties have been assessed by tests
according to ASTM E328 for the maximum
permissible stress in the tendon.
2.4 C.Joint reinforcement
l. Provide joint reinforcement that conforms to ASTM
A951. Maximum spacing of cross wires in Jadder-
type joint reinforcement and of points of connection
of cross wires to longitudinal wires of truss-type
joint reinforcement shall be 16 in. (400 mm).
2. Deformed reinforcing wire - Provide deformed
reinforcing wire that conforms to ASTM
A496/A496M.
3. Welded wire reinforcement- Provide welded wire
reinforcement that conforms to one of the following
specifications:
a. Plain ....................................ASTM A185/A185M
b. Deformed .............................ASTM A497/A497M
2.4 D.Anchors, ties, and accessories- Provide anchors,
ties, and accessories that conform to the following
specifications, except as otherwise specified:
l. Plate and bent-bar anchors..........ASTM A36/A 36M
2. Sheet-metal anchors and ties .....................................
.............................................ASTM AI008/AI008M
3. Wire mesh ties .........................ASTM Al85/Al85M
4. Wire ties and anchors ..................ASTM A82/A82M
5. Headed anchor bolts ..............ASTM A307, Grade A
TMS 602-11/AC1530.1-11/ASCE 6-11
COMMENTARY
2.4 B. Prestressing tendons - The constructibility
aspects of prestressed masonry favor the use of rods or
rigid strands with mechanical anchorage in ungrouted
construction. Mild strength steel bars have been used in
prestressed masonry installations in the United States25
•
The stress-relaxation characteristics of mild strength bars
(ofless than 150 ksi [1034 MPa]) should be determined by
tests and those results should be documented.](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-281-320.jpg)
![S-78
1.23. "CodeMaster, Special Inspection for Masonry",
Structures & Codes Institute and Masonry Institute of
America, Torrance, CA, 2006
1.24. "CodeMaster, Masonry Materials", Structures &
Codes Institute and Masonry Institute of America,
Torrance, CA, 2006.
1.25. "Recommended Practices and Guide
Specifications for Cold Weather Masonry Construction,"
International Masonry Industry All-Weather Council,
Washington, DC, 1973.
1.26. Tomasetti, A.A., "Problems and Cures in
Masonry" ASTM STP 1063, Masonry Components to
Assemblages, ASTM, Philadelphia. PA ,1990, 324-338.
1.27. "All Weather Construction" Technical Notes on
Brick Construction Number 1 Revised, Brick Institute of
America, Restan, VA, March 1992
1.28. "Hot Weather Masonry Construction," Trowel
Tips, Portland Cement Association, Skokie, IL, 1993
1.29. Panarese, W.C., S.H. Kosmatka, and F.A.
Randall Jr "Concrete Masonry Handbook for Architects,
Engineers, and Builders," Portland Cement Association,
Skokie, IL, 1991, pp. 121-123.
1.30. "Research Evaluation of Flexura! Tensile
Strength of Concrete Masonry," National Concrete
Masonry Association, Herndon, VA, 1994.
References, Part 2
2.1. "PC Glass Block Products," (GB 185),
Pittsburgh Corning Corp., Pittsburgh, PA, 1992.
2.2. "WECK Glass Blocks," Glashaus Inc.,
Arlington Heights, IL, 1992.
2.3. Beall, C., "Tips on Designing, Detailing, and
Specifying Glass Block Panels," The Magazine of
Masonry Construction, 3-89, Addison, IL, pp 92- 99.
2.4. "Follow up Service Procedure," (File R2556),
Underwriters Laboratories, Inc., Northbrook, IL, 111.1,
Sec.1,Vol.1.
2.5. Schultz, A.E. and Scolforo, M.J., 'An Overview
of Prestressed Masonry," The Masonry Society Journal,
V. LO, No. l, The Masonry Society, Boulder, CO,
August 1991, pp. 6-21.
2.6. Grimm, C.T., "Corrosion of Steel in Brick
Masonry," Masonry: Research, Application, and
Problems, STP-871, ASTM, Philadelphia, PA, 1985, pp.
67-87.
TMS 602-11/ACI530.1-11/ASCE 6-11
2.7. Catani, M.J., "Protection of Embedded Steel in
Masonry," Construction Specifier, V. 38, No. 1,
Construction Specifications Jnstitute, Alexandria, VA,
Jan. 1985, p. 62.
2.8. "Steel for Concrete Masonry Reinforcement,"
NCMA TEK 12-4A, National Concrete Masonry
Association, Herndon, VA, 1995, 6 pp.
2.9. "Specifications for Unbonded Single Strand
Tendons," Post-Tensioning Manual, 5th Edition, Post-
Tensioning Jnstitute, Phoenix, AZ, 1990, pp. 217-229.
2.10. Garrity, S.W., "Corrosion Protection of
Prestressing Tendons for Masonry," Proceedings,
Seventh Canadian Masonry Symposium, McMaster
University, Hamilton, Ontario, June 1995, pp. 736-750.
2.11. Grimm, C.T., "Masonry Cracks: A Review ofthe
Literature," Masonry: Materials, Design, Construction,
and Maintenance, STP-992, ASTM, Philadelphia, PA,
1988.
2.12. "Volume Changes - Analysis and Effects of
Movement," Technical Notes on Brick Construction 18,
Brick Industry Association, Reston, VA, Oct. 2006, 9 pp.
2.13. "Accommodating Expansion of Brickwork",
Technical Notes on Brick Construction 18A, Brick
Industry Association, Restan, VA, Oct. 2006, 11 pp.
2.14. "Control Joints for Concrete Masonry Walls-
Empirical Method," NCMA TEK l0-2B, National
Concrete Masonry Association, Hemdon, VA, 2005, 4 pp.
2.15. ACI-SEASC Task Committee on Slender Walls,
"Test Report on Slender Walls," ACI Southern
California Chapter/Structural Engineers Association of
Southern California, Los Angeles, CA, 1982, 125 pp.
2.16. Li, D., and Neis, V.V., "The Performance of
Reinforced Masonry Beams Subjected to Reversa]
Cyclic Loadings," Proceedings, 4th Canadian Masonry
Symposium, Fredericton, New Brunswick, Canada, June
1986, V. 1, pp. 351-365.
2.17. Unpublished Field Test Report, File 80-617,
B'Nai B'Rith Housing, Associated Testing Laboratories,
Houston, TX, 1981.
2.18. "Details and Detailing of Concrete
Reinforcement", ACI 315-99, American Concrete
Institute, Farmington Hills, MI.](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-321-320.jpg)
![1-12
S
Sample panels ............................................................ S-26
Samples ............................... S-21, S-25, S-27, S-52, S-70
Sampling............ C-68, S-8, S-JO, S-11 , S-18, S-31, S-70
brick.......................................................................S-10
concrete masonry ...................................................S-1 O
grout ......................................................................S-11
Sealant, specification.............................. S-11, S-26, S-44
Section properties ..........C-26, C-27, C-65, C-74, C-106,
.............................C-129, C-140, C-176, C-177, C-1 90
Seismic design................C-42, C-5~7, C-131, C-143,
.......................................................C-163--166, C-193
categories .............................................................. C-63
empírica! design restrictions ............................... C-143
limits for lightly loaded columns .......................... C-42
veneer requirements .................................. C-163--166
Seismic force-resisting system.....C-54--56, C-59, C-60,
........................................................ C-65, C-66, C-143
Seismic load (earthquake load, seismic force)........C-21,
................... C-23, C-53, C-54, C-56, C-60, C-64--67,
.......... C-77, C-93, C120, C-143, C-147, C-165, C-166
Self-consolidating grout
definition ........................................................ C-15, S-5
mixing ...................................... C-33, C-46, S-34, S-47
placement............................................................... S-67
submittals ............................................................... S-20
tests ............................. C-70, C-72, S-7, S-9, S-22-24
Service loads......................C-1, C-2, C-21, C-101, C-135
Settlement.................................. C-21, C-84, C-162, S-67
Shale masonry ...................................... see Clay masonry
Shear
AAC masonry .....C-54--66, C-175, C-178, C-1 80, C-
184, C-189
bolts....................................................................... C-49
force, notation ....................................................... C-11
reinforcement ........C-6, C-8, C-11, C-41, C-59, C-87,
....................C-88, C-1 00-102, C-115, C-122, C-123,
.................C-126, C-132, C-1 82, C-185, C-189, C-191
prestressed masonry ................................ C-139, C-140
reinforced masonry ..................................... C-57, C-58
transfer at wall interfaces .......................... C-57, C-102
unreinforced .............................C-17, C-1 8, C-54, C-56
Shear stress
composite action ......................C-14, C-26, C-79, C-96
reinforced members .................................. C-97, C-106
INDEX
unreinforced members ............................ C-11 O
, C-111
Shear wall(s)
definition ..................................................... C-17, C-18
design for in-plane loads, AAC masonry........... C-1 89
detailed plain (unreinforced) AAC MSW ............ C-17,
.................................................C-54, C-55, C-57, C-60
detailed plain (unreinforced) MSW ............ C-18, C-57
empírica] design .............................C-145-147, C-1 51
intermediate reinforced prestressed MSW ..........C-18,
...........................................................C-57, C-61, C-62
intermediate reinforced MSW.............. .....C-18, C-57,
.........................................................C-61, C-64, C-118
intersections .................................................. C-28-30
lateral load distribution ......................................... C-21
ordinary plain (unreinforced) AAC MSW............C-18,
...........................................................C-54, C-55, C-60
ordinary plain (unreinforced) MSW .......... C-18, C-54,
.........................................................C-55, C-57, C-138
ordinary plain (unreinforced) prestressed MSW ..C-18,
.....................................................................C-61, C-62
ordinary reinforced AAC MSW ......C-18, C-54, C-55,
................................................. C-57, C-61, C-64, C-66
ordinary reinforced MSW ...............C-18, C-55, C-57,
.................................................................... C-58, C-64
reinforced masonry, design................C-28, C-57--66,
.............................C-100, C-101, C-118, C-126, C-130
seismic requirements..................................... C-54--66
specia1 reinforced MSW .........C-18, C-57--66, C-100,
................................................................ C-1O1, C-118
special reinforced prestressed MSW................... C-18,
.................................................................... C-57, C-62
stiffness ................................................................. C-22
unreinforced .......................................................... C-56
Sheet-metal anchors............................C-45, C-162-165,
............................................................ S-38, S-39, S-64
Shrinkage .. .. .. ...C-3, C-5, C-9, C-1 1, C-21 , C-34, C-43,
......................... C-90, C-1 40, C-1 77, S-34, S-44, S-52
coefficient..................................................... C-9, C-25
deformation................................................... C-3, C-21
notation ......................................................... C-9, C-11
provisions, drawings ............................................... C-3
SI equivalents ............................................... C-201- 211
Site tolerances.........................................S-56, S-57, S-69
Sleeves.................................. C-3, C-74, S-44, S-73, S-74
Slump ................. S-6, S-10, S-34, S-47, S-65, S-67, S-68
Slump flow ................C-5, C-18, C-70, C-72, S-6, S-1 1,
.................................................... S-20- 24, S-34, S-47
Solid masonry unit, .......... C-36, C-152, S-1 O, S-36, S-62
definition ............................................................... C-16
* AAC Autoclaved Aerated Concrete, ASO Allowable Stress Oesign, MSW - Masonry Shear Wall, SO- Strength Oesign](https://image.slidesharecdn.com/aci530-11buildingcoderequirementsandspecificationformasonry-230807161923-a3b02ef5/85/ACI-530-11-Building-Code-Requirements-and-Specification-for-Masonry-pdf-335-320.jpg)
ACI 530-11 Building Code Requirements and Specification for Masonry.pdf
- 1. American Concrete lnstitute® Advancing concrete knowledge Building Code Requirements and Specification for Masonry Structures r- - - ~ - - · - - - .. -. Document ID: ; Q000-15FE-OE94-000111 B4 r7J Automatically sign me into this document in the future. lY..J (Do not s~ l ec t this when using a public computer)
- 2. Building Code Requirements and Specification for Masonry Structures Containing Building Code Requirements for Masonry Structures (TMS 402-11/ACI 530-11/ASCE 5-11) Specification for Masonry Structures (TMS 602-11/ACI 530.1-11/ASCE 6-11) and Companion Commentaries Developed by the Masonry Standards Joint Committee (MSJC) IIITHE MASONRY SOCIETY Advancing the knowledge of masonry The Masonry Society 3970 Broadway, Suite 201-D Boulder, Co 80304 www.masonrysociety.org (~- American Concrete lnstitute<!J Advancing concrete knowledge American Concrete lnstitute P.O. Box 9094 Farmington Hills, MI 48333 www.concrete.org STRUCTURAL ENGINEERING INSTITUTE Structural Engineering lnstitute ofthe American Society of Civil Engineers 1801 Alexander Bell Orive Reston, VA 20191 www.seinstitute.org
- 3. ABSTRACT Building Code Requirements and Specification for Masonry Structures contains two standards and their commentaries: Building Code Requirements for Masonry Structures {TMS 402-11/ACI 530-11/ASCE 5-11) and Specification for Masonry Structures (TMS 602-11/ACI 530.1-1l/ASCE 6-11). These standards are produced through the joint efforts of The Masonry Society (TMS), the American Concrete Institute (ACI), and the Structural Engineering Institute of the American Society of Civil Engineers (SEIIASCE) through the Masonry Standards Joint Committee (MSJC). The Code covers the design and construction of masonry structures while the Specification is concerned with mínimum construction requirements for masonry in structures. Sorne ofthe topics covered in the Codeare: definitions, contract documents; quality assurance; materials; placement of embedded items; analysis and design; strength and serviceability; flexura! and axial loads; shear; details and development of reinforcement; walls; co1umns; pilasters; beams and lintels; seismic design requirements; glass unit masonry; veneers; and autoclaved aerated concrete masonry. An empírica! design method and a prescriptive method applicable to buildings meeting specific location and construction criteria are also included. The Specification covers subjects such as quality assurance requirements for materials; the placing, bonding and anchoring of masonry; and the placement of grout and of reinforcement. This Specification is meant to be modified and referenced in the Project Manual. The Code is written as a legal document and the Specification as a master specification required by the Code. The commentaries present background details, committee considerations, and research data used to develop the Code and Specification. The Commentaries are not mandatory and are for information ofthe user only. The Masoruy Standards Joint Committee, which is sponsored by The Masonry Society, the American Concrete Tnstitute, and the Structural Engineering Institute ofthe American Society ofCivil Engineers, is responsible for these standards and strives to avoid ambiguities, omissions, and errors in these documents. In spite of these efforts, the users of these documents occasionally find information or requirements that may be subject to more than one interpretation or may be incomplete or incorrect. Users who have suggestions for the improvement ofthese documents are requested to contact TMS. These documents are intended for the use of individuals who are competent to evaluate the significance and 1imitations of its content and recommendations and who will accept responsibility for the application of the material it contains. Individuals who use this publication in any way assume all risk and accept total responsibility for the application and use of this information. All information in this publication is provided "as is" without warranty ofany kind, either express or implied, including but not limited to, the implied warranties ofmerchantability, fitness for a particular purpose or non-infringement. The sponsoring organizations, TMS, ACI, and SEIIASCE, and their members disclaim liability for damages of any kind, including any special, indirect, incidental, or consequential damages, including without limitation, lost revenues or lost profits, which may result from the use ofthis publication. It is the responsibility of the user of this document to establish health and safety practices appropriate to the specific circumstances involved with its use. The sponsoring organizations do not make any representations with regard to health and safety issues and the use of this document. The user must determine the applicability ofall regulatory limitations before applying the document and must comply with all applicable laws and regulations, including but not limited to, United States Occupational Safety and Health Administration (OSHA) health and safety standards. COPYRIGHT© 2011, The Masoruy Society, Boulder, CO, American Concrete Institute, Farmington Hills, MI, Structural Engineering Institute of the American Society of Civil Engineers, Reston, VA. lncludes errata through July 13, 2011. Watch http://www.masonrysociety.org/2011MSJC/Errata.htrn for possible additional errata. ALL RIGHTS RESERVED. This material may not be reproduced or copied, in whole or part, in any printed, mechanical, electronic, film, or other distribution and storage media, without the written consent ofTMS. Adopted as standards of the American Concrete Institute (March 14, 20 11), the Structural Engineering Institute of the American Society of Civil Engineers February 17, 2001, and The Masonry Society (March 23, 20 11) to supersede the 2008 edition in accordance with each organization's standardization procedures. These standards were originally adopted by the American Concrete Institute in November, 1988, the American Society of Civil Engineers in August, 1989, and The Masonry Society in July, 1992. ISBN 978-1-929081-36-3 ISBN 1-929081-36-7 Produced in the United States ofAmerica
- 4. About the MSJC and its Sponsors Masonry Standards Joint Committee The Masonry Standards Joint Committee (MSJC) is, as its name suggests, a joint committee sponsored by The Masonry Society (TMS), the American Concrete Institute (ACI), and the Structural Engineering lnstitute of the American Society of Civil Engineers (SEl/ASCE). lts mission is to develop and maintain design and construction standards for masonry for reference by or incorporation into model building codes regulating masonry construction. In practice, the MSJC is responsible for the maintenance of the Building Code Requirementsfor Masonry Structures (TMS 402/AC1530/ASCE 5), Specificationfor Masonry Structures (TMS 602/ACI 530.1/ASCE 6) and their companion Commentaries. Committee membership is open to al] qualified individuals, within the constraints of balance requirements, balloting schedules and particular needs for technical expertise. Committee meetings are open to the public. Committee Activities include: 1. Evaluate and ballot proposed changes to existing standards ofthe committee. 2. Develop and ballot new standards for masonry. 3. Resolve Negative votes from ballot items. 4. Provide interpretation ofexisting standards of the Committee. 5. Identify areas of needed research. 6. Sponsor educational seminars and symposia. 7. Monitor intemational standards. Additional details ofthe Committee, its work, and its meeting schedule are posted at www.masonrysociety.org and can be obtained from The Masonry Society. A roster ofthe Committee Members during the 2011 Revision Cycle is shown on the following page. THE MASONRY SOCIETY Advancing the knowledge of masonry The Masonry Society (TMS) was founded in 1977 as a not-for-profit professional, technical, and educational association dedicated to the advancement of knowledge on masonry. Today TMS is an intemational gathering of people interested in the art and science of masonry, and its members include design engineers, architects, builders, researchers, educators, building officials, material suppliers, manufacturers, and others who want to contribute to and benefit from the global pool ofknowledge on masonry. TMS gathers and disseminates technical information through its committees, publications, codes and standards, newsletter, refereed joumal, educational programs, workshops, scholarships, disaster investigation team, and conferences. The work ofTMS is conducted by individual TMS members and through the volunteer committees composed of both members and non-members. The Masonry Society serves as the lead Society for the support ofthe MSJC, andas such, meetings ofthe committee are held at TMS meetings and activities ofthe Committee are managed by TMS. For more information about TMS, contact The Masonry Society, 3970 Broadway, Suite 201-0, Boulder, CO 80304-11 35, U.S.A; Phone: 303-939-9700; Fax:303-541-9215; E-mail: info@masonrysociety.org; Website: www.masonrysociety.org
- 5. <H@) American Concrete lnstitute41 Advancingconcrete knowledge The AMERICAN CONCRETE INSTITUTE ACI was founded in 1904 as a nonprofit membership organization dedicated to public service and representing the user interest in the field of concrete. ACI gathers and distributes information on the improvement of design, construction, and maintenance of concrete products and structures. The work of ACI is conducted by individual ACI members and through volunteer committees composed ofboth members and non-members. The committees, as well as ACI as a whole, operate under a consensus format, which assures all participants the right to have their views considered. Committee activities include the development of building codes requirements and specifications, analysis of research and development results, presentation of construction and repair techniques, and education. Individuals interested in the activities of ACI are encouraged to become members. There are no educational or employment requirements. ACI's membership is composed of engineers, architects, scientists, contractors, educators, and representatives from a variety of companies and organizations. Members are encouraged to participate in committee activities that relate to their specific areas ofinterest. For more information about ACI, contact the American Concrete Institute, 38800 Country Club Orive, Farmington Hills, MI48331 U.S.A; Phone: 248-848-3700; Fax: 248-848-3701; Website: www.concrete.org STRUCTURAL ENGINEERING INSTITUTE • The Structural Engineering Institute (SEI) is a 22,000 plus member organization within the American Society of Civil Engineers (ASCE). SEI is organized into four Oivisions. The Business and Professional Activities Oivision (BPAO), promotes needed change in business and professional development issues unique to the structural engineering profession. The Codes and Standards Activities Oivision (CSAO) develops and maintains leading design standards that are used worldwide. The Local Activities Oivision (LAO) provides technical, educational, and professional program support to the local structural technical groups within ASCE's sections and branches. The Technical Activities Division (TAD) advances the profession with the dedicated work of its 70 plus technical committees that produce technical papers and publications and produce the Journal of Structural Engineers, the Journal ofBridge Engineers, and the Practice Periodical on Structural Design and Construction. Through its four divisions, SEI advances the profession in many ways including developing standards such as ASCE 7, encouraging discussion about licensure issues, enriching local Structural Technical Group programs, leading coordination efforts with other standards organizations, conducting an annual Structures Congress, offering cutting edge presentations, offering specialty conferences on tapies of interest to the Structural Engineering community, coordinating efforts with other structural engineering organizations, responding to the community's need for help in crisis, and providing low-cost seminars and webinars to the Structural Engineering community For more information about SEI, contact the Structural Engineering Institute, 1801 Alexander Bell Orive, Restan, VA 20191 ; Phone: 703-295-6196; E-mail: jrossberg@asce.org; Website: www.seinstitute.org
- 6. 2 3 * + Daniel P. Abrams Jennifer R. Bean Popehn Richard M. Bennett* David T. Biggs* J. Gregg Borchelt Robert N. Chittenden John Chrysler* Chukwuma G. Ekwueme Susan M. Frey Edward L. Freyermuth Thomas A. Gangel Bruce Barnes Olene L. Bigelow Russell H. Brown James Leroy Caldwell Angelo Coduto George E. Crow Ill Terry M. Curtís Majed A. Dabdoub Manuel A. Diaz Steve M. Dill Mohamed EIGawady Sergio M. Alcocer (C) James E. Amrhein (C) Ronald E. Bamett (C) Christine Beall (C) Frank J. Berg (C) Dean Brown (C) Jim Bryja (C) John M. Bufford (C) Mario J. Catani (CN) Charles B. Clark Jr. (C) Paul Curtís (C) Jamie L. Davis (C) Masonry Standards Joint Committee Diane B. Throop - Chair David I. McLean - Vice Chair Gerald Andrew Dalrymple - Secretary Voting Members on Masonry Committee1 S. K. Ghosh David l. McLean H. R. Hamilton III Darrell W. McMillian Benchmark Henry Harris John M. Melander R. Craig Henderson* Raymond Thomas Ronald J Hunsicker Miller* Keith Itzler* Vilas Mujumdar Rochelle C. Jaffe* Jerry M. Painter Eric N. Johnson* Thomas M. Petreshock Rashod R. Johnson Max L. Porter Richard E. Klingner* Arturo Ernest Schultz* W. Mark McGinley* Kurtis K. Siggard Voting Members ofSubcommittees Only2 James A. Farny Edwin T. Huston James Feagin Matthew D. Jackson Sonny James Fite John J. Jacob Fernando Fonseca Yasser Korany David C. Gastgeb James M. LaFave David Gillick Walter Laska Edgar F. Gluck Jr. Nicholas T. Loomis Dennis W. Graber Peter J. Loughney Brian J. Grant Sunup Sam Mathew David Chris H ines Ali M. Memari Augusto F. Holmberg Franklin L. Moon Subcommittee Corresponding (C) and Consulting (CN) Members3 John W. Diebold (C) James Daniel Dolan (C) Richard Filloramo (C) Hans Rudolf Ganz (CN) Janos Gergely (C) Brenda Harris (C) Charles Alan Haynes (C) Timothy S. Hess (C) Joshua T. Hewes (C) Jason M. lngham (CN) John Kariotis (CN) Bill Kjorlien (C) Mervyn J. Kowalsky (CN) David G. Kurtanich (C) James Lai (C) Andres Lepage (C) Shelley Lissel (C) Timothy Stanley Mallis (C) John Maloney (C) John H. Matthys (C) Scott E. Maxwell (C) Donald G. McMican (C) Ehsan Minaie (C) Jennifer E. Tanner John G. Tawresey Jason J. Thompson Margaret L. Thomson Diane B. Throop Charles J. Tucker* Scott W. Walkowicz* Terrence A. Weigel* A. Rhett Whitlock Daniel Zechmeister Michael C. Mota James P. Mwangi David L. Pierson Paul G. Scott John J. Smith William A. Wood+ David B. Woodham Rick Yelton Tianyi Yi Mel Oller (C) Adrian W. Page (CN) William D. Palmer Jr. (C) Guilherme Aris Parsekian (C) Michael J. Robinson (C) Nigel G. Shrive (CN) Christopher Sieto (C) Gary R. Sturgeon (C) Christine A. Subasic (C) Itzhak Tepper (C) Thomas C. Young (C) Main Committee Members during the 2011 Revision Cycle. They participated in Committee activities, voted on Main Committee ballots and participated in Subcommittee activities including voting and correspondence. Subcommittee Members during the 2011 Revision Cycle. They participated in Committee activities, voted on Subcommittee ballots and were able to comment on Main Committee ballots. Corresponding and Consulting Members during the 20 11 Revision Cycle. They could participate in Subcommittee activities but did not have voting privileges. Subcommittee Chair during the 2011 Revision Cycle Deceased
- 7. Additional Recognitions and Credits In addition to the Masonry Standards Joint Committee, a number of individuals assisted in the development, review, and layout ofthe provisions. Their contributions are greatly appreciated. TMS Technical Activities Cornmittee J. Gregg Borchelt, Chair1 David l. McLean, Chair1 • 2 Peter Babaian2 Robert Haukohl2 Rashod R. Johnson1 • 2 Sunup Mathew2 John H. Matthys1 • 2 Jason J. Thompson1 • 2 1 During the Review ofthe Standards 2 During the Review ofResponses to Public Comments and Final Approval Sergio Alcocer George W. Bomar David J. Eaton David Hein ACI Technical Activities Cornmittee Review Group Michael Kreger Kevin MacDonald ASCE Codes and Standards Cornmittee James H. Anspach, Chair Neil M. Hawkins, Vice-Chair Gayle S. Johnson Bonnie E. Manley Max L. Porter Michael W. Salmon Howard P. Thomas Donald G. Wittmer Staff Liaisons A. Rhett Whitlock1 • 2 Hani Nassif Warren K. Wray Khaled Nahlawi, ACI James A. Rossberg, SEI ofASCE Phillip J. Samblanet, TMS Kathy Keller, Administrative Assistant, WDP Manassas office BaUoting Assistance Cover Design Susan Scheurer, Committee Liaison, The Masonry Society Thomas Escobar, Design Director, Masonry Institute of America Luis Dominguez, Production Manager, Masonry Institute of Americas Final Editing & Proofing Indexing Susan Scheurer, Committee Liaison, The Masonry Society Christen Snydal - Publications Manager, The Masonry Society Editorial Assistance during Initial Developrnent Gay Hofteig, Retired, Formerly with the Intemational Masonry Institute
- 8. Building Code Requirements for Masonry Structures (TMS 402-11/ACI 530-11/ASCE 5-11) TABLE OF CONTENTS SYNOPSIS AND KEYWORDS, pg. C-vü CHAPTER 1- GENERAL DESIGN REQUIREMENTS FOR MASONRY, pg. C-1 1.1 -Scope................................................................................................................................................................ C-1 1.1.1 Mínimum requirements............................................................................................................................. C-1 1.1 .2 Goveming building code........................................................................................................................... C-1 1.1.3 Design procedures..................................................................................................................................... C-1 1.1.4 SI information .......................................................................................................................................... C-2 1.2 - Contract documents and calculations............................................................................................................... C-3 1.3 - Approval ofspecial systems ofdesign or construction .................................................................................... C-4 1.4- Standards cited in this Code............................................................................................................................. C-5 1.5 - Notation ........................................................................................................................................................... C-6 1.6 - Definitions ..................................................................................................................................................... C-13 1.7 - Loading .......................................................................................................................................................... C-20 1.7.1 General .................................................................................................................................................... C-20 1.7.2 Load provisions ....................................................................................................................................... C-20 1.7.3 Latera11oad resistance............................................................................................................................. C-20 1.7.4 Load transfer at horizontal connections .................................................................................................. C-21 l.7.5 Other effects ............................................................................................................................................ C-21 1.7.6 Lateral load distribution .......................................................................................................................... C-21 1.8 - Material properties ......................................................................................................................................... C-22 1.8.1 General.................................................................................................................................................... C-22 1.8.2 Elastic moduli ......................................................................................................................................... C-23 1.8.3 Coefficients ofthermal expansion........................................................................................................... C-25 1.8.4 Coefficients ofmoisture expansion for elay masonry ............................................................................. C-25 1.8.5 Coefficients ofshrinkage ........................................................................................................................ C-25 1.8.6 Coefficients ofcreep ............................................................................................................................... C-25 1.8.7 Prestressing steel ..................................................................................................................................... C-26 1.9 - Section properties........................................................................................................................................... C-26 1.9.1 Stress computations................................................................................................................................. C-26 1.9.2 Stiffness................................................................................................................................................... C-27 1.9.3 Radius ofgyration................................................................................................................................... C-27 1.9.4 Intersecting walls .................................................................................................................................... C-28 1.9.5 Bearing area ............................................................................................................................................ C-29 1.9.6 Effective compressive width per bar....................................................................................................... C-31 1.9.7 Concentrated loads.................................................................................................................................. C-32 1.1O- Connection to structural frames ................................................................................................................... C-34 1.11 - Masonry not laid in running bond ................................................................................................................ C-35
- 9. C-ii TMS 402-11/ACI530-11/ASCE 5-11 1.12- Corbels ......................................................................................................................................................... C-36 1.12.1 Loadbearing corbels ................................................................................................................................ C-36 1.12.2 Non-loadbearing corbels ......................................................................................................................... C-36 1.13- Beams........................................................................................................................................................... C-38 1.13.1 General beam design ............................................................................................................................... C-38 1.13.2 Deep beams ............................................................................................................................................. C-40 1.14- Columns ....................................................................................................................................................... C-41 1.14.1 General column design............................................................................................................................ C-41 1.14.2 Lightly loaded columns........................................................................................................................... C-42 1.15 - Pilasters........................................................................................................................................................ C-43 1.16 - Details ofreinforcement and metal accessories ........................................................................................... C-43 1.16.1 Embedment ............................................................................................................................................. C-43 1.16.2 Size ofreinforcement .............................................................................................................................. C-43 1.16.3 Placement ofreinforcement .................................................................................................................... C-45 1.16.4 Protection of reinforcement and metal accessories ................................................................................. C-45 1.16.5 Standardhooks........................................................................................................................................ C-46 1.16.6 Mínimum bend diameter for reinforcing bars ......................................................................................... C-47 1.17 - Anchor Bolts ................................................................................................................................................ C-47 1.17.1 Placement ................................................................................................................................................ C-47 1.17.2 Projected area for axial tension ............................................................................................................... C-47 1.17.3 Projected area for shear........................................................................................................................... C-49 1.17.4 Effective embedment length for headed anchor bolts ............................................................................. C-51 1.17.5 Effective embedment length ofbent-bar anchor bolts ............................................................................ C-51 1.17.6 Mínimum permissible effective embedment length ................................................................................ C-52 1.17.7 Anchor bolt edge distance....................................................................................................................... C-52 1.18 - Seismic design requirements........................................................................................................................ C-53 1.18.1 Scope....................................................................................................................................................... C-53 1.18.2 General analysis ...................................................................................................................................... C-54 1.18.3 Element classification ............................................................................................................................. C-56 1.18.4 Seismic Design Category requirements .................................................................................................. C-63 1.19 - Quality Assurance program ......................................................................................................................... C-67 1.19.1 Leve! A Quality Assurance .................................................................................................................... C-68 1.19.2 Leve! B Quality Assurance .................................................................................................................... C-68 1.19.3 Leve! C Quality Assurance .................................................................................................................... C-68 1.19.4 Procedures ..............................................................................................................................................C-68 1.19.5 Qualifications .........................................................................................................................................C-69 1.19.6 Acceptance relative to strength requirements ........................................................................................ C-73 1.20 - Construction ................................................................................................................................................ C-73 1.20.1 Grouting, mínimum spaces ..................................................................................................................... C-73 1.20.2 Embedded conduits, pipes, and sleeves................................................................................................... C-74 CHAPTER 2 - ALLOWABLE STRESS DESIGN OF MASONRY, pg. C-77 2. 1- General........................................................................................................................................................... C-77 2.1.1 Scope....................................................................................................................................................... C-77 2.1.2 Load combinations .................................................................................................................................. C-77 2.1.3 Design strength ....................................................................................................................................... C-77 2.1.4 Anchor bolts embedded in grout............................................................................................................. C-77 2.1.5 Multiwythe walls..................................................................................................................................... C-79 2.1.6 Bearing stress .......................................................................................................................................... C-82 2.1.7 Development ofreinforcement embedded in grout ................................................................................ C-83 Pg 60
- 10. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES C-iii 2.2 - Unreinforced masonry ................................................................................................................................... C-90 2.2.1 Scope....................................................................................................................................................... C-90 2.2.2 Stresses in reinforcement ........................................................................................................................ C-90 2.2.3 Axial compression and flexure................................................................................................................ C-90 2.2.4 Axial tension ........................................................................................................................................... C-96 2.2.5 Shear ....................................................................................................................................................... C-96 2.3 - Reinforced masonry ...................................................................................................................................... C-97 2.3.1 Scope....................................................................................................................................................... C-97 2.3.2 Design assumptions................................................................................................................................. C-97 2.3.3 Steel reinforcement - Allowable stresses.............................................................................................. C-97 2.3.4 Axial compression and flexure................................................................................................................ C-97 2.3.5 Axial tension and flexura! tension......................................................................................................... C-100 2.3.6 Shear ..................................................................................................................................................... C-100 CHAPTER 3 -STRENGTH DESIGN OF MASONRY, pg. C-105 3.1 - General ........................................................................................................................................................ C-105 3.1.1 Scope..................................................................................................................................................... C-105 3.1.2 Required strength .................................................................................................................................. C-105 3.1.3 Design strength ..................................................................................................................................... C-105 3.1.4 Strength-reduction factors ..................................................................................................................... C-105 3.1.5 Deformation requirements .................................................................................................................... C-106 3.1.6 Anchor bolts embedded in grout ........................................................................................................... C-106 3.l.7 Nominal bearing strength ...................................................................................................................... C-108 3.1.8 Material properties ................................................................................................................................ C-108 3.2 - Unreinforced (plain) masonry ..................................................................................................................... C-110 3.2.1 Scope..................................................................................................................................................... C-110 3.2.2 Flexura! and axial strength of unreinforced (plain) masonry members................................................. C-110 3.2.3 Axial tension ......................................................................................................................................... C-113 3.2.4 Nominal shear strength .........................................................................................................................C-113 3.3 - Reinforced masonry .................................................................................................................................... C-114 3.3.1 Scope..................................................................................................................................................... C-1 14 3.3.2 Design assumptions............................................................................................................................... C-114 3.3.3 Reinforcement requirements and details ............................................................................................... C-114 3.3.4 Design ofbeams, piers, and columns .................................................................................................... C-121 3.3.5 Wall design for out-of-plane loads........................................................................................................ C-124 3.3.6 Wall design for in-plane loads .............................................................................................................. C-1 26 CHAPTER 4- PRESTRESSED MASONRY, pg. C-133 4.1- General ........................................................................................................................................................ C-133 4.1 .1 Scope..................................................................................................................................................... C-133 4.2 - Design methods ........................................................................................................................................... C-134 4.2.1 General.................................................................................................................................................. C-134 4.2.2 After transfer ......................................................................................................................................... C-134 4.3 - Permissible stresses in prestressing tendons ............................................................................................... C-134 4.3.1 Jacking force ......................................................................................................................................... C-134 4.3.2 Immediately after transfer..................................................................................................................... C-134 4.3.3 Post-tensioned masonry members......................................................................................................... C-134 4.3.4 Effectiveprestress ................................................................................................................................. C-135
- 11. C-iv TMS 402-11/ACI 530-11/ASCE 5-11 4.4 - Axial compression and flexure ..................................................................................................................... C-136 4.4.1 General.................................................................................................................................................. C-136 4.4.2 Service load requirements ..................................................................................................................... C-137 4.4.3 Strength requirements ........................................................................................................................... C-138 4.5 - Axial tension ............................................................................................................................................... C-139 4.6 - Shear ........................................................................................................................................................... C-139 4.7- Deflection .................................................................................................................................................... C-140 4.8 - Prestressing tendon anchorages, couplers, and end blocks ......................................................................... C-140 4.8.1 .............................................................................................................................................................. C-140 4.8.2 .............................................................................................................................................................. C-140 4.8.3 .............................................................................................................................................................. C-140 4.8.4 Bearing stresses..................................................................................................................................... C-140 4.9 - Protection of prestressing tendons and accessories ..................................................................................... C-140 4.1O- Deve1opment ofbonded tendons ............................................................................................................... C-141 CHAPTER 5- EMPIRICAL DESIGN OF MASONRY, pg. C-143 5.1 - General ........................................................................................................................................................ C-143 5.1.1 Scope..................................................................................................................................................... C-143 5.1.2 Limitations ............................................................................................................................................ C-143 5.2 - Height .......................................................................................................................................................... C-145 5.3- Lateral stability ........................................................................................................................................... C-145 5.3.1 Shearwalls ............................................................................................................................................ C-145 5.3.2 Roofs..................................................................................................................................................... C-145 5.4 - Compressive stress requirements ................................................................................................................ C-147 5.4.1 Calculations........................................................................................................................................... C-147 5.4.2 Allowable compressive stresses ............................................................................................................ C-147 5.5- Lateral support ............................................................................................................................................ C-150 5.5.1 Maximum lit and hit.............................................................................................................................. C-150 5.5.2 Cantilever walls..................................................................................................................................... C-151 5.5.3 Support elements................................................................................................................................... C-151 5.6 - Thickness ofmasonry ................................................................................................................................. C-151 5.6.1 Generai .................................................................................................................................................. C-1 51 5.6.2 Minimum thickness............................................................................................................................... C-151 5.6.3 Foundation walls ................................................................................................................................... C-152 5.6.4 Parapet walls ......................................................................................................................................... C-153 5.7- Bond ............................................................................................................................................................ C-153 5.7.1 Generai.................................................................................................................................................. C-153 5.7.2 Bonding with masonry headers ............................................................................................................. C-153 5.7.3 Bonding with wall ties orjoint reinforcement....................................................................................... C-153 5.7.4 Natural or cast stone.............................................................................................................................. C-155
- 12. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES C-v 5.8- Anchorage ................................................................................................................................................... C-155 5.8.1 General.................................................................................................................................................. C-155 5.8.2 lntersecting walls .................................................................................................................................. C-155 5.8.3 Floor and roofanchorage ...................................................................................................................... C-155 5.8.4 Walls adjoining structural framing........................................................................................................ C-156 5.9- Miscellaneous requirements ........................................................................................................................ C-156 5.9.1 Chases and recesses .............................................................................................................................. C-156 5.9.2 Lintels ...................................................................................................................................................C-156 5.9.3 Supportonwood ................................................................................................................................... C-1 56 CHAPTER 6 - VENEER, pg. C-157 6.1 - General ........................................................................................................................................................ C-157 6.1 .1 Scope..................................................................................................................................................... C-1 57 6.1.2 Design ofanchored veneer.................................................................................................................... C-158 6.1.3 Design ofadhered veneer...................................................................................................................... C-160 6.1.4 Dimension stone.................................................................................................................................... C-160 6.1.5 Autoclaved aerated concrete masonry veneer....................................................................................... C-160 6.1.6 General design requirements................................................................................................................. C-160 6.2 - Anchored Veneer ........................................................................................................................................ C-161 6.2.1 Altemative design of anchored masonry veneer................................................................................... C-161 6.2.2 Prescriptive requirements for anchored masonry veneer ...................................................................... C-161 6.3 - Adhered Veneer ..........................................................................................................................................C-167 6.3.1 Altemative design ofadhered masonry veneer ..................................................................................... C-1 67 6.3.2 Prescriptive requirements for adhered masonry veneer ........................................................................ C-167 CHAPTER 7- GLASS UNIT MASONRY, pg. C-169 7.1 - General......................................................................................................................................................... C-169 7.1.1 Scope..................................................................................................................................................... C-169 7.1.2 General design requirements................................................................................................................. C-169 7.1.3 Units...................................................................................................................................................... C-169 7.2 - Panel Size..................................................................................................................................................... C-169 7.2.1 Exterior standard-unit panels ................................................................................................................ C-169 7.2.2 Exterior thin-unit panels........................................................................................................................ C-171 7.2.3 Interior panels ....................................................................................................................................... C-171 7.2.4 Curved panels........................................................................................................................................ C-172 7.3- Support ......................................................................................................................................................... C-172 7.3.1 General requirements ............................................................................................................................ C-172 7.3.2 Vertical.................................................................................................................................................. C-172 7.3.3 Lateral ................................................................................................................................................... C-172 7.4 - Expansionjoints .......................................................................................................................................... C-174 7.5 - Base surface treatment ................................................................................................................................ C-174 7.6 - Mortar ......................................................................................................................................................... C-174 7.7 - Reinforcement ............................................................................................................................................. C-174
- 13. C-vi TMS 402-11/ACISJ0-11/ASCE 5-11 CHAPTER8-STRENGTH DESIGN OF AUTOCLAVED AERATED CONCRETE (AAC) MASONRY, pg. C-175 8.1 - General......................................................................................................................................................... C-175 8.1.1 Scope..................................................................................................................................................... C-175 8.1.2 Required strength .................................................................................................................................. C-175 8.1.3 Design strength ..................................................................................................................................... C-175 8.1.4 Strength ofjoints ................................................................................................................................... C-175 8.1.5 Strength-reduction factors ..................................................................................................................... C-176 8.1.6 Deformation requirements .................................................................................................................... C-176 8.1.7 Anchor bolts .......................................................................................................................................... C-177 8.1.8 Material properties ................................................................................................................................ C-177 8.1.9 Nominal bearing srength ....................................................................................................................... C-178 8.1.10 Corbels .................................................................................................................................................. C-179 8.2- Unreinforced (plain) AAC masonry............................................................................................................. C-179 8.2.1 Scope..................................................................................................................................................... C-179 8.2.2 Flexura( strength ofunreinforced (plain) AAC masonry members....................................................... C-179 8.2.3 Nominal axial strength ofunreinforced (plain) AAC masonry members ............................................. C-180 8.2.4 Axial tension ......................................................................................................................................... C-180 8.2.5 Nominal shear strength ofunreinforced (plain) AAC masonry members............................................. C-180 8.2.6 Flexura) cracking................................................................................................................................... C-180 8.3- Reinforced AAC masonry............................................................................................................................ C-181 8.3.1 Scope..................................................................................................................................................... C-181 8.3.2 Design assumptions............................................................................................................................... C-181 8.3.3 Reinforcement requirements and details ............................................................................................... C-181 8.3.4 Design ofbeams, piers, and columns .................................................................................................... C-183 8.3.5 Wall design for out-of-plane loads........................................................................................................ C-187 8.3.6 Wall design for in-plane loads .............................................................................................................. C-189 APPENDIX B- DESIGN OF MASONRYINFILL, pg. C-193 8.1 - General ........................................................................................................................................................ C-193 8.1.1 Scope..................................................................................................................................................... C-193 8.1.2 Required strength .................................................................................................................................. C-193 8.1.3 Design strength ..................................................................................................................................... C-194 8.1.4 Strength-reduction factors ..................................................................................................................... C-194 8.1.5 Limitations .............................................................................................................................................. C-94 8.2 - Non-Participating Infills.............................................................................................................................. C-194 8.2.1 In-plane isolation joints for non-participating infills............................................................................. C-194 8.2.2 Design of for non-participating infills for out-of-plane loads ............................................................... C-194 8.3- Participating Infills...................................................................................................................................... C-195 8.3.1 General.................................................................................................................................................. C-195 8.3.2 In-plane connection requirements for participating infills .................................................................... C-195 8.3.3 Out-of-plane connection requirements for participating infills ............................................................. C-196 8.3.4 Design offor participating infills for in-plane loads ............................................................................. C-196 8.3.5 Design of frame elements with participating infills for in-plane loads ................................................. C-197 CONVERSION OF INCH-POUND UNITS TO SI UNITS, pg. C-201 REFERENCE FOR THE CODE COMMENTARY, pg. 213
- 14. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES C-vii Building Code Requirements for Masonry Structures (TMS 402-11/ACI 530-11/ASCE 5-11) SYNOPSIS This Code covers the design and construction of masonry structures. It is written m such form that it may be adopted by reference in a legally adopted building code. Among the subjects covered are: definitions; contract documents; quality assurance; materials; placement of embedded items; analysis and design; strength and serviceability; flexura! and axial loads; shear; details and development of reinforcement; walls; columns; pilasters; beams and lintels; seismic design requirements; glass unit masonry; and veneers. An empírica! design method applicable to buildings meeting specific location and construction criteria are also included. The quality, inspection, testing, and placement of materials used in construction are covered by reference to TMS 602-11/ACI 530.1-11/ASCE 6-11 Specification for Masonry Structures and other standards. Keywords: AAC, masonry, allowable stress design, anchors (fasteners); anchorage (structural); autoclaved aerated concrete masonry, beams; building codes; cements; clay brick; clay tile; columns; compressive strength; concrete block; concrete brick; construction; detai1ing; empírica! design; flexura! strength; glass units; grout; grouting; joints; loads (forces); masonry; masonry cements; masonry load bearing walls; masonry mortars; masonry walls; modulus of elasticity; mortars; pilasters; prestressed masonry, quality assurance; reinforced masonry; reinforcing steel; seismic requirements; shear strength; specifications; splicing; stresses; strength design, structural analysis; structural design; ties; unreinforced masonry; veneers; walls.
- 15. C-viii TMS 402-11 /ACISJ0-11/ASCE 5-11 This page is intentionally left blank.
- 16. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-1 CHAPTER 1 GENERAL DESIGN REQUIREMENTS FOR MASONRY CODE 1.1- Scope 1.1.1 Minimum requirements This Code provides mínimum requirements for the structural design and construction of masonry elements consisting ofmasonry units bedded in mortar. 1.1.2 Governíng building code This Code supplements the legally adoptcd building code and shall govem in matters pertaining to structural design and construction of masonry elements, except where this Code is in conflict with requirements in the legally adopted building code. In areas without a legally adopted building code, this Code defines the mínimum acceptable standards ofdesign and construction practice. 1.1.3 Desígn procedures Masonry structures and their component members shall be designed in accordance with the provisions of this Chapter and one ofthe following: (a) Allowable Stress Design ofMasonry: Chapter 2. (b) Strength Design ofMasonry: Chapter 3. (e) Prestressed Masonry: Chapter 4. (d) Empírica! Design ofMasonry: Chapter 5. (e) Veneer: Chapter 6. (f) Glass Unit Masonry: Chapter 7. (g) Strength Design of Autoclaved Aerated Concrete (AAC) Masonry: Chapter 8. (h) Masonry Infill, Appendix B. COMMENTARY 1.1-Scope This Code covers the structural design and construction ofmasonry elements and serves as a part ofthe legally adopted building code. Since the requirements for masonry in this Code are interrelated, this Code may need to supersede when there are conflicts on masonry design and construction with the legally adopted building code or with documents referenced by this Code. The designer must resolve the conflict for each specific case. 1.1.1 Minimum requírements This code govems structural design of both structural and non-structural masonry elements. Examples of non- structural elements are masonry veneer, glass unit masonry, and masonry partitions. Structural design aspects of non-structural masonry elements include, but are not limited to, gravity and lateral support, and load transfer to supporting elements. 1.1.2 Governing building code 1.1.3 Design procedures Design procedures in Chapter 2 are allowable stress methods in which the stresses resulting from service loads must not exceed permissible service load stresses. Design procedures in Chapters 3 and 8 are strength design methods in which interna! forces resulting from application of factored loads must not exceed design strength (nominal member strength reduced by a strength- reduction factor rjJ). For allowable stress design, linear elastic materials following Hooke's Law are assumed, that is, deformations (strains) are linearly proportional to the loads (stresses). All materials are assumed to be homogeneous and isotropic, and sections that are plane before bending remain plane after bending. These assumptions are adequate within the low range of working stresses under consideration. The allowable stresses are fractions of the specified compressive strength, resulting in conservative factors ofsafety. Service load is the load that is assumed by the legally adopted building code to actually occur when the structure
- 17. C-2 CODE 1.1.4 Slinformation SI values shown in parentheses are not part of this Code. The equations in this document are for use with the specified inch-pound units only. The equivalent equations for use with SI units are provided in Conversion of Units on Page C-201. TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY 1s m service. The stresses allowed under the action of service loads are limited to values within the elastic range ofthe materials. For strength design methods, interna! forces arising from application of combinations of factored loads are the basis for design. Such load combinations are specified in the legally adopted building code. Nominal member strengths are typically computed using mínimum specified material strengths. Materials are assumed to be homogenous, isotropic, and exhibit nonlinear behavior. Under loads that exceed service levels, nonlinear material behavior, cracking, and reinforcing bar slip invalidate the assumption regarding the linearity of the stress-strain relation for masonry, grout, and reinforcing steel. If nonlinear behavior is modeled, however, nominal strength can be accurately predicted. Strength-reduction (¡p) factors are assigned values based on limiting the probability of failure to an acceptably small value, with sorne adjustment based onjudgment and experience. Empirical design procedures ofChapter 5 are permitted in certain instances. Elements not working integrally with the structure, such as partition or panel walls, or any element not (or not permanently) absorbing or transmitting forces resulting from the behavior of the structure under loads, may be designed empirically. A masonry shear wall would be an integral structural element while sorne wall partitions, because of their method of construction or attachment, would not. Empírica! design is permitted for buildings oflimited height and low seismic risk. Masonry structures may be required to have enhanced structural integrity as part of a comprehensive design against progressive collapse due to accident, misuse, sabotage or other causes. General design guidance addressing this issue is available in Commentary Section 1.4 of ASCE 7. Suggestions from that Commentary, of specific application to many masonry structures, include but are not limited to: consideration of plan layout to incorporate retums on walls, both interior and exterior; use of load-bearing interior partitions; adequate continuity ofwalls, ties, and joint rigidity; providing walls capable of beam action; ductile detailing and the use of compartmentalized construction. 1.1.4 SI information
- 18. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-3 CODE 1.2- Contract documents and calculations 1.2.1 Project drawings and project specifications for masonry structures shall identify the individual responsible for their preparation. 1.2.2 Show all Code-required drawing items on the project drawings, including: (a) Name and date of issue of code and supplement to which the design conforms. (b) Loads used in the design ofmasonry. (e) Specified compressive strength of masonry at stated ages or stages of construction for which masonry is designed, except where specifically exempted by Code provisions. (d) Size and location of structural elements. (e) Details of anchorage of masonry to structural members, frames, and other construction, including the type, size, and location ofconnectors. (f) Details of reinforcement, including the size, grade, type, and location ofreinforcement. (g) Reinforcing bars to be welded and welding requirements. (h) Provision for dimensional changes resulting from elastic deformation, creep, shrinkage, temperature, and moisture. (i) Size and permitted location of conduits, pipes, and sleeves. 1.2.3 The contract documents shall be consisten! with design assumptions. 1.2.4 Contrae! documents shall specify the mínimum level of quality assurance as defined in Section 1.19, or shall include an itemized quality assurance program that equals or exceeds the requirements ofSection 1.19. COMMENTARY 1.2- Contract documents and calculations 1.2.1 The provisions for preparation of project drawings, project specifications, and issuance ofpermits are, in general, consisten! with those ofmost legally adopted building codes and are intended as supplements to those codes. This Code is not intended to be made a part of the contrae! documents. The contractor should not be required through contract documents to assume responsibility regarding design (Code) requirements, unless the construction entity is acting in a design-build capacity. A Commentary on TMS 602/ACI 530.1/ASCE 6 follows the Specification. 1.2.2 This Code lists sorne of the more importan! items of information that must be included in the project drawings or project specifications. This is not an aH- inclusive list, and additional items may be required by the building official. Masonry does not always behave in the same manner as its structural supports or adjacent construction. The designer should consider differential movements and the forces resulting from their restraint. The type of connection chosen should transfer only the loads planned. While sorne connections transfer loads perpendicular to the wall, other devices transfer loads within the plane of the wall. Figure CC-1.2-1 shows representative wall anchorage details that allow movement within the plane of the wall. While load transfer usually involves masonry attached to structural elements, such as beams or columns, the connection of nonstructural elements, such as door and window frames, should also be addressed. Connectors are of a variety ofsizes, shapes, and uses. In order to perform properly they should be identified on the project drawings. 1.2.3 The contract documents must accurately retlect design requirements. For example, joint and opening locations assumed in the design should be coordinated with locations shown on the drawings. Verification that masonry construction conforms to the contrae! documents is required by this Code. A program of quality assurance must be included in the contract documents to satisfy this Code requirement.
- 19. C-4 TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY Dovetail Slot V V V Anchor Plan Section (a) Wall Anchorage to Concrete Beams Dovetail Slot V V V Anchor V V Plan Section (b ) Wall Anchorage to Concrete Columns Flexible Anchor Plan Section (e) wa11 Anchorage !o Steel Column Flexible Anchor Plan Section Figure CC-1.2-1- Wa/1 anchorage details CODE 1.3 - Approval of special systems of design or construction Sponsors of any system of design or construction within the scope of this Code, the adequacy of which has been shown by successful use or by analysis or test, but that does not conform to or is not covered by this Code, shall have the right to present the data on which their design is based to a board of examiners appointed by the building official. The board shall be composed of licensed design professionals and shall have authority to investigate the submitted data, require tests, and formulate rules goveming design and construction of such systems to meet the intent ofthis Code. The rules, when approved and promulgated by the building official, shall be of the same force and effect as the provisions ofthis Code. COMMENTARY 1.3 - Approval of special systems of design or construction New methods of design, new materials, and new uses of materials must undergo a period of development before being specifically covered in a code. Hence, valid systems or components might be excluded from use by implication if means were not available to obtain acceptance. This section permits proponents to submit data substantiating the adequacy of their system or component to a Board of Examiners. Such a board should be created and named in accordance with local laws and should be headed by a registered engineer. Board members should be directly associated with, and competent in, the fields of structural design or construction of masonry. For special systems considered under this section, specific tests, load factors, detlection limits, and other pertinent requirements should be set by the board of examiners, and should be consistent with the intent ofthe Code.
- 20. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-5 CODE 1.4 - Standards cited in this Code Standards of the American Concrete Institute, the American Society of Civil Engineers, ASTM lnternational, the American Welding Society, and The Masonry Society cited in this Code are listed below with their serial designations, including year of adoption or revision, and are declared to be part ofthis Codeas iffully set forth in this document. TMS 602-ll/ACI 530.1-111 ASCE 6-ll - Specification for Masonry Structures ASCE 7-10 - Minimum Oesign Loads for Buildings and Other Structures ASTM A416/A416M-06 - Standard Specification for Steel Strand, Uncoated Seven-Wire for Prestressed Concrete ASTM A42l/A421M-05 - Standard Specification for Uncoated Stress-Relieved Steel Wire for Prestressed Concrete ASTM A722/A722M-07 - Standard Specification for Uncoated High-Strength Steel Bars for Prestressing Concrete ASTM C34-03 - Standard Specification for Structural Clay Load-Bearing Wall Tile ASTM C426-07 - Standard Test Method for Linear Orying Shrinkage ofConcrete Masonry Units ASTM C476-09 - Standard Specification for Grout for Masonry ASTM C482-02 (2009) - Standard Test Method for Bond Strength of Ceramic Tile to Portland Cement Paste ASTM Cl006-07 - Standard Test Method for Splitting Tensile Strength of Masonry Units ASTM C1386-07 - Standard Specification for Precast Autoclaved Aerated Concrete (AAC) Wall Construction Units ASTM Cl 6ll/Cl611M-09 - Standard Test Method for Slump Flow of Self-Consolidating Concrete ASTM E1ll-04 - Standard Test Method for Young's Modulus, Tangent Modulus, and Chord Modulus ASTM E488-96 (2003) - Standard Test Methods for Strength of Anchors in Concrete and Masonry Elements AWS O 1.4-05 - Structural Welding Code - Reinforcing Stee1 COMMENTARY 1.4- Standards cited in this Code These standards are referenced in this Code. Specific dates are listed here since changes to the standard may resu1 t in changes ofproperties or procedures. Contact information for these organizations is given below: American Concrete Institute 38800 Country Club Orive Farmington Hills, MJ 48331 www.aci-int.org American Society ofCivil Engineers 1801 Alexander Bell Orive Resten, VA 20191 www.asce.org ASTM Intemationa1 100 Barr Harbor Orive West Conshohocken, PA 19428-2959 www.astm.org American Welding Society 550 N.W. LeJeune Road Miami, Florida 33126 www.aws.org The Masonry Society (TMS) 3970 Broadway, Suite 201-0 Boulder, CO 80304 www.masonrysociety.org
- 21. C-6 CODE 1.5 - Notation As As/ cross-sectional area of an anchor bolt, in.2 (mm2 ) bearing area, in.Z (mm2 ) gross cross-sectional area ofa member, in?(mm2 ) net cross-sectional area of a member, in.Z (mm2 ) net shear area, in.2 (mm2 ) area ofprestressing steel, in.Z (mm2 ) projected tension area on masonry surface of a right circular cone, in.Z (mm2 ) projected shear area on masonry surface of one- halfof a right circular cone, in.2 (mm2 ) area of nonprestressed longitudinal tension reinforcement, in.2 (mm2 ) area of reinforcement placed within the lap, near each end of the lapped reinforcing bars and transverse to them, in2 (mm2 ) total area of laterally tied longitudinal reinforcing steel, in.2 (mm2 ) cross-sectional area of shear reinforcement, in.Z (mm2 ) A¡ loaded area, in.2 (mm2 ) A2 supporting bearing area, in.Z (mm2 ) a depth of an equivalent compression stress block at nominal strength, in. (mm) Ba allowable axial load on an anchor bolt, lb (N) B ah allowable axial tensile load on an anchor bolt when govemed by masonry breakout, lb (N) B an nominal axial strength ofan anchor bolt, lb (N) B anb nominal axial tensile strength of an anchor bolt when govemed by masonry breakout, lb (N) Banp nominal axial tensile strength ofan anchor bolt when govemed by anchor pullout, lb (N) Bans nominal axial tensile strength of an anchor bolt when govemed by steel yielding, lb (N) B ap allowable axial tensile load on an anchor bolt when govemed by anchor pullout, lb (N) Bas allowable axial tensile load on an anchor bolt when govemed by steel yielding, lb (N) Bv allowable shear load on an anchor bolt, lb (N) Bvb allowable shear load on an anchor bolt when governed by masonry breakout, lb (N) TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY 1.5 - Notation Notations used in this Code are summarized here. The thickness of the infill, t;11¡; is the specified thickness ofthe infill. The net thickness ofthe infill, t11, 1111¡; is the mínimum total thickness of the net cross-sectional area. These values are shown in Figure CC-1.5-J. Vertical Cross-Section lhrough lnfill Figure CC-1.5-1 - Thickness and net thickness of an infill
- 22. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY CODE B,'C allowable shear load on an anchor bolt when govemed by masonry crushing, lb (N) B,.11 nominal shear strength ofan anchor bolt, lb (N) B.,11b nominal shear strength ofan anchor bolt when govemed by masonry breakout, lb (N) B,,11c nominal shear strength ofan anchor bolt when governed by masonry crushing, lb (N) B,,11pry nominal shear strength ofan anchor bolt when governed by anchor pryout, lb (N) B,.,IS nominal shear strength ofan anchor bolt when governed by steel yielding, lb (N) B.,pry allowable shear load on an anchor bolt when governed by anchor pryout, lb (N) Bvs allowable shear load on an anchor bolt when governed by steel yielding, lb (N) b width of section, in. (mm) ba total applied design axial force on an anchor bolt, lb (N) ba¡ factored axial force in an anchor bolt, lb (N) b., total applied design shear force on an anchor bolt, lb (N) b,1 factored shear force in an anchor bolt, lb (N) bw width ofwall beam, in. (mm) cd deflection amplification factor e distance from the fiber of maximum compressive strain to the neutral axis, in. (mm) D dead load or related interna! moments and forces d distance from extreme compression fiber to centroid oftension reinforcement, in. (mm) db nominal diameter of reinforcement or anchor bolt, in. (mm) d,, actual depth of a member in direction of shear considered, in. (mm) E load effects of earthquake or related interna( moments and forces EAAc modulus of elasticity of AAC masonry in compression, psi (MPa) E bb modulus of elasticity of bounding beams, psi (MPa) Ebc modulus of elasticity of bounding columns, psi (MPa) COMMENTARY C-7
- 23. C-8 CODE Em modulus of elasticity of masonry in compression, psi (MPa) Eps modulus ofelasticity of prestressing steel, psi (MPa) Es modulus ofelasticity ofsteel, psi (MPa) Ev modulus ofrigidity (shear modulus) ofmasonry, psi (MPa) e eccentricity ofaxialload, in. (mm) eb projected leg extension of bent-bar anchor, measured from inside edge of anchor at bend to farthest point ofanchor in the plane ofthe hook, in. (mm) e11 eccentricity of P,1, in. (mm) F lateral pressure of liquids or related interna! moments and forces Fa allowable compressive stress available to resist axial load only, psi (MPa) Fb allowable compressive stress available to resist flexure only, psi (MPa) Fs allowable tensile or compressive stress m reinforcement, psi (MPa) Fv allowable shear stress, psi (MPa) Fvm allowable shear stress resisted by the masonry, psi (MPa) Fvs allowable shear stress resisted by the shear reinforcement, psi (MPa) fa calculated compressive stress in masonry due to axial load only, psi (MPa) Ji, calculated compressive stress in masonry due to flexure only, psi (MPa) f'AAc specified compressive strength of AAC masonry, psi (MPa) f'g specified compressive strength ofgrout, psi (MPa) f'm specified compressive strength of masonry, psi (MPa) f'm; specified compressive strength of masonry at the time ofprestress transfer, psi (MPa) fps stress in prestressing tendon at nominal strength, psi (MPa) /¡,11 specified tensile strength of prestressing tendon, psi (MPa) /¡,y specified yield strength of prestressing tendon, psi (MPa) f, modulus ofrupture, psi (MPa) TMS 402-11/AC1530-11/ASCE 5-11 COMMENTARY Pg.121
- 24. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY CODE frAAc modulus ofrupture ofAAC, psi (MPa) fs calculated tensile or compressive stress m reinforcement, psi (MPa) !se effective stress in prestressing tendon after all prestress losses have occurred, psi (MPa) .ftAAC splitting tensile strength of AAC as determined in accordance with ASTM Cl006, psi (MPa) f., calculated shear stress in masonry, psi (MPa) ¡;, specified yield strength of steel for reinforcement and anchors, psi (MPa) H h 1, j lateral pressure of soil or related interna) moments and forces effective height of column, wall, orpilaster, in. (mm) vertical dimension of infill, in. (mm) height of entire wall or of the segment of wall considered, in. (mm) moment of inertia of bounding beam for bending in the plane ofthe infill, in.4 (mm4 ) moment of inertia of bounding column for bending in the plane of the infill, in.4 (mm4 ) moment of inertia of cracked cross-sectional area ofa member, in.4 (mm4 ) effective moment ofinertia, in.4 (mm4 ) moment of inertia of gross cross-sectional area ofa member, in.4 (mm4 ) moment of inertia of net cross-sectional area of a member, in.4 (mm4 ) ratio of distance between centroid of flexura) compressive forces and centroid of tensile forces to depth, d K Dimension used to calculate reinforcement development, in. (mm) KAAc Dimension used to calculate reinforcement development for AAC masonry, in. (mm) kc coefficient ofcreep of masonry, per psi (MPa) ke coefficient of irreversible moisture expansion of clay masonry k111 coefficient of shrinkage of concrete masonry k, coefficient ofthermal expansion ofmasonry per degree Fahrenheit (degree Celsius) L live load or related interna) moments and forces COMMENTARY C-9
- 25. C-10 CODE clear span between supports, in. (mm) lb effective embedment length of headed or bent anchor bolts, in. (mm) lb• anchor bolt edge distance, in. (mm) /á development length or lap length of straight reinforcement, in. (mm) le equivalent embedment length provided by standard hooks measured from the start of the hook (point oftangency), in. (mm) leff effective span length for a deep beam, in. (mm) l;n¡ plan length of infill, in. (mm) lp clear span of the prestressed member in the direction ofthe prestressing tendon, in. (mm) 1.. length of entire wall or of the segment of wall considered in direction ofshear force, in. (mm) M maximum moment at the section under consideration, in.-lb (N-mm) Ma maximum moment in member due to the applied loading for which deflection is computed, in.-lb (N-mm) Me factored moment magnified for the effects of member curvature, in.-lb (N-mm) Mcr nominal cracking moment strength, in.-lb (N-mm) Mn nominal moment strength, in.-lb (N-mm) Mser service moment at midheight of a member, including P-delta effects, in.-lb (N-mm) M., factored moment, in.-lb (N-mm) n modular ratio, E/ Em N11 factored compressive force acting normal to shear surface that is associated with the v;, loading combination case under consideration, lb (N) Nv compressive force acting normal to shear surface, lb (N) P axial load, lb (N) Pa allowable axial compressive force m a reinforced member, lb (N) P, Euler buckling load, lb (N) Pn nominal axial strength, lb (N) Pps prestressing tendon force at time and location relevant for design, lb (N) P11 factored axial load, lb (N) P11 ¡ factored load from tributary floor or roof areas, lb (N) TMS 402-11/AC1530-11/ASCE 5-11 COMMENTARY
- 26. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY CODE P,.., factored weight of wall area tributary to wall section under consideration, lb (N) Q first moment about the neutral axis of an area between the extreme fiber and the plane at which the shear stress is being calculated, in.3 (mm 3 ) Q¡; the effect of horizontal seismic (earthquake- induced) forces q, ;11 ¡ nominal out-of-plane flexura( capacity of infill per unit area, psf(Pa) R response modification coefficient r radius ofgyration, in. (mm) S, section modulus of the net cross-sectional area ofa member, in.3 (mm3 ) s spacing of reinforcement, in. (mm) s1 total linear drying shrinkage of concrete masonry units determined in accordance with ASTM C426 T forces and moments caused by restraint of temperature, shrinkage, and creep strains or differential movements nominal thickness ofmember, in. (mm) 1;, ¡ specified thickness of infill, in. (mm) 1,.1 ;11 ¡ net thickness of infill, in. (mm) l sp specified thickness ofmember, in. (mm) v shear stress, psi (MPa) V shear force, lb (N) VnAAC = nominal shear strength provided by AAC masonry, lb (N) V, nominal shear strength, lb (N) V,,;,¡ nominal horizontal in-plane shear strength of infill, lb (N) V,,, nominal shear strength provided by masonry, lb (N) V,s nominal shear strength provided by shear reinforcement, lb (N) V,, factored shear force, lb (N) W wind loador related interna! moments and forces Ws dimension of the structural wall strip defined in Section 5.5. 1 and shown in Figure 5.5.1-1. WT dimension of the tributary length of wall, defined in Section 5.5.1 and shown in Figure 5.5.1-1. w ;11 ¡ width ofequivalent strut, in. (mm) COMMENTARY C-11
- 27. C-14 CODE Bonded prestressing tendon - Prestressing tendon that is encapsulated by prestressing grout in a corrugated duct that is bonded to the surrounding masomy through grouting. Bounding frame - The columns and upper and lower beams or slabs that surround masonry infill and provide structural support. Building ojjicial - The officer or other designated authority charged with the administration and enforcement of this Code, or the building official's duly authorized representative. Cavity wa/1 - A masonry wall consisting oftwo or more wythes, at least two of which are separated by a continuous air space; air space(s) between wythes may contain insulation; and separated wythes must be connected by wall ties. Collar joint - Vertical longitudinal space between wythes of masonry or between masonry wythe and back- up construction, which is permitted to be filled with mortar or grout. Column - An isolated vertical member whose horizontal dimension measured at right angles to its thickness does not exceed 3 times its thickness and whose height is greater than 4 times its thickness. Composite action - Transfer of stress between components ofa member designed so that in resisting loads, the combined components act together as a single member. Composite masonry - Multiwythe masonry members with wythes bonded to produce composite action. Compressive strength ofmasomy- Maxirnum compressive force resisted per unit of net cross-sectional area of masomy, determined by testing masomy prisms or a function of individual masomy units, mortar, and grout, in accordance with the provisions ofTMS 602/ACI 530.1/ASCE 6. Connector - A mechanical device for securing two or more pieces, parts, or members together, including anchors, wall ties, and fasteners. Contrae! documents - Documents establishing the required work, and including in particular, the project drawings and project specifications. Corbel - A projection of successive courses from the face ofmasonry. Cover, grout - thickness of grout surrounding the outer surface ofembedded reinforcement, anchor, or tie. Cover, masonry - thickness of masonry units, mortar, and grout surrounding the outer surface of embedded reinforcement, anchor, or tie. Cover, mortar - thickness of mortar surrounding the outer surface ofembedded reinforcement, anchor, or tie. TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY
- 28. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY CODE Deep beam - A beam that has an effective span-to- depth ratio, 1.¡/d,, less than 3 for a continuous span and less than 2 for a simple span. Depth - The dimension of a member measured in the plane ofa cross section perpendicular to the neutral axis. Design story drifi - The difference of deflections at the top and bottom of the story under consideration, calculated by multiplying the detlections determined from an elastic analysis by the appropriate deflection amplification factor, Cd, from ASCE 7. Design strength - The nominal strength of an element multiplied by the appropriate strength-reduction factor. Diaphragm - A roof or tloor system designed to transmit lateral forces to shear walls or other lateral-force- resisting elements. Dimension, nominal - The specified dimension plus an allowance for the joints with which the units are to be laid. Nominal dimensions are usually stated in whole numbers. Thickness is given first, followed by height and then length. Dimensions, specijied - Dimensions specified for the manufacture or construction ofa unit, joint, or element. Eflective height - Clear height of a braced member between lateral supports and used for calculating the slenderness ratio of a member. Effective height for unbraced members shall be calculated. Eflective prestress- Stress remaining in prestressing tendons after alllosses have occurred. Foundation pier- An isolated vertical foundation member whose horizontal dimension measured at right angles to its thickness does not exceed 3 times its thickness and whose height is equal to or less than 4 times its thickness. Glass unit masonry - Masonry composed ofglass units bonded by mortar. Grout - (1) A plastic mixture ofcementitious materials, aggregates, and water, with or without admixtures, initially produced to pouring consistency without segregation of the constituents during placement. (2) The hardened equivalent of such mixtures. Grout, seif-consolidating - A highly fluid and stable grout typically with admixtures, that remains homogeneous when placed and does not require puddling or vibration for consolidation. Head joint - Vertical mortar joint placed between masonry units within the wythe at the time the masonry units are laid. Header (bonder)- A masonry unit that connects two or more adjacent wythes ofmasonry. Jnfill - Masonry constructed within the plane of, and bounded by, a structural frame. COMMENTARY C-15
- 29. C-16 CODE Infill, non-participating - lnfill designed so that in- plane loads are not imparted to it from the bounding frame. lnjill, participating - lnfill designed to resist in-plane loads imparted to it by the bounding frame. Inspection, continuous - The lnspection Agency's full- time observation of work by being present in the area where the work is being performed. Inspection, periodic - The Inspection Agency's part- time or intermittent observation of work during construction by being present in the area where the work has been or is being performed, and observation upon completion ofthe work. Laterally restrained prestressing tendon - Prestressing tendon that is not free to move laterally within the cross section ofthe member. Laterally unrestrained prestressing tendon Prestressing tendon that is free to move laterally within the cross section ofthe member. Licensed design professional - An individual who is licensed to practice design as defmed by the statutory requirements ofthe professionallicensing laws ofthe state or jurisdiction in which the project is to be constructed and who is in responsible charge of the design; in other documents, also referred to as registereddesignprof essional. Load, dead - Dead weight supported by a member, as defined by the legally adopted building code. Load, live - Live load specified by the legally adopted building code. Load, service - Load specified by the legally adopted building code. Longitudinal reinforcement - Reinforcement placed parallel to the longitudinal axis ofthe member. Masonry breakout - Anchor failure defined by the separation of a volume ofmasonry, approximately conical in shape, from the member. Masonry unit, hollow - A masonry unit with net cross- sectional area of less than 75 percent of its gross cross- sectional area when measured in any plane parallel to the surface containing voids. Masonry unit, so/id - A masonry unit with net cross- sectional area of 75 percent or more of its gross cross- sectional area when measured in every plane parallel to the surface containing voids. Modulus ofelasticity- Ratio of normal stress to corres- ponding strain for tensile or compressive stresses below proportionallimit of material. Modulus ofrigidity - Ratio of unit shear stress to unit shear strain for unit shear stress below the proportional limit ofthe material. TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY Licensed design projessional - For convenience, the Commentary uses the term "designer" when referring to the licensed design professional.
- 30. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-17 CODE Nominal strength - The strength of an element or cross section calculated in accordance with the requirements and assumptions of the strength design methods of these provisions before application ofstrength-reduction factors. Pier - An isolated vertical member whose horizontal dimension measured at right angles to its thickness is not less than 3 times its thickness nor greater than 6 times its thickness and whose height is less than 5 times its length. Post-tensioning - Method of prestressing in which a prestressing tendon is tensioned after the masonry has been placed. Prestressed masonry - Masonry in which interna! compressive stresses have been introduced by prestressed tendons to counteract potential tensile stresses resulting from applied loads. Prestressing groti/ - A cementitious mixture used to encapsulate bonded prestressing tendons. Prestressing tendon - Steel elements such as wire, bar, or strand, used to impart prestress to masonry. Pretensioning - Method of prestressing in which a prestressing tendon is tensioned before the transfer of stress into the masonry. Prism - An assemblage of masonry units and mortar, with or without grout, used as a test specimen for determining properties ofthe masonry. Project drawings - The drawings that, along with the project specifications, complete the descriptive information for constructing the work required by the contract documents. Project specifications - The written documents that specify requirements for a project in accordance with the service parameters and other specific criteria established by the owner or the owner's agent. Quality assurance - The administrative and procedural requirements established by the contract documents to assure that constructed masonry is in compliance with the contract documents. Reinforcement - Nonprestressed steel reinforcement. Required strength - The strength needed to resist factored loads. Running bond- The placement of masonry units so that head joints in successive courses are horizontally offset at least one-quarter the unit length. Shear wall - A wall, bearing or nonbearing, designed to resist lateral forces acting in the plane of the wall (sometimes referred toas a vertical diaphragm). Shear wall, detailed plain (unreinforced) AAC masomy - An AAC masonry shear wall designed to resist lateral forces while neglecting stresses in reinforcement, although provided with mínimum reinforcement and connections. COMMENTARY Running bond - This Code concerns itself only with the structural effect ofthe masonry bond pattem. Therefore, the only distinction made by this Code is between masonry laid in running bond and masonry that is not laid in running bond. For purposes ofthis Code, architectural bond pattems that do not satisfy the Code definition of running bond are classified as not running bond.
- 31. C-18 CODE Shear wall, detailed plain (unreiriforced) masonry - A masonry shear wall designed to resist lateral forces while neglecting stresses in reinforcement, although provided with mínimum reinforcement and connections. Shew' wa/1, intermediate reiriforcedmasonry- A masonry shear wall designed to resist lateral forces while considering stresses in reinforcement and to satisfy specific mínimum reinforcement and connection requirements. Shear wall, intermediate reinforcedprestressed masonry - A prestressed masonry shear wall designed to resist lateral forces while considering stresses in reinforcement and to satisfy specific mínimum reinforcement and connection requirements. Shear wall, ordinary plain (unreiriforced) AAC masonry - An AAC masonry shear wall designed to resist lateral forces while neglecting stresses in reinforcement, if present. Shear wall, ordinary plain (unreinforced) masonry - A masonry shear wall designed to resist lateral forces while neglecting stresses in reinforcement, ifpresent. Shear wall, ordinary plain (unreinforced) prestressed masonry - A prestressed masonry shear wall designed to resist lateral forces while neglecting stresses in reinforcement, ifpresent. Shear wal/, ordinary reinforced AAC masonry - An AAC masonry shear wall designed to resist lateral forces while considering stresses in reinforcement and satisfying prescriptive reinforcement and connection requirements. Shear wall, ordinary reiriforced masonry - A masonry shear wall designed to resist lateral forces while considering stresses in reinforcement and satisfying prescriptive reinforcement and connection requirements. Shear wall, special reirif orced masonry - A masonry shear wall designed to resist lateral forces while considering stresses in reinforcement and to satisfy special reinforcement and connection requirements. Shear wall, special reinf orced prestressed masonry - A prestressed masonry shear wall designed to resist lateral forces while considering stresses in reinforcement and to satisfy special reinforcement and connection requirements. Slump jlow - The circular spread of plastic self- consolidating grout, which is evaluated in accordance with ASTM Cl61 1/Cl611M. Special boundary e/ements - In walls that are designed to resist in-plane load, end regions that are strengthened by reinforcement and are detailed to meet specific requirements, and may or may not be thicker than the wall. TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY Special boundary elements - Requirements for longitudinal and transverse reinforcement have not been established in general, and must be verified by testing. Research in this area is ongoing.
- 32. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY CODE Specified compressive strength ofAAC masonry, !'Me- Minimum compressive strength, expressed as force per unit of net cross-sectional area, required of the AAC masonry used in construction by the contract documents, and upon which the project design is based. Whenever the quantity f AAC is under the radical sign, the square root of numerical value only is intended and the result has units ofpsi (MPa). Specified compressive strength of masonry, f ', - Minimum compressive strength, expressed as force per unit of net cross-sectional area, required ofthe masonry used in construction by the contract documents, and upon which the project design is based. Whenever the quantityf ~. is under the radical sign, the square root of numerical value only is intended and the result has units ofpsi (MPa). Stirrup - Reinforcement used to resist shear in a flexura( member. Stone masonry- Masonry composed of field, quarried, or cast stone units bonded by mortar. Stone masonry, ash/ar - Stone masonry composed of rectangular units having sawed, dressed, or squared bed surfaces and bonded by mortar. Stone masonry, rubble - Stone masonry composed of irregular-shaped units bonded by mortar. Strength-reduction factor, rjJ - Thc factor by which thc nominal strength is multiplied to obtain the design strength. Tendon anchorage- In post-tensioning, a device used to anchor the prestressing tendon to the masonry or concrete member; in pretensioning, a device used to anchor the prestressing tendon during hardening of masonry mortar, grout, prestressing grout, or concrete. Tendon coupler - A device for connecting two tendon ends, thereby transferring the prestressing force from end to end. Tendon jacking force - Temporary force exerted by a device that introduces tension into prestressing tendons. Thin-bed mortar - Mortar for use in construction ofAAC unit masonry whose joints are 0.06 in. (1.5 mm) or less. Tie, lateral - Loop of reinforcing bar or wire enclosing longitudinal reinforcement. Tie, wall - Metal connector that connects wythes of masonry walls together. Transfer - Act of applying to the masonry member the force in the prestressing tendons. Transverse reinforcement - Reinforcement placed perpendicular to the longitudinal axis ofthe member. Unbonded prestressing tendon - Prestressing tendon that is not bonded to masonry. COMMENTARY C-19
- 33. C-20 CODE Unreinforced (plain) masomy - Masoruy in which the tensile resistance of masomy is taken into consideration and the resistance ofthe reinforcing steel, ifpresent, is neglected. Veneer, adhered - Masonry veneer secured to and supported by the backing through adhesion. Veneer, anchored - Masonry veneer secured to and supported laterally by the backing through anchors and supported vertically by the foundation or other structural elements. Veneer, masonry - A masonry wythe that provides the exterior finish of a wall sys~e m and transfers out-of-plane load directly to a backing, but is not considered to add - strength or stiffness to the wall system. Visual stability index (VSJ) - An index, defined in ASTM Cl611/Cl611M, that qualitatively indicates the stability ofself-consolidating grout Wall- A vertical element with a horizontal length to thickness ratio greater than 3, used to enelose space. Wall, load-bearing - Wall supporting vertical loads greater than 200 lb/lineal ft (2919 N/m) in addition to its own weight. Wall, masonry bonded hollow - A multiwythe wall built with masonry units arranged to provide an air space between the wythes and with the wythes bonded together with masonry units. Width - The dimension of a member measured in the plane ofa cross section parallel to the neutral axis. Wythe - Each continuous vertical section of a wall, one masonry unit in thickness. 1.7- Loading 1.7.1 General Masonry shall be designed to resist applicable loads. A continuous load path or paths, with adequate strength and stiffness, shall be provided to transfer forces from the point of application to the final point ofresistance. l.7.2 Loadprovisions Design loads shall be in accordance with the legally adopted building code ofwhich this Code forms a part, with such live load reductions as are permitted in the legally adopted building code. In the absence of design loads in the legally adopted building code, the load provisions of ASCE 7 shall be used, except as noted in this Code. TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY 1.7- Loading The provisions establish design load requirements. If the design loads specified by the legally adopted building code differ from those of ASCE 7, the legally adopted building code govems. The designer may decide to use the more stringent requirements. 1.7.1 General 1.7.2 Loadprovisions
- 34. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-21 CODE 1.7.3 Latera/loadresistance Buildings shall be provided with a structural system designed to resist wind and earthquake loads and to accommodate the effect ofthe resulting deformations. 1.7.4 Load transfer at horizontal connections 1.7.4.1 Walls, columns, and pilasters shall be designed to resist loads, moments, and shears applied at intersections with horizontal members. 1.7.4.2 Effect of lateral deflection and translation ofmembers providing lateral support shall be considered. 1.7.4.3 Devices used for transferring lateral support from members that intersect walls, columns, or pilasters shall be designed to resist the forces involved. 1.7.5 Other effects Consideration shall be given to effects of forces and deformations due to prestressing, vibrations, impact, shrinkage, expansion, temperature changes, creep, unequal settlement ofsupports, and differential movement. 1.7.6 Latera/loaddistribution Lateral loads shall be distributed to the structural system in accordance with member stiffnesses and shall comply with the requirements ofthis section. l.7.6.1 Flanges of intersecting walls designed in accordance with Section 1.9.4.2 shall be included in stiffness determination. 1.7.6.2 Distribution of load shall be consistent with the forces resisted by foundations. 1.7.6.3 Distribution of load shall include the effect of horizontal torsion of the structure due to eccentricity of wind or seismic loads resulting from the non-uniform distribution of mass. COMMENTARY 1.7.3 Latera/loadresistance Lateral load resistance must be provided by a braced structural system. Partitions, infill panels, and similar elements may not be a part of the lateral-force-resisting system if isolated. However, when they resist lateral forces dueto their rigidity, they should be considered in analysis. 1.7.4 Load transfer at horizontal connections Masonry walls, pilasters, and columns may be connected to horizontal elements ofthe structure and may rely on the latter for lateral support and stability. The mechanism through which the interconnecting forces are transmitted may involve bond, mechanical anchorage, friction, bearing, or a combination thereof. The designer must assure that, regardless of the type of connection, the interacting forces are safely resisted. In flexible frame construction, the relative movement (drift) between floors may generate forces within the members and the connections. This Code requires the effects ofthese movements to be considered in design. l.7.5 Other effects Service loads are not the sole source of stresses. The structure must also resist forces from the sources listed. The nature and extent of sorne of these forces may be greatly influenced by the choice of materials, structural connections, and geometric configuration. 1.7.6 Latera/load distribution The design assumptions for masonry buildings include the use of a lateral-force-resisting system. The distribution of lateral loads to the members of the lateral-force-resisting system is a function ofthe rigidities of the structural system and of the horizontal diaphragms. The method ofconnection at intersecting walls and between walls and floor and roof diaphragms determines if the wall participates in the lateral- force-resisting system. Lateral loads from wind and seismic forces are normally considered to act in the direction of the principal axes ofthe structure. Lateralloads may cause forces in walls both perpendicular and parallel to the direction ofthe load. Horizontal torsion can be developed due to eccentricity ofthe applied load with respect to the center ofrigidity. The analysis of lateral load distribution should be in accordance with accepted engineering procedures. The analysis should rationally consider the effects of openings in shear walls and whether the masonry above the openings allows them to act as coupled shear walls. See Figure CC- 1.7-1. The interaction of coupled shear walls is complex and further information may be obtained from Reference 1.4. Computation of the stiffuess of shear walls should consider shearing and flexura! deformations. A guide for solid shear walls (that is, with no openings) is given in Figure CC-1.7-2. For nongrouted hollow unit shear walls, the use of equivalent solid thickness ofwall in computing web stiffuess is acceptable.
- 35. C-22 TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY ElevationofCoupled ShearWall Elevation ofNoncoupled ShearWall Figure CC-1. 7-1 - Coup/ed and noncoupledshear wal/s hld<0.25 (a) Shear Stiffness Predominales CODE t- d----1 1 0.25 S h/d S 4.0 (b) Both ShearStiffness and Bending Stiffness are Importan! h J Figure CC-1.7-2 - Shear wa/1 stiffness hld>4 (e) Bending Stiffness Predominates COMMENTARY 1.8- Material properties 1.8 - Material properties 1.8.1 General 1.8.1 General Unless otherwise determined by test, the following moduli and coefficients shall be used in determining the effects of elasticity, temperature, moisture expansion, shrinkage, and creep. Proper evaluation of the building material movement from all sources is an important element of masonry design. Clay masonry and concrete masonry may behave quite differently under normal loading and weather conditions. The committee has extensively studied available research information in the development ofthese material properties. However, the Committee recognizes the need for further research on this subject. The designer is encouraged to review industry standards for further design information and movement joint locations. Material properties can be determined by appropriate tests of the materials to be used.
- 36. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-23 CODE 1.8.2 Elastic moduli 1.8.2.1 Steel reinforcement - Modu1us of e1 asticity of stee1 reinforcement shall be taken as: E.= 29,000,000 psi (200,000 MPa) 1.8.2.2 C/ay and concrete masonry 1.8.2.2.1 The design of clay and concrete masonry shall be based on the following modu1us of e1 asticity values: Em =700 f'm for elay masonry; E., =900 f'm for concrete masonry; or the chord modulus of elasticity taken between 0.05 and 0.33 of the maximum compressive strength of each prism deterrnined by test in accordance with the prism test method, Article 1.4 B.3 ofTMS 602/ACI 530.1/ASCE 6, and ASTM E1 11. 1.8.2.2.2 Modulus of rigidity of clay masonry and concrete masonry shall be taken as: Ev =0.4Em 1.8.2.3 AAC masonry 1.8.2.3.1 Modulus of elasticity of AAC masonry shall be taken as: EAAc- 6500 (f'AAc )06 1.8.2.3.2 Modulus of rigidity of AAC masonry shall be taken as: Ev= 0.4 EAAc 1.8.2.4 Grout - Modulus of elasticity of grout shall be taken as 500/'g- COMMENTARY 1.8.2 Elastic moduli Modulus of elasticity for clay and concrete masonry has traditionally been taken as 1000 f '., in previous masonry codes. Researchu. 1. 6 has indicated, however, that there is a large variation in the relationship of elastic modulus versus compressive strength of masonry, and that lower values may be more typical. However, differences in procedures between one research investigation and another may account for much of the indicated variation. Furthermore, the type of elastic moduli being reported (for example, secant modulus, tangent modu1us, or chord modulus) is not a1ways identified. The committee decided the most appropriate e1astic modu1us for allowab1e-stress design purposes is the s1ope ofthe stress-strain curve below a stress va1ue of 0.33/ ~ •. The va1ue of 0.33/~. was originally chosen because it was the allowab1e compressive stress prior to the 2011 Code. The committee did not see the need to change the modu1us with the increase in allowab1e compressive stress to 0.45f ~ in the 20ll Code because previous code editions a1so allowed the allowable compressive stress to be increased by one-third for load combinations including wind or seismic 1 oads and the allowab1e moment capacity using allowable stress design is not significantly affected by the va1ue of the masonry modu1us of elasticity. Data at the bottom of the stress strain curve may be questionab1e due to the seating effect of the specimen during the initia1 1oading phase if measurements are made on the testing machine platens. The committee therefore decided that the most appropriate elastic modulus for design purposes is the chord modulus from a stress va1ue of 5 to 33 percent of the compressive strength of masonry (see Figure CC-1.8-1). The terrns chord modulus and secant modulus have been used interchangeably in the past. The chord modulus, as used here, is defmed as the s1ope of a line intersecting the stress-strain curve at two points, neither ofwhich is the origin ofthe curve. For clay and concrete masonry, the elastic modulus is deterrnined as a function of masonry compressive strength using the re1 ations developed from an extensive survey of modu1us data by Wolde-Tinsae et al.u and results ofa test program by Colville et al1.6 . Code values for Em are higher than indicated by a best fit of data relating Em to the compressive strength of masonry. The higher Code va1ues are based on the fact that actual compressive strength significantly exceeds the specified compressive strength of masonry,f ~., particularly for elay masonry. By using the Code values, the contribution of each wythe to composite action is more accurately accounted for in design ca1cu1ations than wou1d be the case if the e1astic modulus of each part of a composite wall were based on one specified compressive strength of masonry.
- 37. C-24 CODE TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY Compressive Strength Strain Compressive Strength Compressive Stren th Figure CC-1.8-1 - Chord modulus ofelasticity The modulus ofelasticity ofautoclaved aerated concrete (AAC) masonry depends almost entirely on the modulus of elasticity of the AAC material itself. The relationship between modulus of elasticity and compressive strength is given in References 8.3 and 8.4. The modulus of elasticity of a grouted assemblage of clay or concrete masonry can usually be taken as a factor multiplied by the specified compressive strength, regardless of the extent of grouting, because the modulus of elasticity ofthe grout is usually close to that ofthe clay or concrete masonry. However, grout is usually much stiffer than the AAC material. While it is permissible and conservative to compute the modulus of elasticity of a grouted assemblage of AAC masonry assuming that the modulus ofelasticity ofthe grout is the same as that ofthe AAC material, it is also possible to recognize the greater modulus of elasticity of the grout by transforming the cross-sectional area of grout into an equivalent cross- sectional area of AAC, using the modular ratio between the two materials. Because the inelastic stress-strain behavior ofgrout is generally similar to that of clay or concrete masonry, calculations of element resistance (whether based on allowable-stress or strength design) usually neglect possible differences in strength between grout and the surrounding masonry. For the same reasons noted above, the stress-strain behavior of grout usually differs considerably from that of the surrounding AAC material. lt is possible that these differences in stress-strain behavior could also be considered in computing element resistances. Research is ongoing to resolve this issue. The relationship between the modulus ofrigidity and the modulus of elasticity has historically been given as 0.4 Em. No experimental evidence exists to support this relationship.
- 38. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-25 CODE 1.8.3 Coefficients ofthermal expansion 1.8.3.1 Clay masomy k1 =4 x 10-6 in./in./°F (7.2 x 10-6 mm/mm/0 C) 1.8.3.2 Concrete masonry k¡ =4.5 X 10'6 in.fin./ 0 f (8.1 X J0'6 mm/mm/0 C) 1.8.3.3 AAC masonry k1 = 4.5 x 10'6 in./in./ °F (8.1 x 10'6 mm/mm/0 C) 1.8.4 Coefficientofmoisture expansionforclaymasomy k.= 3 x 10"4 in./in. (3 x 10-4 mm/mm) 1.8.5 Coefficients ofshrinkage 1.8.5.1 Concrete masonry km = 0.5 S¡ 1.8.5.2 AAC masonry km =0.8 E:c) l 00 where &es is determined m accordance with ASTM C1386. 1.8.6 Coefficients ofcreep 1.8.6.1 Clay masonry kc=0.7 x 10·7 , per psi (0.1 x 10" per MPa) 1.8.6.2 Concrete masonry kc= 2.5 x 10·7 , per psi (0.36 x 10-4, per MPa) 1.8.6.3 AAC masonry kc= 5.0 x 10·7 , per psi (0.72 x 10-4, per MPa) COMMENTARY 1.8.3 Coefficients oftherma/ expansion Temperature changes cause material expansion and contraction. This material movement is theoretically reversible. These thermal expansion coefficients are slightly higher than mean values for the assemblageu· Ls. ¡_9. Thermal expansion for concrete masonry varíes with aggregate type1.7 • LIO_ Thermal expansion coefficients are given for AAC masonry in Reference 1.11. 1.8.4 Coefficient ofmoisture expansionfor clay masonry Fired clay products expand upon contact with moisture and the material does not return to its original size upon dryingLs, ¡_ 9 • This is a long-term expansion as clay particles react with atmospheric moisture. Continued moisture expansion of clay masonry units has been reported for 7Vz years1.12 . Moisture expansion is not a design consideration for concrete masonry. 1.8.5 Coefficients ofshrinkage 1.8.5.1 Concrete masonry - Concrete masonry is a cement-based material that shrinks due to moisture loss and carbonation1.1°. The total linear drying shrinkage is determined in accordance with ASTM C426. The maximum shrinkage allowed by ASTM specifications for concrete masonry units (for example, ASTM C90), other than calcium silicate units, is 0.065%. Further design guidance for estimating the shrinkage due to moisture loss and carbonation is available1 13 • 1.14 • us. The shrinkage of clay masonry is negligible. 1.8.5.2 AAC masonry- At time of production, AAC masonry typically has a moisture content of about 30%. That value typically decreases to 15% or less within two to three months, regardless of ambient relative humidity. This process can take place during construction or prior to delivery. ASTM C1386 evaluates AAC material characteristics at moisture contents between 5% and 15%, a range that typifies AAC in service. The shrinkage coefficient of this section reflects the change in strain likely to be encountered within the extremes of moisture content typically encountered in service. 1.8.6 Coefficients ofcreep When continuously stressed, these materials gradually deform in the direction ofstress application. This movement is referred to as creep and is load and time dependentuo, 1.16 • 1.11 • The values given are maximum values.
- 39. C-26 CODE 1.8.7 Prestressing steel Modulus of elasticity shall be determined by tests. For prestressing steels not specifically listed in ASTM A416/A416M, A421/A421M, or A722/A722M, tensile strength and relaxation losses shall be determined by tests. 1.9 - Section properties 1.9.1 Stress computations 1.9.1.1 Members shall be designed using section properties based on the m1mmum net cross- sectional area of the member under consideration. Section properties shall be based on specified dimensions. 1.9.1.2 In members designed for composite action, stresses shall be computed using section properties based on the mínimum transformed net cross-sectional area of the composite member. The transformed area concept for elastic analysis, in which areas of dissimilar materials are transformed in accordance with relative elastic moduli ratios, shall apply. TMS 402-1 1/ACI530-11/ASCE 5-11 COMMENTARY 1.8.7 Prestressing steel The material and section properties of prestressing steels may vary with each manufacturer. Most significant for design are the prestressing tendon's cross section, modulus of elasticity, tensile strength, and stress-relaxation properties. Values for these properties for various manufacturers' wire, strand, and bar systems are given elsewhere117 . The modulus ofelasticity ofprestressing steel is often taken egua] to 28,000 ksi (193,000 MPa) for design, but can vary and should be verified by the manufacturer. Stress-strain characteristics and stress-relaxation properties of prestressing steels must be determined by test, because these properties may vary between different steel forros (bar, wire, or strand) and types (mild, high strength, or stainless). 1.9 - Section properties 1.9.1 Stress computations Mínimum net section is often difficult to establish in hollow unit masonry. The designer may choose to use the mínimum thickness of the face shells of the units as the mínimum net section. The mínimum net section may not be the same in the vertical and horizontal directions. For masonry of hollow units, the mínimum cross- sectional area in both directions may conservatively be based on the mínimum face-shell thicknessu8 . Salid clay masonry units are permitted to have coring up to a maximum of 25 percent of their gross cross- sectional area. For such units, the net cross-sectional area may be taken as egua! to the gross cross-sectional area, except as provided in Section 2.1.5.2.2(c) for masonry headers. Severa! conditions of net area are shown in Figure CC-1.9-1. Sínce the elastic properties of the materials used in members designed for composite action differ, egua! strains produce different levels of stresses in the components. To compute these stresses, a convenient transformed section with respect to the axis of resistance is considered. The resulting stresses developed in each fiber are related to the actual stresses by the ratio E1 1 Ex between the moduli of elasticíty of the most deformable material in the member and of the materials in the fiber considered. Thus, to obtain the transformed section, fibers of the actual section are conceptually widened by the ratio ExiE1 • Stresses computed based on the section properties of the transformed section, with respect to the axis of resistance considered, are then multiplied by ExiE1 to obtain actual stresses.
- 40. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-27 COMMENTARY Brick Morethan 75% Solid NetAreaEquals GrossArea Hollow Unit Full Mortar Bedding (RequiresAiignment ofCrosswebs) Hollow Unit Face Shell MortarBed ding Figure CC-1.9-1 - Net cross-sectional areas CODE 1.9.2 Stiffness Computation of stiffuess based on uncracked section is pennissible. Use ofthe average net cross-sectional area ofthe member considered in stiffuess computations is pennitted. 1.9.3 Radius ofgyration Radius of gyration shall be computed using average net cross-sectional area ofthe member considered. COMMENTARY 1.9.2 Stiffness Stiffuess is a function of the extent of cracking. The Code equations for design in Section 2.2, however, are based on the member's uncracked moment of inertia. Also, since the extent of tension cracking in shear walls is not known in advance, this Code allows the detennination of stiffuess to be based on uncracked section properties. For reinforced masonry, more accurate estimates may result if stiffness approximations are based on the cracked section. The section properties ofmasonry members may vary from point to point. For example, in a single-wythe concrete masonry wall made of hollow ungrouted units, the cross-sectional area varies through the unit height. Also, the distribution ofmaterial varies along the length of the wall or unit. For stiffness computations, an average value of the appropriate section property (cross-sectional area or moment of inertia) is considered adequate for design. The average net cross-sectional area of the member would in tum be based on average net cross- sectional area values of the masonry units and the mortar joints composing the member. 1.9.3 Radius ofgyration The radius of gyration is the square root of the ratio of bending moment of inertia to cross-sectional area. Since stiffness is based on the average net cross-sectional area of the member considered, this same area should be used in the computation ofradius ofgyration.
- 41. C-28 CODE 1.9.4 lntersecting walls 1.9.4.1 Wall intersections shall meet one of the following requirements: (a) Design shall conform to the provisions ofSection 1.9.4.2. (b) Transfer of shear between walls shall be prevented. 1.9.4.2 Design ofwall intersection 1.9.4.2.1 Masonry shall be in running bond. 1.9.4.2.2 Flanges shall be considered effective in resisting applied loads. 1.9.4.2.3 The width of fiange considered effective on each side of the web shall be the smaller of the actual fiange on either side of the web wall or the following: (a) 6 multiplied by the nominal flange thickness for unreinforced and reinforced masonry, when the flange is in compression (b) 6 multiplied by the nominal fiange thickness for unreinforced masonry, when the fiange is in flexura! tension (e) 0.75 multiplied by the fioor-to-floor wall height for reinforced masonry, when the flange is in flexura! tension. The effective fiange width shall not extend past a movement joint. 1.9.4.2.4 Design for shear, including the transfer of shear at interfaces, shall conform to the requirements of Section 2.2.5; or Section 2.3.6; or Sections 3.1.3 and 3.3.4.1.2; or Sections 3.1.3 and 3.2.4; or Section 4.6; or Section 8.1.3 and 8.3.4.1.2. 1.9.4.2.5 The connection of intersecting walls shall conform to one ofthe following requirements: (a) At least fifty percent of the masonry units at the interface shall interlock. (b) Walls shall be anchored by steel connectors grouted into the wall and meeting the following requirements: (1) Minimum size: 1 / 4 in. x 11 / 2 in. x 28 in. (6.4 mm x 38.1 mm x 711 mm) including 2-in. (50.8-mm) long, 90-degree bend at each end to form a U or Z shape. (2) Maximum spacing: 48 in. (1219 mm). (e) lntersecting reinforced bond beams shall be provided at a maximum spacing of 48 in. (1219 mm) on center. The area of reinforcement in each bond beam shall not be less than 0.1 in.2 per ft (2 11 mm2 /m) multiplied by the vertical spacing ofthe bond beams in feet (meters). Reinforcement shall be developed on each side ofthe intersection. TMS 402-11/ACI530-11/ASCE 5-11 COMMENTARY 1.9.4 lntersecting walls Connections of webs to flanges of walls may be accomplished by running bond, metal connectors, or bond beams. Achieving stress transfer at a T intersection with running bond only is difficult. A running bond connection should be as shown in Figure CC-1.9-2 with a "T" geometry over their intersection. The alternate method, using metal strap connectors, is shown in Figure CC-1.9-3. Bond beams, shown in Figure CC-1.9-4, are the third means of connecting webs to flanges. When the flanges are connected at the intersection, they are required to be included in the design. The effective width ofthe flange for compression and unreinforced masonry in flexura] tension is based on shear-lag effects and is a traditiona1 requirement. The effective width of the flange for reinforced masonry in flexura] tension is based on the experimental and analytical work ofHe and Priest1eyu9 • They showed that the shear-lag effects are significant for uncracked walls, but become less severe after cracking. He and Priestleyl.l9 proposed that the effective width of the flange be determined as: ¡ 11 1,1 = o.75h +0.511 2.5h 11 1h 5, 1.5 1.5 < 11 1h 5, 3.5 11 1h > 3.5 where l.r is the effective flange width, Ir is the width of the flange, and h is height of the wall. These equations can result in effective flange widths greater than 1.5 times the height ofthe wall. However, a limit ofthe effective flange width of 1.5 times the wall height, or :Y. of the wall height on either side of the web, is provided in the code. This limit was chosen since the testing by He and Priestleyu9 was limited to a flange width of 1.4 times the wall height. Designers are cautioned that longitudinal reinforcement just outside the effective flange width specified by the code can affect the ductility and behavior of the wall. Any participation by the reinforcement in resisting the load can lead to other, more brittle, failure modes such as shear or crushing ofthe compression toe.
- 42. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-29 COMMENTARY ShearWall Figure CC-1.9-2 - Running bond lap at intersection '1'-1 S" rt'rt') "() 1{rt'1 1 ,.!. '2.(· ~ 1J1i :¡A(·~10 n. (Je 'htr¡ Metal Strap Connector Y. in. Thick (6.4 mm) Mínimum Dimensions Metal Straps al 4ft (1.2 m) o.c. Vert. Grouted Cells '-"'V'J Flange ~ ShearWall Sectional Elevation Figure CC-1.9-3 - Metal straps andgrouting at wall intersections CODE 1.9.5 Bearing area The bearing area, Abr, for concentrated loads shall not exceed the following: (a) A¡ ~ A2l A¡ (b) 2A1 The area, A2• is the area of the lower base of the largest frustum of a right pyramid or cone that has the loaded area, A 1• as its upper base, slopes at 45 degrees from the horizontal, and is wholly contained within the support. For walls not laid in running bond, area A2 shall terminate at head joints. COMMENTARY 1.9.5 Bearing area When the supporting masonry area, A 2, is larger on all sides than the loaded area, A 1, this Code allows distribution of concentrated loads over a bearing area Abn larger than A1 • The area A2 is determined as illustrated in Figure CC-1.9-5. This is permissible because the confinement of the bearing area by surrounding masonry increases the bearing capacity of the masonry under the concentrated loads. When the edge of the loaded area, A¡, coincides with the face or edge ofthe masonry, the area A2 is equal to the loaded area A1•
- 43. C-30 l Plan COMMENTARY TMS 402-11/ACI 530-11/ASCE 5-11 Reinforcement in accordance with Code Section 1.9.4.2.5(c) Either open cell bond beam units or solid bottom lintel units may be used. Figure CC-1.9-4 - Bond beam al wa/1 intersection Loaded Area, A1 This Perimeter of Area A2 is Geometrically similar to and Concentric with the Loaded Area, A1 Section A-A Figure CC-1.9-5 - Bearing areas 45 Degrees A2 is Measured on this Plane
- 44. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-31 CODE 1.9.6 Eflective compressive width per bar 1.9.6.1 For masonry not laid in running bond and having bond beams spaced not more than 48 in. ( 12 19 ·mm) center-to-center, and for masonry laid in running bond, the width of the compression area used to calculate element capacity shall not exceed the least of: (a) Center-to-center bar spacing. (b) Six multiplied by the nominal wall thickness. (e) 72 in. ( 1829 mm). 1.9.6.2 For masonry not laid in running bond and having bond beams spaced more than 48 in. ( 1219 mm) center-to-center, the width of the compression area used to calculate element capacity shall not exceed the length ofthe masonry unit. COMMENTARY 1.9.6 Effective compressive width per bar The effective width of the compressive area for each reinforcing bar must be established. Figure CC-1.9-6 depicts the limits for the conditions stated. Limited research l.20 is available on this subject. The limited ability of head joints to transfer stress when masonry is not laid in running bond is recognized by the requirements for bond beams. Open end masonry units that are fully grouted are assumed to transfer stress as indicated in Section 2.2.5.2(d), as for running bond. The center-to-center bar spacing maximum is a limit to keep from overlapping areas of compressive stress. The 72-in. (1829-mm) maximum is an empirical choice ofthe committee. ' Jii5 ·:·.·:.: S i i : J : : ··.·:. ·:.·.· .. . .. ...... - ......·:·~·:·:.. ......·.~ .... L ·.··.·..·....... ·.............. ~ Length of Unit ----1 For masonry not laid in running bond with bond beams spaced less than or equal to 48 in. (1219 mm) and running bond masonry, b equals the lesser of: b=s b =6t b =72 in. (1829 mm) For masonry not laid in running bond with bond beams spaced greater than 48 in. (1219 mm), b equals the lesser of: b=s b =length of unit Figure CC-1.9-6- Width ofcompression area
- 45. C-32 CODE 1.9.7 Concentrated loads 1.9.7.1 Concentrated loads shall not be distributed over a length greaterthan the mínimum ofthe following: (a) The length of bearing area plus the length determined by considering the concentrated load to be dispersed along a 2 vertical: 1 horizontal Iine. The dispersion shall termínate at half the wall height, a movement joint, the end of the wall, or an opening, whichever provides the smallest length. (b) The center-to-centerdistance between concentrated loads. 1.9.7.2 For walls not laid in running bond, concentrated loads shall not be distributed across head joints. Where concentrated loads acting on such walls are applied to a bond beam, the concentrated load is permitted to be distributed through the bond beam, but shall not be distributed across headjoints below the bond beams. TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY 1.9.7 Concentrated loads Reference 1.21 reports the results of tests of a wide variety of specimens under concentrated loads, including AAC masonry, concrete block masonry, and clay brick masonry specimens. Reference 1.21 suggests that a concentrated load can be distributed at a 2:1 slope, terminating at half the wall height, where the wall height is from the point of application of the load to the foundation. Tests on the load dispersion through a bond beam on top of hollow masonry reported in Reference 1.22 resulted in an angle from the horizontal of 59° for a 1-course CMU bond beam, 65° for a 2-course CMU bond beam, and 58° for a 2-course clay bond beam, or approximately a 2: 1 slope. For simplicity in design, a 2:1 slope is used for all cases of load dispersion of a concentrated load. Code provisions are illustrated in Figure CC-1.9-7. Figure CC-1.9-7a illustrates the dispersion of a concentrated load through a bond beam. A hollow wall would be checked for bearing under the bond beam using the effective length. Figure CC-1.9-7b illustrates the dispersion ofa concentrated load in the wall. The effective length would be used for checking the wall under the axial force. A wall may have to be checked at severa! locations, such as under a bond beam and at midheight.
- 46. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY COMMENTARY Check bearing on hollowwall Load is Bond Beam 4+---+- dispersed-+---+• t--r-L-w--,--.__...,.._.__...,.....--J.__""T""--1 at a 2:1 t---h--1----11--"r""ll-----! 1 1 1 1 1 1 1 1 1 Running bond slope Load dispersion terminales at head joints for masonry not laid in running bond Not laid in running bond (a) Distribution of concentrated load through bond beam Load Load 1 Load J ,..J l l 1 rlWfl ~2 f~ 1 l ~1 r 11 _l l '1 1 1 1 1 1 l 1 1 l 1 1 1 1 1 1 1 1 l 1 1 1 1 1 ..Effective Length Effective Effective Length Length 1' ' Load Load ~ ·'....1.. 1~ ,2 1 ,L,1 r 1~ t-2 l ~ ~1 l 1 1 l 1 1 _l 1 1 1 1 Effective Effective ., Length Length (b) Distribution of concentrated load in wall Figure CC-1.9-7. Distribution ofconcentrated /oads 1 C-33 1 1
- 47. C-34 CODE 1.1O- Connection to structural trames Masonry walls shall not be connected to structural frames unless the connections and walls are designed to resist design interconnecting forces and to accommodate calculated detlections. TMS 402·11IACI 530-111ASCE 5-11 COMMENTARY 1.10 -Connection to structural trames Exterior masonry walls connected to structural frames are used primarily as nonbearing curtain walls. Regardless of the structural system used for support, there are differential movements between the structure and the wall. These differential movements may occur separately or in combination and may be due to the following: 1) Temperature increase or decrease of either the structural frame or the masonry wall. 2) Moisture and freezing expansion of brick or shrinkage ofconcrete block walls. 3) Elastic shortening of columns from axial loads, shrinkage, or creep. 4) Detlection ofsupporting beams. 5) Sidesway in multiple-story buildings. 6) Foundation movement. Since the tensile strength of masonry is low, these differential movements must be accommodated by sufficient clearance between the frame and masonry and flexible or slip-type connections. Structural frames and bracing should not be infilled with masonry to increase resistance to in-plane lateral forces without considering the differential movements listed above. Wood, steel, or concrete columns may be surrounded by masonry serving as a decorative element. Masonry walls may be subject to forces as a result of their interaction with other structural components. Since the masonry element is often much stiffer, the load will be carried primarily by the masonry. These forces, if transmitted to the surrounding masonry, should not exceed the allowable stresses of the masonry. Altemately, there should be sufficient clearance between the frame and masonry. Flexible ties should be used to allow for the deformations. Beams or trusses supporting masonry walls are essentially embedded, and their detlections should be limited to the allowable deflections for the masonry being supported. See Section 1.13.1.4 for requirements.
- 48. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-35 CODE 1.11- Masonry not laid in running bond For masonry not laid in running bond, the minimum area of horizontal reinforcement shall be 0.00028 multiplied by the gross vertical cross-sectional area of the wall using specified dimensions. Horizontal reinforcement shall be placed at a maximum spacing of 48 in. (1219 mm) on center in horizontal mortarjoints or in bond beams. Typical Running Bond Brick Units Overlap COMMENTARY 1.11 - Masonry not laid in running bond The requirements for masonry laid in running bond are shown in Figure CC-1.11-1. The amount of horizontal reinforcement required in masonry not laid in running bond is a prescriptive amount to provide continuity across the head joints. Because lateral loads are reversible, reinforcement should either be centered in the element thickness by placement in the center of a bond beam, or should be symmetrically located by placing multiple bars in a bond beam or by using joint reinforcement in the mortar bed along each face shell. This reinforcement can be also used to resist load. Although continuity across head joints in masonry not laid in running bond is a concern for AAC masonry as well as masonry of elay or concrete, the use of horizontal reinforcement to enhance continuity in AAC masonry is generally practica( only by the use ofbond beams. 1 Typical Running Bond Concrete Masonry Units 1 - · Umt Length - - f- Masonry is considered to be laid in running bond when units overlap a mínimum of Y. of the unit length 1/4 Unit Overlap Figure CC-1.11-1 - Running bond masonry
- 49. C-36 CODE 1.12- Corbels 1.12.1 Load-bearing corbels Load-bearing corbels shall be designed in accordance with Chapter 2, 3 or 4. 1.12.2 Non-load-bearing corbels Non-load-bearing corbels shall be designed in accordance with Chapter 2, 3 or 4 or detailed as follows: (a) Solid masonry units or hollow units filled with mortar or grout shall be used. (b) The maximum projection beyond the face of the wall shall not exceed: (1) one-half the wall thickness for multiwythe walls bonded by mortar or grout and wall ties or masonry headers, or (2) one-half the wythe thickness for single wythe walls, masonry bonded hollow walls, multiwythe walls with open collarjoints, and veneer walls. (e) The maximum projection ofone unit shall not exceed: (1) one-halfthe nominal unit height. (2) one-third the nominal thickness of the unit or wythe. (d) The back surface of the corbelled section shall remain within 1 in. (25.4 mm) ofplane. TMS 402-11/ACISJ0-11/ASCE 5-11 COMMENTARY 1.12- Corbels The provision for corbelling up to one-halfofthe wall or wythe thickness is theoretically valid only if the opposite side of the wall remains in its same plane. The addition of the 1-in. (25.4-mm) intrusion into the plane recognizes the impracticality of keeping the back surface plane. See Figure CC-1.12-1 and CC-1.12-2 for maximum permissible unit projection.
- 50. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES A NO COMMENTARY a+ 1 in. (25 mm) ~~ r- COMMENTARY Limitations on Corbelling: p$hl2 pS d/3 Where: Pe Allowable total horizontal projection of corbelling p Allowable projection of one unit nominal wall thickness d nominal unit thickness (specified thickness plus the thickness of one mortar joint) h nominal unit height (specified height plus the thickness of one mortar joint Note: Neither ties nor headers shown. Figure CC-1.12-1 - Limits on corbelling in so/idwalls Limitations on Corbelling: p s h / 2 ps d13 Where: Pe = Allowable total horizontal projection of corbelling p =Allowable projection of one unit d = Nominal unit thickness (specified thickness plus the thickness of one mortarjoint) h =Nominal unit height (specified height plus the thickness of one mortar joint) a =Air space thickness Ties shown for illustration only Figure CC-1.12-2 - Limits on corbelling in walls with air space C-37
- 51. C-38 CODE 1.13- Beams Design of beams shall meet the requirements of Section 1.13.1 or Section 1.13.2. Design of beams shall also meet the requirements of Section 2.3, Section 3.3 or Section 8.3. Design requirements for masonry beams shall apply to masonry lintels. 1.13.1 General beam design 1.13.1.1 Span length - Span length shall be in accordance with the following: 1.13.1.1.1 Span length of beams not built integrally with supports shall be taken as the clear span plus depth of beam, but need not exceed the distance between centers ofsupports. 1.13.1.1.2 For determination of moments in beams that are continuous over supports, span length shall be taken as the distance between centers ofsupports. 1.13.1.2 Lateral support - The compression face of beams shall be laterally supported at a maximum spacing based on the smaller of: (a) 32b. (b) 120b2 /d 1.13.1.3 Bearing length - Length of bearing of beams on their supports shall be a mínimum of 4 in. (102 mm) in the direction ofspan. 100 150 200 TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY 1.13- Beams 1.13.1 General beam design 1.13.1.1 Span length 1.13.1.2 Lateral support - To minimize lateral torsional buckling, the Code requires lateral bracing ofthe compression face. Hansell and Winterl.23 suggest that the slenderness ratios should be given in terms of Ldlb2 . Revathi and Menonl.24 report on tests of seven under- reinforced slender concrete beams. In Figure CC-1.13-1, a straight line is fitted to the W,.,/W,1 ratio vs. Ldlb2 , where w,.,, is the experimental capacity and W,1 is the calculated capacity based on the full cross-sectional moment strength. W,es!Wu equals 1 where Ldlb2 equals 146. Based on this, the Code limit of 120Ldlb1 is reasonable and slightly conservative. 1.13.1.3 Bearing length - The mínimum bearing length of4 in. ( 102 mm) in the direction ofspan is considered a reasonable mínimum to reduce concentrated compressive stresses at the edge ofthe support. 250 300 350 Ld/t>2 Figure CC-1.13-1 Beam capacity vs. beam slenderness
- 52. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-39 CODE 1.13.1.4 Dejlections - Masonry beams shall be designed to have adequate stiffness to limit detlections that adversely affect strength or serviceability. 1.13.1.4.1 The computed deflection of beams providing vertical support to masonry designed in accordance with Section 2.2, Section 3.2, Chapter 5, or Section 8.2, shall not exceed //600 under unfactored dead plus live loads. 1.13.1.4.2 Deflection of masonry beams shall be computed using the appropriate load-detlection relationship considering the actual end conditions. Unless stiffness values are obtained by a more comprehensive analysis, immediate deflections shall be computed with an effective moment of inertia, leff• as follows. (Equation 1-1) For continuous beams, feff shall be permitted to be taken as the average ofvalues obtained from Equation 1-1 for the critica! positive and negative moment regions. For beams of uniform cross-section, l eff shall be permitted to be taken as the value obtained from Equation 1-1 at midspan for simple spans and at the support for cantilevers. For masonry designed in accordance with Chapter 2, the cracking moment, Me" shall be computed using the allowable flexura! tensile stress taken from Table 2.2.3.2 multiplied by a factor of 2.5. For masonry designed in accordance with Chapter 3, the cracking moment, Mcr. shall be computed using the value for the modulus of rupture, f,. , taken from Table 3.1.8.2. For masonry designed in accordance with Chapter 8, the cracking moment, Mcr. shall be computed using the value for the modulus of rupture, frAAc. as given by Section 8. 1.8.3. 1.13.1.4.3 Deflections of reinforced masonry beams need not be checked when the span length does not exceed 8 multiplied by the effective depth to the reinforcement, d, in the masonry beam. COMMENTARY 1.13.1.4 Dejlections - The provisions of Section 1.13.1.4 address deflections that may occur at service load levels. 1.13.1.4.1 The deflection limits apply to beams and lintels of all materials that support unreinforced masonry. The deflection requirements may also be applicable to supported reinforced masonry that has vertical reinforcement only. The deflection limit of//600 should preven! long-term visible deflections and serviceability problems. In most cases, deflections of approximately twice this amount, or l/300, are required before the detlection becomes visiblel.25. This deflection limit is for imrnediate detlections. Creep will cause additional long-term detlections. A larger deflection limit of l/480 has been used when considering long-term detlectionst.26 • 1.13.1.4.2 The effective moment of inertia was developed to provide a transition between the upper and lower bounds of IJ~ and f e, as a function of the ratio Mc/M/27 • This procedure was selected as being sufficiently accurate for use to control deflections1.28 • Calculating a more accurate effective moment of inertia using a moment-curvature analysis may be desirable for sorne circumstances. Most masonry beams have sorne end restraint due to being built integrally with a wall. Tests have shown that the end restraint from beams being built integrally with walls reduces the detlections from 20 to 45 percent of those ofthe simply supported specimenst.29 • 1.13.1.4.3 Reinforced masonry beams and lintels with span lengths of 8 times d have immediate detlections of approximately 1/600 of the span lengtht.30 . Masonry beams and lintels with shorter spans should have sufficient stiffness to prevent serviceability problems and, therefore, deflections do not need to be checked.
- 53. C-40 CODE 1.13.2 Deep beams Design of deep beams shall meet the requirements of Section 1.13.1.2 and 1.13.1.3 in addition to the requirements of 1.13.2.1 through 1.13.2.5. 1.13.2.1 E.ffective span length - The effective span length, leg; shall be taken as the center-to-center distance between supports or 1.15 multiplied by the clear span, whichever is smaller. 1.13.2.2 Interna/ lever arm - Unless the interna! lever arm, z, between the compressive and tensile forces is determined by a more comprehensive analysis, it shall be taken as: (a) For simply supported spans. /eff (1) When 1 ::;; - < 2 dv z =o.zv.ff +2d. ) /eff (2) When - < 1 dv ; =0.6/eff (b) For continuous spans leff ( 1) When 1:=;-<3 dv l eff (2) When - < 1 dv Z = 0.5/eff (Equation l-2a) (Equation l-2b) (Equation 1-3a) (Equation l-3b) 1.13.2.3 Flexura! reinforcement - Distributed horizontal tlexural reinforcement shall be provided in the tension zone of the beam for a depth equal to half of the total depth of the beam, d•. The maximum spacing of distributed horizontal tlexural reinforcement shall not exceed one-fifth of the total depth of the beam, d., nor 16 in. (406 mm). Joint reinforcement shall be permitted to be used as distributed horizontal flexura! reinforcement in deep beams. Horizontal flexura! reinforcement shall be anchored to develop the yield strength of the reinforcement at the face of supports TMS 402-11/ACI 530·11/ASCE 5·11 COMMENTARY 1.13.2 Deep beams Shear warping of the deep beam cross section and a combination of diagonal tension stress and tlexural tension stress in the body of the deep beam require that these members be designed using deep beam theory when the span-to-depth ratio is within the limits given in the defmition of deep beams. The provisions for deep beams were developed based on requirements and recommendations m other codes and m the literature1.26 • 1.31-LJ?. 1.13.2.1 E.ffective span /ength 1.13.2.2 Interna/ lever arm - The theory used for design of beams has limited applicability to deep beams. Specifically, there will be a nonlinear distribution ofstrain in deep beams. The intemal lever arm, z, between the centroid of the interna! compressive forces and the interna! tensile forces will be less than that calculated assuming a linear strain distribution. The Code equations for interna! lever arm, z, can be used with either allowable stress design or strength design. For allowable stress design, z is commonly known as jd, and for strength design, z is commonly known as d-(a/2). The interna! lever arm provisions in the Codeare based on Ref. 1.33. 1.13.2.3 Flexura/ reinjorcement The distribution of tensile stress in a deep beam is generally such that the lower one-half of the beam is required to have distributed flexura! reinforcement. However, other loading conditions, such as uplift, and support conditions, such as continuous and fixed ends, should be considered in determining the portien of the deep beam that is subjected to tension. Distributed horizontal reinforcement resists tensile stress caused by shear as well as by tlexure.
- 54. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-41 CODE 1.13.2.4 Mínimum shear reinforcement - The following provisions shall apply when shear reinforcement is required in accordance with Section 2.3.6, Section 3.3.4.1.2, or Section 8.3.4.1.2. (a) The mínimum area of vertical shear reinforcement shall be 0.0007 bdv. (b) Horizontal shear reinforcement shall have cross- sectional area equal to or greater than one half the area of the vertical shear reinforcement. Such reinforcement shall be equally distributed on both side faces ofthe beam when the nominal width ofthe beam is greater than 8 inches (203 mm). (e) The maximum spacing of shear reinforcement shall not exceed one-fifth the total depth of the beam, dv, nor 16 in. (406 mm). 1.13.2.5 Total reinforcement - The sum of the cross-sectional areas of total horizontal and vertical reinforcement shall be at least 0.001 multiplied by the gross cross-sectional area, bdv, of the deep beam, using specified dimensions. 1.14-Columns Design of columns shall meet the requirements of Section 1.14.1 or Section 1.14.2. Design of columns shall also meet the requirements of Section 2.3, or Section 3.3, or Section 8.3. 1.14.1 General column design 1.14.1.1 Dimensional limits - Dimensions shall be in accordance with the following: (a) The distance between lateral supports of a column shall not exceed 99 multiplied by the least radius of gyration, r. (b) Mínimum side dimension shall be 8 in. (203 mm) nominal. 1.14.1.2 Construction - Columns shall be fully grouted. 1.14.1.3 Vertical reinforcement - Vertical reinforcement in columns shall not be less than 0.0025A, nor exceed 0.04A,. The mínimum number ofbars shall be four. COMMENTARY 1.13.2.4 Mínimum shear reinforcement - Distributed flexura! reinforcement may be included as part of the provided shear reinforcement to meet the mínimum distributed shear reinforcement ratio. The spacing of shear reinforcement is limited to restrain the width ofthe cracks. 1.13.2.5 Total reinforcement - Load applied along the top surface of a deep beam is transferred to supports mainly by arch action. Typically, deep beams do not need transverse reinforcement and it is sufficient to provide distributed flexura! reinforcement1 31 • 1.14- Columns Columns are defined in Section 1.6. They are isolated members usually under axial compressive loads and flexure. If damaged, columns may cause the collapse of other members; sometimes of an entire structure. These critica! structural elements warrant the special requirements ofthis section. 1.14.1 General column design 1.14.1.1 Dimensionallimits - The limit of 99 for the slenderness ratio, hlr, is judgment based. See Figure CC-1.14-1 for effective height determination.The mínimum nominal side dimension of 8 in. (203 mm) results from practica! considerations. 1.14.1.2 Construction 1.14.1.3 Vertical reinforcement - Mínimum vertical reinforcement is required in masonry columns to prevent brittle failure. The maximum percentage limit in column vertical reinforcement was established based on the committee's experience. Four bars are required so ties can be used to provide a confined core of masonry.
- 55. C-42 CODE 1.14.1.4 Lateral ties - Lateral ties shall conform to the following: (a) Vertical reinforcement shall be enclosed by lateral ties at least 1 / 4 in. (6.4 mm) in diameter. (b) Vertical spacing of lateral ties shall not exceed 16 longitudinal bar diameters, 48 lateral tie bar or wire diameters, or least cross-sectional dirnension of the member. (e) Lateral ties shall be arranged so that every comer and altemate longitudinal bar shall have lateral support provided by the comer of a lateral tie with an included angle of not more than 135 degrees. No bar shall be farther than 6 in. (152 mm) clear on each side along the lateral tie from such a laterally supported bar. Lateral ties shall be placed in either a mortarjoint or in grout. Where longitudinal bars are located around the perimeter of a circle, a complete circular lateral tie is permitted. Lap length for circular ties shall be 48 tie diameters. (d) Lateral ties shall be located vertically not more than one-half lateral tie spacing above the top of footing or slab in any story, and shall be spaced not more than one-half a lateral tie spacing below the lowest horizontal reinforcement in beam, girder, slab, or drop panel above. (e) Where beams or brackets frarne into a column from four directions, lateral ties shall be permitted to be terminated not more than 3 in. (76.2 mm) below the lowest reinforcement in the shallowest ofsuch beams or brackets. 1.14.2 Lightly loaded columns Masonry columns used only to support light frame roofs of carports, porches, sheds or similar structures assigned to Seismic Design Category A, B, or e, which are subject to unfactored gravity loads not exceeding 2,000 lbs (8,900 N) acting within the cross-sectional dimensions of the column are permitted to be constructed as follows: (a) Mínimum side dimension shall be 8 in. (203 mm) nominal. (b) Height shall not exceed 12ft (3.66 m). (e) eross-sectional area of longitudinal reinforcement shall not be less than 0.2 in.2 (129 mm2 ) centered in the column. (d) eolumns shall be fully grouted. TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY 1.14.1.4 Lateral ties - Lateral reinforcement in columns performs two functions. It provides the required support to prevent buckling of longitudinal column reinforcing bars acting in compression and provides resistance to diagonal tension for columns acting in shear1 38 • Ties may be located in the mortar joint, when the tie diameter does not exceed Y2 the specified mortar joint thickness. For example, Y4 in. (6.4 mm) diameter ties may be placed in Y2 in. (12.7 mm) thick mortarjoints. The requirements of this eode are modeled on those for reinforced concrete columns. Except for permitting 4-in. (6.4-mm) ties in Seismic Design eategory A, B, and e' they reflect the applicable provisions ofthe reinforced concrete code. 1.14.2 Light/y loaded columns Masonry columns are often used to support roofs of carports, porches, sheds or similar light structures. These columns do not need to meet the detailing requirements of Section 1.14.1. The axial load limit of 2,000 pounds (8,900 N) was developed based on the flexura] strength of a nominal 8 in. (203 mm) by 8 in. (203 mm) by 12ft high (3.66 m) column with one No. 4 (M#13) reinforcing bar in the center and.fm of 1350 psi (9.31 MPa). An axial load of 2,000 pounds (8,900 N) at the edge of the member will result in a moment that is approximately equal to the nominal flexura! strength ofthis member.
- 56. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-43 COMMENTARY Column, Wall or Pilasler h =Clear Heighl h ~ 2 x Heighl Braced al Supports Canlilevered Column, __W;.:.:::all or Pilasler f Fixed or Conlinuous al Base Ifdata (see Section 1.3) show that there is reliable restraint against translation and rotation at the supports, the "effective height" may be taken as low as the distance between points of inflection for the loading case under consideration. Figure CC-1.14-1 - Effective height, h, ofcolumn, wall, or pilaster CODE 1.15- Pilasters Walls interfacing with pilasters shall not be considered as flanges, unless the construction requirements of Sections 1.9.4.2.1 and 1.9.4.2.5 are met. When these construction requirements are met, the pilaster's flanges shall be designed in accordance with Sections 1.9.4.2.2 through 1.9.4.2.4. 1.16 - Details of reinforcement and metal accessories 1.16.1 Embedment Reinforcing bars shall be embedded in grout. 1.16.2 Size ofreinforcement 1.16.2.1 The maximum size of reinforcement used in masonry shall be No. 11 (M #36). 1.16.2.2 The diameter of reinforcement shall not exceed one-half the least clear dimension of the cell, bond beam, or collarjoint in which it is placed. 1.16.2.3 Longitudinal and cross wires of joint reinforcement shall have a mínimum wire size of Wl.l (MW7) and a maximum wire size of one-half the joint thickness. COMMENTARY 1.15- Pilasters Pilasters are masonry members that can serve severa! purposes. They may project from one or both sides of the wall, as shown in Figure CC-1.15-1. Pilasters contribute to the lateral load resistance of masonry walls and may resist verticalloads. 1.16 - Details of reinforcement and metal accessories When the provisions of this section were originally developed in the late 1980s, the Committee used the then current ACI 318 Code139 as a guide. Sorne of the requirements were simplified and others dropped, depending on their suitability for application to masonry. 1.16.1 Embedment 1.16.2 Size ofreinforcement 1.16.2.1 Limits on size of reinforcement are based on accepted practice and successful performance in construction. The No. 11 (M#36) limit is arbitrary, but Reference 1.40 shows that distributed small bars provide better performance than fewer large bars. Properties of reinforcement are given in Table CC-1.16.2. 1.16.2.2 Adequate flow of grout necessary for good bond is achieved with this limitation. lt also limits the size ofreinforcement when combined with Section 1.20.1. 1.16.2.3 The function of joint reinforcement is to control the size and spacing ofcracks caused by volume changes in masonry as well as to resist tension.1.41 Joint reinforcement is commonly used in concrete masonry to minimize shrinkage cracking. The restriction on wire size ensures adequate performance. The maximum wire size of one-half the joint thickness allows free flow of mortar around joint reinforcement. Thus, a 3 /win. (4.8-mm) diameter wire can be placed in a 3 / 8-in. (9.5-mm) joint.
- 57. C-44 TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY (a) Single Face Alternate COIJses D08:D Ir:'] r:"ll lt::J ~· 11, _ _ _ ¿¡ (a) Single Face Ties Embedded In Mortar Joints Brick Pilasters Ties Embedded InMarta" Joints Block Pilasters 000 000 (b) Double Face Alternale CC~Jses •1 :.:11:·.1 ~: 1!, _____ _ ::!1 (b) DOlble Faca Figure CC-1.15-J - Typical pilasters Table ce 11s 2 P - - f hvsical propert1es o stee remforcinQ wire andbars Designation Diameter, in. Area, in.2 Perimeter, in. (mm) (mm2 ) (mm) Wire W1.1 (11 gage) (MW7) 0.121 (3. 1) 0.011 (7.1) 0.380 (9.7) Wl.7 (9 gage) (MW11) 0.148 (3.8) 0.017 (11.0) 0.465 (11.8) W2.1 (8 gage) (MW13) 0.162 (4.1) 0.020 (12.9) 0.509 (12.9) W2.8 (3/16 in. wire) (MW18) 0.187 (4.8) 0.027 (17.4) 0.587 (14.9) W4.9 (1/4 in. wire) (MW32) 0.250 (6.4) 0.049 (31.6) 0.785 (19.9) Bars No. 3 (M#lO) 0.375 (9.5) 0.11 (71.0) 1.178 (29.9) No. 4 (M#l3) 0.500 (12.7) 0.20 (129) 1.571 (39.9) No. 5 (M#16) 0.625 (15.9) 0.31 (200) 1.963 (49.9) No. 6 (M#19) 0.750 (19.1) 0.44 (284) 2.356 (59.8) No. 7 (M#22) 0.875 (22.2) 0.60 (387) 2.749 (69.8) No. 8 (M#25) 1.000 (25.4) 0.79 (510) 3.142 (79.8) No. 9 (M#29) 1.128 (28.7) 1.00 (645) 3.544 (90.0) No. 1O (M#32) 1.270 (32.3) 1.27 (8 19) 3.990 (101) No. 11 (M#36) 1.410 (35.8) 1.56 (1006) 4.430 (113)
- 58. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-45 CODE 1.16.3 Placement ofreinforcement 1.16.3.1 The clear distance between parallel bars shall not be less than the nominal diameter of the bars, nor less than 1 in. (25.4 mm). 1.16.3.2 In columns and pilasters, the clear distance between vertical bars shall not be less than one and one-half multiplied by the nominal bar diameter, nor less than 11 / 2 in. (38.1 mm). 1.16.3.3 The clear distance limitations between bars required in Sections L.L6.3.1 and 1.16.3.2 shall also apply to the clear distance between a contact lap splice and adjacent splices or bars. 1.16.3.4 Groups of parallel reinforcing bars bundled in contact to act as a unit shall be limited to two in any one bundle. Individual bars in a bundle cut off within the span of a member shall termínate at points at least 40 bar diameters apart. 1.16.3.5 Reinforcement embedded in grout shall have a thickness of grout between the reinforcement and masonry units not less than 1 / 4 in. (6.4 mm) for fine grout or 1 / 2 in. (12.7 mm) for coarse grout. 1.16.4 Protection ofreinforcement and metalaccessories 1.16.4.1 Reinforcing bars shall have a masonry cover not less than the following: (a) Masonry face exposed to earth or weather: 2 in. (50.8 mm) for bars larger than No. 5 (M #16); 11 / 2 in. (38.1 mm) for No. 5 (M #16) bars or smaller. (b) Masonry not exposed to earth or weather: 11 / 2 in. (38.1 mm). 1.16.4.2 Longitudinal wires ofjoint reinforcement shall be fully embedded in mortar or grout with a mínimum cover of% in. (15.9 mm) when exposed to earth or weather and 1 /2 in. (12.7 mm) when not exposed to earth or weather. Joint reinforcement shall be stainless steel or protected from corrosion by hot-dipped galvanized coating or epoxy coating when used in masonry exposed to earth or weather and in interior walls exposed to a mean relative humidity exceeding 75 percent. All other joint reinforcement shall be mili galvanized, hot-dip galvanized, or stainless steel. 1.16.4.3 Wall ties, sheet-metal anchors, steel plates and bars, and inserts exposed to earth or weather, or exposed to a mean relative humidity exceeding 75 percent shall be stainless steel or protected from corrosion by hot-dip COMMENTARY 1.16.3 Placement ofreinforcement P1acement limits for reinforcement are based on successful construction practice over many years. The Limits are intended to facilitate the tlow of grout between bars. A mínimum spacing between bars in a layer prevents longitudinal splitting of the masonry in the plane of the bars. Use ofbundled bars in masonry construction is rarely required. Two bars per bundle is considered a practica! maximum. It is importan! that bars be placed accurately. Reinforcing bar positioners are availableto control bar position. 1.16.4 Protection ofreinforcementandmetalaccessories 1.16.4.1 Reinforcing bars are traditionally not coated for corrosion resistance. The masonry cover retards corrosion ofthe steel. Cover is measured from the exterior masonry surface to the outerrnost surface of the reinforcement to which the cover requirement applies. lt is measured to the outer edge of stirrups or ties, iftransverse reinforcement encloses main bars. Masonry cover includes the thickness of masonry units, mortar, and grout. At bed joints, the protection for reinforcement is the total thickness of mortar and grout from the exterior of the mortar joint surface to outer-most surface of the reinforcement or metal accessory. The condition " masonry face exposed to earth or weather" refers to direct exposure to moisture changes (altemate wetting and drying) and not just temperature changes. 1.16.4.2 Since masonry cover protection for joint reinforcement is minimal, the protection of joint reinforcement in masonry is required in accordance with the Specification. Examples of interior walls exposed to a mean relative humidity exceeding 75 percent are natatoria and food processing plants. 1.16.4.3 Corrosion resistance requirements are included since masonry cover varíes considerably for these items. The exception for anchor bolts is based on current industry practice.
- 59. C-46 CODE galvanized coating or epoxy coating. Wall ties, anchors, and inserts shall be mili galvanized, hot-dip galvanized, or stainless steel for all other cases. Anchor bolts, steel plates, and bars not exposed to earth, weather, nor exposed to a mean relative humidity exceeding 75 percent, need not be coated. 1.16.5 Standard hooks Standard hooks shall consist ofthe following: (a) 180-degree bend plus a minimum 4db extension, but not less than 2-112 in. (64 mm) at free end ofbar; (b) 90-degree bend plus a minimum l2db extension at free end ofbar; or (e) for stirrup and tie hooks for a No. 5 bar and smaller, either a 90-degree or 135-degree bend plus a minimum 6 db extension, but not less than 2-112 in. (64 mm) at free end ofbar. TMS 402-11/ACI530-11/ASCE 5-11 COMMENTARY 1.16.5 Standard hooks Standard hooks are shown in Figure CC-1.16-1. 4 t41outno11ess Paintorr ·~..,.~ t--""--t-t llan :2 :.Sin.(64mn) (e) 180degreeBend (b) 90degreeBend ~ .....,.,~~==== ======== :::=f ====::::=::::J (e) Stim.lp endTie~agowt190degreeor 135degreeBend Figure CC-1.16-1- Standard hooks
- 60. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES AND COMMENTARY C-47 CODE 1.16.6 Minimum bend diameterfor reinforcing bars The diameter of bend measured on the inside of reinforcing bars, other than for stirrups and ties, shall not be less than values specified in Table 1.16.6. Table 1.16.6- Minimum diameters of bend Bar size and type Mínimum diameter No. 3 through No. 7 (M #10 5 bar diameters through #22) Grade 40 (Grade 280) No. 3 through No. 8 (M #10 6 bar diameters through #25) Grade 50 or 60 (Grade 350 or 420) No. 9, No. 10, and No. 11 8 bar diameters (M #29, #32, and #36) Grade 50 or 60 (Grade 350 or 420) 1.17 - Anchor bolts Headed and bent-bar anchor bolts shall conform to the provisions of Sections 1.17.1 through 1.17.7. 1.17.1 Placement Headed and bent-bar anchor bolts shall be embedded in grout. Anchor bolts of Y.. in. (6.4 mm) diameter are permitted to be placed in mortar bed joints that are at least Y, in. (12.7 mm) in thickness and, for purposes ofapplication ofthe provisions ofSections 1.17, 2.1.4 and 3.1.6, are permitted to be considered as ifthey are embedded in grout. Anchor bolts placed in the top of grouted cells and bond beams shall be positioned to maintain a mínimum of Y.. in. (6.4 mm) of fine grout between the bolts and the masonry unit or Y, in. (12.7 mm) of coarse grout between the bolts and the masonry unit. Anchor bolts placed in drilled holes in the face shells ofhollow masonry units shall be permitted to contact the masonry unit where the bolt passes through the face shell, but the portion ofthe bolt that is within the grouted cell shall be positioned to maintain a mínimum of Y.. in. (6.4 mm) offine grout between the head or bent leg of each bolt and the masonry unit or Y, in. (12.7 mm) of coarse grout between the head or bent leg of each bolt and the masonry unit. The clear distance between parallel anchor bolts shall not be less than the nominal diameter ofthe anchor bolt, nor less than 1 in. (25.4 mm). 1.17.2 Projectedareafor axial tension The projected area ofheaded and bent-bar anchor bolts loaded in axial tension, Ap1, shall be determined by Equation 1-4. COMMENTARY 1.16.6 Mínimum bend diameterfor reinforcing bars Standard bends in reinforcing bars are ·described in terms ofthe inside diameter of bend since this is easier to measure than the radius ofbend. A broad survey of bending practices, a study of ASTM bend test requirements, and a pilot study of and experience with bending Grade 60 (Grade 420) bars were considered in establishing the mínimum diameter of bend. The primary consideration was feasibility of bending without breakage. Experience has since established that these mínimum bend diameters are satisfactory for general use without detrimental crushing ofgrout. 1.17 -Anchor bolts These design values apply only to the specific types of bolts mentioned. These bolts are readily available and are depicted in Figure CC-1.17-l. 1.17.1 Placement Most tests on anchor bolts in masonry have been performed on anchor bolts embedded in grout. Placement limits for anchor bolts are based on successful construction practice over many years. The limits are intended to facilitate the flow of grout between bolts and between bolts and the masonry unit. Research at Portland State Universityl.42 and at Washington State Universityl.43 has established that there is no difference in the performance of an anchor bolt installed through a tight-fitting hole in the face shell of a grouted hollow masonry unit and in an over-sized hole in the face shell of a grouted hollow masonry unit. Therefore, the clear distance requirement for grout to surround an anchor bolt is not needed where the bolt passes through the face shell. See Figure CC-1 .17-2. Quality/assurance/control (QA) procedures should ensure that there is sufficient clearance around the bolts prior to grout placement. These procedures should also require observation during grout placement to ensure that grout completely surrounds the bolts, as required by the QA Tables in Section 1.19. 1.17.2 Projected areafor axial tension Results of testsl.44 • I.4S on headed anchor bolts in tension showed that anchor bolts often failed by breakout of a conically shaped section of masonry. The area, Ap~> is
- 61. C-48 CODE (Equation 1-4) The portian of projected area overlapping an open cell, or open head joint, or that lies outside the masonry shall be deducted from the value of Ap1 ca1cu1ated using Equation 1-4. Where the projected areas of anchor bolts overlap, the value of Ap1 calculated using Equation 1-4 shall be adjusted so that no portian of masonry is included more than once. Hex Head Square Head (a) Headed Anchor Bolts TMS 402-11/ACI 530-11 /ASCE 5-11 COMMENTARY the projected area of the assumed fai lure cone. The cone originales at the compression bearing point of the embedment and radiates at 45° in the direction of the pull (See Figure CC-1.17-3). Other modes of!ensile failure are possible. These modes include pullout (straightening ofJ- or L-bolts) and yield 1fracture ofthe anchor steel. When anchor bolts are closely spaced, stresses within the masonry begin to become additive, as shown in Figure CC-1.1 7-4. The Code requires that when projected areas of anchor bolts overlap, an adjustment be made so that the masonry is not overloaded. When the projected areas oftwo or more anchors overlap, the anchors with overlapping projected areas should be treated as an anchor group. The projected areas ofthe anchors in the group are summed, this area is adjusted for overlapping areas, and the capacity of the anchor group is calculated using the adjusted area in place of Ap¡. See Figure CC-1.17-5 for examples of calculating adjusted values ofApt· "L" Bolts "J" Bolts (b) Bent-Bar Anchor Bolts Figure CC-1.17-1- Anchor bolts Minimum Y. in. (12.7mm) for coarse grout orY. in. (6,4mm) forfinegrout AnchorboH AnchorboH Bond beam Figure CC-1.17-2 - Anchor bolt clearance requrirementsfor headed anchor bo/ts - bent-bars are similar
- 62. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES (TMS 402/ACI 530/ASCE 5) C-49 COMMENTARY f P (failure) Assumed Conefor Calculation ofA P~ Equation 1-4 r p (failure) _ _ ...J Figure CC-1.17-3-Anchor bolt tensíle breakout cone Figure CC-1.17-4- Overfappinganchorbo/tbreakout eones CODE 1.17.3 Projectedarea for shear The projected area of headed and bent-bar anchor bolts loaded in shear, Ap.. shall be determined from Equation 1- 5. A ="!'te pv 2 (Equation 1-5) The portion of projected area overlapping an open cell, or open head joint, or that lies outside the masonry shall be deducted from the value of A pv calculated using Equation 1-5. Where the projected areas of anchor bolts overlap, the value of A p,· calculated using Equation 1-5 shall be adj usted so that no portion of masonry is included more than once. COMMENTARY 1.17.3 Projectedarea for shear Results of tests1. 44 • I.4S on anchor bolts in shear showed that anchor bolts often failed by breakout of a conically shaped section of masonry. The area Apv is the projected area ofthe assumed failure cone. The cone originates at the compression bearing point ofthe embedment and radiates at 45° in the direction of the pull towards the free edge of the masonry (See Figure CC-1.17-6). Pryout (See Figure CC-1.17-7), masomy crushing, and yielding 1 fracture of the anchor steel are other possible failure modes. When the projected areas of two or more anchors overlap, the shear design of these anchors should follow the same procedure as for the tension design of overlapping anchors. See Commentary Section 1.17.2.
- 63. C-50 1 j r l y X '· X =]_ ~ 4(l b ) 2 -1 2 2 COMMENTARY A111 at Top of Wall for Uplift ' ) z z y= lb - X= lb_]_ ~ 4(l bY -1 2 2 TMS 402-11/ACI530-11/ASCE 5-11 1 J r X y l J '· :. AP1 =(2X +Z)t-:t·t f( ~~ -sin B) whereB =2arcsinc::}n degrees 1 1 j 1 J 1 r 1 r ly ' y l X Z/2 Zf2 X ] '· z '· :. Apr = (2X+Z)t+tlc~~ -sinO} whereB =2arcsi{t~Z }ndegrees 1 1 1 j 1 J 1 í 1 ) í 'y X Z/2 Z/2 X yl ] '• z '• :.AP, =(2X+Z)t+tl(" 0 - sine} whereB=2arcsi{t/2)indegrees IW 4 Figure CC-1.17-5 - Ca/culalion ofAdjusled Values ofAfJ/ (Plan Views)
- 64. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-51 COMMENTARY Figure CC-1.17-6 - Anchor bolt shear breakout Figure CC-1.17-7 - Anchor bolt shear pryout CODE 1.17.4 Effective embedment length for headed anchor bolts The effective embedment length for a headed anchor bolt, lb, shall be the length of the embedment measured perpendicular from the masonry surface to the compression bearing surface ofthe anchor head. 1.17.5 Effective embedment length of bent-bar anchor bolts The effective embedment for a bent-bar anchor bolt, h, shall be the length of embedment measured perpendicular from the masonry surface to the compression bearing surface of the bent end, minus one anchor bolt diameter. COMMENTARY 1.17.4 Effective embedment length for headed anchor bolts 1.17.5 Effective embedment length for bent-bar anchor bolts Testsl.44 have shown that the pullout strength of bent- bar anchor bolts correlated best with a reduced embedment length. This may be explained with reference to Figure CC- 1.17-8. Due to the radius of the bend, stresses are concentrated at a point less than the full embedment length.
- 65. C-52 TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY Bolt Diameter,db Bo lt Diameter,db Figure CC-1.17-8 - Stress distribution on bent anchor bars CODE 1.17.6 Mínimum permissible effective embedment length The mínimum permissible effective embedment length for headed and bent-bar anchor bolts shall be the greater of4 bolt diameters or 2 in. (50.8 mm). 1.17.7 Anchor bolt edge distance Anchor bolt edge distance, h., shall be measured in the direction of load from the edge ofmasonry to center of the cross section of anchor bolt. COMMENTARY 1.17.6 Mínimum permissible effective embedment length The minimum embedment length requirement is considered a practica! minimum based on typical construction methods for embedding anchor bolts in masonry. The validity of Code equations for shear and tension capacities of anchor bolts have not been verified by testing of anchor bolts with embedment lengths less than four bolt diameters. 1.17.7 Anchor bolt edge distance
- 66. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-53 CODE 1.18- Seismic design requirements 1.18.1 Scope The seismic design requirements ofSection 1.18 shall apply to the design and construction of masonry, except glass unit masonry and masonry veneer. COMMENTARY 1.18- Seismic design requirements 1.18.1 Scope The requirements in this section have been devised to improve performance of masonry construction when subjected to earthquake loads. Mínimum seismic loading requirements are drawn from the legally adopted building code. In the event that the legaiJy adopted building code does not contain appropriate criteria for the determination of seismic forces, the Code requires the use of ASCE 7, which represented the state-of-the-art in seismic design at the time these requirements were developed. Obviously, the seismic design provisions ofthis section may not be compatible with every edition of every building code that could be used in conjunction with these requirements. As with other aspects of structural design, the designer should understand the implications and limits of combining the mínimum loading requirements of other documents with the resistance provisions of this Code. The designer should be aware that the use of "strength" leve! loads should not be used in conjunction with allowable stress design procedures as overly conservative design can result. Similarly, the use of "allowable stress" leve! loads in conjunction with strength design procedures could result in unconservative designs. Seismic design is not optional regardless of the assigned Seismic Design Category, the absolute value of thc dcsign scismic Joads, or the relative difference between the design seismic loads and other design lateral forces such as wind. Unlike other design loads, seismic design of reinforced masonry elements permits inelastic response of the system, which in tum reduces the seismic design load. This reduction in load presumes an inherent leve! of inelastic ductility that may not otherwise be present if seismic design was neglected. When nonlinear response is assumed by reducing the seismic loading by an R factor greater than 1.5, the resulting seismic design load may be less than other loading conditions that assume a linear elastic model of the system. This is often misinterpreted by sorne to mean that the seismic loads do not 'control' the design and can be neglected. For the masonry system to be capable of achieving the ductility-related lower seismic loads, however, the mínimum seismic design and detailing requirements ofthis section must be met. The seismic design requirements are presented in a cumulative format. Thus, the provisions for Seismic Design Categories E and F include provisions for Seismic Design Category D, which include provisions for Seismic Design Category C, and so on. This section does not apply to the design or detailing of masonry veneers or glass unit masonry systems. Seismic requirements for masonry veneers are provided in Chapter 6, Veneers. Glass unit masonry systems, by definition and design, are isolated, non-load-bearing elements and therefore cannot be used to resist seismic loads other than those induced by their own mass.
- 67. C-54 CODE 1.18.2 General analysis 1.18.2.1 Element interaction - The interaction of structural and nonstructural elements that affect the linear and nonlinear response of the structure to earthquake motions shall be considered in the analysis. 1.18.2.2 Load path - Structural masonry elements that transmit forces resulting from seismic events to the foundation shall comply with the requirements of Section 1.18. 1.18.2.3 Anchorage design - Load path connections and mínimum anchorage forces shall comply with the requirements ofthe legally adopted building code. When the legally adopted building wdt: does not provide mínimum load path connection requirements and anchorage design forces, the requirements ofASCE 7 shall be used. 1.18.2.4 Drift limits Under loading combinations that include earthquake, masonry structures shall be designed so the calculated story drift, Ll, does not exceed the allowable story drift, L1a, obtained from the legally adopted building code. When the legally adopted building code does not provide allowable story drifts, structures shall be designed so the calculated story drift, Ll, does not exceed the allowable story drift, L1a, obtained from ASCE 7. It shall be perrnitted to assume that the following shear wall types comply with the story drift limits of ASCE 7: empirical, ordinary plain (unreinforced), detailed plain (unreinforced), ordinary reinforced, interrnediate reinforced, ordinary plain (unreinforced) AAC masonry shear walls, and detailed plain (unreinforced) AAC masonry shear walls. TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY 1.18.2 General analysis The designer is permitted to use any of the structural design methods presented in this Code to design to resist seismic loads. There are, however, limitations on sorne of the design methods and systems based upon the structure's assigned Seismic Design Category. For instance, empirical design procedures are not perrnitted to be used in structures assigned to Seismic Design Categories D, E, or F. Further, empirically designed masonry elements can only be used as part ofthe seismic-force-resisting system in Seismic Design Category A. 1.18.2.1 Element interaction - Even if a nonstructural element is not part ofthe seismic-force-resisting system, it is possible for it to influence the structural response ofthe system during a seismic event. This may be particularly apparent due to the interaction of structural and nonstructural elements at displacements larger than those detennined by linear elastic analysis. 1.18.2.2 Load path - This section clarifies load path requirements and alerts the designer that the base ofthe structure as defined in analysis may not necessarily correspond to the ground level. 1.18.2.3 Anchorage design - Previous editions ofthe Code contained mínimum anchorage and connection design forces based upon antiquated service-level earthquake loads and velocity-related acceleration parameters. As these are mínimum design loads, their values should be deterrnined using load standards. Experience has demonstrated thatone ofthe chiefcauses of failure of masonry construction during earthquakes is inadequate anchorage of masonry walls to floors and roofs. For this reason, an arbitrary mínimum anchorage based upon previously established practice has been set as noted in the referenced documents. When anchorage is between masonry walls and wood frarned floors or roofs, the designer should avoid the use ofwood ledgers in cross-graín bending. 1.18.2.4 Drift limits - Excessive deforrnation, particularly resulting from inelastic displacements, can potentially result in instability of the seismic-force-resisting system. This section provides procedures for the limitation of story drift. The terrn "drift" has two connotations: l . "Story drift'' is the maximum calculated lateral displacement within a story (the calculated displacement ofone leve( relative to the leve( below caused by the effects ofdesign seismic loads). 2. The calculated lateral displacement or deflection due to design seismic loads is the absolute dísplacement ofany point in the structure relative to the base. This is not "story drift" and is not to be used for drift control or stability considerations since it may give a false impression ofthe effects in critica( stories. However, it is important when considering seismic separation requirements.
- 68. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-55 CODE COMMENTARY Overall or total drift is the lateral displacementofthe top ofa building relative to the base. The overall drift ratio is the total drift divided by the building height. Story drift is the lateral displacement ofone story relative toan adjacent story. The story drift ratio is the story drift divided by the corresponding story height. The overall drift ratio is usually an indication of moments in a structure and is also related to seismic separation demands. The story drift ratio is an indication of local seismic deformation, which relates to seismic separation demands within a story. The maximum story drift ratio could exceed the overall drift ratio. There are many reasons for controlling drift in seisrnic design: (a) To control the inelastic strain within the affected elements. Although the relationship between lateral drift and maximum nonlinear strain is imprecise, so is the current state ofknowledge ofwhat strain limitations should be. (b) Under smalllateral deformations, secondary stresses are normally within tolerable lirnits. However, larger deformations with heavy vertical loads can lead to significan! secondary moments from P-delta effects in the design. The drift limits indirectly provide upper bounds for these effects. (e) Buildings subjected to earthquakes need drift control to restrict damage to partitions, shaft and stair enclosures, glass, and other fragile nonstructural elements and, more importantly, to minimize differential movement demands on the seismic-force-resisting elements. The designer must keep in mind that the allowable drift limits, 4,, correspond to story drifts and, therefore, are applicable to each story. They must not be exceeded in any story even though the drift in other stories may be well below the limit. Although the provisions of this Code do not give equations for computing building separations, the distance should be sufficient to avoid damaging contact under total calculated deflection for the design loading in order to avoid interference and possible destructive hammering between buildings. The distance should be equal to the total of the lateral deflections ofthe two units assumed deflecting toward each other (this involves increasing the separation with height). lf the effects of hammering can be shown not to be detrimental, these distances may be reduced. For very rigid shear wall structures with rigid diaphragms whose lateral deflections are difficult to estímate, older code requirements for structural separations ofat least 1 in. (25.4 mm) plus Y2 in. (12.7 mm) for each 10 ft (3.1 m) of height above 20ft (6.1 m) could be used as a guide. Empirical, ordinary plain (unreinforced), detailed plain (unreinforced), ordinary reinforced, intermediate reinforced, ordinary plain (unreinforced) AAC, and detailed plain (unreinforced) AAC masonry shear walls are inherently
- 69. C-56 CODE 1.18.3 Element classijicatíon Masoruy elements shall be classified in accordance with Section 1.18.3.1 and 1.18.3.2 as either participating or nonparticipating elements of the seismic-force-resisting system. 1.18.3.1 Nonparticipating elements - Masonry elements that are not part of the seismic-force-resisting system shall be classified as nonparticipating elements and shall be isolated in their own plane from the seismic- force-resisting system except as required for gravity support. Isolation joints and connectors shall be designed to accommodate the design story drift. 1.18.3.2 Participating elements - Masonry walls that are part of the seismic-force-resisting system shall be classified as participating elements and shall comply with the requirements of Section 1.18.3.2.1, 1.18.3.2.2, 1.18.3.2.3, 1.18.3.2.4, 1.18.3.2.5, l.18.3.2.6, 1.18.3.2.7, 1.18.3.2.8, 1.18.3.2.9, 1.18.3.2.10, 1.18.3.2.11 or 1.18.3.2.12. TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY designed to have relatively low inelastic deformations under seismic loads. As such, the Committee felt that requiring designers to check story drifts for these systems of low and moderate ductility was superfluous. 1.18.3 Element classification Classifying masoruy elements as either participating or nonparticipating in the seismio-force-resisting system is largely a function ofdesign intent. Participating elements are those that are designed and detailed to actively resist seismic forces, including such elements as shear walls, oolumns, piers, pilasters, beams, and coupling elements. Nonparticipating elements can be any masonry assembly, but are not designed to collect and resist earthquake loads from other portions ofthe structure. 1.18.3.1 Nonparticipating elements - In previous editions ofthe Code, isolation of elements that were not part of the seismic-force-resisting system was not required in Seismic Design Categories A and B, rationalized, in part, due to the low hazard associated with these Seismic Design Categories. Non-isolated, nonparticipating elements, however, can influence a structure's strength and stiffness, and as a result the distribution oflateral loads. In considering the influence nonparticipating elements can inadvertently have on the performance of a structural system, the Committee opted to require that all nonpartioipating elements be isolated from the seismic-force-resisting system. The Committee is continuing to discuss alternative design options that would allow non-isolated, nonparticipating elements with corresponding checks for strength, stiffness, and oompatibility. 1.18.3.2 Participating elements - A seismic- force-resisting system must be defined for every structure. Most masoruy buildings use masoruy shear walls to serve as the seisrnic-force-resisting system, although other systems are sometimes used (such as concrete or steel frames with masonry infill). Such shear walls must be designed by the engineered methods in Chapter 2, 3, or 4 or 8, unless the structure is assigned to Seismic Design Category A, in which case empirical provisions ofChapter 5 may be used. Twelve shear wall types are defined by the Code. Depending upon tbe masoruy material and detailing method used to design the shear wall, each wall type is intended to have a different capacity for inelastic response and energy dissipation in the event of a seismic event. These twelve shear wall types are assigned system design parameters such as response modification factors, R, based on their expected performance and ductility. Certain shear wall types are permitted in each seismic design category, and unreinforced shear wall types are not permitted in regions of intermediate and high seismic risk. Table CC-1.18.3.2-1 summarizes the requirements of each ofthe twelve types of masonry shear walls.
- 70. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-57 COMMENTARY TABLE CC-1.18.3.2-1 Requirements for Masonry Shear Walls Based on Shear Wall Designation1 Shear wall Designation Design Methods Reinforcement Permitted In Requirements Empírica(Design ofMasonry Section 5.3 None SDeA Shear Walls Ordinary Plain (Unreinforced) Section 2.2 or None SDe A and B Masonry Shear Walls Section 3.2 Detailed Plain (Unreinforced) Section 2.2 or Section 1.18.3.2.3.1 SDe A and B Masonry Shear Walls Section 3.2 Ordinary Reinforced Masonry Section 2.3 or Section 1.18.3.2.3.1 SDe A, B, and e Shear Walls Section 3.3 lntermediate Reinforced Section 2.3 or Section 1.18.3.2.5 SDe A, B, and e Masonry Shear Walls Section 3.3 Special Reinforced Masonry Section 2.3 or Section 1.18.3.2.6 SDe A, B, e, D, E, and F Shear Walls Section 3.3 Ordinary Plain (Unreinforced) Section 8.2 Section 1.18.3.2.7.1 SDeA andB AAe Masonry Shear Walls Detailed Plain (Unreinforced) Section 8.2 Section 1.18.3.2.8.1 SDe A andB AAe Masonry Shear Walls Ordinary Reinforced AAe Section 8.3 Section 1.18.3.2.9 SDe A, B, e, D, E, and F Masonry Shear Walls Ordinary Plain (Unreinforced) Prestressed Masonry Shear ehapter 4 None SDe A andB Walls Jntermediate Reinforced Prestressed Masonry Shear ehapter 4 Section 1.18.3.2.11 SDe A, B, and e Walls Special Reinforced Prestressed ehapter 4 Section 1.18.3.2.12 SDe A, B, e, D, E, and F Masonry Shear Walls 1 Section and ehapter references in this table refer to eode Sections and e hapters. CODE 1.18.3.2.1 Empirical design of masonry shear walls - Empirical design of shear walls shall comply with the requirements ofSection 5.3. 1.18.3.2.2 Ordinary plain (unreinforced) masonry shear walls - Design of ordinary plain (unreinforced) masonry shear walls shall comply with the requirements of Section 2.2 or Section 3.2. 1.18.3.2.3 Detailed plain (unreinforced) masonry shear wal/s - Design of detailed plain (unreinforced) masonry shear walls shall comply with the requirements of Section 2.2 or Section 3.2, and shall comply with the requirements of Section 1.18.3.2.3.1. COMMENTARY 1.18.3.2.1 Empirica/ design of masonry shear wa/ls - These shear walls are permitted to be used only in Seismic Design eategory A. Empírica( masonry shear walls are not designed or required to contain reinforcement. 1.18.3.2.2 Ordinary plain (unreinforced) masonry shear walls- These shear walls are permitted to be used only in Seismic Design eategories A and B. Plain masonry walls are designed as unreinforced masonry, although they may in fact contain reinforcement. 1.18.3.2.3 Detai/ed p/ain (unreinforced) masomy shear walls - These shear walls are designed as plain (unreinforced) masonry in accordance with the sections noted, but contain mínimum reinforcement in the horizontal and vertical directions. Walls that are designed as unreinforced, but that contain mínimum prescriptive reinforcement, have more favorable seismic design parameters, including higher response modification coefficients, R, than ordinary plain (unreinforced) masonry shear walls.
- 71. C-58 CODE 1.18.3.2.3.1 Minimum reinforcement requirements- Vertical reinforcement of at least 0.2 in? (129 mm2 ) in cross-sectional area shall be provided at corners, within 16 in. (406 mm) of each side of openings, within 8 in. (203 mm) of each side of movement joints, within 8 in. (203 mm) of the ends of walls, and at a maximum spacing of 120 in. (3048 mm) on center. Vertical reinforcement adjacent to openings need not be provided for openings smaller than 16 in. (406 mm), unless the distributed reinforcement is interrupted by such openings. Horizontal reinforcement shall consist of at least two longitudinal wires of Wl.7 (MW II ) joint reinforcement spaced not more than 16 in. (406 mm) on center, or at least 0.2 in.2 (129 mm2 ) in cross-sectional area of bond beam reinforcement spaced not more than 120 in. (3048 mm) on center. Horizontal reinforcement shall also be provided at the bottom and top of wall openings and shall extend not less than 24 in. (6 1O mm) nor less than 40 bar diameters past the opening, continuously at structurally connected roof and floor levels, and within 16 in. (406 mm) ofthe top ofwalls. Horizontal reinforcement adjacent to openings need not be provided for openings smaller than 16 in. (406 mm), unless the distributed reinforcement is interrupted by such openings. 1.18.3.2.4 Ordinary reinforced masonry shear walls - Design of ordinary reinforced masonry shear walls shall comply with the requirements of Section 2.3 or Section 3.3, and shall comply with the requirements ofSection 1.18.3.2.3.1. 1.18.3.2.5 Intermedia/e reinforced masonry shear walls - Design of intermediate reinforced masonry shear walls shall comply with the requirements of Section 2.3 or Section 3.3. Reinforcement detailing shall also comply with the requirements of Section 1.1 8.3.2.3. 1, except that the spacing of vertical reinforcement shall not exceed 48 in. (1219 mm). TMS 402-11/ACI530-11 /ASCE 5·11 COMMENTARY 1.18.3.2.3.1 Minimum reinforcement requirements - The provisions of this section require a judgment-based mínimum amount of reinforcement to be included in reinforced masonry wall construction. Tests reported in Reference 1.46 have confumed that masonry construction, reinforced as indicated, performs adequately considering the highest Seismic Design Category permitted for this shear wall type. This mínimum required reinforcement may also be used to resist design loads. 1.18.3.2.4 Ordinary reinforced masonry shear walls - These shear walls are required to meet mínimum requirements for reinforced masonry as noted in the referenced sections. Because they contain reinforcement, these walls can generally accommodate larger deformations and exhibit higher capacities than sirnilarly configured plain (unreinforced) masonry walls. Hence, they are permitted in both areas of low and moderate seismic risk. Additionally, these walls have more favorable seismic design parameters, including higher response moditication factors, R, than plain (unreinforced) masonry shear walls. To provide the mínimum leve! of assumed inelastic ductility, however, mínimum reinforcement is required as noted in Section 1.18.3.2.3.1. 1.18.3.2.5 Jntermediate reinforced masonry shear walls- These shear walls are designed as reinforced masonry as noted in the referenced sections, and are also required to contain a mínimum amount of prescriptive reinforcement. Because they contain reinforcement, their seismic performance is better than that of plain (unreinforced) masonry shear walls, and they are accordingly permitted in both areas of low and moderate seismic risk. Additionally, these walls have more favorable seismic design parameters including higher response modification factors, R, than plain (unreinforced) masonry shear walls and ordinary reinforced masonry shear walls.
- 72. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-59 CODE 1.18.3.2.6 Special reinforced masonry shear walls - Design of special reinforced masonry shear walls shall comply with the requirements of Section 2.3 or Section 3.3. Reinforcement detailing shall also comply with the requirements ofSection 1.18.3.2.3.1 and the following: (a) The maximum spacing of vertical reinforcement shall be the smallest ofone-third the length ofthe shear wall, one-third the height of the shear wall, and 48 in. (1219 mm) for masonry laid in running bond and 24 in. (610 mm) for masonry not laid in running bond. (b) The maximum spacing of horizontal reinforcement required to resist in-plane shear shall be uniformly distributed, shall be the smaller of one-third the length of the shear wall and one-third the height of the shear wall, and shall be embedded in grout. The maximum spacing ofhorizontal reinforcement shall not exceed 48 in. (1219 mm) for masonry laid in running bond and 24 in. (6 10 mm) for masonry not laid in running bond. (e) The mínimum cross-sectional area of vertical reinforcement shall be one-third of the required shear reinforcement. The sum of the cross-sectional area of horizontal and vertical reinforcement shall be at least 0.002 multiplied by the gross cross-sectional area of the wall, using specified dimensions. l . for masonry laid in running bond, the mínimum cross-sectional area of reinforcement in each direction shall be not less than 0.0007 multiplied by the gross cross-sectional area of the wall, using specified dimensions. 2. For masonry not laid in running bond, the mm1mum cross-sectional area of vertical reinforcement shall be not less than 0.0007 multiplied by the gross cross-sectional area ofthe wall, using specified dimensions. The mínimum cross-sectional area of horizontal reinforcement shall be not less than 0.0015 multiplied by the gross cross-sectional area of the wall, using specified dimensions. (d) Shear reinforcement shall be anchored around vertical reinforcing bars with a standard hook. (e) Masonry not laid in running bond shall be fully grouted and shall be constructed of hollow open-end units or two wythes ofsolid units. 1.183.2.6.1 Shear capacity design COMMENTARY 1.183.2.6 Special reinforced masonry shear walls - These shear walls are designed as reinforced masonry as noted in the referenced sections and are also required to meet restrictive reinforcement and material requirements. Accordingly, they are permitted to be used as part of the seismic-force-resisting system in any Seismic Design Category. Additionally, these walls have the most favorable seismic design parameters, including the highest response modification factor, R, of any of the masonry shear wall types. The intent of Sections 1.18.3.2.6(a) through 1.18.3.2.6(e) is to provide a minimum level of in-plane shear reinforcement to improve ductility. 1.183.2.6.1 Shear capacity design - While different concepts and applications, the requirements of Code Section 1.18.3.2.6.1.1 and 1.18.3.2.6.1.2 are different methods ofattempting to limit shear failures prior to nonlinear flexural behavior - or if one prefers - increase element ductility. The MSJC recognizes the slight discrepancy between the 2.5 design cap in Code Section 1.18.3.2.6.1.1 and the 1.5 load factor in Code Section 1.18.3.2.6.1.2. Given the historical precedence of each of
- 73. C-60 CODE 1.18.3.2.6.1.1 When designing special reinforced masonry shear walls in accordance with Section 3.3, the design shear strength, t/J V," shall exceed the shear corresponding to the development of 1.25 times the nominal flexura! strength, M11 , of the element, except that the nominal shear strength, V,,, need not exceed 2.5 times required shear strength, V,,. 1.18.3.2.6.1.2 When designing special reinforced masonry shear walls in accordance with Section 2.3, the shear or diagonal tension stress resulting from in-plane seismic forces shall be increased by a factor of 1.5. The 1.5 multiplier need not be applied to the overturning moment. 1.18.3.2.7 Ordinary plain (unreinforced) AAC masonry shear walls - Design of ordinary plain (unreinforced) AAC masonry shear walls shall comply with the requirements ofSection 8.2 and Section 1.18.3.2.7.l. 1.18.3.2.7.1 Anchorage ofjloor and roofdiaphragms in AAC masonry structures- Floor and roof diaphragms in AAC masonry structures shall be anchored to a continuous grouted bond beam reinforced with at least two longitudinal reinforcing bars, having a total cross-sectional area of at least 0.4 in? (260 mm2 ). 1.18.3.2.8 Detailed plain (unreinforced) AAC masonry shear walls - Design of detailed plain (unreinforced) AAC masonry shear walls shall comply with the requirements of Section 8.2 and Sections 1.18.3.2.7.1 and 1.18.3.2.8.1. TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY these values, the Committee opted to maintain the two distinct values. When all factors and requirements for special reinforced masonry shear walls are considered, the resulting difference between the two requirements is small. 1.18.3.2.6.1.1 ln previous editions of the Code, this design requirement was applied to all masonry elements designed by the strength design method (elements participating in the seismic-force-resisting system as well as those not participating in the seismic-force- resisting system, reinforced masonry elements, and unreinforced masonry elements) as well as all loading conditions. Upon further review, this design check was considered by the Committee to be related to inelastic ductility demand for seismic resistance and was therefore specifically applied to the seismic design requirements. Further, because unreinforced masonry systems by nature exhibit limited ductility, this check is required only for special reinforced masonry shear walls. 1.18.3.2.6.1.2 The 1.5 load factor for reinforced masonry shear walls that are part of the seismic-force-resisting system designed by allowable stress design procedures is applied only to in-plane shear forces. It is not intended to be used for the design of in- plane overturning moments or out-of-plane overturning moments or shear. Increasing the design seismic load is ínlended to make the flexure mode of faílure more domínant, resulting in better ductile performance. 1.18.3.2.7 Ordinary plain (unreinforced) AAC masonry shear walls- These shear walls are philosophically similar in concept to ordinary plain (unreinforced) masonry shear walls. As such, prescriptive mild reinforcement is not required, but may actually be present. 1.18.3.2.8 Detailed plain (unreinforced) AAC masonry shear walls - Prescriptive seismic requirements for AAC masonry shear walls are less severe than for conventional masonry shear walls, and are counterbalanced by more restrictive Code requirements for bond beams and additional requirements for floor diaphragms, contained in evaluation service reports and other documents dealing with tloor diaphragms ofvarious materials. AAC masonry shear walls and a full-scale, two-story assemblage specimen with prescriptive reinforcement meeting the requirements of this section have performed satisfactorily under reversed cyclic loads representing seismic excitation (References 8.3 and 8.1). The maximum distance from the edge of an opening or end of a wall to the vertical reinforcement is set at 24 in. (61Omm) since the typical length of an AAC unit is 24 in. (610 mm).
- 74. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-61 CODE 1.18.3.2.8.1 Minimum reinforcement requirements - Vertical reinforcement of at least 0.2 in.2 (129 mm2 ) shall be provided within 24 in. (6 10 mm) of each side ofopenings, within 8 in. (203 mm) of movement joints, and within 24 in. (610 mm) of the ends of walls. Vertical reinforcement adjacent to openings need not be provided for openings smaller than 16 in. (406 mm), unless the distributed reinforcement is interrupted by such openings. Horizontal reinforcement shall be provided at the bottom and top of wall openings and shall extend not less than 24 in. (610 mm) nor less than 40 bar diameters past the opening. Horizontal reinforcement adjacent to openings need not be provided for openings smaller than 16 in. (406 mm), unless the distributed reinforcement is interrupted by such openings. 1.18.3.2.9 Ordinary reinforced AAC masonry shear wal/s - Design of ordinary reinforced AAC masonry shear walls shall comply with the requirements ofSection 8.3 and Sections 1.18.3.2.7. 1 and 1.18.3.2.8. 1. 1.18.3.2.9.1 Shear capacity design - The design shear strength, ~ Vn , shall exceed the shear corresponding to the development of 1.25 times the nominal flexura) strength, M,, , of the element, except that the nominal shear strength, Vn , need not exceed 2.5 times required shear strength, V.,. 1.18.3.2.10 Ordinary plain (unreinforced) prestressed masonry shear walls - Design of ordinary plain (unreinforced) prestressed masonry shear walls shall comply with the requirements ofChapter 4. 1.18.3.2.11 Intermedia/e reinforced prestressed masonry shear wal/s - Interrnediate reinforced prestressed masonry shear walls shall comply with the requirements of Chapter 4, the reinforcement detailing requirements ofSection 1.18.3.2.3.1, and the following: (a) Reinforcement shall be provided in accordance with Sections 1.18.3.2.6(a) and 1.18.3.2.6(b). (b) The mínimum area of horizontal reinforcement shall be 0.0007bdv. (e) Shear walls subjected to load reversals shall be symmetrically reinforced. (d) The nominal moment strength at any section along the shear wall shall not be Jess than one-fourth the maximum moment strength. (e) The cross-sectional area of bonded tendons shall be considered to contribute to the mtmmum reinforcement in Sections 1.18.3.2.3.1, 1.18.3.2.6(a), and 1. 18.3.2.6(b). (t) Tendons shall be located in cells that are grouted the COMMENTARY 1.18.3.2.9 Ordinary masonryshear walls reinforced AAC 1.18.3.2.10 Ordinary plain (unreinforced) prestressed masonry shear walls - These shear walls are philosophically similar in concept to ordinary plain (unreinforced) masonry shear walls. As such, prescriptive mild reinforcement is not required, but may actually be present. 1.18.3.2.11 Intermedia/e reinforced prestressed masonry shear walls - These shear walls are philosophically similar in concept to interrnediate reinforced masonry shear walls. To provide the intended leve! of inelastic ductility, prescriptive mild reinforcement is required. For consistency with 2003 lBC, interrnediate reinforced prestressed masonry shear walls should include the detailing requirements from Section 1.18.3.2.6 (a) as well as Sections 3.2.3.5 and 3.2.4.3.2 (e) from the 2002 MSJC. ASCE 7, Tables 12.2-1 and 12.14-1 conservatively combine all prestressed masonry shear walls into one category for seismic coefficients and structural system limitations on seismic design categories and height. The design limitations included in those tables are representative ofordinary plain (unreinforced) prestressed masonry shear walls. The criteria specific to intermediate reinforced prestressed shear walls have not yet been included from JBC 2003, Table 1617.6.2. To utilize the seismic criteria from lBC 2003, the structure would have to be accepted under 1.3 Approval of special systems of design and construction. The seismic coefficients from IBC 2003, Table
- 75. C-62 CODE full height ofthe wall. 1.18.3.2.12 Special reinforced prestressed masonry shear walls - Special reinforced prestressed masonry shear walls shall comp1y with the requirements of Chapter 4, the reinforcement detailing requirements of Sections 1.18.3.2.3.1 and 1.18.3.2.11 and thefollowing: (a) The cross-sectional area of bonded tendons shall be considered to contribute to the mínimum reinforcement in Sections 1.18.3.2.3.1 and 1.18.3.2.11. (b) Prestressing tendons shall consist of bars conforming to ASTM A722/A722M. (e) All cells ofthe masonry wall shall be grouted. (d) The requirements ofSection 3.3.3.5 or 3.3.6.5 shall be met. Dead load axial forces shall include the effective prestress force, Ap/s.. (e) The design shear strength, ~ Vn , shall exceed the shear corresponding to the development of l.25 times the nominal flexura( strength, Mn , of the element, except that the nominal shear strength, V,, , need not exceed 2.5 times required shear strength, V,, . TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY 1617.6.2 and the building height limitations based upon seismic design category are shown in Table CC-1.18.3.2-2. 1.18.3.2.12 Special reinforced preslressed masonry shear walls - These shear walls are philosophically similar in concept to special reinforced masonry shear walls. To provide the intended leve! of inelastic ductility, prescriptive mild reinforcement is required. For consistency with 2003 lBC, special reinforced prestressed masonry shear walls should include the detailing requirements from Sections 3.2.3.5 and 3.2.4.3.2 (e) from the 2002 MSJC. ASCE 7, Table 12.2-1 and ASCE 7, Table 12.14-1 conservatively combine all prestressed masonry shear walls into one category for seismic coefficients and structural system limitations on seismic design categories and height. The design limitations included in those tables are representative of ordinary plain (unreinforced) prestressed masonry shear walls. The criteria specific to special reinforced prestressed shear walls have not yet been included from lBC 2003, Table 1617.6.2. To utilize the seismic criteria from lBC 2003, the structure would have to be accepted under 1.3 Approva1 of special systems of design and construction. See Table CC-1.18.3.2-2. The data in this table is similar to ASCE 7, Table 12.2-1. Users that prefer to use the Simplified Design Procedure in ASCE 7 should interpret the tab1e for use in lieu ofASCE 7, Tab1e 12.14-1. TABLE CC-1 .18.3.2-2 2003 IBC Seismic Coefficients for Prestressed Masonry Shear Walls SYSTEM LIMITATIONS AND BUILDING HEIGHT LIMITATIONS (FEET) BY SEISMIC DESIGN CATEGORY Response System Detlection A orB e D E F Modification Overstrength Amplification Coefficient,R Factor,00 Factor,Cd Ordinary 1!h 2!h y. NL NP NP NP NP Plain Prestressed Intermediate 3 for Building 2!h 2!h NL 35 NP NP NP Reinforced Frame System Prestressed and 2-1/2 for Bearing Wall System Special 4!h 2!h 4 for Building NL 35 35 35 35 Reinforced Frame System and Prestressed 3Yzfor Bearing Wall System NL = no Iimit NP = not permitted The data in this table is similar to ASCE 7, Table 12.2-1. Users that prefer to use the Simplified Design Procedure in ASCE 7 should interpret the table for use in lieu ofASCE 7, Table 12.14-1.
- 76. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-63 CODE 1.18.4 Seismic Design eategory requiremenls The design of masonry elements shall comply with the requirements of Sections l.l8.4.1 through 1.18.4.5 based on the Seismic Design Category as defined in the legally adopted building code. When the legally adopted building code does not define Seismic Design Categories, the provisions of ASCE 7 shall be used. 1.18.4.1 Seismic Design eategory A requirements Masonry elements in structures assigned to Seismic Design Category A shall comply with the requirements of Sections 1.1 8.1, 1.18.2, 1.18.4.1.1, and 1.18.4.1.2. 1.18.4.1.1 Design of nonparticipating elements - Nonparticipating masonry elements shall comply with the requirements of Section 1.18.3.1 and Chapter 2, 3, 4, 5 or 8. 1.18.4.1.2 Design ofparlicipaling elemenls - Participating masonry elements shall be designed to comply with the requirements of Chapter 2, 3, 4, or 5 or 8. Masonry shear walls shall be designed to comply with the requirements of Section 1.18.3.2.1, 1.18.3.2.2, 1.18.3.2.3, 1.18.3.2.4, l.l8.3.2.5, 1.18.3.2.6, 1.18.3.2.7, 1.18.3.2.8, 1.18.3.2.9, 1.18.3.2.10, 1.18.3.2.11, or 1.18.3.2.12. 1.18.4.2 Seismic Design eategory B requirements- Masonry elements in structures assigned to Seismic Design Category B shall comply with the requirements of Section 1.18.4.1 and with the additional requirements of Section 1.18.4.2.1. 1.18.4.2.1 Design ofparticipating elements Participating masonry elements shall be designed to comply with the requirements of Chapter 2, 3, or 4 or 8. Masonry shear walls shall be designed to comply with the requirements of Section 1.18.3.2.2, 1.18.3.2.3, 1.18.3.2.4, 1.18.3.2.5, 1.18.3.2.6, 1.18.3.2.7, 1.18.3.2.8, 1.18.3.2.9, 1.18.3.2.10, 1.18.3.2.11, or 1.18.3.2.12. 1.18.4.3 Seismic Design eategory e requirements - Masonry elements in structures assigned to Seismic Design Category C shall comply with the requirements of Section 1.18.4.2 and with the additional requirements ofSection 1.18.4.3.1 and 1.18.4.3.2. COMMENTARY 1.18.4 Seismic Design eategory requirements Every structure is assigned to a Seismic Design Category (SDC) in accordance with the legally adopted building code or per the requirements ofASCE 7, whichever govem for the specific project under consideration. Previous editions of the Code included requirements for Seismic Performance Categories and Seismic Zones, each ofwhich is different than a Seismic Design Category. 1.18.4.1 Seismic Design eategory A requirements - The general requirements of this Code provide for adequate performance of masonry construction assigned to Seismic Design Category A structures. 1.18.4.2 Seismic Design eategory B requirements- Although masonry may be designed by the provisions of Chapter 2, Allowable Stress Design of Masonry; Chapter 3, Strength Design of Masonry; Chapter 4, Prestressed Masonry; Chapter 5, Empirical Design of Masonry; or Chapter 8, Strength Design of Autoclave Aerated Concrete (AAC) Masonry, the seismic-force- resisting system for structures assigned to Seismic Design Category B must be designed based on a structural analysis in accordance with Chapter 2, 3, or 4 or 8. The provisions of Chapter 5 cannot be used to design the seismic-force- resisting system of buildings assigned to Seismic Design Category B or higher. 1.18.4.3 Seismic Design eategory e requirements- In addition to the requirements of Seismic Design Category B, mínimum levels of reinforcement and detailing are required. The mínimum provisions for improved performance of masonry construction in Seismic Design Category C must be met regardless ofthe method of design. Shear walls designed as part of the seismic-force- resisting system in Seismic Design Category C and higher must be designed using reinforced masonry methods because of the increased risk and expected intensity of
- 77. C-64 CODE 1.18.4.3.1 Design of nonparticipating efements - Nonparticipating masonry elements shall comply with the requirements of Section 1.18.3. 1 and Chapter 2, 3, 4, 5, or 8. Nonparticipating masonry elements, except those constructed of AAC masonry, shall be reinforced in either the horizontal or vertical direction in accordance with the following: (a) Horizontal reinforcement- Horizontal reinforcement shall consist of at least two longitudinal wires of W l.7 (MW11) bedjoint reinforcement spaced not more than 16 in. (406 mm) on center for walls greater than 4 in. (102 mm) in width and at least one longitudinal W 1.7 (MWll) wire spaced ·not more 16 in. (406 mm) on center for walls not exceeding 4 in. (102 mm) in width or at least one No. 4 (M #13) bar spaced not more than 48 in. (1219 mm) on center. Where two longitudinal wires of joint reinforcement are used, the space between these wires shall be the widest that the mortar joint will accommodate. Horizontal reinforcement shall be provided within 16 in. (406 mm) of the top and bottom ofthese masonry walls. (b) Vertical reinforcement - Vertical reinforcement shall consist of at least one No. 4 (M #13) bar spaced not more than 120 in. (3048 mm). Vertical reinforcement shall be located within 16 in. (406 mm) ofthe ends of masonry walls. 1.18.43.2 Design of participating elements - Participating masonry elements shall be designed to comply with the requirements of Section 2.3, 3.3, or 8.3. Masonry shear walls shall be designed to comply with the requirements of Section 1.18.3.2.4, 1.18.3.2.5, 1.18.3.2.6, 1.18.3.2.9, 1.18.3.2.11, or 1.18.3.2. 12. 1.18.4.3.2.1 Connections lo masonry co/umns - Connections shall be designed to transfer forces between masonry columns and horizontal elements in accordance with the requirements of Section 1.7.4. Where anchor bolts are used to connect horizontal elements to the tops of columns, anchor bolts shall be placed within lateral ties. Lateral ties shall enclose both the vertical bars in the column and the anchor bolts. There shall be a mínimum of two No. 4 (M # 13) lateral ties provided in the top 5 in. (127 mm) ofthe column. 1.18.4.3.2.2 Anchorage ofjloor and roof diaphragms in AAC masomy structures - Seismic load between floor and roof diaphragms and AAC masonry shear walls shall be transferred through connectors embedded in grout and designed in accordance with Section 1.7.4. TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY seismic activity. Ordinary reinforced masonry shear walls, ordinary reinforced AAC masonry shear walls, intermediate reinforced masonry shear walls, or special reinforced masonry shear walls are required to be used. 1.18.4.3.1 Design of nonparticipating e/ements - Reinforcement requirements of Section 1.18.4.3.1 are traditional for conventional concrete and clay masonry. They are prescriptive in nature. Tbe intent of this requirement is to provide structural integrity for nonparticipating masonry walls. AAC masonry walls differ from concrete masonry walls and clay masonry walls in that the thin-bed mortar strength and associated bond strength is typically greater than that of the AAC units. Also, the unit weight of AAC masonry is typically less than one-third of the unit weight of clay or concrete masonry, reducing seismic inertial forces. This reduced load, combined with a tensile bond strength that is higher than the strength of the AAC material itself, provides a mínimum leve! ofstructural integrity and prescriptive reinforcement is not required. All masonry walls, including non-participating AAC masonry walls, are required to be designed to resist out-of-plane forces. If reinforcement is required, it must be provided in the direction ofthe span. 1.18.4.3.2.1 Connections to masonry co/umns - Experience has demonstrated that connections of structural members to masonry columns are vulnerable to damage during earthquakes unless properly anchored. Requirements are adapted from previously established practice developed as a result ofthe 1971 San Fernando earthquake. 1.18.4.3.2.2 Anchorage ofjloor and roof diaphragms in AAC masonry structures - In Seismic Design Categories C and D additional connectors are required, with the intention of ensuring ductile behavior.
- 78. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-65 CODE 1.18.4.3.2.3 Material requirements - ASTM C34, structural clay load-bearing wall tiles, shall not be used as part of the seismic-force-resisting system. 1.18.4.3.2.4 Lateral stiffness - At each story leve!, at least 80 percent of the lateral stiffness shall be provided by seismic-force-resisting walls. Along each line of lateral resistance at a particular story leve!, at least 80 percent of the lateral stiffness shall be provided by seismic-force-resisting walls. Where seismic loads are deterrnined based on a seismic response modification factor, R, not greater than 1.5, piers and columns shall be perrnitted to be used to provide seismic load resistance. 1.18.4.3.2.5 Design of columns, pilasters, and beams supporting discontinuous elements - Columns and pilasters that are part of the seismic- force-resisting system and that support reactions from discontinuous stiff elements shall be provided with transverse reinforcement spaced at no more than one- fourth of the least nominal dimension of the column or pilaster. The mínimum transverse reinforcement ratio shall be 0.00 15. Beams supporting reactions from discontinuous walls shall be provided with transverse reinforcement spaced at no more than one-half of the nominal depth of the bearn. The mínimum transverse reinforcement ratio shall be 0.0015. COMMENTARY 1.18.4.3.2.3 Material requirements - The limitation on the use of ASTM C34 structural clay tile units in the seismic-force-resisting system is based on these units' limited ability to provide inelastic strength. 1.18.4.3.2.4 Lateral stiffness - In order to accurately distribute loads in a structure subjected to lateral loading, the lateral stiffness of all structural members should be considered. Although structures may be designed to use shear walls for lateral-load resistance, columns may also be incorporated for vertical capacity. The stipulation that seismic-force-resisting elements provide at least 80 percent of the lateral stiffness helps ensure that additional elements do not significantly contribute to the lateral stiffness. Based on typical design assumptions, the lateral stiffness of structural elements should be based on cracked section properties for reinforced masonry and uncracked section properties for unreinforced masonry. The designer may opt to increase the percentage of lateral stiffuess provided by piers and columns ifthe structure is designed to perforrn elastically under seismic loads. 1.18.4.3.2.5 Design of columns, pilasters, and beams supporting discontinuous elements - Discontinuous stiff members such as shear walls have global overturning forces at their edges that may be supported by columns, pilasters and bearns. These vertical support elements are required to have a mínimum leve! of confinement and shear detailing at the discontinuity leve!. The mínimum detailing requirements in this section may be in excess of those requirements that are based on calculations using full-height relative stiffnesses of the elements ofthe seismic-force-resisting system. A common example is a building with interna! shear walls, such as interior corridor walls, that are discontinuous at the first story above grade or in a basement leve!. If this structure has a rigid diaphragm at all floor and roof levels; the global (full height) relative stiffnesses of the discontinuous elements is minor in comparison to the relative stiffnesses of the continuous elements at the perimeter of the structure. All shear walls above the discontinuity, however, have a forced common interstory displacement. This forced interstory displacement induces overturning forces in the discontinuous shear walls at all levels having this forced story displacement. The accumulated overturning forces at the ends of the walls above the discontinuity in tum are likely to be supported by columns and pilasters in the discontinuous levels and the beams at the leve! above the discontinuity. This section specifies minimum detailing requirements for these columns, pilasters, and beams. The detennining of the stiffness of the discontinuous element should be based on the relative stiffness of the discontinuous members above and below the discontinuity. Guidance as to the definition of stiff can be based on the
- 79. C-66 CODE 1.18.4.4 Seismic Design Category D requirements - Masonry elements in structures assigned to Seismic Design Category D shall comply with the requirements of Section 1.18.4.3 and with the additional requirements of Sections 1.18.4.4.1 and 1.18.4.4.2. Exception: Design of participating elements of AAC masonry shall comply with the requirements of 1.18.4.3. 1.18.4.4.1 Design of nonparticipating elements - Nonparticipating masonry elements shall comply with the requirements of Chapter 2, 3, 4, or 8. Nonparticipating masonry elements, except those constructed ofAAC masonry, shall be reinforced in either the horizontal or vertical direction in accordance with the following: (a) Horizontal reinforcement - Horizontal reinforcement shall comply with Section 1.1 8.4.3.1(a). (b) Vertical reinforcement - Vertical reinforcement shall consist of at least one No. 4 (M #13) bar spaced not more than 48 in. (1219 mm). Vertical reinforcement shall be located within 16 in. (406 mm) ofthe ends of masonry walls. 1.18.4.4.2 Design ofparticipating elements - Masonry shear walls shall be designed to comply with the requirements ofSection 1.1 8.3.2.6, 1.18.3.2.9, or 1.18.3.2.12. 1.18.4.4.2.1 Mínimum reinforcement for masonry columns - Lateral ties in masonry columns shall be spaced not more than 8 in. (203 mm) on center and shall be at least 3/8 in. (9.5 mm) diameter. Lateral ties shall be embedded in grout. TMS 402-11IACI 530-11 /ASCE 5-1 1 COMMENTARY relative interstory stiffness of the discontinuous member above and below the discontinuity is given in Code Sections 1.18.4.3.2.5, 3.1.3, and 8.1.3. If the interstory stiffness of the discontinuous wall below the discontinuity is less than 20% of the interstory stiffness above the discontinuity; the discontinuous member should be considered stiff. 1.18.4.4 Seismic Design Category D requirements - Masonry shear walls for structures assigned to Seismic Design Category D are required to meet the requirements ofspecial reinforced masonry shear walls or ordinary reinforced AAC masonry shear walls because of the increased risk and expected intensity of seismic activity. The mm1mum amount of wall reinforcement for special reinforced masonry shear walls has been a long-standing, standard empírica! requirement in areas of high seismic loading. lt is expressed as a percentage of gross cross-sectional area of the wall. lt is intended to improve the ductile behavior ofthe wall under earthquake loading and assist in crack control. Since the mínimum required reinforcement may be used to satisfy design requirements, at least 1 /3 ofthe mínimum amount is reserved for the lesser stressed direction in order to ensure an appropriate distribution of loads in both directions. 1.18.4.4.1 Design of nonparticipating elements 1.18.4.4.2 Design ofparticipatingelements 1.18.4.4.2.1 Mínimum reinforcement for masonry columns - Adequate lateral restraint is important for column reinforcement subjected to overtuming forces due to earthquakes. Many column failures during earthquakes have been attributed to inadequate lateral tying. For this reason, closer spacing of ties than might otherwise be required is prudent. An arbitrary mínimum spacing has been established through experience. Columns not involved in the seismic-force-resisting system should also be more heavily tied at the tops and bottoms for more ductile performance and better resistance to shear.
- 80. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-67 CODE 1.18.4.4.2.2 Material requirements - Participating elements shall be designed and specified with Type S or Type M cement-lime mortar or mortar cement mortar. 1.18.4.4.2.3 Lateral tie anchorage- Standard hooks for lateral tie anchorage shall be either a 135-degree standard hook ora 180-degree standard hook. 1.18.4.5 Seismic Design Categories E and F requirements - Masonry elements in structures assigned to Seismic Design Category E or F shall comply with the requirements of Section 1.18.4.4 and with the additional requirements ofSection 1.18.4.5.1. 1.18.4.5.1 Mínimum reinforcement for nonparticipating masonry elements not laid in running bond - Masonry not laid in running bond in nonparticipating elements shall have a cross-sectional area of horizontal reinforcement of at least 0.0015 multiplied by the gross cross-sectional area of masonry, using specified dimensions. The maximum spacing ofhorizontal reinforcement shall be 24 in. (610 mm). These elements shall be fully grouted and shall be constructed of hollow open-end units or two wythes of solid units. 1.19- Quality Assurance program The quality assurance program shall comply with the requirements of this section, depending on the Risk Category, as defined in ASCE 7 or the legally adopted building code. The quality assurance program shall itemize the requirements for verifying conformance of material compostttOn, quality, storage, handling, preparation, and placement with the requirements ofTMS 602/ACI 530.1/ASCE 6. COMMENTARY 1.18.4.5 Seismic Design Categories E and F requirements - See Commentary Sections 1.18.3.2.3.1 and 1.18.4.4. The ratio of mínimum horizontal reinforcement is increased to reflect the possibility of higher seismic loads. Where fully grouted open end hollow units are used, part of the need for horizontal reinforcement is satisfied by the mechanical continuity provided by the grout core. 1.19 - Quality Assurance program Mac;onry design provisions in this Code are valid when the quality of masonry construction meets or exceeds that described in the Specification. Therefore, in order to design masonry by this Code, verification of good quality construction is required. The means by which the quality of construction is monitored is the quality assurance program. A quality assurance program must be defined in the contract documents, to answer questions such as "how to", "what method", "how often", and "who determines acceptance". This information is part ofthe administrative and procedural requirements. Typical requirements of a quality assurance program include review of material certifications, field inspection, and testing. The acts of providing submittals, inspecting, and testing are part of the quality assurance program. Since the design and the complexity of masonry construction vary from project to project, so must the extent of the quality assurance program. The contract documents must indicate the testing, inspection, and other measures that are required to assure that the Work is in conformance with the project requirements. Section 1.19 establishes the mínimum criteria required to assure that the quality of masonry construction conforms to the quality upon which the Code-permissible values are based. The scope of the quality assurance program depends on whether the structure is an Risk Category IV structure or not, as defined by ASCE 7 or the legally adopted building code. Because of their importance, Risk Category IV structures are subjected to
- 81. C-68 CODE 1.19.1 Leve! A Quality Assurance The minimum quality assurance program for masonry in Risk Category 1, II, or III structures and designed in accordance with Chapter 5, 6, or 7 shall comply with Table 1.19.l. 1.19.2 Leve! B Quality Assurance 1.19.2.1 The mtmmum quality assurance program for masonry in Risk Category IV structures and designed in accordance with Chapter 6 or 7 shall comply with Table 1.19.2. 1.19.2.2 The mmtmum quality assurance program for masonry in Risk Category 1, II, or III structures and designed in accordance with chapters other than Chapter 5, 6, or 7 shall comply with Table 1.19.2. 1.19.3 Leve! e Quality Assurance The mínimum quality assurance program for masonry in Risk Category IV structures and designed in accordance with chapters other than Chapter 5, 6, or 7 shall comply with Table 1.19.3. 1.19.4 Procedures The quality assurance program shall set forth the procedures for reporting and review. The quality assurance program shall also include procedures for resolution of noncompliances. TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY more extensive quality assurance measures. The leve! of required quality assurance depends on whether the masonry was designed in accordance with Chapters 2, 3, 4, 8, or Appendix B (engineered) or in accordance with Chapters 5, 6, or 7 (empirical or prescriptive). 1.19.1 Leve! A Quality Assurance 1.19.2 Leve/ B Quality Assurance Implementation of testing and inspection requirements contained in Table 1.19.2 requires detailed knowledge of the appropriate procedures. Comprehensive testing and inspection procedures are available from recognized industry sourcesl.47 • 148 • 1. 49 • uo, which may be referenced for assistance in developing and implementing a Quality Assurance program. Installation techniques for AAC masonry and thin-bed mortar differ from concrete and clay masonry. Once it has been demonstrated in the field that compliance is attained for the installation of AAC masonry and thin-bed mortar, the frequency of inspection may be revised from continuous to periodic. However, the frequency of inspection should revert to continuous for the prescribed period whenever new AAC masonry installers work on the project. 1.19.3 Leve! e Quality Assurance Premixed mortars and grouts are delivered to the project site as "trowel ready" or "pourable" materials, respectively. Preblended mortars and grouts are dry combined materials that are mixed with water at the project site. Verification of proportions of premixed or preblended mortars and grouts can be accomplished by review of manufacture's batch tickets (if applicable), a combination of preconstruction and construction testing, or other acceptable documentation. 1.19.4 Procedures In addition to specifying testing and inspection requirements, the quality assurance program must define the procedures for submitting the testing and inspection reports (that is, how many copies and to whom) and define the process by which those reports are to be reviewed. Testing and evaluation should be addressed in the quality assurance program. The program should allow for the selection and approval of a testing agency, which agency should be provided with prequalification test information and the rights for sampling and testing of specific masonry construction materials in accordance with referenced standards. The evaluation of test results by the testing agency should indicate compliance or noncompliance with a referenced standard. Further quality assurance evaluation should allow an
- 82. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-69 CODE 1.19.5 Qua/ifications The quality assurance program shall define the qualifications for testing laboratories and for inspection agencies. Table 1.19.1 - Leve! A Quality Assurance COMMENTARY appraisal of the testing program and the handling of nonconformance. Acceptable values for all test methods should be given in the contract documents. ldentification and resolution of noncomplying conditions should be addressed in the contract documents. A responsible person should be identified to allow resolution of nonconformances. In agreement with others in the design/construct team, the resolutions should be repaired, reworked, accepted as is, or rejected. Repaired and reworked conditions should initiate a reinspection. Records control should be addressed in the contract documents. The distribution of documents during and after construction should be delineated. The review ofdocuments should persist throughout the construction period so that each party is informed and that records for documenting construction occurrences are available and correct after construction has been completed. 1.19.5 Qua/ifications The entities verifying compliance must be competent and knowledgeable of masonry construction and the requirements of this Code. Therefore, mtmmum qualifications for those individuals must also be established by the quality assurance program in the contract documents. The responsible party performing the quality control measures should document the organizational representatives who will be a part of the quality control segment, their qualifications, and their precise conduct during the performance ofthe quality assurance phase. Laboratories that ,comply with the requirements of ASTM Cl093151 are more likely to be familiar with masonry materials and testing. Specifying that the testing agencies comply with the requirements of ASTM C1093 should improve the quality ofthe resulting masonry. MINIMUM TESTS None MINIMUM INSPECTION Verify compliance with the approved submittals
- 83. C-70 TMS 402-11/ACI 530-11/ASCE 5-11 Table 1.19.2- Level B Quality Assurance MINIMUM TESTS Verification ofSlump flow and Visual Stability Index (VSI) as delivered to the project site in accordance with Specification Article 1.5 B.l.b.3 for self- consolidating grout Verification off'm andf'AACin accordance with Specification Article 1.4 B prior to construction, except where specifically exempted by this Code MINIMUM INSPECTION Inspection Task Frequency <•> Reference for Criteria Continuous Periodic TMS 402/ TMS 602/ ACT 530/ ACI 530.1/ ASCE5 ASCE6 l. Verify compliance with the approved submittals X Art. 1.5 2. As masonry construction begins, verify that the following are in compliance: a. Proportions ofsite-prepared mortar X Art. 2.1, 2.6A b. Construction ofmortar joints X Art. 3.3 B c. Grade and size ofprestressing tendons and X Art. 2.4 B, anchorages 2.4 H d. Location ofreinforcement, connectors, and X Art. 3.4, 3.6 A prestressing tendons and anchorages e. Prestressing technique X Art. 3.6 B f. Properties ofthin-bed mortar for AAC masonry x <b> x<cJ Art. 2.1 e 3. Prior to grouting, verify that the following are in compliance: a. Grout space X Art. 3.2 D, 3.2 F b. Grade, type, and size ofreinforcement and X Sec. 1.16 Art. 2.4, 3.4 anchor bolts, and prestressing tendons and anchorages c. Placement of reinforcement, connectors, and X Sec. 1.16 Art. 3.2 E, 3.4, prestressing tendons and anchorages 3.6 A d. Proportions ofsite-prepared grout and X Art. 2.6 B, prestressing grout for bonded tendons 2.4 G.l.b e. Construction ofmortar joints X Art. 3.3 B
- 84. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-71 Table 1.19.2- Level B Quality Assurance (Continued) MINIMUM INSPECTION Inspection Task Frequency (a¡ Reference for Criteria Continuous Periodic TMS 402/ TMS 602/ ACf 530/ ACI 530.1/ ASCE5 ASCE6 4. Verify during construction: a. Size and location of structural elements X Art. 3.3 F b. Type, size, and location of anchors, including X Sec. 1.16.4.3, other details of anchorage ofmasonry to 1.17.1 structural members, frames, or other construction c. Welding ofreinforcement X Sec. 2.1.7.7.2, 3.3.3.4 (e), 8.3.3.4(b) d. Preparation, construction, and protection of X Art. 1.8 e, masonry during cold weather (temperature below 1.8 D 40°F (4.4°C)) or hot weather (temperature above 90°F (32.2°C)) e. Application and measurement ofprestressing X Art. 3.6 B force f. Placement ofgrout and prestressing grout for X Art. 3.5, 3.6 C bonded tendons is in compliance g. Placement ofAAC masonry units and x<b> x<c) Art. 3.3 B.8 construction ofthin-bed mortar joints 5. Observe preparation ofgrout specimens, mortar X Art. 1.4 B.2.a.3, specimens, and/or prisms 1.4 B.2.b.3, 1.4 B.2.c.3, 1.4 B.3, 1.4 B.4 (a) Frequency refers to the frequency ofinspection, which may be continuous during the task listed or periodically during the listed task, as defined in the table. (b) Required for the first 5000 square feet (465 square meters) ofAAC masonry. (e) Required after the first 5000square feet (465 square meters) ofAAC masonry
- 85. C-72 TMS 402-11/ACI 530-11/ASCE 5-11 Table 1.19.3- Level C Quality Assurance MINIMUM TESTS Verification off'm andf'AAc in accordance with Article 1.4 B prior to construction and for every 5,000 sq. ft (465 sq. m) during construction Verification ofproportions ofmaterials in premixed or preblended mortar, prestressing grout, and grout other than self-consolidating grout, as delivered to the project site Verification of Slump flow and Visual Stability lndex (VSI) as delivered to the project site in accordance with Article 1.5 B.l.b.3 for self-consolidating grout MINIMUM INSPECTION Inspection Task Frequency <•> Reference for Criteria eontinuous Periodic TMS 402/ TMS 602/ Aei 530/ Ael530.11 ASeE5 ASeE6 l. Verify compliance with the approved submittals X Art. 1.5 2. Verify that the following are in compliance: a. Proportions of site-mixed mortar, grout and X Art. 2.1, 2.6 A, prestressing grout for bonded tendons 2.6 B, 2.6 e, 2.4 G.l.b b. Grade, type, and size ofreinforcement and anchor X Sec. 1.16 Art. 2.4, 3.4 bolts, and prestressing tendons and anchorages c. Placement ofmasonry units and construction of X Art. 3.3 B mortar joints d. Placement ofreinforcement, connectors, and X Sec. 1.16 Art. 3.2 E, 3.4, prestressing tendons and anchorages 3.6A e. Grout space prior to grouting X Art. 3.2 D, 3.2 F f. Placement ofgrout and prestressing grout for X Art. 3.5, 3.6 e bonded tendons g. Size and location ofstructural elements X Art. 3.3 F h. Type, size, and location ofanchors including X Sec. 1.16.4.3, other details ofanchorage ofmasonry to 1.17.1 structural members, frames, or other construction l. Welding ofreinforcement X Sec. 2.1.7.7.2, 3.3.3.4 (e), 8.3.3.4(b) J. Preparation, construction, and protection of X Art. 1.s e, masonry during cold weather (temperature below 1.8D 40°F (4.4°C)) or hot weather (temperature above 90°F (32.2°e)) k. Application and measurement ofprestressing X Art. 3.6 B force l. Placement ofAAe masonry units and X Art. 3.3 B.8 construction ofthin-bed mortar joints m. Properties ofthin-bed mortar for AAe masonry X Art. 2.1 e. l 3. Observe preparation of grout specimens, mortar X Art. 1.4 B.2.a.3, specimens, and/or prisms 1.4 B.2.b.3, 1.4 B.2.c.3, 1.4 B.3, 1.4 B.4 (a) Frequency refers to the frequency ofinspection, which may be continuous during the task listed or periodically during the listed task, as defíned in the table.
- 86. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-73 CODE 1.19.6 Acceptance relative to strength requirements 1.19.6.1 Compliance with f ', - Compressive strength of masonry shall be considered satisfactory if the compressive strength of each masonry wythe and grouted collarjoint equals or exceeds the value off', . 1.19.6.2 Determina/ion of compressive strength - Compressive strength of masonry shall be determined in accordance with the provisions of TMS 602/ACJ 530.1/ASCE 6. 1.20 - Construction 1.20.1 Grouting, mínimum spaces The mínimum dimensions of spaces provided for the placement of grout shall be in accordance with Table 1.20.1. Grout pours with heights exceeding those shown in Table 1.20.1, cavity widths, or cell sizes smaller than those permitted in Table 1.20.1 or grout lift heights exceeding those permitted by Article 3.5 D of TMS 602/ACI 530.1/ASCE 6 are permitted if the results of a grout demonstration panel show that the grout spaces are filled and adequately consolidated. In that case, the procedures used in constructing the grout demonstration panel shall be the mínimum acceptable standard for grouting, and the quality assurance program shall include inspection during construction to verify grout placement. COMMENTARY 1.19.6 Acceptance relative to strength requirements Fundamental to the structural adequacy of masonry construction is the necessity that the compressive strength of masonry equals or exceeds the specified strength. Rather than mandating design based on different values off', for each wythe of a multiwythe wall construction made of differing material, this Code requires the strength ofeach wythe and of grouted collar joints to equal or exceedf ~. for the portian of the structure considered. Tfa multiwythe wall is designed as a composite wall, the compressive strength of each wythe or grouted collarjoint should equal or exceedf~ •. 1.20 - Construction The TMS 602/ACI 530.1/ASCE 6 Specification covers material and construction requirements. lt is an integral part of the Code in terms of mínimum requirements relative to the composition, quality, storage, handling, and placement of materials for masonry structures. The Specification also includes provisions requiring verification that construction achieves the quality specified. The construction must conform to these requirements in arder for the Code provisions to be valid. 1.20.1 Grouting, minimum spaces Code Table 1.20.1 contains the least clear dimension for grouting between wythes and the mínimum cell dimensions when grouting hollow units. Selection of units and bonding pattern should be coordinated to achieve these requirements. Vertical alignment of cells must also be considered. Projections or obstructions into the grout space and the diameter of horizontal reinforcement must be considered when calculating the mínimum dimensions. See Figure CC-1.20-l. Coarse grout and fine grout are differentiated by aggregate size in ASTM C476. The grout space requirements of Code Table 1.20.1 are based on usual grout aggregate size and cleaning practice to permit the complete filling of grout spaces and adequate consolidation using typical methods of construction. Grout spaces smaller than specified in Table 1.20.1 have been used successfully in sorne areas. When the designer is requested to accept a grouting procedure that exceeds the limits in Table 1.20.1, construction of a grout demonstration panel is required. Destructive or non-destructive evaluation can confirm that filling and adequate consolidation have been achieved. The designer should establish criteria for the grout demonstration panel to assure that critica) masonry elements included in the construction will be represented in the demonstration panel. Because a single grout demonstration panel erected prior to masonry construction cannot account for all conditions that may be encountered during construction, the designer should establish inspection procedures to verify grout placement
- 87. C-74 CODE 1.20.2 Embedded conduits, pipes, and sleeves Conduits, pipes, and sleeves of any material to be embedded in masonry shall be compatible with masonry and shall comply with the following requirements. 1.20.2.1 Conduits, pipes, and sleeves shall not be considered to be structural replacements for the displaced masonry. The masonry design shall consider the structural effects ofthis displaced masonry. 1.20.2.2 Conduits, pipes, and sleeves in masonry shall be no closer than 3 diameters on center. Mínimum spacing of conduits, pipes or sleeves of different diameters shall be deterrnined using the larger diameter. 1.20.2.3 Vertical conduits, pipes, or sleeves placed in masonry columns or pilasters shall not displace more than 2 percent ofthe net cross section. 1.20.2.4 Pipes shall not be embedded in masonry when: (a) Containing Iiquid, gas, or vapors at temperature higher than 150° F (66°C). (b) Under pressure in excess of 55 psi (379 kPa). (e) Containing water or other liquids subject to freezing. TMS 402-111ACI 530-111ASCE 5-11 COMMENTARY during construction. These inspection procedures should include destructive or non-destructive evaluation to confirm that filling and adequate consolidation have been achieved. 1.20.2 Embedded conduits, pipes, and sleeves 1.20.2.1 Conduits, pipes, and sleeves not harmful to mortar and grout may be embedded within the masonry, but the masonry member strength should not be less than that required by design. Effects of reduction in section properties in the areas of conduit, pipe, or sleeve embedment should be considered. For the integrity of the structure, conduit and pipe fittings within the masonry should be carefully positioned and assembled. The coupling size should be considered when deterrnining sleeve size. Aluminum should not be used in masonry unless it is effectively coated or covered. Aluminum reacts with ions, and may also react electrolytically with steel, causing cracking ancl/or spalling of the masonry. Aluminum electrical conduits present a special problem since stray electric current accelerates the adverse reaction. Pipes and conduits placed in masonry, whether surrounded by mortar or grout or placed m unfilled spaces, need to allow unrestrained movement.
- 88. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-75 Table 1.20.1- Grout space requirements Grout type1 Maximum grout Minimum clear width Minimum clear grout space dimensions for grouting cells of hollow units,3•4•5 pour height, of grout space/,3 ft(m) in. (mm) Fine 1(0.30) 3/4 (19.1) Fine 5.33 (1.63) 2 (50.8) Fine 12.67 (3.86) i/2 (63.5) Fine 24 (7.32) 3 (76.2) Coarse 1 (0.30) 11 /2(38.1) Coarse 5.33 (1.63) 2 (50.8) Coarse 12.67 (3.86) 21 /2 (63.5) Coarse 24 (7.32) 3 (76.2) 1 Fine and coarse grouts are defined in ASTM C476. 2 For grouting between masonry wythes. in. x in. (mm x mm) 11 /2 X 2 (38.1 X 50.8) 2 X 3 (50.8 X 76.2) i /2 X 3 (63.5 X 76.2) 3 X 3 (76.2 X 76.2) ! 1 /2 X 3 (38. 1 X 76.2) i / 2 X 3 (63.5 X 76.2) 3 X 3 (76.2 X 76.2) 3 X 4 (76.2 X 102) 3 Mínimum clear width of grout space and mínimum clear grout space dimension are the net dimension of the space determined by subtracting masonry protrusions and the diameters ofhorizontal bars from the as-designed cross-section of the grout space. Grout type and maximum grout pour height shall be specified based on the mínimum clear space. 4 Area ofvertical reinforcement shall not exceed 6 percent ofthe area ofthe grout space. 5 Mínimum grout space dimension for AAC masonry units shall be 3 in. (76.2 mm) x 3 in. (76.2 mm) or a 3-in. (76.2 mm) diameter cell. COMMENTARY a > Minimum Grout Space Dimension b > Minimum Grout Space Dimension Plus Horizontal Bar Diameter Plus Horizontal Protrusions a > Minimum Grout Space Dimension Plus Horizontal Bar Diameter Plus Horizontal Protrusions Protrusion Protrusion Web Section A-A - Protrusion rzn.....¡..¡:;¡¡::z:¡_ Protrusion - Protrusion Section B-B Figure CC-1.20-1- Grout space requirements
- 89. C-76 TMS 402-11/ACI 530-11/ASCE 5-11 This page is intentionally left blank.
- 90. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-77 CHAPTER 2 ALLOWABLE STRESS DESIGN OF MASONRY CODE 2.1 -General 2.1.1 Scope This chapter provides requirements for allowable stress design of masonry. Masonry design in accordance with this chapter shall comply with the requirements of Chapter 1, Sections 2.1.2 through 2.1.7, and either Section 2.2 or 2.3. 2.1.2 Loadcombinations When the legally adopted building code does not provide allowable stress load combinations, structures and members shall be designed to resist the combinations of load specified by the building official. 2.1.3 Design strength 2.1.3.1 Project drawings shall show the specified compressive strength of masonry,f'm, for each part ofthe structure. 2.1.3.2 Each portian of the structure shall be designed based on the specified compressive strength of masonry,f'nr , for that part ofthe work. 2.1.3.3 Computed stresses shall not exceed the allowable stress requirements ofthis Chapter. 2.1.4 Anchor bo/ts embedded in grout 2.1.4.1 Design requirements - Anchor bolts shall be designed using either the provisions of Section 2. 1.4.2 or, for headed and bent-bar anchor bolts, by the COMMENTARY 2.1- General 2.1.1 Scope Historically, a one-third increase in allowable stress has been permitted for load combinations that include wind or seismic loads. The origin and the reason for the one-third stress increase are unclear 2 · 1 . From a structural reliability standpoint, the one-third stress increase is a poor way to handle load combination effects. Therefore, the one-third stress increase is no longer permitted in this Code. The allowable stresses of this Chapter should not be increased by one-third for wind and load combinations. 2.1.2 Loadcombinations When there is no legally adopted building code or the legally adopted building code does not have allowable stress load combinations, possible sources of allowable stress load combinations are ASCE 72 · 2 and IBC2 .3. 2.1.3 Design strength The structural adequacy of masonry construction requires that the compressive strength of masonry equal or exceed the specified strength. The specified compressive strength f 'm on which design is based for each part of the structure must be shown on the project drawings. The 1995, 1999, 2002, and 2005 editions of the Code contained provisions to permit use of strength-level load combinations in allowable stress design, to compensate for lack of service-level load combinations in previously referenced load standards. This procedure, which enabled the calculation of 'pseudo-strengths' on the basis of allowable stresses, is no longer included in the Code because recent editions of ASCE 7 include both service-level and strength- level load combinations. The 2005 edition of the Code provides guidance for using strength-level load combinations whenever the legally adopted building code does not provide service-levelload combinations. 2.1.4 Anchor bolts embedded in grout Allowable Stress Design anchor bolt provisions were obtained by calibrating corresponding Strength Design provisions to produce similar results. See Code
- 91. C-78 CODE provisions ofSection 2.1.4.3. 2.1.4.2 Allowable loads determined by test 2.1.4.2.1 Anchor bolts shall be tested m accordance with AS1M E488, except that a minimum offive tests shall be performed. Loading conditions ofthe test shall be representative ofintended use ofthe anchor bolt. 2.1.4.2.2 Anchor bolt allowable loads used for design shall not exceed 20 percent of the average failure load from the tests. 2.1.4.3 Allowable loads determined by calculation for headed and bent-bar anchor bolts Allowable loads for headed and bent-bar anchor bolts embedded in grout shall be determined in accordance with the provisions of Sections 2.1.4.3.1 through 2.1.4.3.3. 2.1.4.3.1 Allowable axial !ensile load of headed and bent-bar anchor bolts - The allowable axial tensile load of headed anchor bolts shall be computed using the provisions ofSections 2.1.4.3.1.1. The allowable axial tensile load of bent-bar anchor bolts shall be computed using the provisions of Section 2.1.4.3.1.2. 2.1.4.3.1.1 Allowable axial tensile load ofheaded anchor bolts- The allowable axial tensile load, Ba, of headed anchor bolts embedded in grout shall be the smaller of the values determined by Equation 2-1 and Equation 2-2. (Equation 2-1) (Equation 2-2) 2.1.4.3.1.2 Allowable axial tensile load of bent-bar anchor bolts - The allowable axial tensile load, Ba, for bent-bar anchor bolts embedded in grout shall be the smallest of the values determined by Equation 2-3, Equation 2-4, and Equation 2-5. (Equation 2-3) (Equation 2-4) (Equation 2-5) 2.1.4.3.2 Allowable shear load of headed and bent-bar anchor bolts - The allowable shear load, B.., ofheaded and bent-bar anchor bolts embedded in grout shall be the smallest ofthe values determined by Equation 2-6, Equation 2-7, Equation 2-8, and Equation 2-9. (Equation 2-6) (Equation 2-7) TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY Commentary 3.1.6. 2.1.4.3.1 Allowable axial !ensile load ofheaded and bent-bar anchor bolts - Equation 2-1 defines the allowable axial tensile load govemed by masonry breakout. Equation 2-2 defines the allowable axial tensile load govemed by slt:d yidding. The lowt:r of these loads is the allowable axial tensile load on the anchor. 2.1.4.3.1.2 Allowable axial !ensile load of bent-bar anchor bolts - Equation 2-3 defmes the allowable axial tensile load govemed by masonry breakout. Equation 2-4 defines the allowable axial tensile load govemed by anchor pullout. Equation 2-5 defines the allowable axial tensile load governed by steel yielding. The lower ofthese loads is the allowable axial tensile load on the anchor. 2.1.4.3.2 Allowable shear load ofheaded and bent-bar anchor bolts - Equation 2-6 defines the allowable shear load govemed by masonry breakout. Equation 2-7 defines the allowable shear load govemed by masonry crushing. Equation 2-8 defines the allowable shear load govemed by anchor pryout. Equation 2-9 defines the allowable shear load govemed by steel yielding. The lower of these loads is the allowable shear load on the anchor.
- 92. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-79 CODE (Equation 2-8) (Equation 2-9) 2.1.4.3.3 Combined axial tension and shear -Anchor bolts subjected to axial tension in combination with shear shall satisfY Equation 2-1 O. ~ + .5:._ $ 1 Ba Bv (Equation 2-1O) 2.1.5 Multiwythe walls 2.1.5.1 Design of walls composed of more than one wythe shall comply with the provisions of this section. 2.1.5.2 Composite action 2.1.5.2.1 Multiwythe walls designed for composite action shall have collarjoints either: (a) crossed by connecting headers, or (b) filled with mortar or grout and connected by wall ties. 2.1.5.2.2 Shear stresses developed in the planes of interfaces between wythes and collar joints or within headers shall not exceed the following: (a) mortared collarjoints, 7 psi (48.3 kPa). (b) grouted collarjoints, 13 psi (89.6 kPa). (e) headers, , u .j' sp _e_c_ ifi- ¡e_ d _ u_ n- it_c_o_ m_p_r_ e_ ss -iv - e - st -r- en_ gt _h_o_ f_he _a _d- er psi (MPa) (over net area ofheader). 2.1.5.2.3 Headers used to bond adjacent wythes shall meet the requirements of Section 2.1.5.2.2 and shall be provided as follows: (a) Headers shall be uniformly distributed and the sum of their cross-sectional areas shall be at least 4 percent ofthe wall surface area. (b) Headers connecting adjacent wythes shall be embedded a mínimum of3 in. (76.2 mm) in each wythe. 2.1.5.2.4 Wythes not bonded by headers shall meet the requirements of Section 2.1.5.2.2 and shall be bonded by wall ties provided as follows: Wire size Wl.7 (MW11) W2.8 (MW18) Minimum number o[wall ties required one per 22 / 3 ft2 (0.25 m2 ) ofwall one per 41 / 2 ft2 (0.42 m2 ) of wall The maximum spacing between ties shall be 36 in. (914 mm) horizontally and 24 in. (610 mm) vertically. The use of rectangular wall ties to tie walls made with any type of masonry units is permitted. The use of Z wall ties to tie walls made with other than hollow masonry COMMENTARY 2.1.5 Multiwythe walls 2.1.5.2 Composite action - Multiwythe walls act monolithically if sufficient shear transfer can occur across the interface between the wythes. See Figure CC-2.1-1. Shear transfer is achieved with headers crossing the collarjoint or with mortar- or grout-filled collar joints. When mortar- or grout-filled collar joints are relied upon to transfer shear, wall ties are required to ensure structural integrity ofthe collar joint. Composite action requires that the stresses occurring at the interfaces are within the allowable limits prescribed. Composite masonry walls generally consist of brick- to-brick, block-to-block, or brick-to-block wythes. The collar joint can be filled with mortar or grout, or the wythes can be connected with metal ties. The collar joint thickness ranges from 3 / 8 to 4 in. (9.5 to 102 mm). The joint may contain either vertical or horizontal reinforcement, or reinforcement may be placed in either the brick or block wythe. Composite walls are particularly advantageous for resisting high loads, both in-plane and out-of-plane. Limited test data2 .4, 25 • 2 · 6 are available to document shear strength of collar joints in masonry. Test results2 .4, 2 · 5 show that shear bond strength of collar joints could vary from as low as 5 psi (34.5 kPa) to as higb as 100 psi (690 kPa), depending on type and condition of the interface, consolidation of the joint, and type of loading. McCarthy et al.2 .4 reported an average value of52 psi (359 kPa) with a coefficient ofvariation of 21.6 percent. An allowable shear stress value of 7 psi (48.3 kPa), which is four standard deviations below the average, is considered to account for the expected high variability of the interface bond.With sorne units, Type S mortar slushed collar joints may have better shear bond characteristics than Type N mortar. Results show that thickness of joints, unit absorption, and reinforcement have a negligible effect on shear bond strength. Grouted collar joints have higher allowable shear bond stress than the mortared collar joint ~· 5 • Requirements for masonry headers (Figure CC-5.7-1) are empírica! and taken from prior codes. The net area of the header should be used in
- 93. C-80 CODE units is permitted. Cross wires of joint reinforcement are permitted to be used instead ofwall ties. Collar Joint Filled Vertical Bending Tension Perpendicular to Bed Joints TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY calculating the stress even if a solid unit, which allows up to 25 percent coring, is used. Headers do not provide as much ductility as metal tied wythes with filled collar joints. The influence of differential movement is especially critica) when headers are used. The committee does not encourage the use ofheaders. A strength analysis has been demonstrated by Porter and Wolde-Tinsae2 · 7 • 2 · 8 for composite walls subjected to combined in-plane shear and gravity loads. In addition, these authors have shown adequate behavioral characteristics for both brick-to-brick and brick-to-block composite walls with a grouted collar joint2 9 • 2 · 10 • 2 · 11 • 2 • 12 • Finite element models for analyzing the interlaminar shearing stresses in collar joints of composite walls have been investigated by Anand et at.2 · 13 • 2 · 14 • 2 · 15 • 2 • 16 • They found that the shear stresses were principally transferred in the upper portion of the wall near the point of load application for the in-plane loads. Thus, below a certain distance, the overall strength of the composite is controlled by the global strength of the wall, providing that the wythes are acting compositely. The size, number, and spacing of wall ties, shown in Figure CC-2.1-2, has been determined from past experience. The limitation of Z-ties to walls of other than hollow units is also based on past experience. Horizontal Bending Tension Parallel to Bed Joints Figure CC-2.1-1 - Stress distribution in multiwythe walls of composite masonry
- 94. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-81 COMMENTARY C) e - ·ü E "' E~ 2 2/3 Sq. Ft. (0.25 m2) ~ .¿ Maximum Wall Surface ~~ 4 1/2 Sq. Ft. (0.42 m2) Area Pe~r Tie .S ,¿ = B i Maximum Wall Surtace ~ ~ Area Per Tie =:=: •••~••· ·•• :=:r~ I ~•.• ;... :=:== -~--·-- · - - '(: Tie Location J--·--·-- h-i- " - 36 in. (914 mm) 36 in. (914 mm) J Max. Horiz. Spacing Max. Horiz. Spacing Spacing of Metal Ties (W 1.7 (MW 11)) Spacing of Metal Ties (W 2.8 (MW 18)) Figure CC-2.1-2 - Wall tie spacingfor multiwythe walls CODE 2.1.5.3 Non-composite action - Masonry designed for non-composite action shall comply with the following provisions: 2.1.5.3.1 Each wythe shall be designed to resist individually the effects of loads imposed on it. Unless a more detailed analysis is performed, the following requirements shall be satisfied: (a) Collarjoints shall not contain headers, grout,or mortar. (b) Gravity loads from supported horizontal members shall be resisted by the wythe nearest to the center of span of the supported member. Any resulting bending moment about the weak axis of the wall shall be distributed to each wythe in proportion to its relative stiffness. (e) Loads acting parallel to the plane of a wall shall be carried only by the wythe on which they are applied. Transfer of stresses from such loads between wythes shall be neglected. (d) Loads acting transverse to the plane of a wall shall be resisted by all wythes in proportion to their relative flexura! stiffnesses. (e) Specified distances between wythes shall not exceed 4.5 in. (1 14 mm) unless a detailed wall-tie analysis is performed. 2.1.5.3.2 Wythes of walls designed for non-composite action shall be connected by wall ties meeting the requirements of Section 2.1.5.2.4 or by adjustable ties. Where the cross wires of joint reinforcement are used as ties, the joint reinforcement shall be ladder-type or tab-type. Wall ties shall be without cavity drips. COMMENTARY 2.1.5.3 Non-composite action - Multiwythe walls may be constructed so that each wythe is separated from the others by a space that may be crossed only by ties. The ties force compatible lateral deflection, but no composite action exists in the design. Weak axis bending moments caused by either gravity loads or lateral loads are assumed to be distributed to each wythe in proportion to its relative stiffuess. See Figure CC-2.1-3 for stress distribution in non-composite walls. Loads due to supported horizontal members are to be resisted by the wythe closest to center of span as a result ofthe deflection ofthe horizontal member. The size, number, and spacing of metal ties (Figure CC-2.1-2) have been determined from past experience. Ladder-type or tab-type joint reinforcement is required because truss-type joint reinforcement restricts in-plane differential movement between wythes. However, the use of cavity wall ties with drips (bends in ties to prevent moisture migration) has been eliminated because of their reduced strength. In cavity walls, this Code limits the thickness of the cavity to 4~ in. (114 mm) to assure adequate performance. If cavity width exceeds 4 ~ in. (11 4 mm), the ties must be designed to resist the loads imposed upon them based on a rational analysis that takes into account buckling, tension, pullout, and load distribution. The NCMA2 · 17 and Canadian Standards Association (CSA)2 · 18 have recommendations for use in the design of ties for walls with wide cavities. The term cavity is used when the net thickness is 2 in. (51 mm) or greater. Two inches (51 mm) is considered the mínimum space required for resistance to water Eenetration. A continuous air ~ace of lesser thickness is referred to as a void (unfilled) collar joint. Requirements for adjustable ties are shown in Figure CC-2.1-4. They are based on the results in Reference 2.19.
- 95. C-82 CODE Adjustable ties shall meet the following requirements: (a) One tie shall be provided for each 1.77 f¡2 (0.16 m2 ) ofwall area. (b) Horizontal and vertical spacing shall not exceed 16 in. (406 mm). (e) Adjustable ties shall not be used when the misalignment of bed joints from one wythe to the other exceeds 11 / 4 in. (31.8 mm). (d) Maximum clearance between connecting parts of the tie shall be 1 / 16 in. (1.6 mm). (e) Pintle ties shall have at least two pintle legs of wire size W2.8 (MW18). 2.1.6 Bearing stress Bearing stresses on masonry shall not exceed 0.33 f'm and shall be computed over the bearing area, Abr, as defined in Section 1.9.5. Vertical Bending Tension Perpendicular lo Bed Joints TMS 402-11/ACI530-11/ASCE 5-11 COMMENTARY Horizontal Bending Tension Parallel lo Bed Joints Figure CC-2.1-3 - Stress distribution in multiwythe walls ofnon-composite masonry
- 96. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-83 COMMENTARY 16 in. (406 mm) Max. Vert. Spacing 1.77 Sq. Ft. (0.16 m2) Maximum Wall Surface Area PerTie - ¡• '-'j T;e Loc~tion J "'--16 in. (406 mm) Max. Horiz. Spacing Spacing of Adjustable Ties Vertical Section Plan View 1t ~.~x. Clear. . ~ in. (1 .6 mm) Figure CC-2.1-4 - Adjustable ties CODE 2.1.7 Development ofreinforcement embeddedin grout 2.1.7.1 General - The calculated tension or compression in the reinforcement at each section shall be developed on each side of the section by development length, hook, mechanical device, or combination thereof. Hooks shall not be used to develop bars in compression. 2.1.7.2 Development ofwires in tension - The development length of wire shall be determined by Equation 2-11, but shall not be less than 6 in. (152 mm). (Equation 2-11) Development length ofepoxy-coated wire shall be taken as 150 percent ofthe length determined by Equation 2-11 . 2.1.7.3 Development of bars in tension or compression - The required development length of reinforcing bars shall be determined by Equation 2-12, but shall not be less than 12 in. (305 mm). COMMENTARY 2.1.7 Development ofreinforcementembeddedin grout 2.1.7.1 General- From a point of peak stress in reinforcement, sorne length of reinforcement or anchorage is necessary through which to develop the stress. This development length or anchorage is necessary on both sides of such peak stress points, on one side to transfer stress into and on the other to transfer stress out of the reinforcement. Often the reinforcement continues for a considerable distance on one side of a critica( stress point so that calculations need involve only the other side; for example, the negative moment reinforcement continuing through a support to the middle ofthe next span. Bars and longitudinal wires must be deformed. 2.1.7.2 Development of wires in tension Equation 2-11 can be derived from the basic development length expression and an allowable bond stress u for deformed bars in grout of 160 psi (1103 k.Pal20 • 2 · 21 . Research 2 · 22 has shown that epoxy-coated reinforcing bars require longer development length than uncoated reinforcing bars. The 50 percent increase in development length is consisten! with the increase required in the ACI 318 provisions1.3 2 for epoxy-coated bars and wires, and does not apply to the 6 in. (1 52 mm) minimum.. Id= dbFsl 4u = dbFs/4(160) =0.0015dbFs (Id = 0.22dbFs in SI units) 2.1.7.3 Development of bars in tension or compression- See the discussion in Code Commentary 3.3.3.4. The 50 percent increase in development length is consistent with the increase required in the AC1318
- 97. C-84 CODE (Equation 2-12) K shall not exceed the smallest of the following: the mínimum masonry cover, the clear spacing between adjacent reinforcement splices, and 9db. y 1.0 for No. 3 (M#lO) through No. 5 (M#l6) bars; y 1.3 for No. 6 (M#19) through No. 7 (M#22) bars; and y = 1.5 for No. 8 (M#25) through No. 11 (M#36) bars. Development length of epoxy-coated bars shall be taken as 150 percent ofthe length determined by Equation 2-12. 2.1.7.4 Embedment ojjlexural reinforcement 2.1.7.4.1 General 2.1.7.4.1.1 Tension reinforcement is permitted to be developed by bending across the neutral axis of the member to be anchored or made continuous with reinforcement on the opposite face ofthe member. 2.1.7.4.1.2 Critica! sections for development of reinforcement in flexura! members are at points of maximum steel stress and at points within the span where adjacent reinforcement terminates or is bent. 2.1.7.4.1.3 Reinforcement shall extend beyond the point at which it is no longer required to resist flexure for a distance equal to the effective depth of the member or 12db, whichever is greater, except at supports of simple spans and at the free end ofcantilevers. TMS 402-11/AC1530-11/ASCE 5·11 COMMENTARY provision 1.3 2 for epoxy-coated bars, and does not apply to the 12 in. (305 mm) mínimum. 2.1.7.4 Embedment offlexura! reinforcement- Figure CC-2.1-5 illustrates the embedment requirements of flexura! reinforcement in a typical continuous beam. Figure CC-2.1-6 illustrates the embedment requírements in a typical contínuous wall that is not part of the lateral- force-resísting system. 2.1.7.4.1 General 2.1.7.4.1.2 Critica! sections for a typícal contínuous beam are indicated with a "e" or an "x" in Figure CC-2.1-5. Critica) sections for a typical continuous wall are indicated with a "e" in Figure CC-2.1-6. 2.1.7.4.1.3 The moment diagrams customarily used in design are approximate. Sorne shíftíng of the locatíon of maximum moments may occur due to changes in loading, settlement ofsupports, lateralloads, or other causes. A diagonal tensíon crack in a flexura) member without stirrups may shift the locatíon of the calculated tensile stress approximately a distance d toward a point of zero moment. When stirrups are provided, this effect is less severe, although still present. To provide for shifts in the locatíon of maximum moments, this Code requires the extension of reinforcement a distance d or 12db beyond the point at whích it is theoretically no longer required to resist flexure, except as noted. Cutoff points of bars to meet this requirement are illustrated in Figure CC-2.1-5. When bars of different sizes are used, the extension should be in accordance with the diameter of bar being terminated. A bar bent to the far face of a beam and continued there may logically be considered effective in satisfying this section, to the point where the bar crosses the middepth ofthe member.
- 98. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY COMMENTARY e Moment Capaeity of Bars a 1 Points of lnfleetion (P.L) : Moment Capacity of Bars b --""""- e / P.I. ~ d, 12 b Figure CC-2.1-5 - Development offlexural reinforcement in a typical continuous beam d Figure CC-2.1-6 - Development ofjlexural reinforcement in a typical wa/1 C-85
- 99. C-86 CODE 2.1.7.4.1.4 Continuing reinforcement shall extend a distance Id beyond the point where bent or terminated tension reinforcement is no longer required to resist flexure as required by Section 2.1.7.2 or 2.1.7.3. 2.1.7.4.1.5 Flexura! reinforcement shall not be terminated in a tension zone unless one of the following conditions is satisfied: (a) Shear at the cutoff point does not exceed two-thirds ofthe allowable shear at the section considered. (b) Stirrup area in excess of that required for shear is provided along each terminated bar or wire over a distance from the termination point equal to three- fourths the effective depth of the member. Excess stirrup area, Av, shall not be less than 60 bws/fy. Spacing s shall not exceed d/(8 fJh)· (e) Continuous reinforcement provides double the area required for flexure at the cutoff point and shear does not exceed three-fourths the allowable shear at the section considered. 2.1.7.4.1.6 Anchorage complying with Section 2.1.7.2 or 2.1.7.3 shall be provided for tension reinforcement in corbels, deep flexura! members, variable-depth arches, members where flexura[ reinforcement is not parallel with the compression face, and in other cases where the stress in flexura! reinforcement does not vary linear!y through the depth ofthe section. 2.1.7.4.2 Development ofpositive moment reinforcement - When a wall or other flexura! member is part of the lateral-force-resisting system, at least 25 percent of the positive moment reinforcement shall extend into the support and be anchored to develop Fs in tension. 2.1.7.4.3 Development ofnegative moment reinforcement 2.1.7.4.3.1 Negative moment reinforcement in a continuous, restrained, or cantilever member shall be anchored in or through the supporting member in accordance with the provisions ofSection 2.1.7.1. 2.1.7.4.3.2 At least one-third of the total reinforcement provided for moment at a support shall extend beyond the point of inflection the greater distance of the effective depth of the member or one-sixteenth of the span. TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY 2.1.7.4.1.4 Peak stresses exist in the remaining bars wherever adjacent bars are cut off or bent in tension regions. In Figure CC-2.1-5 an "x" mark is used to indicate the peak stress points remaining in continuing bars after part ofthe bars have been cut off. If bars are cut off as short as the moment diagrams allow, these stresses become the full Fs, which requires a fui! embedment length as indicated. This extension may exceed the length required for flexure. 2.1.7.4.1.5 Evidence of reduced shear strength and loss of ductility when bars are cut off in a tension zone has been reported in Reference 2.23. As a result, this Code does not permit flexura! reinforcement to be terminated in a tension zone, unless special conditions are satisfied. Flexure cracks tend to open early wherever any reinforcement is terminated in a tension zone. If the stress in the continuing reinforcement and the shear strength are each near their limiting values, diagonal tension cracking tends to develop prematurely from these flexure cracks. Diagonal cracks are less likely to form where shear stress is low. A lower steel stress reduces the probability of such diagonal cracking. 2.1.7.4.1.6 In corbels, deep flexura! members, variable-depth arches, members where the tension reinforcement is not parallel with the compression face, or other instances where the steel stress, J., in flexura! reinforcement does not vary linearly in proportion to the moment, special means of analysis should be used to determine the peak stress for proper development ofthe flexura! reinforcement. 2.1.7.4.2 Development ofpositive moment reinforcement - When a flexura[ member is part of the lateral-force-resisting system, loads greater than those anticipated in design may cause reversa! of moment at supports. As a consequence, sorne positive reinforcement is required to be anchored into the support. This anchorage assures ductility of response in the event of serious overstress, such as from blast or earthquake. The use of more reinforcement at lower stresses is not sufficient. The full anchorage requirement does not apply to excess reinforcement provided at the support. 2.1.7.4.3 Development of negative moment reinforcement - Negative reinforcement must be properly anchored beyond the support faces by extending the reinforcement Id into the support. Other methods of anchoring include the use of a standard hook or suitable mechanical device. Section 2.1.7.4.3.2 provides for possible shifting of the moment diagram at a point of inflection, as discussed under Commentary Section 2.1:7.4.1.3. This requirement may exceed that of Section 2.1.7.4.1.3 and the more restrictive governs.
- 100. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-87 CODE 2.1.7.5 Hooks 2.1.7.5.1 Standard hooks in tension shall be considered to develop an equivalent embedment length, 1 , , equal to 13 d6 • 2.1.7.5.2 The effect of hooks for bars in compression shall be neglected in design computations. 2.1.7.6 Development ofshear reinforcement 2.1.7.6.1 Bar andwire reinforcement 2.1.7.6.1.1 Shear reinforcement shall extend to a distance d from the extreme compression face and shall be carried as close to the compression and tension surfaces of the member as cover requirements and the proximity of other reinforcement permit. Shear reinforcement shall be anchored at both ends for its calculated stress. 2.1.7.6.1.2 The ends of single-leg or U-stirrups shall be anchored by one ofthe following means: (a) A standard hook plus an effective embedment of0.5ld. The effective embedment ofa stirrup leg shall be taken as the distance between the middepth of the member, d/2, and the start ofthe hook (point oftangency). (b) For No. 5 bar (M #16) and D31 (MD200) wire and smaller, bending around longitudinal reinforcement through at least 135 degrees plus an embedment of 0.33 Id. The 0.33 Id embedment of a stirrup leg shall be taken as the distance between middepth of member, d/2, and start ofhook (point oftangency). Point of Tangency COMMENTARY 2.1.7.5 Hooks 2.1.7.5.1 In earlier versions ofthe Code, the allowable stress developed by a standard hook, 7,500 psi (51.7 MPa), was the accepted permissible value in masonry design. Substituting this value into Equation 2-11 resulted in an equivalent embedment length of 11.25 d6 . This value was less than half that given in Reference 1.39. However, since the provisions for development length are now the same for Chapters 2 and 3, the hook provisions were also changed to be the same because the hooks must achieve the same leve! of performance. Refer to Commentary Section 1.16.5 for more information on hooks. 2.1.7.5.2 In compression, hooks are ineffective and cannot be used as anchorage. 2.1.7.6 Development ofshear reinforcement 2.1.7.6.1 Bar and wire reinforcement 2.1.7.6.1.1 Stirrups must be carried as close to the compression face of the member as possible because near ultimate load, flexura! tension cracks penetrate deeply. 2.1.7.6.1.2 The requirements for anchorage of U-stirrups for deformed reinforcing bars and deformed wire are illustraled in Figure CC-2.1-7. 2.1.7.6.1.2(a) When a standard hook is used, 0.5 Id must be provided between d/2 and the point oftangency ofthe hook. This provision may require a reduction in size and spacing ofweb reinforcement, or an increase in the effective depth ofthe beam, for web reinforcement to be fully effective. 0.33 1, Minimum Point of Tangency , -n Section Section 2.1.9.6.1.2(a) 2.1.9.6.1.2(b) Figure CC-2.1-7- Anchorage ofU-stirrups (deformed reinforcing bars anddeformed wire)
- 101. C-88 CODE 2.1.7.6.1.3 Between the anchored ends, each bend in the continuous portien ofa transverse U-stirrup shall enclose a longitudinal bar. 2.1.7.6.1.4 Longitudinal bars bent to act as shear reinforcement, where extended into a region of tension, shall be continuous with longitudinal reinforcement and, where extended into a region of compression, shall be developed beyond middepth of the member, d/2. 2.1.7.6.1.5 Pairs of U-stirrups or ties placed to form a closed unit shall be considered properly spliced when lepgth of laps are l.7 Id. In grout at least 18 in. (457 mm) deep, such splices with Avh not more than 9,000 lb (40 032 N) per leg shall be permitted to be considered adequate if legs extend the full available depth ofgrout. 2.1.7.6.2 Welded wire reinforcement 2.1.7.6.2.1 For each Ieg of welded wire reinforcement forming simple U-stirrups, there shall be either: (a) Two longitudinal wires at a 2-in. (50.8-mm) spacing along the member at the top ofthe U, or (b) One longitudinal wire located not more than d/4 from the compression face and a second wire closer to the compression face and spaced not less than 2 in. (50.8 mm) from the first wire. The second wire shall be located on the stirrup leg beyond a bend, or on a bend with an inside diameter ofbend not less than 8db 2.1.7.6.2.2 For each end of a single-leg stirrup of plain or deformed welded wire reinforcement, there shall be two longitudinal wires spaced a mínimum of 2 in. (50.8 mm) with the inner wire placed at a distance at least d/4 or 2 in. (50.8 mm) from middepth ofmember, d/2. Outer longitudinal wire at tension face shall not be farther from the face than the portien of primary flexura] reinforcement closest to the face. 2.1.7.7 Splices ofreinforcement - Lap splices, welded splices, or mechanical splices are permitted in accordance with the provisions of this section. Welding shall conform to AWS D1.4. 2.1.7.7.1 Lap splices 2.1.7.7.1.1 The mínimum length of lap for bars in tension or compression shall be determined by Equation 2-12, but not less than 12 in. (305 mm). 2.1.7.7.1.2 Where reinforcement consisting of No. 3 (M#1O) or larger bars is placed transversely within the lap, with at least one bar 8 inches (203 mm) or less from each end of the lap, the mínimum length of lap for bars in tension or compression determined by Equation 2-12 shall be permitted to be reduced by multiplying by the confinement factor, (. The clear space between the transverse bars and the lapped bars shall not exceed 1.5 in. (38 mm) and the transverse TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY 2.1.7.6.1.3 and 2.1.7.6.1.5 U-stirrups that enclose a longitudinal bar obviously have sufficient resistance in the tension zone ofthe masonry. 2.1.7.6.2 Welded wire reinforcement - Although not often used in masonry construction, welded wire reinforcement provides a convenient means of placing reinforcement in a filled collar joint. See Reference 2.24 for more information. 2.1.7.7 Splices of reinforcement The importance ofcontinuity in the reinforcement through proper splices is emphasized by the different requirements for the stress level to be transferred in the various types ofsplices2 · 25 • 2.1.7.7.1 Lap splices 2.1.7.7.1.2 An extensive testing program conducted by the National Concrete Masonry Association2 · 26 and additional testing done by Washington State University2 27 show that reinforcement provided transverse to lapped bars controls longitudinal tensile splitting of the masonry assembly. These tranverse bars increase the lap performance significantly, as long as there is at least one No. 3 {M#lO) transverse reinforcing bar placed within 8 in. (203 mm) of each end of the splice.
- 102. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-89 CODE bars shall be fully developed in grouted masonry. The reduced lap splice length shall not be less than 36db. Where · ZJA,c < 1O . d2.5 - . b (Equation 2-13) Ase is the area ofthe transervse bars at each end of the lap splice and shall not be taken greater than 0.35 in2 (226 mm2 ) . 2.1.7.7.1.3 Bars spliced by noncontact lap splices shall not be spaced transversely farther apart than one-fifth the required length of lap nor more than 8 in. (203 mm). 2.1.7.7.2 Welded splices - Welded splices shall have the bars butted and welded to develop in tension at least 125 percent ofthe specified yield strength ofthe bar. 2.1.7.7.3 Mechanical splices Mechanical splices shall have the bars connected to develop in tension or compression, as required, at least 125 percent ofthe specified yield strength ofthe bar. 2.1.7.7.4 End-bearingsplices 2.1.7.7.4.1 In bars required for compression only, the transmission of compressive stress by bearing of square cut ends held in concentric contact by a suitable device is permitted. 2.1.7.7.4.2 Bar ends shall termínate in flat surfaces within 11 / 2 degree of a right angle to the axis of the bars and shall be fitted within 3 degrees of full bearing after assembly. 2.1.7.7.4.3 End-bearing splices shall be used only in members containing closed ties, closed stirrups, or spirals. COMMENTARY These bars must be fully developed and have a clear spacing between the transverse bars and the lapped bars not exceeding 1.5 in. (38 mm). Testing also indicated that the lap length must be at least 36db or the effect of the transverse reinforcement is minimal. As a result, this limit was applied to the lap length. The testing also showed that even when more transverse reinforcement area is provided, it becomes significantly less effective in quantities above 0.35 in2 (226 mm2 ) . Thus, the transervse reinforcement area at each of the lap, Ase. is limited to 0.35 in? (226 mm 2 ), even ifmore is provided. 2.1.7.7.1.3 If individual bars in noncontact lap splices are too widely spaced, an unreinforced section is created, which forces a potential crack to follow a zigzag line. Lap splices may occur with the bars in adjacent grouted cells if the requirements of this section are met. 2.1.7.7.2 Welded sp/ices - A full welded splice is primarily intended for large bars (No. 6 [M#19] and larger) in main members. The tensile strength requirement of 125 percent of specified yield strength is intended to ensure sound welding, adequate also for compression. It is desirable that splices be capable of developing the ultimate tensile strength of the bars spliced, but practica! limitations make this ideal condition difficult to attain. The maximum reinforcement stress ust:d in design under this Code is based upon yield strength. To ensure sufficient strength in splices so that brittle failure can be avoided, the 25 percent increase above the specified yield strength was selected as both an adequate mínimum for safety anda practicable maximum for economy. 2.1.7.7.3 Mechanical splices Full mechanical splices are also required to develop 125 percent of the yield strength in tension or compression as required, for the same reasons discussed for full welded splices. 2.1.7.7.4 End-bearing splices Experience with end-bearing splices has been almost exclusively with vertical bars in columns. lf bars are significantly inclined from the vertical, special attention is required to ensure that adequate end-bearing contact can be achieved and maintained. The lateral tie requirements prevent end-bearing splices from sliding.
- 103. C-90 CODE 2.2- Unreinforced masonry 2.2.1 Scope This section provides requirements for unreinforced masonry as defmed in Section 1.6, except as otherwise indicated in Section 2.2.4. 2.2.2 Stresses in reinforcement The effectofstresses in reinforcement shall be neglected. 2.2.3 Axial compression andjlexure 2.2.3.1 Members subjected to axial compression, flexure, or to combined axial compression and flexure shall be designed to satisfy Equation 2-14 and Equation 2-15. fa+fb::;¡ Fa Fb (Rquation 2- 14) (Equation 2-15) where: (a) For members having an hlr ratio not greater than 99: F- 1 , 1- _h_ [ ( )2] a - Ú{)fm I40r (Equation 2-16) (b) For members having an h/r ratio greater than 99: Fa =Ú{)J ~c ~r r (Equation 2-17) (e) Fb =().{)¡;~ (Equation 2-18) (Equation 2-19) TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY 2.2- Unreinforced masonry 2.2.1 Scope This section provides for the design of masonry members in which tensile stresses, not exceeding allowable limits, are resisted by the masonry. This has previously been referred to as unreinforced or plain masonry. Flexura! tensile stresses may result from bending moments, from eccentric verticalloads, or from lateralloads. A fundamental premise is that under the effects of design loads, masonry remains uncracked. Stresses due to restraint against differential movement, temperature change, moisture expansion, and shrinkage combine with the design load stresses. Stresses due to restraint should be controlled by joints or other construction techniques to ensure that the combined stresses do not exceed the allowable. 2.2.2 Stresses in reinforcement Reinforcement may be placed in masonry walls to control the effects of movements from temperature changes or shrinkage. 2.2.3 Axial compression andjlexure 2.2.3.1 For a member solely subjected to axial load, the resulting compressive stress fa should not exceed the allowable compressive stress Fa; in other words,fa!Fa should not exceed l. Similarly, in a member subjected solely to bending, the resulting compressive stress.lb in the extreme compression fiber should not exceed the allowable compressive stress Fb , or again, fb / Fb should not exceed l. This Code requires that under combined axial and flexure loads, the sum of the quotients of the resulting compression stresses to the allowable (fa iFa+ fb/Fb) does not exceed l. This unity interaction equation is a simple portioning ofthe available allowable stresses to the applied loads, and is used to design masonry for compressive stresses. The unity formula can be extended when biaxial bending is present by replacing the bending stress quotients with the quotients ofthe calculated bending stress over the allowable bending stress for both axes. In this interaction equation, secondary bending effects resulting from the axial load are ignored. A more accurate equation would include the use of a moment magnifier applied to the tlexure term,fb /Fb. Although avoidance of a moment magnifier term can produce unconservative results in sorne cases, the committee decided not to include this term in Equation 2-14 for the following reasons: At larger h/r values, where moment magnification is more critica!, the allowable axial load on the member is limited by Code Equation 2-15. For the practica! range of h/r values, errors induced by ignoring the moment magnifier is relatively small, less than 15 percent. The overall safety factor of 4 included in the allowable stress equations is sufficiently large to
- 104. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-91 CODE COMMENTARY allow this simplification in the design procedure. The requirement of Equation 2-15 that the axial compressive load P not exceed 1 /4 ofthe buckling load P. replaces the arbitrary upper lirnits on slenderness used in ACI 531228 . The purpose ofEquation 2-15 is to safeguard against a premature stability failure caused by eccentrically applied axial load. The equation is not intended to be used to check adequacy for combined axial compression and flexure. Therefore, in Equation 2-19, the value ofthe eccentricity "e" that is to be used to calculate Pe is the actual eccentricity of the applied compressive load. The value of"e" is not to be calculated as Mmax divided by P where Mmax is a moment caused by other than eccentric load. Equation 2-15 is an essential check because the allowable compressive stress for members with an h/r ratio in excess of 99 has been developed assuming only a nominal eccentricity of the compressive load. Thus, when the eccentricity of the compressive load exceeds the mínimum eccentricity of O.lt, Equation 2-17 will overestimate the allowable compressive stress and Equation 2-15 may control. The allowable stress values for Fa presented in Equations 2-16 and 2-17 are based on an analysis ofthe results of axial load tests performed on elay and concrete masonry elements. A fit of an empírica! curve to this test data, Figure CC-2.2-1, indicates that members having an hlr ratio not exceeding 99 fail under loads below the Euler buckling load ata stress leve! equal to: ¡,;J-(h1140r) 2 ] (same with SI units) Thus, for members having an h/r ratio not exceeding 99, this Code allows axial load stresses not exceeding 1 / 4 of the aforementioned failure stress. Applying the Euler theory of buckling to members having resistance in compression but not in tension, References 2.29, 2.30, and 2.31 show that for a solid section, the critica! compressive load for these members can be expressed by the formula P.= (n2 E,,l, 1h2 )(I- 2e / t)3 (same with SI units) in which 1, uncracked moment ofinertia e eccentricity of axial compressive load with respect to the member longitudinal centroidal axis. In the derivation of this buckling load equation, tension cracking is assumed to occur prior to failure. For hlr values in excess of99, the limited test data is approximated by the buckling load.
- 105. C-92 CODE 1.2 o ~ 1.0 8 e o o Ul - "' .<:::2: o,- e o 0.8 ~~ -O> C/Je = <1> 0.6 ~~ -<1> o > o '(ñ 0.4 ~~ O:: a. E o (.) 0.2 o o 5 10 15 o 25 50 TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY For a solid rectangular section, r = ..Jt2/l2.Making this substitution into the buckling load equation gives (Equation 2-19) Transforming the buckling equation using a mínimum eccentricity of O.It (from Section 2.3.4.2) and an elastic modulus equal to 1000f ~., the axial compressive stress at buckling failure amounts approximately to [7Q:r/ h)j2J:n . At the time of the development of this equation, the committee had not developed a relationship between Em and f'm so the traditional relationship of Em = lOOOf'm was used 2 · 32 . The same equation can be developed using Em =667f'm and an eccentricity of 0.05t.Thus, for members having an hlr ratio in excess of 99, this Code allows an axial load compressive stress not exceeding 1 / 4 ofthis failure stress (Equation 2-17). Flexure tests of masonry to failure have shown2 J 3 , 2 · 34 • 2 · 35 • 2 · 36 that the compressive stress at failure computed by the straight-line theory exceeds that of masonry failing under axial load. This phenomenon is attributed to the restraining effect of less highly strained compressive fibers on the fibers ofmaximum compressive strain. This effect is less pronounced in hollow masonry than solid masonry; however, the test data indicate that, computed by the straight-line theory, the compressive stress at failure in hollow masonry subjected to flexure exceeds by 1 / 3 that ofthe masonry under axial load. Thus, to maintain a factor ofsafety of4 in design, the committee considered it conservative to establish the allowable compressive stress in flexure as: f b =~X (X)¡;;, =(X)¡~, o Test Results 20 25 35 40 45 'Yt 75 99 125 150 y, Figure CC-2.2-1 - Slenderness effects on axial compressive strength
- 106. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES AND COMMENTARY C-93 CODE 2.2.3.2 Bending - Allowable tensile stresses for masonry elements subjected to out-of-plane or in-plane bending shall be in accordance with the values in Table 2.2.3.2. For grouted masonry not laid in running bond, tension parallel to the bed j oints shall be assumed to be resisted only by the mínimum cross-sectional area of continuous grout that is parallel to the bedjoints. COMMENTARY 2.23.2 Bending- Prior to the 201 1 edition ofthe Code, allowable stresses were permitted to be increased by one-third when considering load combinations including wind or seisrnic loads. Unreinforced masonry waUs designed under codes that permitted the one-third stress increase have had acceptable performance. However, rather than arbitrarily increasing the allowable flexura! tensile stresses by one-third, the Comrnittee assessed the allowable flexura! tensile stresses using a reliability-based approach to see if an increase in allowable stresses is justified. Kim and Bennett2 .J 7 performed a reliability analysis in which the flexura! tensile stress was assumed to follow a lognormal distribution. They used a mean flexura! tensile strength ofthe allowable flexura! tensile stress in the 2008 Code multiplied by 5.1 based on the exarnination of 327 full-scale tests reported in the literature. Coefficients ofvariations for different data sets (e.g specific mortar type and direction of loading) ranged rrom 0.10 to 0.51, with a weighted average of 0.42. The coefficient of variation of0.50 used by Kim and Bennetf·37 is greater than used in previous studies. For example, Ellingwood et al238 used a coefficient of variation of 0.24 and Stewart and Lawrence2 · 39 used a coefficient ofvariation of0.30. Kirn and Bennett felt, though, that a coefficient ofvariation of 0.50 is more representative of field conditions. The lognormal distribution was determined by comparing the Anderson- Darling statistic for normal, lognormal, and Weibull probability distributions. For unreinforced mac;onry walls subjected to wind loading and designed using the one-third stress increase, the reliability index was determined to be 2.66. This is slightly greater than the value of 2.5 that is typical for the design ofother materials (Eilingwood et al2 .J 8 ) . The reliability analysis by Kim and Bennett assumed the axial load was zero, which is the worst case. With increasing axial load (which has a lower coefficient of variation than 0.50), the reliability index would increase. Based on this reliability analysis, the Code comrnittee felt justified in increasing the allowable flexura! tensile stresses by a factor of 4/3 to compensate for the elirnination of the previously permitted one-third stress increase. Mortar cement is a product that has bond strength requirements that have been established to provide comparable flexura! bond strength to that achieved using portland cement-lime mortar_2.40, 2.4!, 2.4 2 For masonry cement and air entrained portland- cement lime mortar, there are no conclusive research data and, hence, flexura! tensile stresses are based on existing requirements in other codes.
- 107. C-94 TMS 402-1 1/ACI530-11/ASCE 5-11 Table 2.2.3.2- Allowable flexura! tensile stresses for clay and concrete masonry, psi (kPa) Direction offlexural tensile Mortar types stress and masonry type Portland cementllime or Masonry cement or air entrained mortar cement portland cementllime Mor S N Mor S N Normal to bedjoints Solid units 53 (366) 40 (276) 32 (221) 20 (138) Hollow units1 Ungrouted 33 (228) 25 (172) 20 (138) 12 (83) Fully grouted 86 (593) 84 (579) 81 (559) 77 (531) Parallel to bedjoints in running bond Solid units 106 (731) 80 (552) 64 (441) 40 (276) Hollow units Ungrouted and partially 66 (455) 50 (345) 40 (276) 25 (172) grouted Fully grouted 106 (731) 80 (552) 64 (441) 40 (276) Parallel to bed joints in masonry not laid in running bond Continuous grout section 133(917) 133 (917) 133 (917) 133 (917) parallel to bed joints Other O(O) O(O) O(O) O(O) For partially grouted masonry, allowable stresses shall be determmed on the bas1s ofhnear mterpolatwn between fully grouted hollow units and ungrouted hollow units based on amount (percentage) ofgrouting. CODE COMMENTARY The tensile stresses listed are for tension due to flexure under out-of-plane or in-plane loading. While it is recognized that in-plane and out-of-plane strain gradients are different, at these low stress levels this effect should be small. Flexura! tensile stresses can be offset by axial compressive stress, but the resultant tensile stress due to combined bending and axial compression cannot exceed the allowable flexura! tensile stress. Variables affecting tensile bond strength of brick masonry normal to bed joints include mortar properties, unit initial rate of absorption, surface condition, workmanship, and curing condition. For tension parallel to bed joints, the strength and geometry ofthe units also affect tensile strength. Historically, masonry not laid in running bond has been assumed to have no flexura! bond strength across mortared head joints; thus the grout area alone is used to resist bending. Examples of continuous grout parallel to the bedjoints are shown in Figure CC-2.2-2. Test data using a bond wrench2 .4J, 2 .4 4 revealed tensile bond strength normal to bed joints ranging from 30 psi (207 kPa) to 190 psi (1,310 kPa). This wide range is attributed to the multitude of parameters affecting tensile bond strength.
- 108. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-95 CODE COMMENTARY Test results2 · 44 • 2 · 45 show that masonry cement mortars and mortars with high air content generally have lower bond strength than portland cement-lime mortars. Tests conducted by Hamid2 .4 6 show the significant effect of the aspect ratio (height to least dimension) ofthe brick unit on the flexura! tensile strength. The increase in the aspect ratio ofthe unit results in an increase in strength parallel to bed joints and a decrease in strength normal to bedjoints. Research work2 .4 7 on flexura! strength of concrete masonry has shown that grouting has a significant effect in increasing tensile strength over ungrouted masonry. A three-fold increase in tensile strength normal to bed joints was achieved using fine grout as compared to ungrouted masonry. The results also show that, within a practica! range ofstrength, the actual strength ofgrout is not ofmajor importance. For tension parallel to bed joints, a 133 percent increase in flexura! strength was achieved by grouting the cells. Grout cores change the failure mode from stepped-wise cracking along the bed and head joints for hollow walls to a straight line path along the head joints and unit for grouted walls. Research2 .4 8 has shown that flexura! strength of unreinforced grouted concrete and clay masonry is largely independent ofmortar type or cementitious materials. For partial grouting, the footnote permits interpolation between the fully grouted value and the hollow unit value based on the percentage of grouting. A concrete masonry wall with Type S portland cement-lime mortar grouted 50 percent and stressed normal to the bed joints would have an allowable stress midway between 86 psi (593 kPa) and 33 psi (228 kPa), hence an allowable stress of 59.5 psi (410 kPa). The presence offlashing and other conditions at the base of the wall can significantly reduce the flexura! bond. The values in this Table apply only to the flexura! tensile stresses developed between masonry units, mortar, and grout. Mínimum cross-sectional area of continuous grout Figure CC-2.2-2- Continuous grout sections para/le/ to the bedjoints
- 109. C-96 CODE 2.2.4 Axial tension The tensile strength of unreinforced masonry shall be neglected in design when the masonry is subjected to axial tension forces. 2.2.5 Shear 2.2.5.1 Shear stresses due to forces acting in the direction considered shall be computed in accordance with Section 1.9.1 and determined by Equation 2-20. (Equation 2-20) 2.2.5.2 In-plane shear stresses shall not exceed any of: (a) 1.5 .Jf 'm (b) 120 psi (827 kPa) (e) For running bond masonry not fully grouted; 37 psi + 0.45 Nv!An (d) For masonry not laid in running bond, constructed of open end units, and fully grouted; 37 psi + 0.45 Nv!An (e) For running bond masonry fully grouted; 60 psi + 0.45 NviAn (f) For masonry not laid in running bond, constructed of other than open end units, and fully grouted; 15 psi (103 kPa) TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY 2.2.4 Axial tension Net axial tension in unreinforced masonry walls due to axially applied load are not permitted. If axial tension develops in walls due to uplift of connected roofs or floors, the walls must be reinforced to resist the tension. Compressive stress from dead load can be used to offset axial tension. 2.2.5 Shear Three modes of shear failure in unreinforced masonry are possible: (a) Diagonal tension cracks form through the mortar and masonry units. (b) Sliding occurs along a straight crack at horizontal bed joints. (e) Stepped cracks form, altemating from head joint to bedjoint. In the absence of suitable research data, the committee recommends that the allowable shear stress values given in Code Section 2.2.5.2 be used for limiting out-of-plane shear stresses. 2.2.5.1 The theoretical parabolic stress distribution is used to calculate shear stress rather than the average stress. Many other codes use average shear stress so direct comparison of allowable values is not valid. Effective area requirements are given in Section 1.9.1 . For rectangular sections, this equates to 3 /2 x V/A. This equation is also used to calculate shear stresses for composite action. 2.2.5.2 Shear stress allowable values are applicable to shear walls without reinforcement. The values given are based on recent research2 .4 9 • 2 · 50 • 2 · 51 • 2 · 52 • The 0.45 coefficient of friction, increased from 0.20, is shown in these tests. Nv is normally based on dead load.
- 110. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-97 CODE 2.3- Reinforced masonry 2.3.1 Scope This section provides requirements for the design of structures neglecting the contribution of tensile strength of masonry, except as provided in Section 2.3.6. 2.3.2 Design assumptions The following assumptions shall be used in the design ofreinforced masonry: (a) Strain compatibility exists between the reinforcement, grout, and masonry. (b) Strains in reinforcement and masonry are directly proportional to the distances from the neutral axis. (e) Stress is linearly proportional to the strain. (d) Stresses remain in the elastic range. (e) Masonry in tension does not contribute to axial and flexura) strength. 2.3.3 Stee/ reinforcement- Allowab/e stresses 2.3.3.1 Tensile stress in bar reinforcement shall not exceed the following: (a) Grade 40 or Grade 50 reinforcement: 20,000 psi (137.9 MPa) (b) Grade 60 reinforcement: 32,000 psi (220.7 MPa) 2.3.3.2 Tensile stress in wire j oint reinforcement shall not exceed 30,000 psi (206.9 MPa). 2.3.3.3 When lateral reinforcement is provided in compliance with the requirements of Section 1.14.1.4, the compressive stress in bar reinforcement shall not exceed the values given in Section 2.3.3.1. Otherwise, the compressive resistance of steel reinforcement shall be neglected. 2.3.4 Axial compression andjlexure 2.3.4.1 Members subjected to axial compression, flexure, or combined axial compression and flexure shall be designed in compliance with Sections 2.3.4.2 through 2.3.4.4. 2.3.4.2 A//owableforces and stresses COMMENTARY 2.3 - Reinforced masonry 2.3.1 Scope The requirements covered in this section pertain to the design of masonry in which flexura[ tension is assumed to be resisted by reinforcement alone, and the flexura) tensile strength of masonry is neglected. Tension still develops in the masonry, but it is not considered to be effective in resisting design Joads. 2.3.2 Design assumptions The design assumptions listed have traditionally been used for allowable stress design of reinforced masonry members. Although tension may develop in the masonry of a reinforced element, it is not considered effective in resisting axial and flexura] design loads. 2.3.3 Steel reinforcement - A//owable stresses - The allowable steel stresses have a sufficiently large factor ofsafety that second-order effects do not need to be considered in allowable stress design. 2.3.4 Axial compression andjlexure See Commentary for 2.2.3.1. 2.3.4.1 No Commentary. 23.4.2 A//owable forces and stresses - This Code limits the compressive stress in masonry members based on the type of load acting on the member. The compressive force at the section resulting from axial loads or from the axial component of combined loads is calculated separately, and is limited to the values permitted in Section 2.3.4.2.1. Equation (2-21) or (2-22) controls the capacity of columns with large axial Joads. The coefficient of0.25 provides a factor ofsafety ofabout
- 111. C-98 CODE 2.3.4.2.1 The compressive force in reinforced masonry due to axial load only shall not exceed that given by Equation 2-21 or Equation (2-22: (a) For members having an hlr ratio not greater than 99: P, = (0.25/ ~ A. +0.65A,F,{l-C~, )'] (Equation 2-21) (b) For members having an hlr ratio greater than 99: Pa=(0.25/,;,An + 0.65A 51 F 5 {?~r J(Equation 2-22) 2.3.4.2.2 The compressive stress in masonry due to tlexure or due to flexure in combination with axial load shall not exceed 0.45!'m provided that the ca!culated compressive stress due to the axial load component,fa, does not exceed the allowable stress, Fa, in Section 2.2.3.1. TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY 4.0 against crushing of masonry. The coefficient of 0.65 was determined from tests of reinforced masonry columns and is taken from previous masonry codes2 · 28 • 2 · 53 . A second compressive stress calculation must be performed considering the combined effects of the axial load component and flexure at the section and should be limited to the values permitted in Section 2.3.4.2.2. (See Commentary for Section 2.2.3.) 2.3.4.2.2 Figure CC-2.3-1 shows the allowable moment (independent of member size and material strength) versus the ratio of steel reinforcement (Grade 60) multiplied by the steel yield stress and divided by the specified compressive strength of masonry (modified steel reinforcement ratio) for both clay and concrete masonry members subjected to pure tlexure. When the masonry compressive stress controls the design, there is little increase in moment capacity with increasing steel reinforcement. This creates a limit on the amount of reinforcement that is practica! to use in allowable stress design of masonry. Even when the masonry allowable compressive stress controls the design, the failure of the member will still be ductile. For clay masonry, the masonry stress begins to control the design at 0.39pba1 and for concrete masonry, the masonry stress begins to control the design at 0.38pba1, where Pbal is the reinforcement ratio at which the masonry would crush simultaneously with yielding ofthe reinforcement. The reinforcement ratio as a fraction of the balanced reinforcement ratio, Pbal, is also shown in Figure CC-2.3-1. The interaction equation used in Section 2.2.3 is not applicable for reinforced masonry and is therefore not included in Section 2.3.
- 112. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-99 CODE COMMENTARY 2.3.4.3 Columns 2.3.4.3 Columns Design axial loads shall be assumed to act at an eccentricity at least egua! to 0.1 multiplied by each side dimension. Each axis shall be considered independently. The mínimum eccentricity of axial load (Figure CC- 2.3-2) results from construction imperfections not otherwise anticipated by analysis. 0.1 0.09 0.08 0.07 • E .... "' 0.06 -e 0.05 .Q ~ 0.04 0.03 0.02 0.01 o In the event that actual eccentricity exceeds the mínimum eccentricity required by this Code, the actual eccentricity should be used. This Code requires that stresses be checked independently about each principal axis ofthe member (Figure CC-2.3-2). Additional column design and detailing requirements are given in Section 1.14. .•...................•...•....¡.............•........•......¡..............................¡..............................¡..............................;............................. ··· ·························································¡······················ ···· ······ ········· ·· ~ .I~Y. ..J.. ¡ :.:.:...·.::.:..:.::·:·····.:..:..·..·:...·:·: ·:·: ·:·:·: ·:·:·:.:_..,:.,.::·:·:·:·:·:·: ···:·:·:·····:···:·:·:·:·:·:·:·:·:·:·:·:·:·:·'··,::::::::::::::···············;............. ........................................1 .....9..M .Y......... ············ ····························l··..·..·..·..·: ... ·:·:·:·..·:...·..·..·..·:.:... .. .................. ...... ..~.i.,,·:.:.......................... . .............:. .. · .. ·:·:·:·:·: · :·:·:·:·····:: . ;-:=] _: :r::= :c:r== ............................L..........................J...§.~~~.~ ..~~ ..~ ·~ ·~ ·~ ·~ .~~~':~ .~ .~ .~ ...L.......................... l ! ¡ i j o 0.05 0.1 0.15 0.2 0.25 o 0.125 0.25 0.375 0.50 0.625 0.75 0.825 bal )cMU Figure CC-2.3-1 Allowable moment vs. modifiedsteel reinforcement ratio Load =P Load Acting at Centroid Figure CC-2.3-2 - Minimum design eccentricity in columns
- 113. C-100 CODE 2.3.4.4 Wal/s - Special reinforced masonry shear walls having a shear span ratio, MI(Vd), equal to or greater than 1.0 and having an axial load, P, greater than 0 . 0 5/~,A ,, whjch are subjected to in-plane forces, shall have a maximum ratio of flexura! tensile reinforcement, Pmax• not greater than that computed as follows: Pmax =2/y(n+ ~~) fm (Equation 2-23) The maximum reinforcement ratio does not apply in the out-of-plane direction. 2.3.5 Axial tension andflexura/ tension Axial tension and flexura! tension shall be resisted entirely by steel reinforcement. 2.3.6 Shear 2.3.6.1 Members shall be designed m accordance with Sections 2.3.6.1.1 through 2.3.6.1.5. 2.3.6.1.1 Calculated shear stress m the masonry shall be determined by the relationship: f =_!__ v Anv (Equation 2-24) 2.3.6.1.2 The calculated shear stress, ¡;, shall not exceed the allowable shear stress, Fv , where Fv shall be computed using Equation 2-25 and either TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY 2.3.4.4 Walls - The balanced reinforcement ratio for a masonry element with a single layer of reinforcement designed by allowable stress design can be derived by applying principies of engineering mechanics to a cracked, transformed section. The resulting equation is: nFb pb =-----;--=-- ~ 2Fs(n+ ;: ) where Pb is the balanced reinforcement ratio resulting in a condition in which the reinforcement and the masonry simultaneously reach their specified allowable stresses. However, the ratio of allowable steel tensile stress to the specified yield strength of the reinforcement, and the ratio of allowable masonry compressive stress to the specified compressive strength ofthe masonry are not consistent (Fs can range from 40 percent to 53 percent offv while Fb is taken equal to 0.45f~,). Therefore, allowable stresses in the equation above are replaced with the corresponding specified strengths, as shown in Code Equation 2-23. The equation is directly applicable for reinforcement concentrated at the end of the shear wall. For distributed reinforcement, the reinforcement ratio is obtained as the total area oftension reinforcement divided by bd. 2.3.5 Axial tension andflexural tension 2.3.6 Shear Prior to the 2011 edition of the Code, the shear resistance provided by the masonry was not added to the shear resistance provided by the shear reinforcement (in allowable stress design). A recent studl54 examined eight different methods for predicting the in-plane shear capacity of masonry walls. The design provisions of Chapter 3 (strength design) of this Code were found to be the best predictor of shear strength. The 2008 Chapter 2 (allowable stress design) provisions had a greater amount of scatter. Therefore, the provisions of Chapter 3, which allow for the shear resistance provided by the masonry to be added to the shear resistance provided by the shear reinforcement, were appropriately modified and adopted for Chapter 2. See the flow chart for design of masonry members resisting shear shown in Figure CC-2.3-3. 2.3.6.1.2 Allowable shear stress Equations 2-25 through 2-27 are based on strength design provisions, but reduced by a factor of safety of 2 to obtain allowable
- 114. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-101 CODE Equation 2-26 or Equation 2-27, as appropriate.: F. shall not exceed the following: (a) Where MI(Vd) :S 0.25: F.:::; 3..[1: (b) Where MI( Vd) 2: .1.0 (Equation 2-25) (Equation 2-26) (Equation 2-27) (e) The maximum value ofF. for MI(Vd) between 0.25 and 1.0 shall be permitted to be linearly interpolated. 2.3.6.1.3 The allowable shear stress resisted by the masonry, Fvm, shall be computed using Equation 2-28: Fvm = ~[ ( 4 .0 - 1.75 ( ~ )] ..¡¡: ]+0.25 ~ (Equation 2-28) MI(Vd) shall always be taken as a positive number and need not be taken greater than 1.0. 2.3.6.1.4 For special reinforced masonry shear walls, the allowable shear stress resisted by the masonry, F,.,, shall be computed using Equation (2-29): (Equation 2-29) MI( Vd) shall always be taken as a positive number and need not be taken greater than 1.0. 2.3.6.1.5 The allowable shear stress resisted by the steel reinforcement, F,,s, shall be computed using Equation 2-30: Fvs =O.j AvFsd) 1 Ans (Equation 2-30) 2.3.6.2 Shear reinforcement shall be provided when /v exceeds F,.m . When shear reinforcement is required, the provisions of Section 2.3.6.2.1 and 2.3.6.2.2 shall apply. 2.3.6.2.1 Shear reinforcement shall be provided parallel to the direction of applied shear force. Spacing ofshear reinforcement shall not exceed the lesser of d/2 or 48 in. (12 19 mm). COMMENTARY stress values. The provisions of this Section were developed through the study of and calibrated to cantilevered shear walls. The ratio MI( Vd), can be difficult to interpret or apply consistently for other conditions such as for a uniformly loaded, simply supported beam. Concurren! values of M and Vd must be considered at appropriate locations along shear members, such as beams, to determine the critica! MI(Vd) ratio. To simplify the analytical process, designers are permitted to use MI(Vd) = l. Commentary Section 3.3.4.1.2 provides additional information. 2.3.6.1.3 Equation 2-28 is based on strength design provisions with the masonry shear strength reduced by a factor of safety of 2 and service loads used instead offactored loads. 2.3.6.1.4 A reduced value is used for the allowable masonry shear stress in special reinforced masonry shear walls to account for degradation of masonry shear strength in plastic hinging regions. Davis254 proposed a factor with a value of 1.0 for wall ductility ratios of2.0 or less, and a linear decrease to zero as the ductility ratio increases from 2.0 to 4.0. The committee chose a constan! value of 0.5, resulting in the allowable stress being reduced by a factor of2, for design convenience. 2.3.6.1.5 Commentary Section 3.3.4.1.2.2 provides additional information. 2.3.6.2.1 The assumed shear crack is at 45 degrees to the longitudinal reinforcement. Thus, a maximum spacing of d/2 is specified to assure that each crack is crossed by at least one bar. The 48-in. (1219-mm) maximum spacing is an arbitrary choice tbat has been in codes for many years.
- 115. C-102 CODE 2.3.6.2.2 Reinforcement shall be provided perpendicular to the shear reinforcement and shall be at least equal to one-third Av. The reinforcement shall be uniformly distributed and shall not exceed a spacing of 8 ft (2.44 m). 23.6.3 ln composite masonry walls, shear stresses developed in the planes of interfaces between wythes and filled collar joints or between wythes and headers shall meet the requirements ofSection 2.1.5.2.2. 2.3.6.4 In cantilever beams, the maximum shear shall be used. In noncantilever beams, the maximum shear shall be used except that sections located within a distance d/2 from the face ofsupport shall be designed for the same shear as that computed at a distance d/2 from the face of support when the following conditions are met: (a) support reaction, in direction of applied shear force, introduces compression into the end regions of the beam, and (b) no concentrated load occurs between face of support and a distance d/2 from face. ldentify Critica! Section, Determine Design Forces, Compute Maximum Stresses from Combined Forces Calculate fv by Eq. 2-24 See Fig. 2.3-4(a) TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY 2.3.6.3 Shear across collar joints in composite masonry walls is transferred by the mortar or grout in the collar joint. Shear stress in the collar joint or at the interface between the wythe and the collar joint is limited to the allowable stresses in Section 2.1.5.2.2. Shear transfer by wall ties or other reinforcement across the collar joint is not considered. 2.3.6.4 The beam or wall loading within d/2 of the support is assumed to be transferred in direct compression or tension to the support without increasing the shear load, provided no concentrated load occurs within the d/2 distance. Reproportion and Redesign. Shear Requirement Satisfied . Provide Shear Reinforcement to supplement Fvmas necessary per 2.3.4.4, 2.3.6.1.5and 2.3.6.2. Shear Requirement Satisfied. Figure CC-2.3-3 - Flow chartf orshear design
- 116. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-103 COMMENTARY 1tlt ttt Flexure Axial Combined Flexure and Axial V Shear f =- v An Figure CC-2.3-4(a) -1//ustration ofdesign section that is subjected to tension tttttlt Flexure Axial Combined Flexure and Axial V Shear f =- v An Figure CC-2.3-4(b) - 1//ustration ofdesign section that is notsubjected to tension
- 117. C-104 TMS 402-11/ACI 530-11/ASCE 5-11 This page is intentionally left blank.
- 118. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-105 CHAPTER 3 STRENGTH DESIGN OF MASONRY CODE 3.1 -General 3.1.1 Scope This Chapter provides mrmmum requirements for strength design of masonry. Masonry design by the strength design method shall comply with the requirements of Chapter 1, Sections 3.1.2 through 3. 1.8, and either Section 3.2 or 3.3. 3.1.2 Requiredstrength Required strength shall be deterrnined in accordance with the strength design load combinations of the legally adopted building code. When the legally adopted building code does not provide factored load combinations, structures and members shall be designed to resist the combination of loads specified in ASCE 7 for strength design. Members subject to compressive axial load shall be designed for the factored moment accompanying the factored axial load. The factored moment, M11 , shall include the moment induced by relative lateral displacement. 3.1.3 Design strength Masonry members shall be proportioned so that the design strength equals or exceeds the required strength. Design strength is the nominal strength multiplied by the strength-reduction factor,~. as specified in Section 3.1.4. 3.1.4 Strength-reductionfactors 3.1.4.1 Anchor bolts - For cases where the nominal strength of an anchor bolt is controlled by masonry breakout, by masonry crushing, or by anchor bolt pryout, ~ shall be taken as 0.50. For cases where the nominal strength of an anchor bolt is controlled by anchor bolt steel, ~ shall be taken as 0.90. For cases where the nominal strength of an anchor bolt is controlled by anchor pullout, ~ shall be taken as 0.65. 3.1.4.2 Bearing - For cases involving bearing on masonry, ~ shall be taken as 0.60. 3.1.4.3 Combinations ofjlexure and axial load in unreinforced masomy - The value of ~ shall be taken as 0.60 for unreinforced masonry subjected to flexure, axial load, or combinations thereof. COMMENTARY 3.1- General 3.1.1 Scope 3.1.2 Requiredstrength 3.1.3 Design strength 3.1.4 Strength-reductionfactors The strength-reduction factor incorporates the difference between the nominal strength provided in accordance with the provisions of Chapter 3 and the expected strength of the as-built masonry. The strength- reduction factor also accounts for the uncertainties in construction, material properties, calculated versus actual member strengths, as well as anticipated mode offailure. 3.1.4.1 Anchor bolts - Because of the general similarity between the behavior of anchor bolts embedded in grout and in concrete, and because available research data for anchor bolts in grout indicate similarity, the strength-reduction values associated with varrous controlling anchor bolt failures are derived from expressions based on research into the performance of anchor bolts embedded in concrete. 3.1.4.2 Bearing - The value of the strength- reduction factor used in bearing assumes that sorne degradation has occurred within the masonry material. 3.1.4.3 Combinations ofjlexure and axial load in unreinforced masonry - The same strength-reduction factor is used for the axial load and the flexura! tension or compression induced by bending moment in unreinforced masonry elements. The lower strength-reduction factor
- 119. C-106 CODE 3.1.4.4 Combinations ofjlexure and axial load in reinforced masonry - The value of ~ shall be taken as 0.90 for reinforced masomy subjected to flexure, axial load, or combinations thereof. 3.1.4.5 Shear - The value of ~ shall be taken as 0.80 for masonry subjected to shear. 3.1.5 Deformation requirements 3.1.5.1 Dejlection of unreinf orced (plain) masonry - Deflection calculations for unreinforced (plain) masonry members shall be based on uncracked section properties. 3.1.5.2 Dejlection of reinforced masonry - Deflection calculations for reinforced masonry members shall consider the effects of cracking and reinforcement on member stiffness. The flexura! and shear stiffness properties assumed for deflection calculations shall not exceed one-half of the gross section properties, unless a cracked-section analysis is performed. 3.1.6 Anchor bolts embedded in grout 3.1.6.1 Design requirements - Anchor bolts shall be designed using either the provisions of 3.1.6.2 or, for headed and bent-bar anchor bolts, by the provisions of Section 3.1.6.3. 3.1.6.2 Nominal strengths determinedby test 3.1.6.2.1 Anchor bolts shall be tested m accordance with ASTM E488, except that a minimum offive tests shall be performed. Loading conditions ofthe test shall be representative of intended use ofthe anchor bolt. 3.1.6.2.2 Anchor bolt nominal strengths used for design shall not exceed 65 percent of the average TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY associated with unreinforced elements (in comparison to reinforced elements) reflects an increase in the coefficient of variation of the measured strengths of unreinforced elements wben compared to similarly configured reinforced elements. 3.1.4.4 Combinations ofjlexure and axial load in reinforced masonry - Tbe same strength-reduction factor is used for the axial load and the flexura) tension or compression induced by bending moment in reinforced masonry elements. The higher strength-reduction factor associated with reinforced elements (in comparison to unreinforced elements) reflects a decrease in the coefficient of variation of the measured strengths of reinforced elements wben compared to similarly configured unreinforced elements. 3.1.4.5 Shear - Strength-reduction factors for calculating the design shear strength are commonly more conservative than those associated with the design flexura) strength. However, the strength design provisions of Chapter 3 require that shear strength considerably exceed flexura! strength. Hence, the strength-reduction factor for shear is taken as 0.80, a value 33 percent larger than tbe historical value. 3.1.5 Deformation requirements 3.1.5.1 Dejlection of unreinforced (p/ain) masonry- The deflection calculations of unreinforced masonry are based on elastic performance of the masonry assemblage as outlined in the design criteriaofSection 3.2.1.3. 3.1.5.2 Dejlection of reinforced masonry - Values ofI.rrare typically about one-halfofJI!: for common configurations of elements that are fully grouted. Calculating a more accurate value using the cracked transformed section may be desirable for sorne circumstances. 3.1.6 Anchor bo/ts embedded in grout Design of anchor bolts embedded in grout may be based on physical testing or, for headed and bent-bar anchor bolts, by calculation. Due to the wide variation in configurations of post-installed anchors, designers are referred to product literature published by manufacturers for these anchors. 3.1.6.1 Design requirements 3.1.6.2 Nominal strengths determined by test - Many types of anchor bolts, such as expansion anchors, toggle bolts, sleeve anchors, etc., are not covered by Code Section 3.1.6.3 and, therefore, such anchors must be designed using test data. Testing may also be used to establish higher strengths than those calculated by Code Section 3.1.6.3. ASTM E448 requires only three tests. The variability of anchor bolt strength in masonry and the
- 120. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-107 CODE failure load from the tests. 3.1.6.3 Nominal strengths determined by calcula/ion for headed and bent-bar anchor bolts Nominal strengths of headed and bent-bar anchor bolts embedded in grout shall be determined in accordance with the provisions ofSections 3.1.6.3.1 through 3.1.6.3.3. 3.1.6.3.1 Nominal /ensile strength ofheaded and bent-bar anchor bolts - The nominal axial tensile strength of headed anchor bolts shall be computed using the provisions of Sections 3.1.6.3.1.1. The nominal axial tensile strength ofbent-bar anchor bolts shall be computed using the provisions ofSection 3.1.6.3.1.2. 3.1.63.1.1 Axial tensile strength of headedanchor bolts-The nominal axial tensile strength, 80 ,, ofheaded anchor bolts embedded in grout shall be determined by Equation 3-1 (nominal axial tensile strength govemed by masonry breakout) or Equation 3-2 (nominal axial tensile strength governed by steel yielding). The design axial tensile strength, ~8 0 ,, shall be the smaller ofthe values obtained from Equations 3-l and 3-2 multiplied by the applicable ~ value. (Equation 3-1) Bans = Ab/ y (Equation 3-2) 3.1.6.3.1.2 Axial /ensile strength of bent-bar anchor bolts - The nominal axial tensile strength, Bam for bent-bar anchor bolts embedded in grout shall be determined by Equation 3-3 (nominal axial tensile strength governed by masonry breakout), Equation 3-4 (nominal axial tensile strength governed by anchor bolt pullout), or Equation 3-5 (nominal axial tensile strength governed by steel yielding). The design axial tensile strength, ~B a"' shall be the smallest of the values obtained from Equations 3-3, 3-4 and 3-5 multiplied by the applicable ~ value. (Equation 3-3) (Equation 3-4) (Equation 3-5) COMMENTARY possibility that anchor bolts may be used in a non- redundan! manner warrants an increase to the mínimum of five tests stipulated by the Code. Assuming a normal distribution and a coefficient of variation of20 percent for the test data, a fifth-percentile value for nominal strength is approximately obtained as 65 percent of the average strength value. Failure modes obtained from testing should be reported and appropriate ~ factors used when establishing design strengths. 3.1.6.3 Nominal strength determined by calculation for headed and bent-bar anchor bolts Design equations provided in the Code stem from research3 · 1 • 3 7 conducted on headed anchor bolts and bent- bar anchor bolts (J- or L-bolts) embedded in grout. 3.1.6.3.1 Nominal /ensile strength ofheaded and bent-bar anchor bolts 3.1.6.3.1.1 Axial /ensile strength of headed anchor bolts - Tensile strength of a headed anchor bolt is governed by yield and fracture ofthe anchor steel, Equation 3-2, or by breakout of an approximately conical volume of masonry starting at the anchor head and having a fracture surface oriented at approximately 45 degrees to the masonry surface, Equation 3-1. Steel strength is calculated using the effective tensile stress area of the anchor (that is, including the reduction in area of the anchor shank dueto threads). 3.1.6.3.1.2 Axial /ensile strength of bent-bar anchor bo/ts- The tensile strength ofa bent-bar anchor bolt (J- or L-bolt) is govemed by yield and fracture ofthe anchor steel, Equation 3-5, by tensile cone breakout of the masonry, Equation 3-3, or by straightening and pullout ofthe anchor bolt from the masonry, Equation 3-4. Capacities corresponding to the first two failure modes are calculated as for headed anchor bolts. Code Equation 3-4 corresponds to anchor bolt pullout. The second term in Equation 3-4 is the portion ofthe anchor bolt capacity due to bond between bolt and grout. Accordingly, Specification Article 3.28 requires that precautions be taken to ensure that the shanks of the bent-bar anchor bolts are clean and free of debris that would otherwise interfere with the bond between anchor bolt and grout.
- 121. C-108 CODE 3.1.6.3.2 Shear strength oj headed and bent-bar anchor bolts - The nominal shear strength, Bw, of headed and bent-bar anchor bolts shall be determined by Equation 3-6 (nominal shear strength govemed by masonry breakout), Equation 3-7 (nominal shear strength govemed by masonry crushing), Equation 3-8 (nominal shear strength governed by anchor bolt pryout) or Equation 3-9 (nominal shear strength governed by steel yielding). The design shear strength ~Bvn. shall be the smallest of the values obtained from Equations 3-6, 3-7, 3-8 and 3-9 multiplied by the applicable ~ value. (Equation 3-6) Bvnc =1050Vf'111 Ab (Equation 3-7) (Equation 3-8) (Equation 3-9) 3.1.6.3.3 Combined axial tension and shear - Anchor bolts subjected to axial tension in combination with shear shall satisfy Equation 3-1O. baj bv¡ - - + - - :::; 1 ifJ Ban ~ Bvn (Equation 3-1O) 3.1.7 Nominal bearing strength The nominal bearing strength of masonry shall be computed as 0.8 f'm multiplied by the bearing area, Abr. as defined in Section 1.9.5. 3.1.8 Material properties 3.1.8.1 Compressive strength 3.1.8.1.1 Masonry compressive strength - The specified compressive strength of masonry, f ~, shall equal or exceed 1,500 psi (10.34 MPa). The value of f ~~ used to determine nominal strength values in this chapter shall not exceed 4,000 psi (27.58 MPa) for concrete masonry and shall not exceed 6,000 psi (41.37 MPa) for clay masonry. 3.1.8.1.2 Grout compressive strength - For concrete masonry, the specified compressive strength of grout, j'g, shall equal or exceed the specified compressive strength of masonry, f'm, but shall not exceed 5,000 psi (34.47 MPa). For clay masonry, the specified compressive strength of grout, j'g, shall not exceed 6,000 psi (41.37 MPa). TMS 402-11/ACI530-11/ASCE 5-11 COMMENTARY 3.1.6.3.2 Shear strength of headed and bent-bar anchor bolts -- Shear strength ofa headed or bent- bar anchor bolt is govemed by yield and fracture of the anchor steel, Equation 3-9, by masonry crushing, Equation 3-7, or by masonry shear breakout, Equation 3-6. Steel strength is calculated using the effective tensile stress area (that is, threads are conservatively assumed to lie in the critica! shear plane). Pryout (see Figure CC-1.17-7) is also a possible failure mode. The pryout equation (Equation 3-8) is adapted from ACI-3183 · 8 • Under static shear loading, bent-bar anchor bolts do not exhibit straightening and pullout. Under reversed cyclic shear, however, available research3 · 9 suggests that straightening and pullout may occur. 3.1.6.3.3 Combined axial tension and shear -- Anchor bolts subjected to combined axial tension and shear must satisfy the linear interaction equation given by Equation 3-1O. 3.1.7 Nominal bearing strength Commentary Section 1.9.5 provides further information. 3.1.8 Material properties Commentary Section 1.8 provides additional information. 3.1.8.1 Compressive strength 3.1.8.1.1 Masonry compressive strength - Design criteria are based on research3 · 11 conducted on structural masonry components having compressive strengths from 1,500 to 6,000 psi (10.34 to 41.37 MPa). Design criteria are based on these research results. Design values therefore are limited to compressive strengths in the range of 1,500 to 4,000 psi (10.34 to 27.58 MPa) for concrete masonry and 1,500 to 6,000 psi (10.34 to 41.37 MPa) for clay masonry. 3.1.8.1.2 Grout compressive strength - Since most empirically derived design equations calculate nominal strength as a function of the specified compressive strength ofthe masonry, the specified compressive strength of the grout is required to be at least equal to the specified compressive strength for concrete masonry. This requirement is an attempt to ensure that where the grout compressive strength may significantly control the design (such as anchors embedded in grout), the nominal strength will not be affected. The limitation on the maximum grout compressive strength is due to the lack ofavailable research using higher material strengths.
- 122. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES AND COMMENTARY C-109 CODE 3.1.8.2 Masonry modulus of rupture - The modulus of rupture,J,, for masonry elements subjected to out-of-plane or in-plane bending shall be in accordance with the values in Table 3.1.8.2. For grouted masonry not laid in running bond, tension parallel to the bed joints shall be assumed to be resisted only by the minimum cross-sectional area of continuous grout that is parallel to the bedjoints. 3.1.8.3 Reinforcement strength - Masonry design shall be based on a reinforcement strength equal to the specified yield strength of reinforcement, ¡;,, which shall not exceed 60,000 psi (413.7 MPa). The actual yield strength shall not exceed 1.3 multiplied by the specified yield strength. Table 3.1.8.2- Modulus of rupture, fr, psi (kPa) Direction offlexura! tensile stress and masonry type COMMENTARY 3.1.8.2 Masonry modulus of rupture - The modulus ofrupture values provided in Code Table 3.1.8.2 are directly proportional to the allowable stress values for flexural tension. While it is recognized that in-plane and out-of-plane strain gradients are different, at these low stress levels this effect should be small. Historically, masonry not laid in running bond has been assumed to have no flexural bond strength across mortared head joints; thus, the grout area alone is used to resist bending. Examples of a continuous grout section parallel to the bed joints are shown in Figure CC-2.2-2. The presence oftlashing and other conditions at the base of the wall can significantly reduce the tlexural bond. The values in this Table apply only to the flexural tensile stresses developed between masonry units, mortar, and grout. 3.1.8.3 Reinforcement strength - Research3 11 conducted on reinforced masonry components used Grade 60 reinforcement. To be consistent with laboratory documented investigations, design is based on a nominal steel yield strength of 60,000 psi (413.7 MPa). The limitation on the steel yield strength of 130 percent of the nominal yield strength is to minimize the over-strength unintentionally incorporated into a design. Mortar types Portland cementllime or mortar Masonry cement or air cement entrained portland cementllime Mor S N Mor S N Normal to bed joints Solid units 100 (689) 75 (517) 60 (413) 38 (262) Hollow units1 Ungrouted 63 (431) 48 (331) 38 (262) 23 (158) Fully grouted 163 (1124) 158 (1089) 153 (1055) 145(1000) Parallel to bed joints in running bond Solid units 200 (1379) 150 (1033) 120 (827) 75 (517) Hollow units Ungrouted and partially grouted 125 (862) 95 (655) 75 (517) 48(331) Fully grouted 200 (1379) 150 (1033) 120 (827) 75 (517) Parallel to bed joints in masonry not laid in running bond Continuous grout section parallel to bed joints 250 (1734) 250 (1734) 250(1734) 250 (1734) Other O(O) O(O) O(O) O(O) For parttally grouted masonry, modulus of rupture values shall be deterrnmed on the basts of lmear mterpolat10n between fully grouted hollow units and ungrouted hollow units based on amount (percentage) ofgrouting.
- 123. C-110 CODE 3.2- Unreinforced (plain) masonry 3.2.1 Scope The requirements of Section 3.2 are in addition to the requirements ofChapter 1and Section 3.1 and govem masoruy design in which masomy is used to resist tensile forces. 3.2.1.1 Strength for resisting loads Unreinforced (plain) masonry members shall be designed using the strength of masonry units, mortar, and grout in resisting design loads. 3.2.1.2 Strength contribution from reinforcement - Stresses in reinforcement shall not be considered effective in resisting design loads. 3.2.1.3 Design criteria - Unreinforced (plain) masonry members shall be designed to remain uncracked. 3.2.2 Flexura! and axial strength of unreinforced (plain) masonry members 3.2.2.1 Design assumptions - The following assumptions shall apply when determining the flexura! and axial strength ofunreinforced (plain) masonry members: (a) Strength design of members for factored flexure and axial load shall be in accordance with principies of engineering mechanics. (b) Strain in masonry shall be directly proportional to the distance from the neutral axis. (e) Flexura! tension in masonry shall be assumed to be directly proportional to strain. (d) Flexura! compressive stress in combination with axial compressive stress in masonry shall be assumed to be directly proportional to strain. 3.2.2.2 Nominal strength - The nominal strength of unreinforced (plain) masoruy cross-sections for combined flexure and axialloads shall be determined so that: (a) the compressive stress does not exceed 0.80f'm· (b) the tensile stress does not exceed the modulus of rupture determined from Section 3.1.8.2. 3.2.2.3 Nominal axial strength - The nominal axial strength, P,, shall not be taken greater than the following: (a) For members having an hlr ratio not greater than 99: TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY 3.2- Unreinforced (plain) masonry 3.2.1 Scope 3.2.1.1 Strengthfor resisting loads 3.2.1.2 Strength contribution from reinforcement - Although reinforcement may still be present in unreinforced masonry, it is not considered in calculating design strength. 3.2.13 Design criteria - The design of unreinforced masonry requires that the structure performs elastically under design Joads. The system response factors used in the design ofunreinforced masonry assume an elastic response. 3.2.2 Flexure and axial strength of unreinforced (plain) masonry members 3.2.2.1 Design assumptions 3.2.2.2 Nominal strength - This section gives requirements for constructing an interaction diagram for unreinforced masonry members subjected to combined flexure and axjalloads. The requirements are illustrated in Figure CC-3.2-1. Also shown in Figure CC-3.2-1 are the requirements of Section 3.2.2.3, which give a maximum axial force. 3.2.2.3 Nominal axial strength - Commentary Section 3.3.4.1.1. gives additional information.
- 124. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-111 COMMENTARY Axial strength limit, Section 3.2.2.3 Compression controlled: Compression stress does not exceed 0.80 f ;, Tension controlled: Tension stress does not exceed modulus of rupture, Table 3.1.8.2 Moment Strength Figure CC-3.2-1 Jnteraction diagramfor unreinforced masonry members CODE (b) For members having an hlr ratio greater than 99: P.=0+80 A.f~e ~r n (Equation 3-12) 3.2.2.4 P-Delta effects 3.2.2.4.1 Members shall be designed for the factored axial load, P,, and the moment magnified for the effects of member curvature, M,. 3.2.2.4.2 The magnified moment, Me, shall be determined either by a second-order analysis, or by a first-order analysis and Equations 3-13 and 3-14. (Equation 3-13) o= --------- 1- P¡, A f' (70r) 2 n m h (Equation 3-14) 3.2.2.4.3 It shall be permitted to take b = 1 for members in which h1r :s; 45. COMMENTARY 3.2.2.4 P-delta e.ffects - P-delta effects are either determined by a second-order analysis, which includes P- delta effects, ora first-order analysis, which excludes ?-delta effects and the use of moment magnifier. The moment magnifier is determined as: o=--C....::::m__ 1- --p-=-"- 1/JkPeu/er where 1/Jk is a stiffness reduction factor or a resistance factor to account for variability in stiffuess, Cm is a factor relating the actual moment diagram to an equivalent uniform moment diagram, and Peuter is Euler's buckling load. For reinforced concrete design, a value of 1/Jk =0.75 is used3 · 12 . Euler's buckling load is obtained as P.,1 ., =7r 2 EmA.r2 /h 2 • Using E., =700f~, which is the lower value of clay and concrete masonry, Euler's buckling load becomes:
- 125. C-112 CODE 3.2.2.4.4 It shall be permitted to take 6 = 1 for members in which 45 < h1r s; 60 , provided that the nominal strength defined in Section 3.2.2.2 is reduced by 10 percent. TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY 1!2 EmAnr2 Peu/er = h2 7! 2 700/'111 Anr 2 =A / ' (83.lr) 2 h2 n m h Current design provisions calculate the axial strength of walls with hlr>99 as Anf'm(70r 1h)2 • Section 2.2.3.1 ofthe Commentary gives the background ofthis equation. lt is based on using Em=1000/'111, neglecting the tensile strength of the masonry, and considering an accidental eccentricity ofO.lOt. In spite ofthe fact that this equation was developed using a higher modulus than in the current code, the equation gives a strength of(70/83.1i = 0.71 of Euler's buckling load for clay masonry. The value of0.71 is approximately the value of ~k that has been used as a stiffness reduction factor. For ease of use and because of designer's familiarity, a value of (70 r 1 h) is used for Euler's buckling load instead of an explicit stiffness reduction factor. For most walls, Cm = l. The moment magnifier can thus be deterrnined as: o=---::---- 1- pu A /' (70r) 2 n m h Figure CC-3.2-2 shows the ratio of the second-order P oM stress - " +--" - divided by the first-order stress, ' An Sn ' pu + M u , when the second-order stress is at the strength An Sn design limit ~(0.8/' 111 ). Typically slenderness effects are ignored if they contribute less than 5 percene 13 . From Figure CC-3.2-2, slenderness effects contribute less than 5 percent for values of h1r s; 45 . An intermediate wall is one with a slenderness h/r greater than 45 but not greater than 60. Slenderness effects contribute about 1Opercent to the design at h/r = 60. Intermediate walls can be designed using either the moment magnifier approach or a simplified method in which the nominal stresses are reduced by 1O percent. Tall walls are those with hlr > 60 and must be designed using the moment magnifier approach.
- 126. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-113 COMMENTARY 1.4 1.35 VI VI ~ u; 1.3 ... Q) 'tl ... 1.25 j! VI ... ¡¡:: 1.2 VI VI Q) ... 1.15 u; ... Q) 'tl 1.1 9 'tl e: o 1.05 u Q) 11) o 20 40 60 80 100 120 140 hlr Figure CC-3.2-2 Ratio ofsecond-order stress tojirst-order stress CODE COMMENTARY 3.2.3 Axial tension 3.2.3 Axial tension - The tensile strength of unreinforced masonry shall be neglected in design when the masonry is subjected to axial tension forces. Commentary Section 2.2.4 provides further 3.2.4 Nominal shear strength - Nominal shear strength, V, , shall be the smallest of (a), (b) and the applicable condition of(c) through (f): (a) 3.8A, ¡¡:: (b) 300A, (e) For running bond masonry not fully grouted; 56A, +0.45Nu (d) For masonry not laid in running bond, constructed of open end units, and fully grouted; 56A, + 0.45Nu (e) For running bond masonry fully grouted; 90A, +0.45Nu (f) For masonry not laid in running bond, constructed of other than open end units, and fully grouted; information.
- 127. C-114 CODE 3.3- Reinforced masonry 3.3.1 Scope The requirements ofthis Section are in addition to the requirements of Chapter 1 and Section 3.1 and govem masonry design in which reinforcement is used to resist tensile forces. 3.3.2 Design assumptions The following assumptions apply to the design of reinforced masonry: (a) There is strain compatibility between the reinforcement, grout, and masonry. (b) The nominal strength ofreinforced masonry cross- sections for combined flexure and axial load shall be based on applicable conditions ofequilibrium. (e) The maximum usable strain, E:nw , at the extreme masonry compression fiber shall be assumed to be 0.0035 for clay masonry and 0.0025 for concrete masonry. (d) Strain in reinforcement and masonry shall be assumed to be directly proportional to the distance from the neutral axis. (e) Compression and tension stress in reinforcement shall be taken as Es multiplied by the steel strain, but not greater than /y . Except as permitted in Section 3.3.3.5.1 (e) for determination of maximum area of flexura! reinforcement, the compressive stress of steel reinforcement shall be neglected unless lateral restraining reinforcement is provided in compliance with the requirements of Section 1.14.1.4. (f) The tensile strength of masonry shall be neglected in calculating axial and flexura! strength. (g) The relationship between masonry compressive stress and masonry strain shall be assumed to be defined by the following: Masonry stress of 0.80 f ~' shall be assumed uniformly distributed over an equivalent compression stress block bounded by edges of the cross section and a straight line located parallel to the neutral axis and located at a distance a = 0.80 e from the fiber of maximum compressive strain. The distance e from the fiber of maximum strain to the neutral axis shall be measured perpendicular to the neutral axis. 3.3.3 Reinforeement requirements and details 3.33.1 Reiriforcing bar size limitations Reinforcing bars used in masonry shall not be larger than No. 9 (M#29). The nominal bar diameter shall not exceed one- eighth ofthe nominal member thickness and shall not exceed one-quarter ofthe least clear dimension ofthe cell, course, or collarjoint in which the bar is placed. The area ofreinforcing bars placed in a cell orina course ofhollow unit construction shall not exceed 4 percent ofthe cell area. TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY 3.3- Reinforced masonry 3.3.1 Seope Reioforcement complements the high compressive strength of masonry with high tensile strength. Increased strength and greater ductility result from the use of reinforcement in masonry structures. 3.3.2 Design assumptions The design principies listed are those that traditionally have been used for reinforced masonry members. The values for the maximum usable strain are based on research3 · 12 .3· 15 on masonry materials. Concem has been raised as to the implied precision of the values. However, the Committee agrees that the reported values for the maximum usable strain reasonably represent those observed during testing. While tension may develop in the masonry of a reinforced element, the tensile strength of the masonry is not considered effective in calculating axial and flexura! strength. 3.3.3 Reinforeement requirements anddetails 3.3.3.1 Reinforeing bar size limitations - The limit ofusing a No. 9 (M #29) bar is motivated by the goal of having a larger number of smaller diameter bars to transfer stresses rather than a fewer number of larger diameter bars. Sorne research investigations3 · 10 have concluded that in certain applications masonry reinforced with more uniformly distributed smaller diameter bars performs better than similarly configured masonry elements using fewer larger diameter bars. While not
- 128. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-115 CODE 3.3.3.2 Standard hooks - Standard hooks in tension shall be considered to develop an equivalent emedment length, t., as determined by Equation 3-15: (Equation 3-15) 3.3.3.3 Development - The required tension or compression reinforcement shall be developed in accordance with the following provisions: The required development length of reinforcement shall be determined by Equation 3-16, but shall not be less than 12 in. (305 mm). (Equation 3-16) K shall not exceed the smallest of the following: the mínimum masonry cover, the clear spacing between adjacent reinforcement splices, and 9db . y 1.0 for No. 3 (M#1O) through No. 5 (M#16) bars; y 1.3 for No. 6 (M#19) through No. 7 (M#22) bars; and y = 1.5 for No. 8 (M#25) through No. 9 (M#29) bars. Development length of epoxy-coated reinforcing bars shall be taken as 150 percent of the length determined by Equation 3-16. 3.3.3.3.1 Bars spliced by noncontact lap splices shall not be spaced farther apart than one-fifth the required length oflap nor more than 8 in. (203 mm). 3.3.3.3.2 Shear reinforcement shall extend the depth ofthe member less cover distances. 3.3.3.3.2.1 Except at wall intersections, the end of a horizontal reinforcing bar needed to satisfy shear strength requirements of Section 3.3.4.1.2 shall be bent around the edge vertical reinforcing bar with a 180- degree hook. The ends of single-leg or U-stirrups shall be anchored by one ofthe following means: (a) A standard hook plus an effective embedment of 1 ) 2. The effective embedment ofa stirrup leg shall be taken as the distance between the mid-depth of the member, d/2, and the start ofthe hook (point oftangency). COMMENTARY every investigation is conclusive, the Committee does agree that incorporating larger diameter reinforcement may dictate unreasonable cover distances or development 1 engths. The limitations on clear spacing and percentage of cell area are indirect methods of preventing problems associated with over-reinforcing and grout consolidation. At sections containing lap splices, the maximum area of reinforcement should not exceed 8 percent ofthe cell area. 3.3.3.2 Standard hooks Refer to Commentary Section 1.16.5 for further information. 3.3.3.3 Development - The clear spacing between adjacent reinforcement does not apply to the reinforcing bars being spliced together. Refer to Commentary 3.3.3.4 for further information. Schult:?·22 studied the performance ofthe 2005 MSJC formula for splice lengths in masonry relative to a database of splice tests conducted in the US 3 · 15 • 3 · 16 • 3 · 17 .. 3 · 24 • 3 · 25 • 3 · 26 • 3 · 27 , and Canada3 · 28 • Schultz3 · 23 • 3 · 22 found that for clear cover in excess of Sdb, the 2005 MSJC lap splice formula gains accuracy, relative to the experimental database, when a Sdb limit is not imposed on the coefficient. Additional testing and subsequent analysis by the National Concrete Masonry Association3 · 29 also found the Sdb overly conservative and recommended that the limit on K be increased to 8.8 which is rounded to the current 9db Iimit.The 50 percent increase in development length is consistent with the increase required in the ACI 318 provision 1.n for epoxy-coated bars, and does not apply to the 12 in. (305 mm) mínimum. 3.3.3.3.1 If individual bars in noncontact lap splices are too widely spaced, an unreinforced section is created, which forces a potential crack to follow a zigzag line. Lap splices may occur with the bars in adjacent grouted cells ifthe requirements ofthis section are met. 3.3.3.3.2.1 The edge vertical bar is the last reinforcing bar in walls without intersecting walls and is the bar at the intersection of walls that intersect. Hooking the horizontal reinforcement around a vertical bar located within the wall running parallel to the horizontal reinforcement would cause the reinforcement to protrude from the wall.
- 129. C-116 CODE (b) For No. 5 (M #16) bars and smaller, bending around longitudinal reinforcement through at least 135 degrees plus an embedment of /J3. The /J3 embedment of a stirrup leg shall be taken as the distance between mid-depth of the member, d/2, and the start ofthe hook (point oftangency). (e) Between the anchored ends, each bend in the continuous portion of a transverse U-stirrup shall enclose a longitudinal bar. 3.3.3.3.2.2 At wall intersections, horizontal reinforcing bars needed to satisfy shear strength requirements of Section 3.3.4.1.2 shall be bent around the edge vertical reinforcing bar with a 90-degree standard hook and shall extend horizontally into the intersecting wall a mínimum distance at least equal to the development length. 3.3.3.4 Splices - Reinforcement splices shall comply with one ofthe following: (a) The mínimum length of lap for bars shall be 12 in. (305 mm) or the development length determined by Equation 3-16, whichever is greater. (b) Where reinforcement consisting of No. 3 (M#lO) or larger bars is placed within the lap, with at least one bar 8 in. (203 mm) or less from each end of the lap, the mínimum length of lap for bars in tension or compression be determined by Equation 2-12 shall be pennitted to be reduced by multiplying the confinement reinforcement factor, ~. The clear space between the transverse bars and the lapped bars shall not exceed 1.5 in. (38 mm) and the transverse bars shall be fully developed in grouted masonry. The reduced lap splice length shall not be less than 36db. ( = 1.0- 2.3Asc d;·s Wh . 2.3Asc < 1O ere . --;¡u-_ . b (Equation 3-17) Ase is the area of the transverse bars at each end ofthe lap splice and shall not be taken greater than 0.35 in2 (226 mm2 ). (e) A welded splice shall have the bars butted and welded to develop at least 125 percent of the yield strength, ¡;,, ofthe bar in tension or compression, as required. (d) Mechanical splices shall have the bars connected to develop at least 125 percent of the yield strength,¡;,, ofthe bar in tension or compression, as required. TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY 3.33.4 Splices - The required length ofthe lap splice is based on developing a mínimum reinforcing steel stress of 1.25fv. This requirement provides adequate strength while maintaining consistent requirements between lap, mechanical, and welded splices. Historically, the length of lap has been based on the bond stress that is capable of being developed between the reinforcing steel and the surrounding grout. Testing3 · 16 • 3.17 • 3.18 • 3 · 19 • 3 · 20 has shown that bond stress failure (or pull-out of the reinforcing steel) is only one possible mode of failure for lap splices. Other failure modes include rupture of the reinforcing steel and longitudinal splitting ofmasonry along the length ofthe lap. Experimental results of severa! independent research programs3 · 16 • 3 .1 7 • 3 · 18 • 3 19 • 3 .3° were combined and analyzed to provide insight into predicting the necessary lap lengths for reinforcement splices in masonry construction. To develop a reasonable design equation, multiple regression analysis was used to tind the fonn of a good predictive model. The following equation resulted in the best prediction of measured capacities of the tested splices3.16 : T, = - 17624.0 + 305.315 + 25204.3db 2 + 321.7..¡¡:;+3331.7cc/ Where: T, predicted tensile strength ofthe splice, lb (N); 1 , tested length of lap splice, in. (mm); f ~ ~~ = tested compressive strength ofmasonry, psi (MPa); and cc1 = cover ofstructural reinforcement, in. (mm). The square of the Pearson product moment correlation coefficient of this equation is 0.932, showing excellent correlation between the measured and predicted strength ofthe splices. Figure CC-3.3-1 graphically shows the equation predictions compared to results of the individual test programs.
- 130. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-111 100,000 90,000 80,000 ~ 70,000 i!' 60.000 ü .. 1:1. .. u 50,000 , ~ " 40,000 "' .. .. :E 30,000 20,000 10,000 o COMMENTARY Multiple Linear Regression of Spllce Capacities Predicted Capacity = -17624.0 + 305.3 ls + 25204.3 dl + 321 .7 (fmJ112 + 3331.7 ce/ 1 V._ A ·~. .~/. X 6 X • 1 1 .. ~ ~ W « .•~ "'x X )( ~~· ~ :.; o 10,000 20,000 30,000 40,000 50,000 60,000 70,000 80,000 90,000 100,000 Predicted Capaclty (lb) • WSU 1 CPAR 6 NCMA 1 X NCMA 11 X NCMA 111 • NCMA IV -unear(Best Fit ) Figure CC-3.3-1 - Relationship between measuredandpredictedsplice capacities CODE COMMENTARY Next, after replacing the predicted strength of the splice with l.25Abfv (imposing the same requirement on lap splices as required for mechanical and welded splices) and solving for the resulting splice length, the following equation is generated: 2 r;;- 1.25Abfy + l7624.0- 25204.3db - 321.7..¡/,, -3331.7cc/ 1 =----=----------....:...,_____ S 305.3 Since the form of this equation is impractical for design applications, Code Equation 3-16 was fitted to the equation shown above. An extensive testing program conducted by the National Concrete Masonry Association3 · 20 and additional testing done by Washington State University3 · 2 1 show that reinforcement provided transverse to lapped bars controls longitudinal tensile splitting of the masonry assembly. These bars increase the lap performance significantly, as long as there is at least one No. 3 (M#1O) transverse reinforcing bar placed within 8 in. (203 mm) of each end of the splice. These bars must be , fully developed and have a clear spacing between the transverse bars and the lapped bars not exceeding 1.5 in. (38 mm). Testing also indicated that the lap length must be at least 36db or the effect of the transverse reinforcement is minimal. As a result, this limit was applied to the lap length.
- 131. C-118 CODE 3.3.3.5 Maximum area of flexura! tensile reinforcement 3.3.3.5.1 For masonry members where M,,!( Vudv) ~ 1, the cross-sectional area of flexura! tensile reinforcement shall not exceed the area required to maintain axial equilibrium under the following conditions: (a) A strain gradient shall be assumed, corresponding toa strain in the extreme tensile reinforcement equal to 1.5 multiplied by the yield strain and a maximum strain in the masonry as given by Section 3.3.2(c). (b) The design assumptions ofSection 3.3.2 shall apply. (e) The stress in the tension reinforcement shall be taken as the product ofthe modulus of elasticity of the steel and the strain in the reinforcement, and need not be taken as greater than,[y. (d) Axial forces shall be taken from the loading combination given by D + 0.75L + 0.525QE. (e) The effect of compression reinforcement, with or without lateral restraining reinforcement, shall be permitted to be included for purposes of calculating maximum flexura! tensile reinforcement. 3.3.3.5.2 For intermediate reinforced masonry shear walls subject to in-plane loads where M,,!(V,,dv) ~ 1, a strain gradient corresponding toa strain in the extreme tensile reinforcement equal to 3 multiplied by the yield strain and a maximum strain in the masonry as given by Section 3.3.2(c) shall be used. Por intermediate reinforced masonry shear walls subject to out-of-plane loads, the provisions of Section 3.3.3.5.1 shall apply. 3.3.3.5.3 For special reinforced masonry shear walls subject to in-plane loads where M,,!(V,d.) ~ 1, a strain gradient corresponding to a strain in the extreme tensile reinforcement equal to 4 multiplied by the yield strain and a maximum strain in the masonry as given by Section 3.3.2(c) shall be used. For special reinforced masonry shear walls subject to out-of-plane loads, the provisions of Section 3.3.3.5.1 shall apply. 3.3.3.5.4 For masonry members where M,,!(V,,d.) :S 1 and when designed using R :S 1.5, there is no upper limit to the maximum flexura! tensile reinforcement. For masonry members where M,/(V.,dv) :S 1 and when designed using R~ 1.5, the provisions of Section 3.3.3.5. 1 shall apply. TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY The testing also showed that even when more transverse reinforcement is provided, it becomes significantly less effective in quantities above 0.35 in2 (226 mm2 ). Thus, the transverse reinforcement area at each end ofthe lap, Ase, is limited to 0.35 in2 (226 mm even ifmore is provided. 3.3.3.5 Maximum area of flexura/ tensi/e reinforcement - Longitudinal reinforcement in flexura! members is limited to a maximum amount to ensure that masonry compressive strains will not exceed ultimate values. In other words, the compressive zone of the member will not crush before the tensile reinforcement develops the inelastic strain consistent with the curvature ductility implied by the R value used in design. For masonry components that are part of the lateral- force-resisting system, maximum reinforcement is limited in accordance with a prescribed strain distribution based on a tensile strain equal to a factor times the yield strain for the reinforcing bar closest to the edge of the member, and a maximum masonry compressive strain equal to 0.0025 for concrete masonry or 0.0035 for clay-unit masonry. By limiting longitudinal reinforcement in this manner, inelastic curvature capacity is directly related to the strain gradient. The tensile strain factor varíes in accordance with the amount of curvature ductility expected, and ranges from 1.5 to 4 for specially reinforced masonry shear walls. Expected curvature ductility, controlled by the factor on tensile yield strain, is assumed to be associated directly with the displacement ductility, or the value of Cdas given for the type of component. For example, a strain factor of 3 for intermediate reinforced masonry shear walls corresponds to the slightly smaller Cd factor of 2.5, and a strain factor of 4 for specially reinforced walls corresponds to the slightly smaller Cdfactor of3.5. The maximum reinforcement is determined by considering the prescribed strain distribution, determining the corresponding stress and force distribution, and using statics to sum axial forces. For example, consider a fully grouted shear wall subjected to in-plane loads with uniformly distributed reinforcement. The strain distribution is shown in Figure CC-3.3-2, where By is the yield strain and a is a tension reinforcement strain factor (3 for intermediate reinforced shear walls, 4 for special reinforced shear walls, and 1.5 for other masonry elements). The masonry force, Cm, the steel tension force, T,, and the steel compression force, C,, are determined as: T = fA +- - ( a&Y Ia&Y - e Y ( 1) e Y l s y S é mu + a&y a & y 2 a&y
- 132. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-119 CODE COMMENTARY e = 1 A '"'' 11111 y + _ _ Y _ ( E )[E -E ( J) E ] S y S Enlll + aEy E mil 2 E mil By statics, P = Cs + Cm -Ts, where: P = D + 0.75L + 0.525QE. The maximum area of reinforcement per unit length ofwall is determined as: For a fully grouted member with only concentrated tension reinforcement, the maximum reinforcement is: 0.64/~,( Enw J-_!_ As Em11 +aEY bd p= - = bd / y ··, ~ Strain ~ cmu Stress rr...,r-r.,0.8f'm fy Steel in compression Figure CC-3.3-2 - Prescribed strain distribution and corresponding stress distribution. If there is concentrated compression reinforcement with an area equal to the concentrated tension reinforcement, As , the maximum reinforcement is: 0.64/ ,;,( Emll )-_!_ As E m11 +aE y bd p= bd = { . } /y -min Em11 - : (Em11 +aey),ey Es where d ' is the distance from the extreme
- 133. C-120 CODE 3.3.3.6 Bundling of reinforcing bars Reinforcing bars shall not be bundled. TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY compression fiber to the centroid of the compression reinforcement. For partially grouted cross-sections subjected to out- of-plane loads, the maximum reinforcement is determined based on a fully grouted member with tension reinforcement only, provided that the neutral axis is in the flange. If the neutral axis is in the web, the maximum reinforcement is determined as: A, p= -bd 0.64/~( E:mu )(~)+0.80/~ 1fs( b-b., )-_!_ E:mu +a& y b bd bd p = - -----''--------''----- -- - - - - - - !y where b.., is the width of the compression section minus the sum of the length of ungrouted cells, and trs is the specified face-shell thickness for hollow masonry units. Because axial force is implicitly considered in the determination of maximum longitudinal reinforcement, inelastic curvature capacity can be relied on no matter what the level of axial compressive force. Thus, the strength-reduction factors, ~. for axial load and flexure can be the same as for flexure alone. Also, confinement reinforcement is not required because the maximum masomy compressive strain will be less than ultimate values. The axial force is the expected load at the time of the design earthquake. It is derived from ASCE 7 Allowable Stress Load Combination 6 and consideration of the horizontal component of the seismic loading.The vertical component ofthe earthquake load, E., should not be included in calculating the axial force for purposes of determining maximum area offlexural tensile reinforcement. For structures expected to respond inelastically, the masonry compressive force is estimated using a rectangular stress block defined with parameters based on research carried out through the Technical Coordinating Committee for Masonry Research (TCCMaR). For structures intended to undergo significant inelastic response, Sections 3.3.3.5.1, 3.3.3.5.2 and 3.3.3.5.3 are technically sound ways of achieving the design objective of inelastic deformation capacity. They are, however, unnecessarily restrictive for those structures not required to undergo significant inelastic deformation under the design earthquake and Section 3.3.3.5.4 addresses a relaxation ofthe maximum reinforcement limits. For further discussion, see Reference 3.1O, Report Nos. 3.1(a)-2, 3.1(c)-1, 3.l(c)-2, 4.1.-1, 4.1-2, and 9.2-4. 3.3.3.6 Bundling of reinforcing bars - This requirement stems from the lack of research on masonry with bundled bars.
- 134. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-121 CODE 3.3.4 Design ofbeams, piers, andcolumns Member design forces shall be based on an analysis that considers the relative stiffness of structural members. The calculation of lateral stiffuess shall include the contribution of all beams, piers, and columns. The effects ofcracking on member stiffuess shall be considered. 3.3.4.1 Nominal strength 3.3.4.1.1 Nominal axial and flexura! strength - The nominal axial strength, P,, and the nominal flexural strength, M,, of a cross section shall be determined in accordance wíth the design assumptions of Section 3.3.2 and the provisions of this Section. The nominal flexural strength at any section along a member shall not be less than one-fourth of the maximum nominal flexural strength at the critica! section. The nominal axial compressive strength shall not exceed Equation (3-18) or Equation (3- 19), as appropriate. (a) For members having an h/r ratio not greater than 99: P. ~ 0.8~0.80 f..(A._A,.)+!yA,,l¡~-e.:. rl (Equation 3-18) (b) For members having an h/r ratio greater than 99: fln =0.80 [ o.8o¡,;,(An- AS/)+! yASI l C~r r (Equation 3-19) 3.3.4.1.2 Nominal shear strength Nominal shear strength, Vn, shall be computed using Equation 3-20 and either Equation 3-21 or Equation 3-22, as appropriate. (Equation 3-20) where Vn shall not exceed the following: (a) Where M,/ (V,, dv) ~ 0.25: (Equation 3-21) (b) Where Mj(V,, dv) ~ 1.0 (Equation 3-22) (e) The maximum value of Vn for M,/(V,, dv) between 0.25 and 1.0 shall be permitted to be linearly interpolated. (d) M,/(V,,dv) shall be taken as a positive number and need not be taken greater than 1.0. 3.3.4.1.2.1 Nominal masonry shear strength - Shear strength provided by the masonry, Vnm , shall be computed using Equation 3-23: COMMENTARY 3.3.4 Design ofbeams, piers, andcolumns 3.3.4.1 Nominal strength 3.3.4.1.1 Nominal axial and flexura! strength - The nominal flexura! strength of a member may be calculated using the assumption of an equivalent rectangular stress block as outlined in Section 3.3.2. Commentary Section 2.2.3 gives further inforrnation regarding slenderness effects on axial load strength as taken into account with the use of Equation 3-18 and Equation 3-19. Equation 3-18 and Equation 3-19 apply to simply supported end conditions and transverse loading which results in·a symmetric deflection (curvature) about the midheight of the element, if present. Where other support conditions or loading scenarios are known to exist, Equation 3-1 8 and Equation 3-19 should be modified accordingly to account for the effective height of the element or shape of the bending moment diagram over the clear span of the element. The weak-axis radius of gyration should be used in calculating slenderness- dependent reduction factors. The first coefficient, 0.80, in Equation 3-18 and Equation 3-19 accounts for unavoidable mínimum eccentricity in the axial load. 3.3.4.1.2 Nominal shear strength - The shear strength equations in Section 3.3.4.1.2 are derived from research3 · 10 . The equations have been compared with results from fifty-six tests of masonry walls failing in in- plane shear. The test data encompassed both concrete masonry walls and elay masonry walls, all of which were fully grouted. The average ratio of the test capacity to the calculated capacity was 1.17 with a coefficient of variation of0.15. The limitations on maximum nominal shear strength are included to preclude critical (brittle) shear-related failures. The provisions of this Section were developed through the study of and calibrated to cantilevered shear walls. The ratio M,/(V, dv) can be difficult to interpret or apply consistently for other conditions such as for a uniformly loaded, simply supported beam. Concurrent values of M,, and V, d,, must be considered at appropriate locations along shear members, such as beams, to determine the critica! M,/(V,dv) ratio. To simplify the analytical process, designers are perrnitted to use M,/ ( V,, dv) = l. 3.3.4.1.2.1 Nominal masomy shear strength - Equation 3-23 is empirically derived from research.3 · 10
- 135. C-122 CODE (Equation 3-23) 3.3.4.1.2.2 Nominal shear strength provided by reinforcement - Nominal shear strength provided by shear reinforcement, V,,s, shall be computed as follows: (Equation 3-24) 3.3.4.2 Beams - Design of beams shall meet the requirements of Section 1.13 and the additional requirements of Sections 3.3.4.2.1 through 3.3.4.2.5. 3.3.4.2.1 The factored axial compressive force on a beam shall not exceed 0.05 Anf'm . 3.3.4.2.2 Longitudinal reinforcement 3.3.4.2.2.1 The variation in longitudinal reinforcing bars in a beam shall not be greater than one bar size. Not more than two bar sizes shall be used in a beam. 3.3.4.2.2.2 The nominal flexura! strength of a beam shall not be less than 1.3 multiplied by the nominal cracking moment of the beam, Me,. The modulus of rupture, f,., for this calculation shall be determined in accordance with Section 3.1.8.2. 3.3.4.2.2.3 The requirements of Section 3.3.4.2.2.2 need not be applied if at every section the area of tensile reinforcement provided is at least one-third greater than that required by analysis. 3.3.4.2.3 Transverse reinforcement Transverse reinforcement shall be provided where V,, exceeds ¡) Vnm. The factored shear, V,, shall include the effects of lateral load. When transverse reinforcement is required, the following provisions shall apply: (a) Transverse reinforcement shall be a single bar with a 180-degree hook at each end. TMS 402-11/ACI530-11/ASCE 5-11 COMMENTARY 3.3.4.1.2.2 Nominal shear strength provided by reinforcement - Equation 3-24 is empirically derived from research.3 · 10 The nominal shear strength provided by shear reinforcement, Equation 3-24, represents half the theoretical contribution. In other words, the nominal shear strength is determined as the full masonry contribution plus one-half the contribution from the shear reinforcement. Other coefficients were evaluated (0.6, 0.8, and 1.0), but the best fit to the experimental data was obtained using the 0.5 factor. 3.3.4.2 Beams - This section applies to the design of lintels and beams. 3.3.4.2.2 Longitudinal reinforcement 3.3.4.2.2.1 Restricting the variation of bar sizes in a beam is included to increase the depth of the member compression zone and to increase member ductility. When incorporating two bars of significantly different sizes in a single beam, the larger bar requires a much higher load to reach yield strain, in effect "stiffening" the beam. 3.3.4.2.2.2 The requirement that the nominal flexura) strength of a beam not be less than 1.3 multiplied by the nominal cracking moment is imposed to prevent brittle failures. This situation may occur where a beam is so lightly reinforced that the bending moment required to cause yielding of the reinforcement is less than the bending moment required to cause cracking. 3.3.4.2.2.3 This exception provides sufficient additional reinforcement in members in which the amount of reinforcement required by Section 3.3.4.2.2.2 would be excessive. 33.4.23 Transverse reinforcement - Beams recognized in this section of the Code are often designed to resist only shear forces due to gravity loads. Beams that are controlled by high seismic forces and lateral drift should be designed as ductile elements. (a) Although sorne concems have been raised regarding the difficulty in constructing beams containing a single bar stirrup, the Committee feels such spacing limitations within beams inhibits the construction of necessary lap lengths required for two-bar stirrups. Furthermore, the added volume of reinforcing steel as a result of lap splicing stirrups may prevent adequate consolidation ofthe grout.
- 136. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-123 CODE (b) Transverse reinforeement shall be hooked around the longitudinal reinforeement. (e) The mínimum area of transverse reinforeement shall be 0.0007 bdv. (e) The first transverse bar shall not be loeated more than one-fourth of the beam depth, dv , from the end ofthe beam. (e) The maximum spaeing shall not exeeed one-half the depth ofthe beam nor 48 in. (1219 mm). 3.3.4.2.4 Construction - Beams shall be fully grouted. 3.3.4.2.5 Dimensional limits - The nominal depth of a beam shall not be less than 8 in. (203 mm). 3.3.4.3 Piers 3.3.4.3.1 The factored axial compression force on piers shall not exceed 0.3 Anf'm . 3.3.43.2 Longitudinal reinforcement - A pier subjected to in-plane stress reversals shall be reinforced symmetrieally about the neutral axis ofthe pier. Longitudinal reinforeement ofpiers shall comply with the following: (a) At least, one bar shall be provided in each end cell. (b) The mínimum area of longitudinal reinforeement shall be 0.0007 bd. 3.3.4.3.3 Dimensional limits - Dimensions shall be in aecordance with the following: (a) The nominal thickness of a pier shall not exceed 16 in. (406 mm). (b) The distance between lateral supports of a pier shall not exceed 25 multiplied by the nominal thickness of a pier except as provided for in Section 3.3.4.3.3(c). (e) When the distanee between lateral supports of a pier exceeds 25 multiplied by the nominal thickness ofthe pier, design shall be based on the provisions of Section 3.3.5. (d) The nominal length of a pier shall not be less than three multiplied by its nominal thickness nor greater than six multiplied by its nominal thickness. The clear height of a pier shall not exceed five multiplied by its COMMENTARY (b) The requirement that shear reinforeement be hooked around the longitudinal reinforeement not only facilitates eonstruction but also confines tbe longitudinal reinforcement and helps ensure the development ofthe shear reinforeement. (e) A mínimum area of transverse reinforcement is established to prevent brittle shear failures. (d) Although different codes contain different spacing requirements for the placement of transverse reinforcement, the Committee has conservatively established this requirement. (e) The requirements of this section establish limitations on tbe spacing and placement of reinforcement in order to increase member ductility. 3.3.4.2.4 Construction - Although beams can physically be constructed of partially grouted masonry, the laek of research supporting the performance of partially grouted beams combined with the increased probability of brittle failure dictates this requirement. 3.3.4.2.5 Dimensionallimits- Insufficient research has been conducted on beams ofnominal depth less than 8 in. (203 mm). 3.3.4.3 Piers 3.3.4.3.1 Due to the less severe requirements imposed for the design of piers with respeet to similar requirements for columns, the maximum axial force is arbitrarily limited to a relatively lower value. 3.3.4.3.2 Longitudinal reinforcement - These provisions are predominantly seismic-related and are intended to provide the greatest ductility for the least eost. Piers not subject to in-plane stress reversals are not required to comply with this section. 3.3.4.3.3 Dimensional limits - Judgment- based dimensional limits are established for piers to distinguish their design from walls and to prevent local instability or buekling modes.
- 137. C-124 CODE nominal length. Exception: When the factored axial force at the location of maximum moment is less than 0.05/'mAg, the length of a pier shall be permitted to be equal to the thickness ofthe pier. 3.3.5 Wal/ designfor out-of-plane loads 3.3.5.1 Scope - The requirements of Section 3.3.5 are for the design ofwalls for out-of-plane loads. 3.3.5.2 Mamen/ and dejleclion calculations - Moment and deflection calculations in Sections 3.3.5.3 and 3.3.5.5 are based on simple support conditions top and bottom. For other support and fixity conditions, moments and deflections shall be calculated using established principies ofmechanics. 3.3.5.3 Walls with factored axial stress of 0.20f'm or less - The procedures set forth in this Section shall be used when the factored axial load stress at the location of maximum moment satisfies the requirement computed by Equation 3-25. [ ~: )~ 0.20/~ (Equation 3-25) When the ratio of effective height to nominal thickness, hit, exceeds 30, the factored axial stress shall not exceed 0.05/'nr . Factored moment and axial force shall be determined at the midheight of the wall and shall be used for design. The factored moment, M,,, at the midheight of the wall shall be computed using Equation 3-26. (Equation 3-26) Where: (Equation 3-27) The deflection due to factored loads (c5,) shall be obtained using Equation. 3-29 and 3-30 and replacing M ser with M,, and O swith ó,,. The nominal shear strength shall be determined by Section 3.3.4.1.2. 3.3.5.4 Nominal axial and flexura! strength - The nominal axial strength, P,, and the nominal flexura( strength, Mn, of a cross-section shall be determined in accordance with the design assumptions TMS 402-11/ACISJ0-11/ASCE 5-11 COMMENTARY 3.3.5 Wal/ designfor out-of-plane /oads 3.3.5.1 Scope 33.5.2 Mamen! and dejlection calculations - The provisions of this section are derived from results of tests on simply supported specimens. Because the maximum bending moment and deflection occur near the mid-height of those specimens, this section includes only design equations for that condition. When actual conditions are not simple supports, the curvature of a wall under out-of-plane lateral loading will be different than that assumed by these equations. Using the principies of mechanics, the points of inflection can be determined and actual moments and deflections can be calculated under different support conditions. The designer should examine all moment and deflection conditions to locate the critica( section using the assumptions outlined in Section 3.3.5. 3.3.53 Wal/s withfactored axial stress of0.20f ', or less - The criterion to limit vertical load on a cross section was included because the slender wall design method was based on data from testing with typical roof loads. For hit ratios greater than 30, there is an additional limitation on the axial stress. There are currently no strength design provisions for axial stress greater than 0.20f ~ .. The required moment due to lateral loads, eccentricity of axial load, and lateral deformations are assumed maximum at mid-height of the wall. ln certain design conditions, such as large eccentricities acting simultaneously with small lateral Ioads, the design maximum moment may occur elsewhere. When this occurs, the designer should use the maximum moment at the critica( section rather than the moment determined from Equation 3-26. 3.3.5.4 Nominal axial and flexura/ strength - When the depth of the equivalent stress block is in the face shell of a wall that is fully or partially grouted, the nominal moment may be approximated as:
- 138. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-125 CODE of Section 3.3.2. The nominal axial compressive strength shall not exceed that determined by Equation 3-18 or Equation 3-19, as appropriate. 3.3.5.5 Dejlections- The horizontal midheight deflection, Os, under allowable stress design load combinations shall be limited by the relation: (Equation 3-28) P-delta effects shall be included in deflection calculation. The midheight deflection shall be computed using either Equation 3-29 or Equation 3-30, as applicable. (a) Where Mser < Mcr O - 5Mserh2 S - 48Emfg (b) Where Mcr < Mser < M, (Equation 3-29) os= 5Mc,h2 + 5(Mser - Mcr )h2 (Equation 3-30) 48E,,fg 48E,,Jcr The cracking moment of the wall shall be computed using the modulus ofrupture,.fr, taken from Table 3.1.8.2. The neutral axis for determining the cracked moment of inertia, len shall be determined in accordance with the design assumptions of Section 3.3.2. The effects of axial load shall be permitted to be included when calculating lcr. Unless stiffness values are obtained by a more comprehensive analysis, the cracked moment of inertia for a wall that is partially or fully grouted and whose neutral axis is in the face shell shall be obtained from Equation 3- 31 and Equation 3-32. 1 = n A +- - -e +-- ( P, lsp )(d )2 bc 3 cr s Jy 2d 3 (Equation 3-3 1) (Equation 3-32) COMMENTARY Asfy +P, /rp a= ---'---- 0.80 f~b The above formulas are valid for both centered and noncentered flexural reinforcement. For centered tlexural reinforcement, d = ls,J2. This results in the nominal moment, M,, being obtained as: M,= (Pu 1,+Asf y {d-~) These formulas take into account the effect of compressive vertical loads increasing the flexura! strength of the section. In the case of axial tension, the flexural strength is decreased. 3.3.5.5 Dejlections Historically, the recommendation has been to limit the detlection under allowable stress load combinations to O.Olh. The committee has chosen a more stringent value of0.007h. The Code limits the lateral detlection under allowable stress load combinations. A wall loaded in this range returns to its original vertical position when the lateral load is removed, because the stress in the reinforcement is within its elastic limit. Equation 3-29 is for mid-height deflection for an uncracked section, and Equation 3-30 is for mid-height deflection for a eracked section. A wall is assumed to deflect as an uncracked section until the modulus ofrupture is reached, after which it is assumed to deflect as a cracked section. The cracked moment of inertia is conservatively assumed to apply over the entire height of the wall. The cracked moment of inertia, Icr, for a fully grouted or partially grouted cross section is usually the same as that for a hollow section because the compression stress block is generally within the thickness ofthe face shell. These formulas represent good approximations to test results, assuming that the wall is simply supported top and bottom, and is subjected to a uniformly distributed lateral load. lf the wall is fixed at top, bottom, or both, other formulas should be developed considering the support conditions at the top or bottom and considering the possible deflection or rotation of the foundation, roof, or floor diaphragm. The cracking moment, Me" is the calculated moment corresponding to first cracking. The cracking moment was previously given in the Code as the section modulus multiplied by the modulus of rupture. The Code has been changed so it is now permissible to include the applied axial force in the calculation ofthe cracking moment. The Code requires that the neutral axis used to calculate the cracked moment of inertia be determined
- 139. C-126 CODE 3.3.6 Wall designfor in-plane loads 3.3.6.1 Scope - The requirements of Section 3.3.6 are for the design ofwalls to resist in-plane loads. 3.3.6.2 Reinforcement - Reinforcement shall be provided perpendicular to the shear reinforcement and shall be at least egua! to one-third Av. The reinforcement shall be uniformly distributed and shall not exceed a spacing of8 ft (2.44 m). 3.3.6.3 Flexura/ and axial strength - The nominal flexura! and axial strength shall be determined in accordance with Section 3.3.4.1.1. 3.3.6.4 Shear strength - The nominal shear strength shall be computed in accordance with Section 3.3.4.1.2. 3.3.6.5 The maximum reinforcement requirements of Section 3.3.3.5 shall not apply if a shear wall is dcsigncd to satisfy the requirements of 3.3.6.5.1 through 3.3.6.5.5. 3.3.6.5.1 Special boundary elements need not be provided in shear walls meeting the following conditions: l. Pu ~ 0.10 Ag/;, for geometrically symmetrical wall sections P" ~ 0.05Ag.[;, for geometrically unsymmetrical wall sections; and either or TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY using the strain distribution at ultimate capacity. Arnrhein and Lee (1984)331 used this condition to develop the original slender wall design provisions. Equation 3-31 and 3-32 are valid for both centered and non-centered vertical reinforcement. The modification term of (t.¡)2d) in Equation 3-31 accounts for a reduction in the contribution of the axial load to the cracked moment of inertia when the reinforcement is near the face ofthe wall. 3.3.6 Wall designfor in-plane loads 3.3.6.5 The maximum reinforcement requirements of Section 3.3.3.5 are intended to ensure that an intermediate or a special reinforced masonry shear wall has sufficient inelastic deformation capacity under the design-basis earthquake of ASCE 7 or the model building codes. Inelastic deformability is the ability of a structure or structural element to continue to sustain gravity loads as it deforms laterally under earthquake (or sorne other type ot) excitation beyond the stage where the response of the structure or the structural element to that excitation is elastic (that is, associated with no residual displacement or damage). In the altemative shear wall design approach given in Sections 3.3.6.5.1 through 3.3.6.5.5, such inelastic deformability is sought to be ensured by means of specially confined boundary elements, making it unnecessary to comply with the maximum reinforcement requirements. These requirements are therefore waived. 3.3.6.5.1 This subsection sets up sorne "screens" with the expectation that many, if not most, shear walls will go through the screens, in which case no special boundary elements would be required. This will be the case when a shear wall is lightly axially loaded and it is either short or is moderate in height and is subject to only moderate shear stresses. The threshold values are adapted from the design procedure for special reinforced concrete shear walls in the 1997 Uniform Building Code (UBC). In the early 1990s, when this procedure of the 1997 UBC was first being developed, an ad hoc subcommittee within the Seismology Committee of the Structural Engineers Association of California had limited, unpublished parametric studies done, showing that a reinforced concrete shear wall passing
- 140. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES (TMS 402/ACI 530/ASCE 5) C-127 CODE 3. 3.3.6.5.2 The need for special boundary elements at the edges of shear walls shall be evaluated in accordance with Section 3.3.6.5.3 or 3.3.6.5.4. The requirements of Section 3.3.6.5.5 shall also be satisfied. 3.3.6.5.3 This Section applíes to walls bending in single curvature in which the flexura! limit state response is governed by yielding at the base of the wall. Walls not satisfying those requirements shall be designed in accordance with Section 3.3.6.5.4 (a) Special boundary elements shall be provided over portions ofcompression zones where: and e is calculated for the P11 given by ASCE 7 Strength Design Load Combination 5 (1.2D+ l.OE+ L + 0.2.5) or the corresponding strength design load combination of the legally adopted building code, and the corresponding nominal moment strength, Mn, at the base critica! section. The load factor on L in Combination 5 is reducible to 0.5, as per exceptions to Section 2.3.2 of ASCE 7. COMMENTARY through the "screens" could not develop sufficiently high compressive strains in the concrete to warrant special confinement. In the case of masonry, strains requiring special confinement would be values exceeding the maximum usable strains ofSection 3.3.2 (e). 3.3.6.5.2 Two approaches for evaluating detailíng requirements at wall boundaries are included in Section 3.3.6.5.2. Section 3.3.6.5.3 allows the use of displacement-based design of walls, in which the structural details are determined directly on the basis of the expected lateral displacements of the wall under the design-basis earthquake. This approach was first introduced in ACI 318-99 for the design of special reinforced concrete shear walls. The provisions of Section 3.3.6.5.4 are similar to those of 1995 and earlíer editions of ACI 318 (retained in ACI 318-99 and 318-02), and have been included because they are conservative for assessing required transverse reinforcement at wall boundaries for many walls. The requirements of Section 3.3.6.5.5 apply to shear walls designed by either Section 3.3.6.5.3 or 3.3.6.5.4. 3.3.6.5.3 Section 3.3.6.5.3 is based on the assumption that inelastic response of the wall is dominated by flexura! action at a critica!, yielding section - typically at the base. The wall should be proportioned so that the critica! section occurs where intended (atthe base). (a) The following explanation, including Figure CC-3.3-3, is adapted from a paper by Wallace3 · 32 , which provides background to the design provisions for special reinforced shear walls of ACI 318-99 (retained unchanged in ACI 318-05). The relationship between the wall top displacement and wall curvature for a wall of uniform cross-section with a single critica! section at the base is presented in Figure CC-3.3-3. The ACI 318 provisions as well as the provisions of this Code are based on a sirnplified version ofthe model presented in Figure CC-3.3-3(a). The simplified model, shown in Figure CC-3.3-3(b), neglects the contribution of elastic deformations to the top displacement, and moves the center ofthe plastic hinge to the base ofthe wall. Based on the model of Figure CC-3.3-3, the relationship between the top displacement and the curvature at the base ofthe wall is: Cdone =ephw =C9lul p)hw =(9lu l ;,,}"' (Equation 1) assuming that l P = l w 12, as is permitted to be assumed by the 1997 UBC, where 9lu = ultimate curvature, and eP= plastic rotation at the base ofthe wall. lf at the stage where the top deflection of the wall is
- 141. C-128 CODE TMS 402-11/ACI 530-1 1/ASCE 5-1 1 COMMENTARY Óne, the extreme fiber compressive strain at the critica! section at the base does not exceed t:11111 , no special confinement would be required anywhere in the wall. Figure CC-3.3-4 illustrates such a strain distribution at the critica! section. The neutral axis depth corresponding to this strain distribution is Ccr, and the corresponding ultimate curvature is ~~~ =t:,11 1c cr . From Equation 1, e <: =(Cmu ~) h dune 2 w ccr (Equation 2a) c,ll e.. or, ccr = 2 (Cdone 1hw) (Equation 2b) It follows from the above (see Figure CC-3.3-4) that special detailing would be required if: because if the neutral axis depth exceeded the critica! value, the extreme fiber compressive strain would exceed the maximum usable strain t:11111 • For purposes ofthis derivation, and to avoid having separate sets of drift-related requirements for clay and concrete masonry, a single useful strain of 0.003 is used, representing an average ofthe design values of0.0025 for concrete masonry and 0.0035 for clay masonry. In ACI 318-99, the term (Cdonelh..) must equal or exceed 0.007. According to Wallace332 , "This lower limit on the mean drift ratio is included to ensure that walls controlled by flexure have modest deformation capacities, as well as to guard against modeling errors that might underestimate the design displacement." This lower limit on (Cdone1h..) has not been adopted for reinforced masonry walls because: • 0.007 is arbitrary and appears to be too high for a system with a maximum drift ofO.Ol; • 1997 UBC concrete provisions do not include this requirement; and • many designs are already stiff, since masonry has never had boundary elements. Furthermore, stiffening the structure is a reasonable design altemative that should not be precluded (or Iimited). Further background related to concrete masonry shear walls is provided in References 3.33, 3.34, and 3.35.
- 142. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-129 COMMENTARY LOAD WALL ELASTIC CURVATURE & DISPLACEMENT INELASTIC CURVATURE dv & DISPLACEMENT W d ;nelestic W H fu H (a) Theoretical Model (b) Simplified Model Figure CC-303-3- Wal/ curvature and displacement e" e--- ~o~ Figure CC-303-4 -Strain distribution at critica! section CODE (b) Where special boundary elements are required by Section 3030605.3 (a), the special boundary element reinforcement shall extend vertically from the critica! section a distance not Jess than the larger of lw or M,/4V.,o 3.3.6.5.4 Shear walls not designed by Section 3.30 60503 shall have special boundary elements at boundaries and edges around openings in shear walls where the maximum extreme fiber compressive stress, corresponding to factored forces including earthquake effect, exceeds 00 2 f'm o The special boundary element shall be permitted to be discontinued where the calculated compressive stress is Jess than 0015f ~, o Stresses shall be calculated for the factored forces using a linearly elastic model and gross section propertieso For walls with flanges, an effective flange width as defined in Section 109.402.3 shall be usedo COMMENTARY (b) Where special detailing is required at the wall boundary, it must be extended vertically a distance not less than the larger of 1,. and M, 1 4V., from the critica! sectiono These Jengths, also specified in ACI 318-99, where intended to be an upper-bound estímate of the plastic hinge length for special reinforced concrete shear wallsoThe same lengths have been adopted for intermediate and special masonry shear wallso 33.6.5.4 A stress-based approach was included in ACI 318-99 to address wall configurations to which the application of displacement-based approach is not appropriate (for example, walls with openings, walls with setbacks, walls not controlled by flexure)o Maintaining the stress-based approach also provided continuity between ACI 318-99 and earlier editions of ACI 318; however, modifications were introduced to address major shortcomings ofthe design approach in pre- 1999 editions ofACI 3180 The stress limit at which special detailing is required at the boundaries of reinforced concrete shear walls was Jeft unchanged in ACI 318-99 at 002 f ~ , a value carried over from prior editions of the Codeo The special detailing, where required, must be extended over the height of the wall from the critica! section until the calculated stress drops below 001 5 f ~ , once again the same value as in prior editions of ACI 3180
- 143. C-1 30 CODE 3.3.6.5.5 Where special boundary elements are required by Section 3.3.6.5.3 or 3.3.6.5.4, requirements (a) through (d) in this section shall be satisfied and tests shall be performed to verifY the strain capacity of the element: (a) The special boundary element shall extend horizontally from the extreme compression fiber a distance not less than the larger of(c- 0.1/,.) and c/2. TMS 402-11/ACI 530-1 1/ASCE 5-11 COMMENTARY A major difference between ACI 318-99 and prior editions of ACI 318 is in the way a shear wall requiring specially detailed boundary elements is to be designed for flexure and axial loads. ACI 318-95 required that the boundary elements be designed to resist (as short columns) the tributary gravity load plus the compressive resultant associated with the overturning moment at the base of the wall (both taken at factored values). The application of this requirement typically resulted in safe boundary elements containing high percentages of reinforcement, resulting in a substantial increase in wall flexura! strength. Constructability suffered as a result, but more importantly, brittle shear failure preceding ductile flexura! failure became more likely, because walls having excessive flexura! strength would draw larger shear forces in an earthquake event, and the Code did not require shear strength to be increased proportionally with the increase in flexura! strength. ACI 318-99 does not require the boundary elements to resist the entire P, and M,, even when the stress-based approach is used. In fact, a shear wall is designed in exactly the same way for flexure and axial load, irrespective of whether the displacement-based approach or the stress-based approach is used to trigger special boundary elements. The Code has adopted the stress-based triggers of ACI 318-99 for cases where the displacement-based nppronch is not applicablc, simp1y changing the.threshold values of0.2f~ and 0.15/ ~ for reinforced concrete walls to 0.2/~, and 0.15/~, respectively, for reinforced masonry walls. Other aspects ofthe ACI 318-99 approach are retained. Design for flexure and axial loads does not change depending on whether the neutral axis-based trigger or the stress-based trigger is used. 3.3.6.5.5 Unlike in the case of concrete, where prescriptive detailing requirements for the specially confined boundary element are given in ACI 318-99, this Code requires that testing be done to verifY that the detailing provided shall be capable of developing a strain capacity in the boundary element that would be in excess of the maximum imposed strain. Jt is hoped that reasonably extensive tests will be conducted in the near future, leading to the development of prescriptive detailing requirements for specially confined boundary elements ofintermediate as well as special reinforced masonry shear walls. (a) Figure CC-3.3-4 shows that when the neutral axis depth e exceeds the critica! neutral axis depth Ccr, the extreme compression fiber strain in the masonry reaches a value Emm in excess ofthe maximum usable strain Em11 • The corresponding ultimate curvature t/J is Em11 1c. Based on the model ofFigure CC-3.3-3(b), (Equation 3)
- 144. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-131 CODE (b) In flanged sections, the special boundary element shall include the effective flange width in compression and shall extend at least 12 in. (305 mm) into the web. (e) Special boundary element transverse reinforcement at the wall base shall extend into the support a mínimum of the development length of the largest longitudinal reinforcement in the boundary element unless the special boundary element terminates on a footing or mat, where special boundary element transverse reinforcement shall extend at least 12 in. (305 mm) into the footing or mat. COMMENTARY From Equation 3: {; = 2(Cdóne )(~) mm hW eIV (Equation 4) The wall length over which the strains exceed the limiting value ofe""" denoted as e", can be determined using similar triangles from Figure CC-3.3-4: e" = e(l - &"'" ) E mm (Equation 5) An expression for the required length of confinement can be developed by combining Equations 2 and 3: e e (emu12) T:: =-¡:- (Cdt5,. 1hw) (Equation 6) The term e1f w in Equation 4 accounts for the influence of material properties (/ ~., fv), axial load, geometry, and quantities and distribution of reinforcement, whereas the term (c,, 12)1(Cdt5nelhw )accounts for the influence of system response (roof displacement) and the maximum usable strain ofmasonry. The wall length over which special transverse reinforcement must be provided is based on Equation 6, with a value of Cdt5ne 1hw = 0.015: ~ = ~ - (0.003/ 2) =~-0.1~~ (Equation 7) fw fw 0.015 fw 2 The value of Cdt5ne 1hw was selected to provide an upper-bound estímate of the mean drift ratio of typical shear wall buildings constructed in the United States of Americam. Thus, the length of the wall that must be confined is conservative for many buildings. The value of e/2 represents a mínimum length of confinement, is adopted from ACI 3 18-99, and is arbitrary. (b) This requirement originated in the 1997 UBC and has been carried over into ACI 318-99 and -02. Where flanges are heavily stressed in compression, the web- to-flange interface is likely to be heavily stressed and may sustain local crushing failure unless special boundary element reinforcement extends into the web. (e) The same extension is required for special boundary element transverse reinforcement in special reinforced concrete shear walls and for special transverse reinforcement in reinforced concrete columns supporting reactions from discontinued stiff members in buildings assigned to high seismic design categories.
- 145. C-132 CODE (d) Horizontal shear reinforcement in the wall web shall be anchored to develop the specified yield strength, ¡;,, within the confined core ofthe boundary element. TMS 402-11/ACISJ0-11/ASCE 5-11 COMMENTARY (d) Because horizontal reinforcement is likely to act as web reinforcement in walls requiring boundary elements, it needs to be fully anchored in boundary elements that act as flanges. According to the Commentary to ACI 318, achievement of this anchorage is difficult when large transverse cracks occur in the boundary elements. That Commentary recommends the use of standard 90-degree hooks or mechanical anchorage schemes, instead of straight bar development.
- 146. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-1 33 CHAPTER4 PRESTRESSED MASONRY 4.1- General 4.1.1 Scope CODE This chapter provides requirements for design of masonry walls that are prestressed with bonded or unbonded prestressing tendons. 4.1.2 Walls shall be designed for strength requirements and checked for service load requirements. 4.1.3 The wall provisions of Chapter 1 and Section 2.1 shall apply to prestressed masonry walls. 4.1.4 The provisions ofSection 4.4.3 shall apply for the computation ofnominal moment strength. 4.1.5 Masonry shall be laid in running bond unless a bond beam or other technique is used to distribute anchorage forces. COMMENTARY 4.1 - General 4.1.1 Scope Prestressing forces are used in masonry walls to reduce or eliminate tensile stresses due to extemally applied loads by using controlled precompression. The precompression is generated by prestressing tendons, either bars, wires, or strands, that are contained in openings in the masonry, which may be grouted. The prestressing tendons can be pre-tensioned (stressed against externa! abutments prior to placing the masonry), or post- tensioned (stressed against the masonry after it has been p1aced). Since most research and applications to date have focused on walls, the chapter applies only to walls, not columns, beams, nor lintels. (Provisions for columns, beams, and Iintels will be developed in future editions of the Code.) Most construction applications to date have involved post-tensioned, ungrouted masonry for its ease of construction and overall economy. Consequently, these code provisions primarily focus on post-tensioned masonry. Although not very common, pn:-lt:nsiuning has been used to construct prefabricated masonry panels. A more detai1ed review of prestressed masonry systems and applications is given elsewhere 41 . Throughout this Code and Specification, references to "reinforcement" app1y to non-prestressed reinforcement. These references do not apply to prestressing tendons, except as explicitly noted in Chapter 4. Requirements for prestressing tendons use the terrns "prestressing tendon" or "tendon." The provisions of Chapter 4 do not require a mandatory quantity of reinforcement or bonded prestressing tendons for prestressed masonry walls. Anchorage forces are distributed within a wall similar to the way in which concentrated loads are distributed (as described in Section 1.9.7; see Figure CC-1.9-7). However, research4 · 2 has indicated that prestress losses can distribute to adjacent tendons as far laterally from the anchorage as the height ofthe wall.
- 147. C-134 CODE 4.1.6 For prestressed masonry members, the prestressing force shall be added to load combinations, except as modified by Section 4.4.2. 4.2 - Design methods 4.2.1 General Prestressed masonry members shall be designed by elastic analysis using loading and load combinations in accordance with the provisions of Sections 1.7 and 2.1.2, except as noted in Section 4.4.3. 4.2.2 After transfer lmmediately after the transfer of prestressing force to the masonry, limitations on masonry stresses given in this chapter shall be based upon/'111;. 4.3- Permissible stresses in prestressing tendons 4.3.1 Jackingforce The stress in prestressing tendons due to the jacking force shall not exceed 0.94/py, nor 0.80_(¡,, nor the maximum value recommended by the manufacturer of the prestressing tendons or anchorages. 4.3.2 Jmmediate/y after transfer The stress in the prestressing tendons immediately after transfer ofthe prestressing force to the masonry shall not exceed 0.82/py nor 0.74/p11 • 4.3.3 Post-tensioned masonry members At the time of application of prestress, the stress in prestressing tendons at anchorages and couplers shall not exceed 0.78j,y nor 0.70j,11 • TMS 402-11/ACISJ0-11/ASCE 5-11 COMMENTARY 4.2 - Design methods Originally, prestressed masonry was designed using allowable stress design with a moment strength check for walls with laterally restrained tendons. The British code for prestressed masonry4 · 3 • 4 .4 and extensive research on the behavior of prestressed masonry were considered. Summaries of prestressed masonry research and proposed design criteria are available in the literature45 - 4 · 9 • Design methods are now based upon strength provisions with serviceability checks. Often, a masonry wall is prestressed prior to 28 days after construction. The specified compressive strength of the masonry at the time of prestressing (/'111; ) is used to determine allowable prestressing levels. This strength will likely be a fraction of the 28-day specified compressive strength. Assessment of masonry compressive strength immediately befare the transfer of prestress should be by testing of masonry prisms or by a record of strength gain over time of masonry prisms constructed of similar masonry units, mortar, and grout, when subjected to similar curing conditions. 4.3- Permissible stresses in prestressing tendons Allowable, prestressing-tendon stresses are based on criteria established for prestressed concrete4 · 10 • Allowable, prestressing-tendon stresses are for jacking forces and for the state of stress in the prestressing tendon immediately after the prestressing has been applied, or transferred, to the masonry. When computing the prestressing-tendon stress immediately after transfer of prestress, consider all sources of short term prestress losses. These sources include such items as anchorage seating loss, elastic shortening ofmasonry, and friction losses.
- 148. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-135 CODE 4.3.4 E.ffective prestress The computed effective stress in the prestressing tendons under service loads, !se, shall include the effects ofthe following: (a) anchorage seating losses, (b) elastic shortening ofmasonry, (e) creep ofmasonry, (d) shrinkage of concrete masonry, (e) relaxation ofprestressing tendon stress, (f) friction losses, (g) irreversible moisture expansion ofclay masonry, and (h) thermal effects. COMMENTARY 4.3.4 E.ffective prestress The state of stress in a prestressed masonry wall must be checked for each stage of loading. For each loading condition, the effective level ofprestress should be used in the computation of stresses and wall strength. Effective prestress is nota fixed quantity over time. Research on the loss and gain of prestress in prestressed masonry is extensive and includes testing of time-dependent phenomena such as creep, shrinkage, moisture expansion, and prestressing-tendon stress relaxation4 · 11 - 4 · 14 . Instantaneous deformation of masonry due to the application of prestress may be computed by the modulus of elasticity ofmasonry given in Section 1.8.2. Creep, shrinkage, and moisture expansion ofmasonry may be computed by the coefficients given in Section 1.8. Change in effective prestress due to elastic deformation, creep, shrinkage, and moisture expansion should be based on relative modulus ofelasticity of masonry and prestressing steel. The stressing operation and relative placement of prestressing tendons should be considered in calculating losses. Elastic shortening during post-tensioning can reduce the stress in adjacent tendons that have already been stressed. Consequently, elastic shortening ofthe wall should be calculated considering the incremental application of post-tensioning. That elastic shortening should then be used to estimate the total loss of prestress. Altematively, post-tensioning tendons can be prestressed to compensate for the elastic shortening caused by the incremental stressing operation. Prestressing steel that is stressed to a large fraction ofits yield stress and held at a constant strain will relax, requiring less stress to maintain a constant strain. The phenomenon of stress relaxation is associated with plastic deformation and its magnitude increases with steel stress as a fraction ofsteel strength. ASTM A416, A421, and A7224 · 15 • 4 · 16 • 4 · 17 prestressing steels are stabilized for low relaxation losses during production. Other steel types that do not have this stabilization treatrnent may exhibit considerably higher relaxation losses. Their relaxation losses must be carefully assessed by testing. The loss of effective prestress due to stress relaxation of the prestressing tendon is dependent upon the level of prestress, which changes with time- dependent phenomenon such as creep, shrinkage, and moisture expansion ofthe masonry. An appropriate formula for predicting prestress loss due to relaxation has been developed412 - 4 · 14 • Altemately, direct addition of the steel stress-relaxation value provided by the manufacturer can be used to compute prestress losses and gains. Friction losses are minimal or nonexistent for most post-tensioned masonry applications, because prestressing tendons are usually straight and contained in cavities. For anchorage losses, manufacturers' information sbouJd be used to compute prestress losses. Changes in prestress due to thermal fluctuations may be neglected if masonry is
- 149. C-136 CODE 4.4- Axial compression and flexure 4.4.1 General 4.4.1.1 Walls subjected to axial compression, flexure, or to combined axial compression and flexure shall be designed according to the provisions of Section 2.2.3, except as noted in Section 4.4.1.2, 4.4.1.3, 4.4.2, and 4.4.3. 4.4.1.2 The allowable compressive stresses due to axialloads, Fa, and flexure, Fh , and the allowable axial force in Equation 2-1 5 shall be permitted to be increased by 20 percent for the stress condition imrnediately after transfer ofprestress. 4.4.1.3 Masonry shall not be subjected to flexura)tensile stress from the combination ofprestressing force and dead load. TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY prestressed with high-strength prestressing steels. Loss of prestressing should be calculated for each design to determine effective prestress. Calculations should be based on the particular construction materials and methods as well as the climate and environmental conditions. Committee experience, research, and field experience with post- tensioned wall designs from Switzerland, Great Britain, Australia, and New Zealand has indicated that prestress losses are expected to be in the following ranges42 • 4 · 184 · 20 : (a) Initialloss afterjacking -5% to 10% (b) Total losses after long-term service for concrete masonry- 30% to 35% (e) Total losses after long-term service for clay masonry - 20% to 25% The values in (b) and (e) include both the short-term and long-term losses expected for post-tensioning. The Committee believes these ranges provide reasonable estimates for typical wall applications, unless calculations, experience, or construction techniques indicate different losses are expected. 4.4- Axial compression and flexure 4.4.1 General The requirements for prestressed masonry walls subjected to axial compression and flexure are separated into those with laterally unrestrained prestressing tendons and those with laterally restrained prestressing tendons. This separation was necessary because the flexura) behavior of a prestressed masonry wall significantly depends upon the lateral restraint of the prestressing tendon. Lateral restraint of a prestressing tendon is typically provided by grouting the cell or void containing the tendon before or after transfer of prestressing force to the masonry. Alternatively, lateral restraint may be provided by building the masonry into contact with the tendon or the protective sheathing of the tendon at periodic intervals along the length ofthe prestressing tendon. Allowable compressive stresses for prestressed masonry address two distinct loading stages; stresses imrnediately after transfer of prestressing force to the masonry wall and stresses after all prestress losses and gains have taken place. The magnitude of allowable axial compressive stress and bending compressive stress after all prestress losses and gains are consistent with those for unreinforced masonry in Section 2.2. Immediately after transfer ofprestressing, allowable compressive stresses and applied axial load should be based upon f ~,; and may be increased by 20 percent. This means that the factors of safety at the time ofthe transfer of prestress may be lower than those after prestress losses and gains occur. The first reason for this is that the effective precompression stress at the time of transfer of prestressing almost certainly decreases over time and masonry compressive strength most likely increases over time. Second, loads at the time of
- 150. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-1 37 CODE 4.4.2 Service load requirements 4.4.2.1 For walls with laterally unrestrained prestressing tendons, the prestressing force, Pps , shall be included in the computation of the axial load, P, in Equation 2-15 and in the computation of the eccentricity ofthe axial load, e, in Equation 2-1 9. 4.4.2.2 For walls with laterally restrained prestressing tendons, the prestressing force, Pps, shall not be considered for the computation of the axial load, P, in Equation 2- 15. The prestressing force, Pps, shall be considered for the computation of the eccentricity of the axial resultant load, e, in Equation 2-1 9. COMMENTARY transfer of prestressing, namely prestress force and dead loads, are known more precisely than loads throughout the remainder ofservice life. Cracking ofprestressed masonry under permanent loads is to be avoided. The prestressing force and the dead weight of the wall are permanent loads. Cracking under permanent loading conditions is not desirable due to the potential for significant water penetration, which may precipitate corrosion of the prestressing tendons and accessories and damage to interior finishes. Masonry provides a significant flexura! tensile resistance to cracking, as reflected by the allowable flexural tensile stress values stated in Section 2.2. Consequently, elimination oftensile stress under prestressing force and dead loads alone is a conservative measure, but one the comrnittee deemed reasonable and reflective of current practice for prestressed masonry members. 4.4.2 Service load requirements Since masonry walls with laterally unrestrained prestressing tendons are equivalent to masonry walls subjected to applied axial loads, the design approach for unreinforced masonry in Section 2.2 has been adopted for convenience and consistency. Buckling of masonry walls under prestressing force must be avoided for walls with laterally unrestrained prestressing tendons. The prestressing force, Pps, is to be added to the design axial load, P, for stress and load computations and in the computation of the eccentricity ofthe axial resultant, e. Lateral restraint of a prestressing tendon is typically provided by grouting the cell or void containing the tendon before or after transfer of prestressing force to the masonry. Altematively, lateral restraint may be provided by building the masonry into contact with the tendon or the tendon's protective sheath at periodic intervals along the length ofthe prestressing tendon4 · 21 . In general, three intermediate contacts within a laterally unsupported wall length or height can be considered to provide full lateral support ofthe tendon. Prestressed masonry walls with laterally restrained prestressing tendons require a modified design approach from the criteria in Section 2.2. Ifthe prestressing tendon is laterally restrained, the wall cannot buckle under its own prestressing force. Any tendency to buckle under prestressing force induces a lateral deformation that is resisted by an equal and opposite restraining force provided by the prestressing tendon. Such walls are susceptible to buckling under axialloads other than prestressing, however, and this loading condition must be checked.4 · 22 For this condition, with both concentrically and eccentrically prestressed masonry walls, the prestressing force must be considered in the computation of the eccentricity of this axial resultant, e, in Equation 2-19 of the Code. The flexura! stress induced by eccentric prestressing causes an increase or decrease in the axial buckling load, depending upon the location and magnitude of the applied axial load relative to the prestressing force.
- 151. C-138 CODE 4.4.3 Strength requirements 4.4.3.1 Required strength shall be determined in accordance with the factored load combinations ofthe Jegally adopted building code. When the legally adopted building code does not provide factored load combinations, structures and members shall be designed to resist the combination of loads specified in ASCE 7 for strength design. Walls subject to compressive axial load shall be designed for the factored design moment and the accompanying factored axial load. The factored moment, M," shall include the moment induced by relative lateral displacement. 4.4.3.2 Values of the response modification coefficient (R) and the detlection amplification factor (Cd), indicated in ASCE 7 Table 12.2-1 for ordinary plain (unreinforced) masonry shear walls shall be used in determining base shear and design story drift. 4.4.3.3 The design moment strength shall be taken as the nominal moment strength, M,, multiplied by a strength-reduction factor (tfj) of0.8. 4.4.3.4 For cross sections with uniform width, b, over the depth ofthe compression zone, the depth ofthe equivalent compression stress block, a, shall be determined by the following equation: /psAps + /yAs + P, a = ___,__..:...__ __.:____ 0.80 1;, b (Equation 4-1) For other cross sections, Equation (4-l) shall be modified to consider the variable width ofcompression zone. 4.4.3.5 For walls with (a) uniform width, b, (b) concentric reinforcement and prestressing tendons, and (e) concentric axial load, the nominal moment strength, M,, shall be computed by the following equation: (Equation 4-2) 4.4.3.5.1 The quantity a shall be computed according to Section 4.4.3.4 and J;,s shall be computed according to Section 4.4.3.7. 4.4.3.5.2 The nominal moment strength for other conditions shall be based on static moment equilibrium principies. 4.4.3.5.3 The distance d shall be computed as the actual distance from the centerline ofthe tendon to the compression face of the member. For walls with laterally unrestrained prestressing tendons and loaded out of plane, d shall not exceed the face-shell thickness plus one-halfthe tendon diameter plus 0.375 in. (9.5 mm). 4.4.3.5.4 When tendons are not placed in the center of the wall, d shall be computed in each direction for out-of-plane bending. 4.4.3.6 The ratio a/d shall not exceed 0.38. TMS 402-11/ACI 530-11/ASCE 5-1 1 COMMENTARY 4.4.3 Strength requirements Computation of the moment strength of prestressed masonry walls is similar to the method for prestressed concrete.4 · 1 ° For bonded tendons, the simplification of taking the tendon stress at nominal moment strength equal to the yield stress can be more conservative for bars than for strands because the yield stress of a prestressing bar is a smaller percentage ofthe ultimate strength ofthe tendon. The response modification coefficient (R) and detlection amplification factor (Cd) used for unreinforced masonry are also used in the design of prestressed masonry. This requirement ensures that the structural response of prestressed masonry structures, designed in accordance with these provisions, will essentially remain in the elastic range. When more experimental and field data are available on the ductility of both unbonded and bonded systems, R and Cd factors can be reviewed. The equation for the unbonded prestressing tendon stress, fps, at the moment strength condition (Equation 4- 3) is based on tests of prestressed masonry walls, which were loaded out-of-plane. Equation 4-3 is used for calculating unbonded tendon stress at nominal moment capacity for members loaded out-of-plane containing either laterally restrained or laterally unrestrained tendons. This equation provides improved estimates of the tendon stresses at ultimate capacity over previous equations in the Code4 · 23 -4· 26 • Equation 4-3 can be solved iteratively for fus· For the first iteration, fus in the parenthetical term can be taken equal tofs•. The equation for the nominal moment strength, Mn, is for the general case of a masonry wall with concentrically applied axial load and concentric tendons and reinforcement. This is representative of most prestressed masonry applications to date. For other conditions, the designer should refer to first principies of structural mechanics to determine the nominal moment strength of the wall. The depth of the equivalent compression stress block must be determined with consideration ofthe cross section of the wall, the tensile resistance of tendons and reinforcement, and the factored design axial load, P,. P11 is an additive quantity in Code Equations 4-1 and 4-2. Prestressing adds to the resistance for ultimate strength evaluations and is used with a load factor of 1.0. Equation 4-1 defining the depth of the equivalent compression stress block, a, is modified to match the value for the equivalent uniform stress parameter specified in Chapter 3 (Strength Design of Masonry) of the Code (0.80f ~,). A review of existing tests of post-tensioned masonry walls indicates that the flexura! strength of the walls is more accurately calculated using uniform stresses smaller than the value specified in Chapter 4 in previous editions ofthe Code (0.85f ~.t 23 ' 4 ' 24 . The ratio, a/d, is limited to assure ductile performance in flexure when using tendons fabricated from steel with
- 152. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES AND COMMENTARY C-139 CODE 4.43.7 Computation of J;,s for out-of-plane bending 4.4.3.7.1 For walls with bonded prestressing tendons, /ps shall be computed based on strain compatibility or shall be taken equal to/¡,y- 4.4.3.7.2 For walls with laterally restrained or laterally unrestrained unbonded prestressing tendons, the following equation shall be permitted to be used instead ofa more accurate determination ofJ;,s: f =J +0.03[Epsd](l-1.56Apsfps+PJ ps se [ r' bd p Jm (Equation 4-3) 4.43.7.3 In Equation 4-3, the value of J,s shall be not less thanfse.and not larger than/¡,y. 4.4.3.8 Computa/ion off psfor shear walls - For walls with bonded prestressing tendons,f ps shall be computed based on strain compatibility or shall be taken equal to /¡,y . Instead of a more accurate determination, /,., for members with unbonded prestressing tendons shall be!se. 4.5 -Axial tension Axial tension shall be resisted by reinforcement, prestressing tendons, or both. 4.6 -Shear 4.6.1 For walls without bonded mild reinforcement, nominal shear strength, Vn, shall be computed in accordance with Sections 3.2.4a, 3.2.4b, 3.2.4c, and 3.2.4e. N, shall include the effective prestress force, A,slse. 4.6.2 For walls with bonded mild reinforcement, nominal shear strength, Vn, shall be computed in accordance with Section 3.3.4.1.2. 4.6.2.1 Nominal masonry shear strength, Vn,, shall be computed in accordance with Section 3.3.4.1.2.1. P, shall include the effective prestress force, A,slse. COMMENTARY yield strengths between 60 ksi (420 MPa) and 270 ksi (1865 MPa). As with reinforced masonry designed in accordance with Chapters 2 and 3, the calculated depth in compression should be compared to the depth available to resist compressive stresses. For sections with uniform width, the value ofthe compression block depth, a, should be compared to the solid bearing depth available to resist compressive stresses. For hollow sections that are ungrouted or partially-grouted, the available depth may be limited to the face shell thickness of the masonry units, particularly if the webs are not mortared. The a/d limitation is intended to ensure significant yielding of the prestressing tendons prior to masonry compression failure. In such a situation, the nominal moment strength is determined by the strength of the prestressing tendon, which is the basis for a strength-reduction factor equal to 0.8. This ductility lirnit was determined for sections with bonded tendons, and when more experimental and field data are available on the ductility of both unbonded and bonded systems, this limit will again be reviewed. The calculation ofthis limit assumes that the effective prestressing stress is equivalent to 0.65 fv. If the magnitude ofthe initial effective prestress (i.e.,fs.) is less than 0.65fv, then the strain in the steel at ultimate strength 6s should be compared to the yield strain (i.e., 6v =fv 1E.). The steel strain at ultimate strength 65 can be approximated by assuming the strain in the steel is equal to an initial strain dueto the effective prestressing (es,; =!se lEs ) plus additional strain due to flexure (ss.flex = 0.003x((d- 1.25a)/1.25a). 4.5 -Axial tension The axial tensile strength of masonry in a prestressed masonry wall is to be neglected, which is a conservative measure. This requirement is consistent with that of Section 2.3. If axial tension develops, for example dueto wind uplift on the roofstructure, the axial tension must be resisted by reinforcement, tendons, or both. 4.6 - Shear This section applies to both in-plane and out-of-plane shear. The shear capacity of prestressed walls is calculated using the provisions ofthe Chapter 3. Calculation of shear capacity is dictated by the presence or absence of bonded mild reinforcement. While the MSJC acknowledges that prestressed masonry walls are reinforced, for walls without bonded mild reinforcement, the unreinforced (plain) masonry shear provisions of Chapter 3 are used to calculate shear capacity. When bonded mild reinforcement is provided, then the reinforced masonry shear provisions ofChapter 3 are used to calculate shear capacity.
- 153. C-140 CODE 4.6.2.2 Nominal shear strength provided by reinforcement, Vns, shall be computed in accordance with Section 3.3.4.1.2.. 4.7- Deflection Computation of member deflection shall include camber, the effects of time-dependent phenomena, and P-delta effects. 4.8- Prestressing tendon anchorages, couplers, and end blocks 4.8.1 Prestressing tendons in masonry construction shall be anchored by either: (a) mechanical anchorage devices bearing directly on masonry or placed inside an end block of concrete or fully grouted masonry, or (b) bond in reinforced concrete end blocks or members. 4.8.2 Anchorages and couplers for prestressing tendons shall develop at least 95 percent of the specified tensile strength of the prestressing tendons when tested in an unbonded condition, without exceeding anticipated set. 4.8.3 Reinforcement shall be provided in masonry members near anchorages if tensile stresses created by bursting, splitting, and spalling forces induced by the prestressing tendon exceed the capacity ofthe masonry. 4.8.4 Bearing stresses 4.8.4.1 In prestressing tendon anchorage zones, local bearing stress on the masonry shall be computed based on the contact surface between masonry and the mechanical anchorage device or between masonry and the end block. 4.8.4.2 Bearing stresses due to maximum jacking force of the prestressing tendon shall not exceed 0.50f ~,¡ o 4.9 - Protection of prestressing tendons and accessories 4.9.1 Prestressing tendons, anchorages, couplers, and end fittings in exterior walls exposed to earth or weather, or walls exposed to a mean relative humidity exceeding 75 percent, shall be corrosion-protected. 4.9.2 Corrosion protection of prestressing tendons TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY No shear strength enhancement dueto arching action of the masonry is recognized in this Code for prestressed masonry walls. The formation of compression struts and tension ties in prestressed masonry is possible, but this phenomenon has not been considered. 4.7 - Deflection In accordance with Chapter 1, prestressed masonry wall deflection should be computed based on uncracked section properties. Computation of wall deflection must inelude the effect of time-dependent phenomenon such as creep and shrinkage of masonry and relaxation of prestressing tendons. There are no limits for the out-of- plane deflection of prestressed masonry walls. This is because appropriate out-of-plane deflection limits are project-specific. The designer should consider the potential for damage to interior finishes, and should limit detlections accordingly. 4.8- Prestressing tendon anchorages, couplers, and end blocks The provisions ofthis section ofthe Code are used to design the tendon anchorages, couplers, and end blocks to withstand the prestressing operation and effectively transfer prestress force to the masonry wall without distress to the masonry or the prestressing accessories. Anchorages are designed for adequate pull-out strength from their foundations. Because the actual stresses are quite complicated around post-tensioning anchorages, experimental data, or a refined analysis should be used whenever possible. Appropriate formulas from the references4 · 27 should be used as a guide to size prestressing tendon anchorages when experimental data or more refined analysis are not available. Additional guidance on design and details for post-tensioning anchorage zones is given in the references4 · 28 • 4.9 - Protection of prestressing tendons and accessories Corrosion protection of the prestressing tendon and accessories is required in masonry walls subject to a moist and corrosive environment. Methods of corrosion protection are addressed in the Specification. Masonry and grout cover is not considered adequate protection due to variable permeability and the sensitivity of prestressing
- 154. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-141 CODE shall not rely solely on masonry cover. 4.93 Parts of prestressing tendons not embedded in masonry shall be provided with mechanical and tire protection equivalent to that ofthe embedded parts ofthe tendon. 4.1O- Development of bonded tendons Development of bonded prestressing tendons in grouted corrugated ducts, anchored in accordance with Section 4.8.1, does not need to be calculated. COMMENTARY tendons to corrosion. The methods ofcorrosion protection given in the Specification provide a minimum leve! of corrosion protection. The designer may wish to impose more substantial corrosion protection requirements, especially in highly corrosive environments. 4.1O- Development of bonded tendons Consistent with design practice in prestressed concrete, development of post-tensioned tendons away from the anchorage does not need to be calculated.
- 155. C-142 TMS 402-11/ACI 530-11/ASCE 5-11 This page is intentionally left blank.
- 156. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-143 CHAPTER 5 EMPIRICAL DESIGN OF MASONRY 5.1 -General 5.1.1 Scope CODE This chapter provides requirements for empírica( design of masonry. 5.1.1.1 The provisions of Chapter 1, excluding Sections 1.2.2(c), 1.7, 1.8, and 1.9, shall apply to empírica! design, except as specifically stated here. 5.1.1.2 Article 1.4 of TMS 602/ACI 530.1/ASCE 6 shall not apply to empirically designed masonry. 5.1.2 Limitations 5.1.2.1 Gravity Loads - The resultant of gravity loads shall be placed within the center third of the wall thickness and within the central area bounded by lines at one-third of each cross-sectional dimension of foundation piers. 5.1.2.2 Seismic - Empírica! requirements shall not apply to the design or construction of masonry for buildings, parts of buildings or other structures in Seismic D e~ i gn Categories O, E, or F as defined in ASCE 7, and shall not apply to the design of the seismic-force-resisting system for structures in Seismic Design Categories B or C. 5.1.2.3 Wind - Empírica! requirements shall be permitted to be applied to the design and construction of masonry elements defined by Table 5.1.1, based on building height and basic wind speed that are applicable to the building. 5.1.2.4 Bui/dings and other structures in Risk Category I V - Empírica) requirements shall not apply to the design or construction of masonry for buildings, parts of buildings or other structures in Risk Category IV as defined in ASCE 7. 5.1.2.5 Other horizontal loads - Empírica! requirements shall not apply to structures resisting horizontal loads other than permitted wind or seismic loads or foundation walls as provided in Section 5.6.3. 5.1.2.6 G/ass unit masonry - The provisions of Chapter 5 shall not apply to glass unit masonry. 5.1.2.7 AAC masonry - The provisions of Chapter 5 shall not apply to AAC masonry. COMMENTARY 5.1 - General Empírica( rules and formulas for the design ofmasonry structures were developed by experience. These are part of the legacy of masonry's long use, predating engineering analysis. Design is based on the condition that gravity loads are reasonably centered on the bearing walts and foundation piers. Figure CC-5.1-1 illustrates the location of the resultant ofgravity loads on foundation piers. The etfect of any steel reinforcement, if used, is neglected. The masonry should be laid in running bond. Specific limitations on building height, seismic, wind, and horizontal loads exist. Buildings are of limited height. Members not participating in the lateral-force-resisting system of a building may be empirically designed even though the lateral-force-resisting system is designed under Chapter 2. These procedures have been compiled through the years5 · 1 " 5 · 5 • The most recent of these documents5 · 5 is the basis for this chapter. Empírica) design is a procedure of sizing and proportioning masonry elements. Tt is not design analysis. This procedure is conservative for most masonry construction. Empírica! design of masonry was developed for buildings of smaller scale, with more masonry interior walls and stiffer floor systems than built today. Thus, the limits imposed are valid. Since empirically designed masonry is based on the gross compressive strength ofthe units, there is no need to specifY the compressive strength ofmasonry. 5.1.2.3 Wind - There is a change in the wind speed values listed in the table from previous versions of the Code. The values listed were adj usted to strength levels for use with ASCE 7-10 wind speed maps and are designed to maintain the strength leve! velocity pressures below approximately 40 psf(1.92 k.Pa) for a wide range of building configurations.
- 157. C-144 TMS 402-11/ACI 530-11/ASCE 5-11 Table 5.1 .1 Limitations based on building height and basic wind speed Element Description Masonry elements that are part of the lateral-force-resisting system Interior masonry elements that are not part ofthe lateral-force-resisting system in buildings other than enclosed as defined by ASCE 7 Exterior masonry elements that are not part ofthe 1 ateral-force-resisting system Exterior masonry elements Baste wmd speed as gtven m ASCE 7 W/3 Basic Wind Speed, mph (mps)1 Building Less than or Over 11 5 Over 120 Height, ft (m) (51)and less (54) and less Over 125 equal to 115 than or equal than or equal (56) (51) to-1 20 (54) to 125 (56) 35 (11) and less Permitted Not Permitted Over 180 (55) Not Permitted Over 60 (18) and less than or equa1 Permitted Not Permitted to 180 (55) Over 35 (11) and 1 ess than or equal Permitted Not Permitted to 60 (18) 35 (11) and less Permitted Not Permitted Over 180 (55) Not Permitted Over 60 (1 8) and less than or equal Permitted Not Permitted to 180 (55) Over 35 (11) and less than or equal Permitted Not Permitted to 60 (18) 35 (11) and Iess Permitted Not Permitted COMMENTARY W/3 W/3 -. 1 Width,W T/3 D Thickness, T Permitted area for axial load resultan! Figure CC-5.1-1 -Areaf or gravity loads applied tof oundation piers
- 158. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-145 CODE 5.2- Height Buildings relying on masonry walls as part of their lateral-force-resisting system shall not exceed 35 ft (10.67 m) in height. 5.3 - Lateral stability 5.3.1 Shear walls Where the structure depends upon masonry walls for lateral stability, shear walls shall be provided parallel to the direction ofthe lateral forces resisted. 5.3.1.1 In each direction in which shear walls are required for lateral stability, shear walls shall be positioned in at least two separate planes parallel with the direction of the lateral force. The mínimum cumulative length of shear walls provided along each plane shall be 0.2 multiplied by the long dimension of the building. Cumulative length of shear walls shall not include openings or any element whose length is less than one- half its height. 5.3.1.2 Shear walls shall be spaced so that the length-to-width ratio of each diaphragm transferring lateral forces to the shear walls does not exceed values given in Table 5.3.1. 5.3.2 Roofs The roof construction shall be designed so as not to impart out-of-plane lateral thrust to the walls under roof gravity load. COMMENTARY 5.2- Height 5.3 - Lateral stability Lateral stability requirements are a key provision of empírica! design. Obviously, shear walls must be in two directions to provide stability. Bearing walls can serve as shear walls. The height of a wall refers to the shortest unsupported height in the plane of the wall such as the shorter of a window jamb on one side and a door jamb on the other. See Figure CC-5.3-1 for cumulative length of shear walls. See Figure CC-5.3-2 for diaphragm panel length to width ratio determination. Table 5.3.1- Diaphragm length-to-width ratios Floor or roof diaphragm construction Maximum length-to-widtb ratio of diaphragm panel Cast-in-place concrete 5: 1 Precast concrete 4:1 Metal deck with concrete fill 3:1 Metal deck with no fill 2:1 Wood 2:1
- 159. C-146 TMS 402-11/ACI530-11/ASCE 5-11 COMMENTARY 1 6' -8" r- 8'-0" 1 6' -8" r- 8'-0" 1 6'-8" 18' - O" 1 6' -8" 1 [U ~----~ r-----_, IJ ----y---y-J ~ o 1 ;,. o 1 ;,. Three Bay Automotive Garage Plan 12 "{205 mm) Composite Masonry Walls Wall Height = 12' {3.7 m) X ~] b b 1 1 ;,. (o ~J ~ o 1 ;,. ~l L10·-·· _J ,._ •.•r 1 8'- O" _j 6' - 8" L8' - 0" _j 5' -4" ....,_______________ 50' - 8" cb Mínimum Cumulative Shear Wall Length Along Each Plane = 0.2 x Long Dimension Min. 1=0.2{50.67') =10.13' {3.09 m) Wallline 1: 1= {24.67 + 7.33) = 32.0' > 10.13· OK 1= {7.52 m+ 2.23 m)= 9.75 m> 3.09 m OK Wall line 2:1 = {6.0' + 6.0' + 6.0' + 6.0') = 24.0' > 10.13' OK 1={1.83 m + 1.83 m + 1.83 m+ 1.83 m) = 7.32 m > 3.09 m OK Wallline A: Note, 5'-4"{1.62 m) wall segments not included as they are less than Y. of 12' (3.66 m) wall height 1=(6.67' + 6.67') =13.33' > 10.13' OK 1= (2.03 m + 2.03 m) = 4.06 m > 3.09 m OK Wallline 8: 1=(6.67' + 6.67' + 6.67' + 6.67') = 26.67' > 10.13· OK 1=(2.03 m+ 2.03 m+ 2.03 m+ 2.03 m)= 8.13 m> 3.09 m OK Figure CC-5.3-1 - Cumulative length ofshear wal/s -B --0
- 160. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-147 COMMENTARY ShearWall D T c::::::::J c::::::::J u ShearWall E CD (.) Diaphragm Panel 1 ro ~ ~ ~ ~ Diaphragm Panel 2 >- ro Q) .r:. .r:. (/) (/) L ShearWall F c:=::::::::J c:=::::::::J JL ShearWall G ~ c:=::::::::J c::::::::J 1· X, ~1· Xz ·1 Diaphragm Panel Length =Dimension perpendicular to the resisting shear wall Diaphragm Panel Width = Dimension parallel to the resisting shear wall For example: For Shear Walls A and 8, the diaphragm panellength to width ratio is X,fY For Shear Walls D and F, the diaphragm panellength to width ratio is Y/X, Note: Shear walls should be placed on all four sides of the diaphragm panel or the resulting torsion should be accounted for. Figure CC-5.3-2 - Diaphragm panellength to width ratio determinationfor shear wall spacing CODE 5.4- Compressive stress requirements 5.4.1 Calculations Dead and live loads shall be in accordance with the legally adopted building code of which this Code forms a part, with such live load reductions as are permitted in the legally adopted building code. Compressive stresses in masonry due to vertical dead plus live Ioads (excluding wind or seismic loads) shall be determined in accordance with the following: (a) Stresses shall be calculated based on specified dimensions. (b) Calculated compressive stresses for single wythe walls and for multiwythe composite masonry walls shall be determined by dividing the design load by the gross cross-sectional area of the member. The area of openings, chases, or recesses in walls shall not be included in the gross cross-sectional area ofthe wall. 5.4.2 Allowable compressive stresses The compressive stresses in masonry shall not exceed the values given in Table 5.4.2. In multiwythe walls, the allowable stresses shall be based on the weakest combination ofthe units and mortar used in each wythe. COMMENTARY 5.4- Compressive stress requirements These are average compressive stresses based on gross area using specified dimensions. The following conditions should be used as guidelines when concentrated loads are placed on masonry: • For concentrated loads acting on the full wall thickness, the allowable stresses under the load may be increased by 25 percent. • For concentrated loads acting on concentrically placed bearing plates greater than one-half but less than full area, the allowable stress under the bearing plate may be increased by 50 percent. The course imrnediately under the point ofbearing should be a solid unit or fully filled with mortar or grout.
- 161. C-148 TMS 402-11/ACI 530-11/ASCE 5-11 Table 5.4.2- Allowable compressive stresses for empirical design of masonry Construction; compressive strength of masonry unit, Allowable compressive stresses1 based gross area, psi (MPa) on gross cross-sectional area, psi (MPa) Type M orS TypeN mortar mortar Solid masonry ofbrick and other solid units ofclay or shale; sand- lime or concrete brick: 8,000 (55.16) or greater 350 (2.41) 300 (2.07) 4,500 (31.03) 225 (1.55) 200 ( 1.38) 2,500 (17.23) 160(1.10) 140 (0.97) 1,500 (10.34) 115 (0.79) 100 (0.69) Grouted masonry of clay or shale; sand-1ime or concrete: 4,500 (31.03) or greater 225 (1.55) 200 (1.38) 2,500 (17.23) 160 (1.10) 140 (0.97) 1,500 (10.34) 115 (0.79) 100 (0.69) So1id masonry ofsolid concrete masonry units: 3,000 (20.69) or greater 225 (1.55) 200 (1.38) 2,000 (13.79) 160 (1.10) 140 (0.97) 1,200 (8.27) 115 (0.79) 100 (0.69) Masonry ofhollow load-bearing units ofclay or shale2 : 2,000 (13.79) or greater 140 (0.97) 120 (0.83) 1,500 (10.34) 115 (0.79) 100 (0.69) 1,000 (6.90) 75 (0.52) 70 (0.48) 700 (4.83) 60(0.41) 55 (0.38) Masonry ofhollow load-bearing concrete masonry units, up to and including 8 in. (203 mm) nominal thickness: 2,000 (13.79) or greater 140 (0.97) 120 (0.81) 1,500 (10.34) 115 (0.79) lOO (0.69) 1,000 (6.90) 75 (0.52) 70 (0.48) 700 (4.83) 60 (0.41) 55 (0.38) Masonry ofhollow 1 oad-bearing concrete masonry units, greater than 8 and up to 12 in. (203 to 305 mm) nominal thickness: 2,000 (13.79) or greater 125 (0.86) J10 (0.76) 1,500 (10.34) 105 (0.72) 90 (0.62) 1,000 (6.90) 65 (0.49) 60 (0.41) 700 (4.83) 55 (0.38 50 (0.35)
- 162. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY Table 5.4.2 (continued)- Allowable compressive stresses for empirical design ofmasonry Construction; compressive strength of masonry unit, Allowable compressive stresses1 based gross area, psi (MPa) on gross cross-sectional area, psi (MPa) Type Mor S TypeN mortar mortar Masonry of hollow load-bearing concrete masonry units, 12 in. (305 mm) nominal thickness and greater: 2,000 (13.79) or greater 115 (0.79) 100 (0,69) 1,500 (10.34) 95 (0.66) 85 (0.59) 1,000 (6.90) 60 (0.41) 55 (0.38) 700 (4.83) 50 (0.35) 45 (0.31)2_ Multiwythe non-composite walls2 : Solid units: 2500 (17.23) or greater 160 (1.1O) 140 (0.97) 1500 (10.34) 115 (0.79) 100 (0.69) Hollow units ofclay or shale 75 (0.52) 70 (0.48) Hollow units ofconcrete masonry ofnominal thickness, up to and including 8 in. (203 mm): 75 (0.52) 70 (0.48) greater than 8 and up to 12 in. (203-305 mm): 70 (0.48) 65 (0.45) 12 in. (305 mm) and greater: 60(0.41) 55(0.38) Stone ashlar masonry: Granite 720 (4.96) 640 (4.41) Limestone or marble 450 (3.1O) 400 (2.76) Sandstone or cast stone 360 (2.48) 320 (2.21) Rubble stone masonry: Coursed, rough, or random 120 (0.83) 100 (0.69) 1 Linear interpolation shall be permitted for determining allowable stresses for masonry units having compressive strengths which are intermediate between those given in the table. 2 In non-composite walls, where floor and roof loads are carried upon one wythe, the gross cross-sectional area is that of the wythe under load; if both wythes are loaded, the gross cross-sectional area is that of the wall minus the area ofthe cavity between the wythes. C-149
- 163. C-150 CODE 5.5- Lateral support 5.5.1 Maximum lit and hit Masoruy walls without openings shall be laterally supported in either the horizontal or the vertical direction so that lit orhitdoes not exceed the valuesgiven in Table 5.5.1. Masonry walls with single or multiple openings shall be laterally supported in either the horizontal or vertical direction so that lit or hit does not exceed the values given in Table 5.5.1 divided by Jwr IWs . Ws is the dimension of the structural wall strip measured perpendicular to the span of the wall strip and perpendicular to the thickness as shown in Figure 5.5.1-1 . Ws is measured from the edge of the opening. Ws shall be no less than 3t on each side of each opening. Therefore, at walls with multiple openings, jambs shall be no less than 6t between openings. For design purposes, the effective Ws shall not be assumed to be greater than 6t. At non- masonry lintels, the edge of the opening shall be considered the edge of the non-masonry lintel. Ws shall occur uninterrupted over the full span ofthe wall. Wr is the dimension, parallel to Ws, from the center of the opening to the opposite end of Ws as shown in Figure 5.5.1-1. Where there are multiple openings perpendicular to Ws, Wr shall be measured from the center of a virtual opening that encompasses such openings. Masonry elements within the virtual opening must be designed in accordance with Chapter 2 or 3. For walls with openings that span no more than 4 feet, parallel to Ws, if Ws is no less than 4 feet, then it shall be permitted to ignore the effect ofthose openings. The span of openings, parallel to Ws, shall be limited so that the span divided by t does not exceed the values given in Table 5.5.1. In addition to these limitations, lintels shall be designed for gravity loads in accordance with Section 5.9.2. TMS 402-11/ACI530-11/ASCE 5-11 COMMENTARY 5.5 - Lateral support Lateral support requirements are included to limit the flexura! tensile stress due to out-of-plane loads. Masonry headers resist shear stress and permit the entire cross- section to perform as a single element. This is not the case for non-composite walls connected with wall ties. For such non-composite walls, the use of the sum of the thicknesses of the wythes has been used successfully for a long time and is a traditional approach that is acceptable within the limits imposed by Code Table 5.5.1. Requirements were added in the 2008 edition to provide relative out-of-plane resistance that limit the maximum width of opening and provide sufficient masoruy sections between the openings. Table 5.5.1 - Walllateral support reauirements Construction Maximum lit or hit Bearing walls Solid units or fully grouted 20 Other than solid units or fully grouted 18 Nonbearing walls Exterior 18 Interior 36 In computmg the ratlo for mult!wythe walls, use the followmg thtckness: l. The nominal wall thicknesses for solid walls and for hollow walls bonded with masonry headers (Section 5.7.2). 2. The sum ofthe nominal thicknesses of the wythes for non-composite walls connected with wall ties (Section 5.7.3).
- 164. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-151 Support Une Ws and Wr for Walls Spanning Vertically Length of Span, 1 :r -~-- ---- C1> e :::; t:: o a. a. :J (J) Ws and Wr for Walls Spanning Horizontally Figure 5.5. 1-1 - Graphical representa/ion ofWs and Wr CODE 5.5.2 Cantilever walls Except for parapets, the ratio of height-to-nominal- thickness for cantilever walls shall not exceed 6 for solid masonry or 4 for hollow masonry. For parapets see Section 5.6.4. 5.5.3 Support elements Lateral support shall be provided by cross walls, pilasters, or structural frame members when the limiting distance is taken horizontally; or by floors, roofs acting as diaphragms, or structural frame members when the limiting distance is taken vertically. 5.6 - Thickness of masonry 5.6.1 General Minimum thickness requirements shall be based on nominal dimensions ofmasonry. 5.6.2 Mínimum thickness 5.6.2.1 Bearing Walls The mm1mum thickness of bearing walls of one story buildings shall be 6 in. (152 mm). The minimum thickness of bearing walls of buildings more than one story high shall be 8 in. (203 mm). 5.6.2.2 Rubb/e stone walls - The minimum thickness ofrough, random, or coursed rubble stone walls shall be 16 in. (406 mm). 5.6.2.3 Shear walls - The minimum thickness ofmasonry shear walls shall be 8 in. (203 mm). COMMENTARY 5.6 - Thickness of masonry 5.6.1 General Experience of the committee has shown that the present ANSI A 41.1 5 · 5 thickness ratios are not always conservative. These requirements represent the consensus ofthe committee for more conservative design.
- 165. C-152 CODE 5.6.2.4 Foundation wal/s - The minimum thickness offoundation walls shall be 8 in. (203 mm). 5.6.2.5 Foundation piers - The minimum thickness offoundation piers shall be 8 in. (203 mm). 5.6.2.6 Parapet walls - The mmtmum thickness ofparapet walls shall be 8 in. (203 mm). 5.6.2.7 Change in thickness - Where walls of masomy of hollow units or masomy bonded hollow walls are decreased in thickness, a course or courses of solid masomy units or fully grouted hollow masomy units shall be interposed between the wall below and the thinner wall above, or special units or construction shall be used to transrnit the loads from face shells orwythes above to those below. 5.6.3 Foundation walls 5.6.3.1 Foundation walls shall comply with the requirements ofTable 5.6.3.1, which are applicable when: (a) the foundation wall does not exceed 8 ft (2.44 m) in height between lateral supports, (b) the terrain surrounding foundation walls is graded to drain surface water away from foundation walls, (e) backfill is drained to remove ground water away from foundation walls, (d) lateral support is provided at the top of foundation walls prior to backfilling, (e) the length of foundation walls between perpendicular masonry walls or pilasters is a maximum of 3 multiplied by the basement wall height, (f) the backfill is granular and soil conditions in the area are non-expansive, and (g) masomy is laid in running bond using Type Mor S mortar. 5.6.3.2 Where the requirements of Section 5.6.3.1 are not met, foundation walls shall be designed in accordance with Chapter 1 and Chapter 2, 3, or 4. TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY 5.6.2.5 Foundation piers - Use of empirically designed foundation piers has been comrnon practice in many areas ofthe country for many years. ANSI A 41.155 provisions for empirically designed piers (Section 5.3) includes a requirement for a maximum hit ratio of 4. The rninimum height-to-thickness ratio of greater than 4 for colurnns is required to clearly differentiate a colurnn from a pier. 5.6.3 Foundation walls Empírica! criteria for masonry foundation wall thickness related to the depth ofunbalanced fill have been contained in building codes and federal govemment standards for many years. The use of Code Table 5.6.3.1, which lists the traditional allowable backfill depths, is Iimited by a number of requirements that were not specified in previous codes and standards. These restrictions are enumerated in Section 5.6.3.1. Further precautions are recomrnended to guard against allowing heavy earth-moving or other equipment near enough to the foundation wall to develop high earth pressures. Experience with local conditions should be used to modify the values in Table 5.6.3.1 when appropriate. Table 5.6.3.1- Foundation wall construction Wall construction Nominal wall Maximum depth of thickness, in. (mm) unbalanced backfill ft (m) Hollow unit masonry 8 (203) 5 (1.52) 10 (254) 6 (1.83) 12 (305) 7 (2.13) Solid unit masonry 8 (203) 5 (1.52) 1o(254) 7(2.13) 12 (305) 7 (2. 13) Fully grouted masonry 8 (203) 7 (2. 13) 1o(254) 8 (2.44) 12 (305) 8 (2.44)
- 166. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-153 CODE 5.6.4 Parapet walls The height of parapet walls shall not exceed 3' multiplied by their thickness. 5.7- Bond 5.7.1 General Wythes of multiple wythe masonry walls shall be bonded in accordance with the requirements of Section 5.7.2, Section 5.7.3, or Section 5.7.4. 5.7.2 Bonding with masonry headers 5.7.2.1 So/id units- Where adjacent wythes of solid masonry walls are bonded by means of masonry headers, no less than 4 percent of the wall surface area of each face shall be composed ofheaders extending not less than 3 in. (76.2 mm) into each wythe. The distance between adjacent full-length headers shall not exceed 24 in. (610 mm) either vertically or horizontally. In walls in which a single header does not extend through the wall, headers from the opposite sides shall overlap at least 3 in. (76.2 mm), or headers from opposite sides shall be covered with another header course overlapping the header below at least 3 in. (76.2 mm). 5.7.2.2 Hollow units - Where two or more wythes are constructed using hollow units, the stretcher courses shall be bonded at vertical intervals not exceeding 34 in. (864 mm) by h1pping at least 3 in. (76.2 nun) over the unit below, or by lapping at vertical intervals not exceeding 17 in. (432 mm) with units which are at least 50 percent greater in thickness than the units below. 5.7.3 Bonding with wall ties orjoint reinforcement 5.7.3.1 Where adjacent wythes of masonry walls are bonded with wire size W2.8 (MW18) wall ties or metal wire of equivalent stiffness embedded in the horizontal mortar joints, there shall be at least one metal tie for each 41 / 2 fe (0.42 m2 ) ofwall area. The maximum vertical distance between ties shall not exceed 24 in. (610 mm), and the maximum horizontal distance shall not exceed 36 in. (914 mm). Rods or ties bent to rectangular shape shall be used with hollow masonry units laid with the celis vertical. In other walls, the ends of ties shall be bent to 90-degree angles to provide hooks no less than 2 in. (50.8 mm) long. Wall ties shall be without drips. Additional bonding ties shall be provided at openings, spaced not more than 3 ft (0.91 m) apart around the perimeter and within 12 in. (305 mm) ofthe opening. 5.73.2 Where adjacent wythes of masonry are bonded with prefabricated joint reinforcement, there shall be at least one cross wire serving as a tie for each 22 / 3 ff (0.25 m2 ) of wall area. The vertical spacing of the joint reinforcement shall not exceed 24 in. (610 mm). Cross wires on prefabricated joint reinforcement shall be not smaller than wire size Wl.7 (MW11) and shall be without drips. The longitudinal wires shall be embedded in the mortar. COMMENTARY 5.7- Bond Figure CC-5.7-1 depicts the requirements listed. Wall ties with drips are not permitted because of their reduced load capacity.
- 167. C-1 54 TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY Header (4% of wall area) Ñ ·e: ·o .s r e;¡ o(! ¡:.¿ ro Q) .S> Q)~ .._ E o E ~oo ~ z!e. Header .. Lapping with Units at Least 3 in. (76.2 mm) over Units Below a. Solid Units .. e: E jg E -N Q)M .... ..,. o~ :E e o;:: z~ .. Lapping with Unit at Least 50% Greater than Units Below c. Hollow Units n -. 77 77 ,_ .... 1./ ....... / / 1 e: E jg E.~ -o o ~;o :e o~o(S :E e . - ·- t:: ~e;¡~ Header (4% of wall area) .. Lapping with Units at Least 3 in. (76.2 mm) over Units Below b. Solid Units Header Course e E N M ::!. .E ,.._ e: ro .S [!? o :E o z Header Course .. Lapping with Units d. Hollow Units Figure CC-5.7-1 - Cross section ofwa/1 elevations
- 168. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-155 CODE 5.7.4 Natural or cast stone 5.7.4.1 Ashlar masonry - In ashlar masonry, uniformly distributed bonder units shall be provided to the extent of not less than 1O percent of the wall area. Such bonder units shall extend not less than 4 in. (102 mm) into the backing wall. 5.7.4.2 Rubble stone masonry - Rubble stone masonry 24 in. (610 mm) or less in thickness shall have bonder units with a maximum spacing of 3 ft (0.91 m) vertically and 3 ft (0.91 m) horizontally, and if the masonry is of greater thickness than 24 in. (610 mm), shall have one bonder unit for each 6 ff (0.56 m2 ) ofwall surface on both sides. 5.8 - Anchorage 5.8.1 General Masonry elements shall be anchored in accordance with this section. 5.8.2 Jntersecting walls Masonry walls depending upon one another for lateral support shall be anchored or bonded at locations where they meet or intersect by one ofthe following methods: 5.8.2.1 Fifty percent of the units at the intersection shall be laid in an overlapping masonry bonding pattem, with alternate units having a bearing of nol k::;:; Lhan 3 in. (76.2 nun) on the unit below. 5.8.2.2 Walls shall be anchored by steel connectors having a minimum section of 1 /4 in. (6.4 mm) by 11 / 2 in. (38.1 mm) with ends bent up at least 2 in. (50.8 mm), or with cross pins to form anchorage. Such anchors shall be at least 24 in. (610 mm) long and the maximum spacing shall be 4ft (1 .22 m). 5.8.2.3 Walls shall be anchored by joint reinforcement spaced at a maximum distance of 8 in. (203 mm). Longitudinal wires of such reinforcement shall be at least wire size Wl.7 (MWll) and shall extend at least 30 in. (762 mm) in each direction at the intersection. 5.8.2.4 Interior non-load-bearing walls shall be anchored at their intersection at vertical intervals of not more than 16 in. (406 mm) with joint reinforcement or 1 / 4 in. (6.4 mm) mesh galvanized hardware cloth. 5.8.2.5 Other metal ties, joint reinforcement or anchors, if used, shall be spaced to provide equivalent area of anchorage to that required by Sections 5.8.2.2 through 5.8.2.4. 5.8.3 Floor and roofanchorage Floor and roof diaphragms providing lateral support to masonry shall be connected to the masonry by one of the following methods: 5.8.3.1 Roof loading shall be determined by the provisions of Section 1.7.2 and, where net uplift occurs, uplift shall be resisted entirely by an anchorage system designed in accordance with the provisions ofSections 2. 1 COMMENTARY 5.8 - Anchorage The requirements of Sections 5.8.2.2 through 5.8.2.5 are less stringent than those of Section 1.9.4.2.5. Anchorage requirements in Section 5.8.3.3 are intended to comply with the Steel Joist Institute's Standard Specification5 · 6 for end anchorage ofsteel joists.
- 169. C-156 CODE and 2.3, Sections 3.1 and 3.3, or Chapter 4. 5.8.3.2 Wood tloor joists bearing on masonry walls shall be anchored to the wall at intervals not to exceed 6 ft ( 1.83 m) by metal strap anchors. Joists parallel to the wall shall be anchored with metal straps spaced not more than 6ft (1 .83 m) on centers extending over or under and secured to at least 3 joists. Blocking shall be provided between joists at each strap anchor. 5.8.3.3 Steel joists that are supported by masonry walls shall bear on and be connected to steel bearing plates. Maximum joist spacing shall be 6 ft (1.83 m) on center. Each bearing plate shall be anchored to the wall with a mínimum of two ~ in. (12.7 mm) diameter bolts, or their equivalent. Where steel joists are parallel to the wall, anchors shall be located where joist bridging terminates at the wall and additional anchorage shall be provided to comply with Section 5.8.3.4. 5.8.3.4 Roof and tloor diaphragms shall be anchored to masonry walls with a mínimum of ~ in. (12.7 mm) diameter bolts at a maximum spacing of 6ft (1.83 m) on center or their equivalent. 5.8.3.5 Bolts and anchors required by Sections 5.8.3.3 and 5.8.3.4 shall comply with the following: (a) Bolts and anchors at steel floor joists and floor diaphragms shall be embedded in the masonry at least 6 in. (152 mm) orshall comply with Section 5.8.3.5 (e). (b) Bolts at steel roofjoists and roof diaphragms shall be embedded in the masonry at least 15 in. (381 mm) or shall comply with Section 5.8.3.5(c). (e) In lieu of the embedment lengths listed in Sections 5.8.3.5(a) and 5.8.3.5(b), bolts shall be permitted to be hooked orwelded to not less than 0.20 in.2 (129 mm2 ) of bond beam reinforcement placed not less than 6 in. (152 mm) below joist bearing or bottom of diaphragm. 5.8.4 Walls acijoining structuralframing Where walls are dependent upon the structural frame for lateral support, they shall be anchored to the structural members with metal anchors or otherwise keyed to the structural members. Metal anchors shall consist of 1 / 2-in. (12.7-mm) bolts spaced at 4ft (1.22 m) on center embedded 4 in. (102 mm) into the masonry, or their equivalent area. 5.9- Miscellaneous requirements 5.9.1 Chases and recesses Masonry directly above chases or recesses wider than 12 in. (305 mm) shall be supported on lintels. 5.9.2 Lintels The design of masonry lintels shall be in accordance with the provisions ofSection 1.13 or Section 3.3.4.2. 5.9.3 Support on wood No masonry shall be supported on wood girders or other forms ofwood construction. TMS 402-11/ACI530-11/ASCE 5-11 COMMENTARY
- 170. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-157 CHAPTER 6 VENEER 6.1 - General 6.1.1 Scope CODE This chapter provides requirements for design and detailing of anchored masonry veneer and adhered masonry veneer. 1-in. (25-mm) Minimum Air Space Weepholes COMMENTARY 6.1- General 6.1.1 Scope Adhered and anchored veneer definitions given in Section 1.6 are straightforward adaptations of existing definitions. See Figures CC-6.1-1 and CC-6.1-2 for typical examples of anchored and adhered veneer, respectively. The traditional definition of veneer as an element without resistance to imposed load is adopted. The definition given is a variation ofthat used in model building codes. Modifications have been made to the defmitions to clearly state how the veneer is handled in design. The design of the backing should be in compliance with the appropriate standard for that material. Exterior-grade Sheathing Building Paper 6-in. (150-mm) Minimum Lap Foundation Figure CC-6.1-1 - Anchored veneer
- 171. C-158 TMS 402-11IACI 530-11IASCE 5-11 COMMENTARY Veneer Unit with Neat Portland Cement Paste Type S Mortar Applied to Unit Concrete Masonry Wall Type S Mortar Neat Portland Cement Paste 318 to 1-112 in. (9.5 to 38.1 mm) Figure CC-6.1-2 - Adhered veneer CODE 6.1.1.1 The provisions of Chapter 1, excluding Sections 1.2.2(c), 1.7, and 1.9, shall apply to design of anchored and adhered veneer except as specifically stated here. 6.1.1.2 Section 1.11 shall not apply to adhered veneer. 6.1.1.3 Articles 1.4 A and B and 3.4 C of TMS 602/ACI 530.1/ASCE 6 shall not apply to any veneer. Articles 3.4 B and F shall not apply to anchored veneer. Articles 3.3 B and 3.4 A, B, E and F shall not apply to adhered veneer. 6.1.2 Desígn ofanchored veneer Anchored veneer shall meet the requirements of Section 6.1.6 and shall be designed rationally by Section 6.2.1 or detailed by the prescriptive requirements of Section 6.2.2. COMMENTARY 6.1.1.1 Since there is no consideration of stress in the veneer, there is no need to specify the compressive strength ofmasonry. 6.1.1.3 The Specification was written for construction of masonry subjected to design stresses in accordance with the other chapters of this Code. Masonry veneer, as defined by this Code, is not subject to those design provisions. The Specification articles that are excluded cover materials and requirements that are not applicable to veneer construction or are items covered by specific requirements in this Chapter and are put here to be inclusive. 6.1.2 Desígn ofanchored veneer Implicit within these requirements is the knowledge that the veneer transfers out-of-plane loads through the veneer anchors to the backing. The backing accepts and resists the anchor loads and is designed to resist the out-of- plane loads. When utilizing anchored masonry veneer, the designer should consider the following conditions and assumptions: a) The veneer may crack in flexure under service load. b) Deflection of the backing should be limited to control crack width in the veneer and to provide veneer stability.
- 172. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTU RES ANO COMMENTARY C-159 CODE COMMENTARY e) Connections ofthe anchor to the veneer and to the backing should be sufficient to transfer applied loads. d) Differential movement should be considered in the design, detailing, and construction. e) Water will penetrate the veneer, and the wall system should be designed, detailed, and constructed to prevent water penetration into the building. t) Requirements for corrosion protection and fire resistance must be included. If the backing is masonry and the exterior masonry wythe is not considered to add to the strength ofthe wall in resisting out-of-plane load, the exterior wythe is masonry veneer. However, ifthe exterior wythe is considered to add to the strength ofthe wall in resisting out-of-plane load, the wall is properly termed a multiwythe, non-composite wall rather than a veneer wall. Manufacturers of steel studs and sheathing materials have published literature on the design of steel stud backing for anchored masonry veneer. Sorne recomrnendations have included composite action between the stud and the sheathing and load carrying participation by the veneer. The Metal Lath/Steel Framing Association has prometed a deflection limit of stud span length divided by 360 6 1 • The Brick Industry Association has held that an appropriate detlection lirnit should be in the range of stud span length divided by 600 to 720. The detlection is computed assuming that all of the load is resisted by the studs65 • Neither set ofassumptions will necessarily ensure that the veneer remains uncracked at service load. In fact, the probability of cracking may be high63 . However, post-cracking performance is satisfactory if the wall is properly designed, constructed and maintained with appropriate materials64 . Plane frame computer prograrns are available for the rational structural design of anchored masonryveneer63 • A detlection limit of stud span length divided by 200 multiplied by the specified veneer thickness provides a maximum uniform crack width for various heights and various veneer thicknesses. Deflection limits do not reflect the actual distribution of load. They are simply a means of obtaining a mínimum backing stiffness. The National Concrete Masonry Association provides a design methodology by which the stiffness properties of the masonry veneer and its backing are proportioned to achieve compatibility6 · 5 . Masonry veneer with wood frame backing has been used successfully on one- and two-family residential construction for many years. Most of these applications are installed without a deflection analysis.
- 173. C-160 CODE 6.1.3 Design ofadhered veneer Adhered veneer shall meet the requirements of Section 6.1.6, and shall be designed rationally by Section 6.3.1 or detailed by the prescriptive requirements of Section 6.3.2. 6.1.4 Dimension stone The provisions of Sections 6.1.1, 6.1.3 and 6.3 shall apply to design of adhered dimension stone veneer. Anchored dimension stone veneer is not covered under this Code. Such a veneer system shall be considered a Special System, and consideration for approval of its use shall be submitted to the Building Official. 6.1.5 Autoc/avedaerated concrete masonry veneer Autoclaved aerated concrete masonry as a veneer wythe is not covered by this Chapter. Such a veneer system shall be considered a Special System, and consideration for approval of its use shall be submitted to the Building Official. 6.1.6 General design requirements 6.1.6.1 Design and detail the backing system of exterior veneer to resist water penetration. Exterior sheathing shall be covered with a water-resistant membrane, unless the sheathing is water resistant and the joints are sealed. 6.1.6.2 Design and detail flashing and weep holes in exterior veneer wall systems to resist water penetration into the building interior. Weepholes shall be at least 3 / 16 in. (4.8 mm) in diameter and spaced less than 33 in. (838 mm) on center. 6.1.6.3 Design and detail the veneer to accommodate differential movement. TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY 6.1.3 Design ofadheredveneer Adhered veneer differs from anchored veneer in its means of attachment. The designer should consider conditions and assumptions given in Code Section 6.3.1 when designing adhered veneer. 6.1.4 Dimension stone Anchored dimension stone veneer should be covered as a Special System ofConstruction, under Code Section 1.3. 6.1.5 Autoclaved aerated concrete masonry veneer Veneer anchors described in Chapter 6 are not suitable for use in AAC masonry because of the narrow joints. No testing of such anchors has been performed for AAC masonry. Therefore AAC masonry anchored veneer must be considered a Special System. The method of adhering veneer, as described in Specification Article 3.3 C, has not been evaluated with AAC masonry and shear strength requirements for adhesion of AAC masonry veneer have not been established. Therefore, AAC masonry adhered veneer must be considered a Special System. 6.1.6 General design requirements Water penetration through the exterior veneer is expected. The wall systcm must be dcsigned and constructed to prevent water from entering the building. The requirements given here and the minimum air space dimensions of Sections 6.2.2.6.3, 6.2.2.7.4, and 6.2.2.8.2 are those required for a drainage wall system. Proper drainage requires weep hales and a clear air space. It may be difficult to keep a 1-in. (25-mm) air space free from mortar bridging. Other options are to provide a wider air space, a vented air space, or to use the rain screen principie. Masonry veneer can be designed with horizontal and vertical bands ofdifferent materials. The dissimilar physical properties of the materials should be considered when deciding how to accommodate differential movement. Industry recommendations are available regarding horizontal bands of clay and concrete masonry, and address such items as joint reinforcement, slip joints, and sealant joints 6 · 6 • 6 · 7 • 6 · 8 • Vertical movement joints can be used to accommodate differential movement between vertical bands ofdissimilar materials.
- 174. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-161 CODE 6.2 - Anchored veneer 6.2.1 Alternative design ofanchoredmasonry veneer The altemative design of anchored veneer, which is perrnitted under Section 1.3, shall satisfy the following conditions: (a) Loads shall be distributed through the veneer to the anchors and the backing using principies ofmechanics. (b) Out-of-plane deflection of the backing shall be limited to maintain veneer stability. (e) Masonry, other than veneer, shall meet the provisions ofSection 1.1.3, excluding subparagraphs (e) and (f). (d) The veneer is not subject to the flexura) tensile stress provisions of Section 2.2 or the nominal flexura! tensile strength provisions of Section 3.2.2. (e) The provisions of Chapter 1, excluding Section 1.2.2(c), Section 6.1, excluding Section 6.1.1.1, Section 6.2.2.9, and Section 6.2.2.10 shall apply. 6.2.2 Prescriptive requirements for anchored masonry veneer 6.2.2.1 Except as provided in Section 6.2.2.11, prescriptive requirements for anchored masonry veneer shall not be used in areas where the velocity pressure, qz, exceeds 40 psf(J.92 kPa) as given in ASCE 7. 6.2.2.2 Connect anchored veneer to the backing with anchors that comply with Section 6.2.2.5 and Article 2.4 ofTMS 602/ACI 530.1/ASCE 6. 6.2.2.3 Vertical support of anchored masonry veneer 6.2.2.3.1 The weight of anchored veneer shall be supported vertically on concrete or masonry foundations or other noncombustible structural supports, except as permitted in Sections 6.2.2.3. 1.1, 6.2.2.3.1.4, and 6.2.2.3. 1.5. 6.2.2.3.1.1 Anchored veneer is perrnitted to be supported vertically by preservative-treated wood foundations. The height of veneer supported by wood foundations shall not exceed 18 ft (5.49 m) above the support. 6.2.2.3.1.2 Anchored veneer with a backing of wood fTaming shall not exceed the height above the noncombustible foundation given in Table 6.2.2.3. 1. COMMENTARY 6.2 - Anchored veneer 6.2.1 Alternative design ofanchoredmasonry veneer There are no rational design provisions for anchored veneer in any code or standard. The intent ofSection 6.2.1 is to permit the designer to use altemative means of supporting and anchoring masonry veneer. See Commentary Section 6. 1.1 for conditions and assumptions to consider. The designer may choose to not consider stresses in the veneer or may limit them to a selected value, such as the allowable stresses of Section 2.2, the anticipated cracking stress, or sorne other limiting condition. The rational analysis used to distribute the loads must be consistent with the assumptions made. See Commentary Section 6.2.2.5 for information on anchors. The designer should provide support of the veneer; control deflection of the backing; consider anchor loads, stiffness, strength and corrosion; water penetration; and air and vapor transmission. 6.2.2 Prescriptive requirements for anchored masonry veneer The provisions are based on the successful performance of anchored masonry veneer. These have been collected fTom a variety of sources and reflect current industry practices. Changes result from logical conclusions baseu un engineering consideration of the backing, anchor, and veneer performance. 6.2.2.1 The wind speed triggers used in the 2008 MSJC were replaced with strength leve! velocity pressures in the 2011 edition. These velocity pressure triggers were based on the 25 psf (1.20 kPa) velocity pressure that had been used in previous editions of this Code. The working stress leve! pressure was multiplied by 1.6 to convert to strength levels. 6.2.2.3 Vertical support of anchored masonry veneer - These requirements are based on current industry practice and current model building codes. Support does not need to occur at the floor leve!; it can occur at a window head or other convenient location. The full provisions for preservative-treated wood foundations are given in the National Forest Products Association Technical Report 76 · 9 • There are no restrictions on the height limit of veneer backed by masonry or concrete, nor are there any requirements that the veneer weight be carried by intermediate supports. The designer should consider the effects of differential movement on the anchors and connection ofthe veneer to other building components.
- 175. C-162 CODE Table 6.2.2.3.1 - Height limit from foundation Height at plate, ft (m) Height at gable, ft (m) 30 (9. 14) 38 (11.58) 6.2.2.3.1.3 If anchored veneer with a backing of cold-forrned steel framing exceeds the height above the noncombustible foundation given in Table 6.2.2.3.1, the weight of the veneer shall be supported by noncombustible construction for each story above the height limit given in Table 6.2.2.3.1. 6.2.2.3.1.4 When anchored veneer is used as an interior fmish on wood framing, it shall have a weight of 40 psf (195 kglm2 ) or less and be installed in conforrnance with the provisions ofthis Chapter. 6.2.2.3.1.5 Exterior masonry veneer having an installed weight of 40 psf (195 kglm2 ) or less and height of no more than 12 ft (3.7 m) shall be permitted to be supported on wood construction. A vertical movement joint in the masomy veneer shall be used to isolate the veneer supported by wood construction from that supported by the foundation. Masomy shall be designed and constructed so that masonry is not in direct contact with wood. The horizontally spanning element supporting the masomy veneer shall be designed so that deflcction duc to dcad plus live loads does not exceed //600 or 0.3 in. (7.6 mm). 6.2.2.3.2 When anchored veneer is supported by floor construction, the floor shall be designed to limit deflection as required in Section 1.13. 1.4.1. 6.2.2.3.3 Provide noncombustible lintels or supports attached to noncombustible framing over openings where the anchored veneer is not self-supporting. Lintels shall have a length of bearing not less than 4 in. (1 02 mm). The deflection ofsuch lintels or supports shall conform to the requirements ofSection 1.13.1.4.1. 6.2.2.4 Masonry units - Masonry units shall be at least 25 /8 in. (66.7 mm) in actual thickness. 6.2.2.5 Anchor requirements 6.2.2.5.1 Corrugatedsheet-metal anchors 6.2.2.5.1.1 Corrugated sheet-metal anchors shall be at least 7 / 8 in. (22.2 mm) wide, have a base metal thickness of at least 0.03 in. (0.8 mm), and shall have corrugations with a wavelength of 0.3 to 0.5 in. (7.6 to 12.7 mm) and an amplitude of 0.06 to 0.10 in. (1.5 to 2.5 mm). TMS 402·11/ACI 530-11/ASCE 5-11 COMMENTARY Support of anchored veneer on wood is permitted in previous model building codes. The vertical movement joint between the veneer on different supports reduces the possibility of cracking due to differential settlement, The height limit of 12 ft (3.7 m) was considered to be the maximum single story height and is considered to be a reasonable fire safety risk. 6.2.2.5 Anchor requirements - It could be argued that the device between the veneer and its backing is not an anchor as detined in the Code. That device is often referred to as a tie. However, the term anchor is used because of the widespread use of anchored veneer in model building codes and industry publications, and the desire to differentiate from tie as used in other chapters.
- 176. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-163 CODE 6.2.2.5.1.2 Cormgated sheet-metal anchors shall be placed as follows: (a) With solid units, embed anchors in the mortar joint and extend into the veneer a mínimum of 11 / 2 in. (38.1 mm), with at least % -in. (15.9-mm) mortar cover to the outside face. (b) With hollow units, embed anchors in mortar or grout and extend into the veneer a mínimum of 11 / 2 in. (38.1 mm), with at least 5 / 8-in. (15.9-mm) mortar or grout cover to the outside face. 6.2.2.5.2 Sheet-metal anchors 6.2.2.5.2.1 Sheet-metal anchors shall be at least 7 / 8 in. (22.2 mm) wide, shall have a base metal thickness ofat least 0.06 in. (1.5 mm), and shall: (a) have corrugations as given in Section 6.2.2.5.1.1, or (b) be bent, notched, or punched to provide equivalent performance in pull-out or push-through. 6.2.2.5.2.2 Sheet-metal anchors shall be placed as follows: (a) With solid units, embed anchors in the mortar joint and extend into the veneer a mínimum of 11 /2 in. (38.1 mm), with at least % -in. (15.9-mm) mortar cover to the outside face. (b) With hollow units, embed anchors in mortar or grout and extend into the veneer a mínimum of 11 / 2 in. (38.1 mm), with at least 5 / 8-in. (15.9-mm) mortar or grout cover to the outside face. 6.2.2.5.3 Wire anchors 6.2.2.5.3.1 Wire anchors shall be at least wire size Wl.7 (MW11) and have ends bent to form an extension from the bend at least 2 in. (50.8 mm) long. Wire anchors shall be without drips. 6.2.2.5.3.2 Wire anchors shall be placed as follows: (a) With solid units, embed anchors in the mortar joint and extend into the veneer a mínimum of 11 / 2 in. (38.1 mm), with at least 5 / 8-in. (15.9-mm) mortar cover to the outside face. (b) With hollow units, embed anchors in mortar or grout and extend into the veneer a mínimum of 11 / 2 in. (38.1 mm), with at least % -in. (15.9-mm) mortar or grout cover to the outside face. 6.2.2.5.4 Joint reinforcement 6.2.2.5.4.1 Ladder-type or tab-type joint reinforcement is permitted. Cross wires used to anchor masoruy veneer shall be at least wire size Wl.7 (MWll) and shall be spaced ata maximum of 16 in. (406 mm) on center. Cross wires shall be welded to longitudinal wires, which shall be at least wire size Wl.7 (MWI1). Cross wires COMMENTARY When first introduced in 1995, U.S. industry practice was combined with the requirements of the Canadian Standards Association6 · 10 to produce the requirements given at that time. Each anchor type has physical requirements that must be met. Mínimum embedment requirements have been set for each of the anchor types to ensure load resistance against push-through or pull-out of the mortar joint. Maximum air space dimensions are set in Sections 6.2.2.6 through 6.2.2.8. There are no performance requirements for veneer anchors in previous codes. Indeed, there are none in the industry. Tests on anchors have been reported6 .4· 6 · 11 • Many anchor manufacturers have strength and stiffness data for their proprietary anchors. Veneeranchors typically allow for movement in the plane of the wall but resist movement perpendicular to the veneer. The mechanical play in adjustable anchors and the stiffuess of the anchor influence load transfer between the veneer and the backing. Stiff anchors with minimal mechanical play provide more uniform transfer ofload, increase the stress in the veneer, and reduce veneer deflection. Veneer anchors of wire with drips are not permitted because of their reduced load capacity. The anchors listed in Section 6.2.2.5.6.1 are thought to have lower strength or stiffness than the more rigid plate-type anchors. Thus fewer plate-type anchors are required. These provisions may result in an increase in the number of anchors required when compared to the editions ofthe BOCA and SBCCI model building codes published in 1993 and 1991, respectivell 12 ' 613 . The number of anchors required by this Code is based on the requirements of the 1991 UBC614 • The number of required anchors is increased in the higher Seismic Design Categories. Anchor spacing is independent ofbacking type. Anchor frequency should be calculated independently for the wall surface in each plane. That is, horizontal spacing of veneer anchors should not be continued from one plane ofthe veneer to another. The term "offset" in Code Section 6.2.2.5.5.4 refers to the vertical distance between a wire eye and the horizontal leg of a bent wire tie inserted into that eye, or the vertical distance between functionally similar components ofa pintle anchor.
- 177. C-164 CODE and tabs shall be without drips. 6.2.2.5.4.2 Embed longitudinal wires of joint reinforcement in the mortar joint with at least 5 / 8-in. (15.9-mm) mortar cover on each side. 6.2.2.5.5 Adjustable anchors 6.2.2.5.5.1 Sheet-metal and wire components of adjustable anchors shall conform to the requirements of Section 6.2.2.5.1 , 6.2.2.5.2, or 6.2.2.5.3. Adjustable anchors with joint reinforcement shall also meet the requirements of Section 6.2.2.5.4. 6.2.2.5.5.2 Maximum clearance between connecting parts ofthe tie shall be 1 / 16 in. (1 .6 mm). 6.2.2.5.5.3 Adjustable anchors shall be detailed to prevent disengagement. 6.2.2.5.5.4 Pintle anchors shall have one or more pintle legs of wire size W2.8 (MW18) and shall have an offset not exceeding 11 / 4 in. (31.8 mm). 6.2.2.5.5.5 Adjustable anchors of equivalent strength and stiffness to those specified m Sections 6.2.2.5.5.1 through 6.2.2.5.5.4 are permitted. 6.2.2.5.6 Anchor spacing 6.2.2.5.6.1 For adjustable two-piece anchors, anchors ofwire size Wl.7 (MWll), and 22 gage (0.8 mm) corrugated sheet-metal anchors, provide at least one anchor for each 2.67 W(0.25 m2 ) ofwall area. 6.2.2.5.6.2 For other anchors, provide at least one anchor for each 3.5 ff (0.33 m2 ) ofwall area. 6.2.2.5.6.3 Space anchors at a maximum of 32 in. (813 mm) horizontally and 25 in. (635 mm) vertically, but not to exceed the applicable requirements of Section 6.2.2.5.6.1 or 6.2.2.5.6.2. 6.2.2.5.6.4 Provide additional anehors around openings larger than 16 in. (406 mm) in either dimension. Space anchors around perimeter of opening at a maximum of 3 ft (0.91 m) on center. Place anchors within 12 in. (305 mm) ofopenings. 6.2.2.5.7 Joint thickness for anchors Mortar bed joint thickness shall be at least twice the thickness ofthe embedded anchor. 6.2.2.6 Masonry veneer anchoredto woodbacking 6.2.2.6.1 Veneer shall be attached with any anchor permitted in Section 6.2.2.5. 6.2.2.6.2 Attach each anchor to wood studs or wood framing with a corrosion-resistant 8d common nail, or with a fastener having equivalent or greater pullout strength. For corrugated sheet-metal anchors, locate the nail or fastener within 1 / 2 in. (12.7 mm) of the 90-degree bend in the anchor. TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY 6.2.2.6 Masonry veneer anchored to wood backing These requirements are similar to those used by industry and given in model building codes for years. The limitation on fastening corrugated anchors at a maximum distance from the bend is new. It is added to achieve better performance. The maximum distances between the veneer and the sheathing or wood stud is provided in order to obtain minimum compression capacity ofanchors.
- 178. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-165 CODE 6.2.2.6.3 When corrugated sheet metal anchors are used, a maximum distance between the inside face of the veneer and outside face of the solid sheathing of 1 in. (25.4 mm) shall be specified. When other anchors are used, a maximum distance between the inside face of the veneer and the wood stud or wood framing of 4 ~ in. (114 mm) shall be specified. A 1-in. (25.4-mm) minimum air space shall be specified. 6.2.2.7 Masonry veneer anchoredto steel backing 6.2.2.7.1 Attach veneer with adjustable anchors. 6.2.2.7.2 Attach each anchor to steel framing with at least a No. 10 corrosion-resistant screw (nominal shank diameter of0.190 in. (4.8 mm)), or with a fastener having equivalent or greater pullout strength. 6.2.2.7.3 Cold-formed steel framing shall be corrosion resistant and have a mínimum base metal thickness of0.043 in. (1.1 mm). 6.2.2.7.4 A 4 ~ in. (1 14-mm) maximum distance between the inside face of the veneer and the steel framing shall be specified. A 1-in. (25.4-mm) mínimum air space shall be specified. 6.2.2.8 Masonry veneer anchored to masomy or concrete backing 6.2.2.8.1 Attach veneer to masonry backing with wire anchors, adjustable anchors, or joint reinforcement. Attach veneer to concrete backing with adjustable anchors. 6.2.2.8.2 A 4 ~ in. (114-mm) maximum distance between the inside face ofthe veneer and the outside face ofthe masonry or concrete backing shall be specified. A 1-in. (25.4-mm) mínimum air space shall be specified. 6.2.2.9 Veneer not laid in running bond - Anchored veneer not laid in running bond shall have joint reinforcement of at least one wire, of size Wl.7 (MWII), spaced ata maximum of 18 in. (457 mm) on center vertically. 6.2.2.10 Requirements in seismic areas 6.2.2.10.1 Seismic Design Category C 6.2.2.10.1.1 The requirements of this section apply to anchored veneer for buildings in Seismic Design Category C. 6.2.2.10.1.2 Isolate the sides and top of anchored veneer from the structure so that vertical and lateral seismic forces resisted by the structure are not imparted to the veneer. 6.2.2.10.2 Seismic Design Category D 6.2.2.10.2.1 The requirements for Seismic Design Category C and the requirements of this section apply to anchored veneer for buildings in Seismic Design Category D. COMMENTARY 6.2.2.7 Masonry veneer anchored lo steel backing- Most of these requirements are new, but they generally follow recommendations in current use6 · 2 • 6 · 18 . The mínimum base metal thickness is given to provide sufficient pull-out resistance ofscrews. 6.2.2.8 Masonry veneer anchored to masonry or concrete backing- These requirements are similar to those used by industry and havc bccn givcn in model building codes for many years. 6.2.2.9 Veneer not laid in running bond- Masonry not laid in running bond has similar requirements in Section 1.11. The area of joint reinforcement required in Section 6.2.2.9 is equivalent to that in Section 1.11 for a nominal 4-in. (102-mm) wythe. 6.2.2.10 Requirements in seismic areas - These requirements provide severa! cumulative effects to improve veneer performance under seismic load. Many of them are based on similar requirements given in Chapter 30 of the Uniform Building Codé- 14 • The isolation from the structure reduces accidental loading and permits larger building deflections to occur without veneer damage. Support at each floor articulates the veneer and reduces the size of potentially damaged areas. An increased number of anchors increases veneer stability and reduces the possibility of falling debris. Joint reinforcement provides ductility and post-cracking strength. Added expansion joints further articulate the veneer, permit greater building deflection without veneer damage and limit stress development in the veneer.
- 179. C-166 CODE 6.2.2.10.2.2 Reduce the maximum wall area supported by each anchor to 75 percent ofthat required in Sections 6.2.2.5.6.1 and 6.2.2.5.6.2. Maximum horizontal and vertical spacings are unchanged. 6.2.2.10.2.3 For masonry veneer anchored to wood backing, attach each veneer anchor to wood studs or wood framing with a corrosion-resistant 8d ring-shank nail, a No. 1Ocorrosion-resistant screw with a minimum nominal shank diameter of 0.190 in. (4.8 mm) or with a fastener having equivalent or greater pullout strength. 6.2.2.10.3 Seismic Design Categories E and F 6.2.2.10.3.1 The requirements for Seismic Design Category D and the requirements of this section apply to anchored veneer for buildings in Seismic Design Categories E and F. 6.2.2.10.3.2 Support the weight of anchored veneer for each story independent ofother stories. 6.2.2.10.3.3 Provide continuous single wire joint reinforcement of wire size Wl.7 (MWil) ata maximum spacing of 18 in. (457 mm) on center vertically. Mechanically attach anchors to the joint reinforcement with clips or hooks. 6.2.2.11 Requirements in areas of high winds - The following requirements apply in areas where the velocity pressure, q" exceeds 40 psf (1.92 kPa) but does not exceed 55 psf(2.63 kPa) and the building's mean roof height is less than or equal to 60ft (18.3 m): (a) Reduce the maximum wall area supported by each anchor to 70 percent of that required in Sections 6.2.2.5.6.1 and 6.2.2.5.6.2. (b) Space anchors at a maximum 18 in. (457 mm) horizontally and vertically. (e) Provide additional anchors around openings larger than 16 in. (406 mm) in either direction. Space anchors around perimeter of opening at a maximum of24 in. (610 mm) on center. Place anchors within 12 in. (305 mm) ofopenings. TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY Shake table tests of pane16 .1 6 and full-scale wood frame/brick veneer buildings6 .1 7 have demonstrated that 8d nails are not sufficient to resist seismic loading under certain conditions. Ring-shank nails or #1O screws were recommended by the researchers for use in areas of significant seismic loading. 6.2.2.11 Requirernents in ureus of high winds - These reductions were historically based on the ratio of (110/130i, the square of the ratio of wind speed in the two locations. The provisions in this section in the 201 1edition are based on a reduction in tributary area by 30%. The velocity pressure trigger was therefore raised by 1/0.7, and rounded to 55 psf(2.63 kPa).
- 180. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-167 CODE 6.3- Adhered veneer 6.3.1 Alternative design ofadheredmasonry veneer The altemative design of adhered veneer, which is permitted under Section 1.3, shall satisfy the following conditions: (a) Loads shall be distributed through the veneer to the backing using principies ofmechanics. (b) Out-of-plane curvature shall be limited to prevent veneer unit separation from the backing. (e) Masonry, other than veneer, shall meet the provisions of Section 1.1.3, excluding subparagraphs (e) and (f). (d) The veneer is not subject to the flexura) tensile stress provisions of Section 2.2 or the nominal flexura) tensile strength provisions ofSection 3.2.2. (e) The provisions of ehapter 1, excluding Section 1.2.2(c), and Section 6.1, excluding Section 6. 1.1, shall apply. 6.3.2 Prescriptive requirements for adhered masonry veneer 6.3.2.1 Unit sizes - Adhered veneer units shall not exceed 25 / 8 in. (66.7 mm) in specified thickness, 36 in. (914 mm) in any face dimension, nor more than 5 ft2 (0.46 m2 ) in total face area, and shall not weigh more than 15 psf(73 kg/m2 ). 6.3.2.2 Wal/ area limitations - The height, length, and area of adhered veneer shall not be limited except as required to control restrained differential movement stresses between veneer and backing. 6.3.2.3 Backing - Backing shall provide a continuous, moisture-resistant surface to receive the adhered veneer. Backing is permitted to be masonry, concrete, or metal lath and portland cement plaster applied to masonry, concrete, steel framing, or wood framing. 6.3.2.4 Adhesion developed between adhered veneer units and backing shall have a shear strength of at least 50 psi (345 kPa) based on gross unit surface area when tested in accordance with ASTM e482, or shall be adhered in compliance with Article 3.3 e of TMS 602/Aei 530.l/ASeE 6. COMMENTARY 6.3 - Adhered veneer 6.3.1 Alternative design ofadheredmasonry veneer There are no rational design provisions for adhered veneer in any code or standard. The intent ofSection 6.3.1 is to permit the designer to use altemative unit thicknesses and areas for adhered veneer. The designer should provide for adhesion ofthe units, control curvature of the backing, and consider freeze-thaw cycling, water penetration, and air and vapor transmission. The Tile eouncil of America limits the detlection of the backing supporting ceramic tiles to span length divided by 3606 · 18 • 6.3.2 Prescriptive requirements for adhered masonry veneer Similar requirements for adhered veneer have been in the Uniform Building eodé-14 since 1967. The construction requirements for adhered veneer in the Specification have performed successfully6 · 19 • 6.3.2.1 Unit sizes - The dimension, area, and weight lirnits are imposed to reduce the difficulties of handling and installing large units and to assure good bond. 63.2.2 Wall area limitations - Selecting proper location for movementjoints involves many variables. These include: changes in moisture content, inherent movement of materials, temperature exposure, temperature differentials, strength ofunits, and stiffuess ofthe backing. 6.3.2.3 Backing - These surfaces have demonstrated the ability to provide the necessary adhesion when using the construction method described in the Specification. Model building codes contain provisions for metal lath and portland cement plaster. For masonry or concrete backing, it may be desirable to apply metal lath and plaster. Also, refer to Ael 524R, "Guide to Portland eement Plastering"6 · 20 for metal lath, accessories, and their installation. These publications also contain recommendations for control ofcracking. 6.3.2.4 The required shear strength of 50 psi (345 kPa) is an empírica) value based on judgment derived from historical use ofadhered veneer systerns similar to those permitted by Article 3.3 e ofTMS 602/Aei 530.1/ASCE 6. This value is easily obtained with workmanship complying with the Specification. It is anticipated that the 50 psi (345 kPa) will account for differential shear stress between the veneer and its backing in adhered veneer systems
- 181. C-168 CODE TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY permitted by this Code and Specification. The test method is used to verify shear strength of adhered veneer systems that do not comply with the construction requirements of the Specification or as a quality assurance test for systems that do comply.
- 182. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-169 CHAPTER 7 GLASS UNIT MASONRY 7.1- General 7.1.1 Scope CODE This chapter provides requirements for empírica! design ofglass unit masonry as non-load-bearing elements in exterior or interior walls. 7.1.1.1 The provisions of Chapter 1, excluding Sections 1.2.2(c), 1.7, 1.8, and 1.9, shall apply to design ofglass unit masonry, except as stated in this Chapter. 7.1.1.2 Article 1.4 of TMS 602/ACl 530. 1 1 ASCE 6 shall not apply to glass unit masonry. 7.1.2 General design requirements Design and detail glass unit masonry to accommodate differential movement. 7.1.3 Units 7.1.3.1 Hollow or solid glass block units shall be standard or thin units. 7.1.3.2 The specified thickness ofstandard units shall be at least 37 / 8 in. (98.4 mm). 7.1.3.3 The specified thickness of thin units shall be 31 / 8 in. (79.4 mm) for hollow units or 3 in. (76.2 mm) for solid units. 7.2- Panel size 7.2.1 Exterior standard-uní!panels The maximum area of each individual standard-unit panel shall be based on the design wind pressure, in accordance with Figure 7.2-1. The maximum dimension between structural supports shall be 25 ft (7.62 m) horizontally or 20 ft (6.1Om) vertically. COMMENTARY 7.1- General 7.1.1 Scope Glass unit masonry is used as a non-load-bearing element in interior and exterior walls, partitions, window openings, and as an architectural feature. Design provisions in the Code are empírica!. These provisions are cited in previous codes, are based on successful performance, and are recommended by manufacturers. 7.1.1.1 Since there is no consideration of stress in glass unit masonry, there is no need to specify the compressive strength ofmasonry. 7.2- Panel size The Code limitations on panel size are based on structural and performance considerations. Height limits are more restrictive than length limits based on historical requirements rather than actual field experience or engineering principies. Fire resistance rating tests of assemblies may also establish limitations on panel size. Contact glass block manufacturers for technical data on the tire resistance ratings of panels, or refer to the latest issue of UL Fire Resistance Directory - Volume 37 ·' and the local building code. 7.2.1 Exterior standard-unit panels The wind load resistance curve7 · 2 • 7 · 3 • 7 · 5 (Figure CC-7.2-1) is representative of the ultimate load limits for a variety of panel conditions. Historically, a 144 - ~ (l3.37-m2 ) area limit has been referenced in building codes as the maximum area permitted in exterior applications, without reference to any safety factor or design wind pressure. The 144-ff (13.37-m2 ) area also reflects the size of panels tested by the National Concrete Masonry
- 183. C-170 -ro ll.. ~ ..... (/) o. <lÍ .... :::J (/) (/) Q) e: u e ~ e O> (/) Q) Cl 'O ~ .8 (.) ro u.. CODE 112 (5.8) 96 (4.6) 80 (3.8) 64 (3.0) 48 (2.2) 32 (1 .5) 16 (0.8) o o lt ~ TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY Association7 · 5 • The 144-ff (13.37-m2 ) area limitation provides a safety factor of 2.7 when the design wind pressure is 20 psf7 .4 (958 Pa). ASCE 7-1O wind speed maps were changed from those in ASCE 7-05. ASCE 7-10 wind speed maps incorporate a strength design approach where the 1.6 load factor is included in the maps. The 2011 MSJC applied a 1.6 factor to the wind provisions in the 2008 MSJC edition to convert service level design wind pressure to factored leve) design wind pressure. In the 2011 Code edition, the referenced wind speeds from ASCE 7-10 are strength levels, thus to use Figure CC.7.2-1, the factored design wind pressures would have to be divided by 1.6 to determine an effective factor ofsafety. ' 50 4.6 100 9.3 ~ ¡...., 150 13.9 AreaofPanel 200 18.6 250 23.2 300 27.9 Figure 7.2-1 - Factored design windpressureforglass unit masonry
- 184. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY 160 (7.7) 140 (6.7) ca- 120 Q. (5.7) ~ ·¡¡; c. 100 1![ :J (4.8) "' "' ~ Q. 80 "O (3.8) ~., ií 60 ,!;; (2.9) 5 40 (1.9) 20 (.96) o o COMMENTARY ~ · X 10' ------ --- 20 1.9 40 3.7 1 1 10' X 10 14' X 7'-4" ~ ""'....... ~ X 12' --- --- --- --- l -..._ 1 ---.r-- 1 10 X 20' r-- 1 - : 16 X 16' 1 60 5.6 60 7.4 100 120 140 160 180 200 220 240 260 (ft2) 9.3 11.1 13.0 14.9 16.7 18.6 20.4 22.3 24.2 (m 2) Example of how to use wind-load resistance curve: lf using a factored strength level design wind pressure of 32 psf (1 ,532 Pa), divide this by 1.6 to give 20 psf (958 Pa), then multiply by a safety factor of 2.7. Locate 54 psf (2,586 Pa) wind pressure (on vertical axis), read across to curve and read corresponding 144 -te (13.37-m 2 ) maximum area per panel (on horizontal axis). Figure CC-7.2-1- G/ass masomy ultimate wind load resistance CODE COMMENTARY 7.2.2 Exterior thin-unit panels 7.2.2 Exterior thin-unitpanels C-171 The maximum area of each individual thin-unit panel shall be 100 ff (9.29 m2 ) . The maximum dimension between structural supports shall be 15 ft (4.57 m) wide or 10 ft (3.05 m) high. Thin units shall not be used in applications where the factored design wind pressure per ASCE 7 exceeds 32 psf ( 1,532 Pa). There is limited historical data for developing a curve for thin units. The Committee recommends limiting the exterior use of thin units to areas where the factored design wind pressure does not exceed 32 psf(1,532 Pa). 7.2.3 Interior panels 7.2.3.1 When the factored wind pressure does not exceed 16 psf (768 Pa), the maximum area of each individual standard-unit panel shall be 250 ff (23.22 m2 ) and the maximum area of each thin-unit panel shall be 150 ft2 (13.94 m2 ). The maximum dimension between structural supports shall be 25 ft (7.62 m) wide or 20 ft (6.1Om) high. 7.2.3.2 When the factored wind pressure exceeds 16 psf (768 Pa), standard-unit panels shall be designed in accordance with Section 7.2.1 and thin-unit panels shall be designed in accordance with Section 7.2.2.
- 185. C-172 CODE 7.2.4 Curvedpanels The width of curved panels shall conform to the requirements of Sections 7.2.1, 7.2.2, and 7.2.3, except additional structural supports shall be provided at Jocations where a curved section joins a straight section and at inflection points in multi-curved walls. 7.3 - Support 7.3.1 General requirements Glass unit masonry panels shall be isolated so that in- plane loads are not imparted to the panel. 7.3.2 Vertical 7.3.2.1 Maximum total deflection of structural members supporting glass unit masonry shall not exceed l/600. 7.3.2.2 Glass unit masonry having an installed weight of 40 psf (195 kg/m2 ) or less and a maximum height of 12 ft (3.7 m) shall be permitted to be supported on wood construction. 7.3.2.3 A vertical expansion joint in the glass unit masonry shall be used to isolate the glass unit masonry supported by wood construction from that supported by other types ofconstruction. 7.3.3 Lateral 7.3.3.1 Glass unit masomy panels, more than one unit wide or one unit high, shall be laterally supported along the top and sides of the panel. Lateral support shall be provided by panel anchors along the top and sides spaced not more than 16 in. (406 mm) on center or by channel-type restraints. Glass unit masonry panels shall be recessed at least 1 in. (25.4 mm) within channels and chases. Channel-type restraints must be oversized to accommodate expansion material in the opening, and packing and sealant between the framing restraints and the glass unit masonry perimeter units. Lateral supports for glass unit masonry panels shall be designed to resist applied loads, or a mínimum of 200 lb per lineal ft (2919 N/m) ofpanel, whichever is greater. 7.3.3.2 Glass unit masonry panels that are no more than one unit wide shall conform to the requirements of Section 7.3.3.1, except that lateral support at the top of the panel is not required. 7.3.3.3 Glass unit masonry panels that are no more than one unit high shall conform to the requirements of Section 7.3.3.1, except that lateral support at the sides ofthe panels is not required. 7.3.3.4 Glass unit masonry panels that are a single glass masonry unit shall conform to the requirements ofSection 7.3.3.1, except that lateral support shall not be provided by panel anchors. TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY 7.3- Support 7.3.1 General requirements 7.3.2 Vertical Support of glass unit masonry on wood has historically been permüted in model building codes. The Code requirements for expansion joints and for asphalt emulsion at the sill isolate the glass unit masonry within the wood frarning. These requirements also reduce the possibility ofcontact ofthe glass units and mortar with the wood framing. The height lirnit of 12 ft. (3.7 m) was considered to be the maximum single story height. 7.3.3 Lateral The Codt: requires glass unil masonry panels Lo be laterally supported by panel anchors or channel-type restraints. See Figures CC-7.3-1 and CC-7.3-2 for panel anchor construction and channel-type restraint construction, respectively. Glass unit masonry panels may be laterally supported by either construction type or by a combinatíon of construction types. The channel-type restraint construction can be made of any channel-shaped concrete, masonry, metal, or wood elements so long as they provide the required lateral support.
- 186. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY COMMENTARY Panel Anchorwith 12-in. (305-mm) Minimum Embedment into Mortar Joint 16 in. (406 mm) o. c. max. spacing at head and jamb Sealant (both sides) Panel Reinforcement at 16 in. o. c. (406 mm) Maximum Spacing Asphalt Emulsion Figure CC-7.3-1 - Panel anchor construction Packing and Sealant (8oth Sides) ----_1 Expansion strip Channel fastener Joint Reinforcement at 16 in. (406 mm) Maximum Spacing Asphalt emulsion Figure CC-7.3-2 - Channel-type restraint construction C-173
- 187. C-174 CODE 7.4- Expansion joints Glass unit masonry panels shall be provided with expansion j oints along the top and sides at structural supports. Expansion joints shall have sufficient thickness to accommodate displacements of the supporting structure, but shall not be less than 3 / 8 in. (9.5 mm) in thickness. Expansion joints shall be entirely free ofmortar or other debris and shall be filled with resilient material. 7.5 - Base surtace treatment The surface on which glass unit masonry panels are placed shall be coated with a water-based asphaltic emulsion or other elastic waterproofing material prior to laying the first course. 7.6- Mortar Glass unit masonry shall be laid with Type S or N mortar. 7.7- Reinforcement Glass unit masonry panels shall have horizontal joint reinforcement spaced not more than 16 in. (406 mm) on center, located in the mortar bed joint, and extending the entire length of the panel but not across expansion joints. Longitudinal wires shall be lapped a minimum of 6 in. (152 mm) at splices. Joint reinforcement shall be placed in the bed joint immediately below and above openings in the panel. The reinforcement shall have not less than two parallellongitudinal wires of size Wl.7 (MWll) and have welded cross wires ofsize Wl.7 (MWII). TMS 402-11/ACI 530·11/ASCE 5·11 COMMENTARY 7.4- Expansion joints 7.5- Base surface treatment Current industry practice and recommendations by glass block manufacturers state that surfaces on which glass unit masonry is placed be coated with an asphalt emulsion7 · 2 • 73 • The asphalt emulsion provides a slip plane at the panel base. This is in addition to the expansion provisions at head and jamb locations. The asphalt emulsion also waterproofs porous panel bases. Glass unit masonry panels subjected to structural investigation tests by the National Concrete Masonry Association75 to confirm the validity and use ofthe Glass Unit Masonry Design Wind Load Resistance chart (Figure CC-7.2-1) ofthe Code, were constructed on bases coated with asphalt emulsion. Asphalt emulsion on glass unit masonry panel bases is needed tobe consistent with these tests.
- 188. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-175 CHAPTER 8 STRENGTH DESIGN OF AUTOCLAVED AERATED CONCRETE (AAC) MASONRY 8.1 -General 8.1.1 Scope CODE This Chapter provides mínimum requirements for design ofAAC masonry. 8.1.1.1 Except as stated elsewhere in this Chapter, design of AAC masonry shall comply with the requirements of Chapter 1, excluding Sections 1.12.1, l. 12.2(d) and 1.14.2. 8.1.1.2 Design of AAC masonry shall comply with Sections 8.1.2 through 8.1.9, and either Section 8.2 or 8.3. 8.1.2 Requiredstrength Required strength shall be determined in accordance with the strength design load combinations of the legally adopted building code. When the legally adopted building code does not provide load combinations, structures and members shall be designed to resist the combination of loads specified in ASCE 7. Members subject to compressive axial load shall be designed for the maximum design moment accompanying the axial load. The factored moment, M,,. shall include the moment induced by relative lateral displacement 8.1.3 Design strength AAC masonry members shall be proportioned so that the design strength equals or exceeds the required strength. Design strength is the nominal strength multiplied by the strength-reduction factor, rp, as specified in Section 8.1.5. 8.1.4 Strength ofjoints AAC masonry members shall be made of AAC masonry units. The tensile bond strength of AAC masonry joints shall not be taken greater than the limits of Section 8.1.8.3. When AAC masonry units with a maximum height of 8 in. (203 mm) (nominal) are used, head joints shall be permitted to be left unfilled between AAC masonry units laid in running bond, provided that shear capacity is calculated using the formulas ofthis Code corresponding to that condition. Open head joints shall not be permitted in AAC masonry not laid in running bond. COMMENTARY 8.1 - General 8.1.1 Scope Refer to Section 8.1. 1O for requirements for corbels constructed ofAAC masonry. 8.1.4 Strength ofjoints Design provisions of Chapter 8 and prescriptive seismic reinforcement requirements of Section 1.1 8 are based on monolithic behavior of AAC masonry. The reduction in shear strength of AAC masonry shear walls laid in running bond with unfilled head joints is accounted for in Equation 8-l3b. AAC masonry walls constructed with AAC masonry units greater in height than 8 in. (203 mm) (nominal) with unfilled head joints and AAC masonry walls not laid in running bond with unfilled head joints do not have sufficient test data to develop design provisions and thus are not permitted at this time.
- 189. C-176 CODE 8.1.5 Strength-reduction factors 8.1.5.1 Anchor bolts - For cases where the nominal strength of an anchor bolt is controlled by AAC masonry breakout, rjJ shall be taken as 0.50. For cases where the nominal strength of an anchor bolt is controlled by anchor bolt steel, rjJ shall be taken as 0.90. For cases where the nominal strength of an anchor bolt is controlled by anchor pullout, rjJ shall be taken as 0.65. 8.1.5.2 Bearing- For cases involving bearing on AAC masonry, rjJ shall be taken as 0.60. 8.1.5.3 Combinations ofjlexure and axial load in unreinforced AAC masonry- The value of rjJ shall be taken as 0.60 for unreinforced AAC masonry designed to resist flexure, axial load, or combinations thereof. 8.1.5.4 Combinations ofjlexure and axial load in reinforced AAC masonry - The value of rjJ shall be taken as 0.90 for reinforced AAC masonry designed to resist flexure, axial load, or combinations thereof. 8.1.5.5 Shear - The value of rjJ shall be taken as 0.80 for AAC masonry designed to resist shear. 8.1.6 Deformation requirements 8.1.6.1 Dejlection of unreinforced (plain) AAC masonry - Deflection calculations for unreinforced (plain) AAC masonry members shall be based on uncracked section properties. TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY 8.1.5 Strength-reductionfactors The strength-reduction factor incorporates the difference between the nominal strength provided in accordance with the provisions of Chapter 8 and the expected strength ofthe as-built AAC masonry. The strength-reduction factor also accounts for the uncertainties in construction, material properties, calculated versus actual member strengths, and anticipated mode offailure. 8.1.5.1 Anchor bolts- Anchor bolts embedded in grout in AAC masonry behave like those addressed in Chapter 3 and are designed identically. Anchors for use in AAC masonry units are available from a variety of manufacturers, and nominal resistance should be based on tested capacities. 8.1.5.2 Bearing - The value of the strength- reduction factor used in bearing assumes that sorne degradation has occurred within the masonry material. 8.1.5.3 Combinations ofjlexure and axial load in unreinforced AAC masonry - The same strength- reduction factor is used for the axial load and the flexura( tension or compression induced by bending moment in unreinforced masonry elements. The lower strength- reduction factor associated with unreinforced elements (in comparison to reinforced elements) reflects an increase in the coefficient of variation of the measured strengths of unreinforced elements when compared to similarly configured reinforced elements. 8.1.5.4 Combinations ofjlexure and axial load in reinforced AAC masonry - The same strength- reduction factor is used for the axial load and the flexura! tension or compression induced by bending moment in reinforced AAC masonry elements. The higher strength- reduction factor associated with reinforced elements (in comparison to unreinforced elements) reflects a decrease in the coefficient of variation ofthe measured strengths of reinforced elements when compared to similarly configured unreinforced elements. 8.1.5.5 Shear - Strength-reduction factors for calculating the design shear strength are commonly more conservative than those associated with the design flexura( strength. However, the capacity design provisions of Chapter 8 require that shear capacity significantly exceed flexura( capacity. Hence, the strength-reduction factor for shear is taken as 0.80, a value 33 percent larger than the historical value. 8.1.6 Deformation requirements 8.1.6.1 Dejlection of unreinforced (plain) AAC masonry - The deflection calculations of unreinforced masonry are based on elastic performance ofthe masonry assemblage as outlined in the design criteria of Section 3.2.1.3.
- 190. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-177 CODE 8.1.6.2 Dejlection ol reinforced AAC masonry - Deflection calculations for reinforced AAC masonry members shall be based on cracked section properties including the reinforcement and grout. The flexura! and shear stiffness properties assumed for deflection calculations shall not exceed one-half of the gross section properties unless a cracked-section analysis is performed. 8.1.7 Anchor bolts Headed and bent-bar anchor bolts shall be embedded in grout, and shall be designed in accordance with Section 3.1.6 using 1 ~ instead of 1 ~. and neglecting the contribution of AAC to the edge distance and embedment depth. Anchors embedded in AAC without grout shall be designed using nominal capacities provided by the anchor manufacturer and verified by an independent testing agency. 8.1.8 Material properties 8.1.8.1 Compressive strength 8.1.8.1.1 Masonry compressive strength- The specified compressive strength of AAC masonry, 1 ÁAc , shall equal or exceed 290 psi (3.45 MPa). 8.1.8.1.2 Grout compressive strength - The specified compressive strength of grout, 1 ~ , shall equal or exceed 2,000 psi (13.8 MPa) and shall not exceed 5,000 psi (34.5 MPa). 8.1.8.2 Masonry splitting !ensile strength- The splitting tensile strength ¡; AAC shall be determined by Equation 8-1. hAAC = 2 .4~ J AAC (Equation 8-1) 8.1.8.3 Masonry modulus ol mpture - The modulus of rupture, frAAC , for AAC masonry elements shall be taken as twice the masonry splitting tensile strength, ftAAc . If a section of AAC masonry contains a COMMENTARY . 8.1.6.2 Dejlection ol reinl orced AAC masonry- Values offetr are typically about one-halfof /K for common configurations of elements that are fully grouted. Calculating a more accurate effective moment of inertia using a moment curvature analysis may be desirable for sorne circumstances. llistorically, an effective moment of inertia has been calculated using net cross-sectional area properties and the ratio of the cracking moment strength based on appropriate modulus of rupture values to the applied moment resulting from unfactored loads as shown in the following equation. This equation has successfully been used for estimating the post-cracking flexura! stiffness of both concrete and masonry. ¡<IT = /"( ~'J +/"H~: )}/"$OSI, 8.1.7 Anchor bolts Headed and bent-bar anchor bolts embedded in grout in AAC masonry behave like those addressed in Chapter 3 and are designed identically. Anchors for use in AAC masonry units are available from a variety of manufacturers. 8.1.8 Material properties 8.1.8.1 Compressive strength 8.1.8.1.1 Masonry compressive strength- Research8 .1. 8 · 2 • 83 • 8 .4 has been conducted on structural components of AAC masonry with a compressive strength of290 to 1,500 psi (2.00 to 10.34 MPa). Design criteria are based on these research results. 8.1.8.1.2 Grout compressive strength - Since most empirically derived design equations relate the calculated nominal strength as a function of the specified compressive strength of the masonry, the specified compressive strength ofthe grout is required to be at least equal to the specified compressive strength. Additionally, due to the hydrophilic nature of AAC masonry, care should be taken to control grout shrinkage by pre-wetting cells to be grouted or by using other means, such as non- shrink admixtures. Bond between grout and AAC units is equivalent to bond between grout and other masonry unitss.z. 8.3, 8.4. 8.1.8.2 Masonry splitting /ensile strength - The equation for splitting tensile strength is based on ASTM e1006 tests8 · 2 • 8 .4. 8.1.8.3 Masonry modulus o l ntpture - The modulus of rupture is based on tests conducted in accordance with ASTM C788 · 5 on AAC masonry with different compressive strengths8 · 2 • 8 .4· 8 · 6 • Modulus of
- 191. C-178 CODE Type M or Type S horizontal leveling bed of mortar, the value offrAAc shall not exceed 50 psi (345 kPa) at that section. Ifa section ofAAC masonry contains a horizontal bed joint of thin-bed mortar and AAC, the value offrAAC shall not exceed 80 psi (552 kPa) at that section. 8.1.8.4 Masonry direct shear strength - The direct shear strength, fv, across an interface of AAC material shall be determined by Equation 8-2, and shall be taken as 37 psi (255 kPa) across an interface between grout and AAC material. fv = 0.15/ ~c (Equation 8-2) 8.1.8.5 Coefficient offriction - The coefficient of friction between AAC and AAC shall be 0.75. The coefficient of friction between AAC and thin-bed mortar or between AAC and leveling-bed mortar shall be 1.0. 8.1.8.6 Reinforcement strength - Masonry design shall be based on a reinforcement strength equal to the specified yield strength of reinforcement, ¡;,, which shall not exceed 60,000 psi (413.7 MPa). The actual yield strength shall not exceed 1.3 multiplied by the specified yield strength. 8.1.9 Nominal bearing strength 8.1.9.1 The nominal bearing strength of AAC masonry shall be computed as f'AAc multiplied by the bearing area, Abr. as defined in Section 1.9.5 8.1.9.2 Bearing for simply supported precast jloor and roofmembers on AAC masonry shear wal/s - The following mínimum requirements shall apply so that after the consideration oftolerances, the distance from the edge of the supporting wall to the end of the precast member in the direction ofthe span is not less than: For AAC floor panels 2 in. (51 mm) For solid or hollow-core slabs 2 in. (51 mm) For beams or stemmed members 3 in. (76 mm) TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY rupture tests show that a thin-bed mortar joint can fail before the AAC material indicating that the tensile-bond strength ofthe thin-bed mortar is less than the modulus of rupture ofthe AAC. This critica! value is 80 psi (552 kPa). The data are consistent with the formation of cracks in thin-bed mortar joints observed in AAC shear wall tests8 · 2 • 8 .4. Shear wall tests8 · 2 show that when a leveling bed is present, flexura! cracking capacity may be controlled by the tensile bond strength across the interface between the AAC and the leveling mortar, which is usually less than the modulus of rupture of the AAC material itself. 8.1.8.4 Masonry direct shear strength - The equation for direct shear strength is based on shear tests8 2 • 8 .4. Based on tests by Kingsley et al8.7, interface shear strength between grout and conventional masonry units varíes from 100 to 250 psi (689 to 1,723 kPA). Based on tests by Tanner82 , interface shear strength between grout and AAC material had a 5% fractile (lower characteristic) value of 37 psi (255 kPa). Based on Kingsley's work, the value of37 psi (255 kPa) is probably a conservative bound to the actual value; it can safely and appropriately be used for AAC masonry. 8.1.8.5 Coefficient offriction - The coefficient of friction between AAC and AAC is based on direct shear tests performed at The University ofTexas at Austin and. the coefficient of friction between AAC and leveling mortar is based on tests on shear walls at the same institution. 8.1.8.6 Reinforcement strength - Research111 conducted on reinforced masonry components used Grade 60 steel. To be consistent with laboratory documented investigations, design is based on a nominal steel yield strength of 60,000 psi (413.7 MPa). The limitation on the steel yield strength of 130 percent ofthe nominal yield strength limits the over-strength that may be present in the construction. 8.1.9 Nominal bearingstrength 8.1.9.1 Commentary Section 1.9.5 gives further information. 8.1.9.2 Bearing for simply supported precast jloor and roof members on AAC shear wal/s - Bearing should be checked wherever floor or roofelements rest on AAC walls. The critica! edge distance for bearing and the critica! section for shear to be used in this calculation are shown in Figure CC-8.1-1.
- 192. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-179 COMMENTARY AAC floor or roof panel Criticar section 7/¡ 45° angle f '<~ critica! edge distance for bearing Figure CC-8.1-1 Critica/ section at bearing ofAACfloor or roofpanel on AAC wall CODE 8.1.10 Corbels- Load bearing corbels of AAC masonry shall not be permitted. Non-loadbearing corbels of AAC masonry shall conform to the requirements of Section 1.12.2(a) through 1.12.2(c). The back section of the corbelled section shall remain within V. inch ofplane. 8.2 -Unreinforced {plain) AAC masonry 8.2.1 Scope The requirements of Section 8.2 are in addition to the requirements of Chapter 1 and Section 8.1, and govem masonry design in which AAC masonry is used to resist tensile forces. 8.2.1.1 Strength for resisting loads Unreinforced (plain) AAC masonry members shall be designed using the strength of masonry units, mortar, and grout in resisting design loads. 8.2.1.2 Strength contribution from reinforcement - Stresses in reinforcement shall not be considered effective in resisting design loads. 8.2.1.3 Design criteria - Unreinforced (plain) AAC masonry members shall be designed to remain uncracked. 8.2.2 Flexura/ strength of unreinforced (plain) AAC masonry members The following assumptions shall apply when determining the flexural strength of unreinforced (plain) AAC masonry members: (a) Strength design of members for factored tlexure and axial load shall be in accordance with principies of engineering mechanics. COMMENTARY 8.1.10 Corbels- Load bearing corbels of AAC masonry are not permitted due to the possibility of a brittle shear failure. Non-load bearing corbels of AAC masonry are permitted, provided that the back section of the corbelled wall remains plane within the code limits. The relative ease in which AAC masonry can be cut and shaped makes this requirement practical. 8.2 -Unreinforced {plain) AAC masonry
- 193. C-180 CODE (b) Strain in masonry shall be directly proportional to the distance from the neutral axis. (e) Flexura! tension in masonry shall be assumed to be directly proportional to strain. (d) Flexura! compressive stress in combination with axial compressive stress in masonry shall be assumed to be directly proportional to strain. Nominal compressive strength shall not exceed a stress corresponding to 0.85fA.4c . (e) The nominal flexura! tensile strength of AAC masonry shall be deterrnined from Section 8.1.8.3. 8.2.3 Nominal axial strength of unreinforced (plain) AAC masonry members Nominal axial strength, Pn , shall be computed using Equation 8-3 or Equation (8-4. (a) For members having an hlr ratio not greater than 99: P" = 0+85A.f~ c [~-c.:,)']} (Equation 8-3) (b) For members having an hlr ratio greater than 99: 8.2.4 Axial tension The tensile strength of unreinforced AAC masonry shall be neglected in design when the masonry is subjected to axial tension forces. 8.2.5 Nominal shear strength of unreinforced (plain) AAC masonry members The nominal shear strength of AAC masonry, VnAAC , shall be the least of the values computed by Sections 8.3.4.1.2.1 through 8.3.4.1.2.3. In evaluating nominal shear strength by Section 8.3.4.1.2.3, effects of reinforcement shall be neglected. The provisions of 8.3.4.1.2 shall apply to AAC shear walls not laid in running bond. 8.2.6 Flexura/ cracking The flexura( cracking strength shall be computed in accordance with Section 8.3.6.5. TMS 402·11/ACI 530·11/ASCE 5-11 COMMENTARY 8.2.4 Axial tension Commentary Section 2.2.4 provides further information.
- 194. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-181 CODE 8.3 - Reinforced AAC masonry 8.3.1 Scope The requirements ofthis section are in addition to the requirements of Chapter 1 and Section 8.1 and govern AAC masonry design in which reinforcement is used to resist tensile forces. 8.3.2 Design assumptions The following assumptions apply to the design of reinforced AAC masonry: (a) There is strain compatibility between the reinforcement, grout, and AAC masonry. (b) The nominal strength of reinforced AAC masonry cross sections for combined flexure and axial load shall be based on applicable conditions of equilibrium. (e) The maximum usable strain, &m11 , at the extreme AAC masonry compression fiber shall be assumed to be 0.003. (d) Strain in reinforcement and AAC masonry shall be assumed to be directly proportional to the distance from the neutral axis. (e) Tension and compression stresses in reinforcement shall be calculated as the product of steel modulus of elasticity, Es, and steel strain, &5 , but shall not be greater thanfr. Except as permitted in Section 8.3.3.5 for determination of maximum area of flexura! reinforcement, the compressive stress of steel reinforcement shall be neglected unless lateral restraining reinforcement is provided in compliance with the requirements of Section 1.14.1.4. (f) The tensile strength of AAC masonry shall be neglected in calculating axial and flexura] strength. (g) The relationship between AAC masonry compressive stress and masonry strain shall be assumed to be defmed by the following: AAC masonry stress of 0.85f ÁAc shall be assumed uniformly distributed over an equivalent compression stress block bounded by edges of the cross section and a straight line parallel to the neutral axis and Jocated at a distance a =0.67 e from the fiber of maximum compressive strain. The distance e from the fiber of maximum strain to the neutral axis shall be measured perpendicular to the neutral axis. 8.3.3 Reinforeement requirements and details 8.3.3.1 Reinforcing bar size limitations Reinforcing bars used in AAC masonry shall not be larger than No. 9 (M#29). The nominal bar diameter shall not exceed one-eighth of the nominal member thickness and shall not exceed one-quarter of the least clear dimension of COMMENTARY 8.3- Reinforced AAC masonry Provisions are identical to those of concrete or clay masonry, with a few exceptions. Only those exceptions are addressed in this Commentary. 8.3.2 Design assumptions For AAC, test results indicate that &mu for Class 4 AAC masonry and higher is 0.003 and the value of the stress in the equivalent rectangular stress block is 0.85 f ÁAc with a = 0.67c. 8 ' 2 ' 8 · 3 • 8 .4 Additional testing88 has indicated a E:m11 of0.0012 for Class 2 AAC masonry. 8.3.3 Reinforcement requirements and details 8.3.3.1 Reinforeing bar size limitations Grout spaces may include, but are not limited to, cores, bond beams, and collar joints. At sections containing lap splices, the maximum area of reinforcement specified in
- 195. C-182 CODE the grout space in which it is placed. In plastic hinge zones, the area ofreinforcing bars placed in a grout space shall not exceed 3 percent ofthe grout space area. In other than plastic hinge zones, the area of reinforcing bars placed in a grout space shall not exceed 4.5 percent ofthe grout space area. 8.3.3.2 Standard hooks - The equivalent embedment length to develop standard hooks in tension, le, shall be determined by Equation 8-5: (Equation 8-5) 8.3.3.3 Development 8.3.3.3.1 Development of tension and compression reinforcement - The required tension or compression reinforcement shall be developed in accordance with the following provisions: The required development length of reinforcement shall be determined by Equation 8-6, but shall not be less than 12 in. (305 mm). (Equation 8-6) KAAc shall not exceed the smallest of the following: the mínimum grout cover, the clear spacing between adjacent reinforcement splices, and 9db. and y = 1.0 forNo. 3 (M#10) through No. 5 (M#16) bars; y = 1.3 forNo. 6 (M#19) through No. 7 (M#22) bars; y = 1.5 for No. 8 (M#25) through No. 9 (M#29) bars. 8.3.3.3.2 Development of shear reinforcement - Shear reinforcement shall extend the depth ofthe member Jess cover distances. 8.3.3.3.2.1 Except at wall intersections, the end ofa horizontal reinforcing bar needed to satisf)r shear strength requirements of Section 8.3.4.1.2, shall be bent around the edge vertical reinforcing bar with a 180-degree hook. The ends ofsingle-leg or U-stirrups shall be anchored by one ofthe following means: (a) A standard hook plus an effective embedment ofld/2. The effective embedment of a stirrup leg shall be taken as the distance between the mid-depth of the member, d/2, and the start of the hook (point of tangency). (b) For No. 5 (M #16) bars and smaller, bending around longitudinal reinforcement through at Jeast 135 degrees plus an embedment of ld/3. The ld/3 embedment of a stirrup Jeg shall be taken as the distance between mid-depth of the member, d/2, and the start ofthe hook (point oftangency). TMS 402-11/ACI 530-11/ASCE 5·11 COMMENTARY the Code may be doubled. 8.3.3.3.1 Development of tension and compression reinforcement- Development and lap splice detailing provisions for conventional masonry are calibrated to the masonry assembly strength, f'm, which includes the contribution of each constituent material (unit, grout, and mortar). Due to the low compressive strength of AAC, however, the AAC masonry component is ignored and the calibration is based onf'g·
- 196. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY CODE (e) Between the anchored ends, each bend in the continuous portion of a transverse U-stirrup shall enclose a longitudinal bar. 8.3.3.3.2.2 At wall intersections, horizontal reinforcing bars needed to satisfy shear strength requirements of Section 8.3.4.1.2 shall be bent around the edge vertical reinforcing bar with a 90-degree standard hook and shall extend horizontally into the intersecting wall a mínimum distance at least equal to the development length. 8.3.3.4 Splices - Reinforcement splices shall comply with one ofthe following: (a) The mínimum length of lap for bars shall be 12 in. (305 mm) or the development length determined by Equation 8-6, whichever is greater. (b) A welded splice shall have the bars butted and welded to develop at least 125 percent of the yield strength, ¡;,, ofthe bar in tension or compression, as required. (e) Mechanical splices shall have the bars connected to develop at least 125 percent of the yield strength,¡;,, ofthe bar in tension or compression, as required. 8.3.3.5 Maximum reir¡forcement percentages - The ratio ofreinforcement, p, shall be calculated in accordance with Section 3.3.3.5 with the following exceptions: The maximum usable strain, &mu , at the extreme masonry compression fiber shall be assumed to be 0.0012 for Class 2 AAC masonry and 0.003 for Class 4 AAC masonry and higher. The strength of the compression zone shall be calculated as 85 percent off ÁAc multiplied by 67 percent ofthe area ofthe compression zone. 8.3.3.6 Bundling of reinforcing bars Reinforcing bars shall not be bundled. 8.3.4 Design ofbeams, piers, andcolumns Member design forces shall be based on an analysis that considers the relative stiffness of structural members. The calculation of lateral stiffness shall include the contribution of beams, piers, and columns. The effects ofcracking on member stiffness shall be considered. 8.3.4.1 Nominal strength 8.3.4.1.1 Nominal axial and flexura! strength- The nominal axial strength, Pn, and the nominal flexural strength, Mn, ofa cross section shall be determined in accordance with the design assumptions ofSection 8.3.2 and the provisions of Section 8.3.4.1. For any value of nominal flexura! strength, the corresponding calculated nominal axial strength shall be modified for the effects of slendemess in accordance with Equation 8-7 or 8-8. The nominal flexural strength at any section along a member shall not be less than one-fourth of the maximum nominal COMMENTARY C-1 83
- 197. C-184 CODE flexura! strength at the critica! section. The nominal axial compressive strength shall not exceed Equation 8-7 or Equation 8-8, as appropriate. (a) For members having an hlr ratio not greater than 99: (Equation 8-7) (b) For members having an hlr ratio greater than 99: (Equation 8-8) 8.3.4.1.2 Nominal shear strength - Nominal shear strength, Vn, shall be computed using Equation 8-9 through Equation 8-12, as appropriate. VIl =VIIAAC + VliS (Equation 8-9) where V,, shall not exceed the following: (Equation 8-1O) At an interface of AAC and thin-bed mortar or leveling-bed mortar, the nominal sliding shear strength shall be calculated using Equation 8-1O and using the coefficient offriction from Section 8.1.8.5. (b) Where M,/ (V,, d.) :S: 0.25: Vn :S: 6An ~ ~~ e (Equation 8-1 1) (e) Where M,/ (V,,d.,) ~ 1.0 (Equation 8-12) (d) The maximum value of Vn for M,/(V,, d.,) between 0.25 and 1.0 shall be permitted to be linearly interpolated. The nominal masonry shear strength shall be taken as the least of the values computed using Section 8.3.4.1.2.1 and 8.3.4.1.2.2. 8.3.4.1.2.1 Nominal masonry shear strength as governed by web-shear cracking - Nominal masonry shear strength as govemed by web-shear cracking, V,IAAc , shall be computed using Equation (8-13a) for AAC masonry with mortared head joints, and Equation (8-13b) for masonry with unmortared headjoints: VnAAC =0.95 /wt~f :.Uc 1+ & 2.4 f:.Uc lwt (Equation 8-13a) TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY 8.3.4.1.2 Nominal shear strength - The nominal shear strength ofAAC walls is based on testing at UT Austin 8 · 2 • 8 .4. Test results show that factory-installed, welded-wire reinforcement is developed primarily by bearing of the cross-wires on the AAC material, which normally crushes before the longitudinal wires develop significant stress. Therefore, the additional shear strength provided by the horizontal reinforcement should be neglected. Joint-type reinforcement will probably behave similarly and is not recommended. In contrast, deforrned reinforcement placed in grouted bond beams is effective and should be included in computing Vns. The upper limit on V"' defined by Equation 8-10, is based on sliding shear. Flexura! cracking can result in an unbonded interface, which typically occurs at a horizontal joint in a shear wall. For this reason, the shear capacity of an AAC bed joint is conservatively limited to the frictional resistance, without considering initial adhesion. The sliding shear capacity should be based on the frictional capacity consistent with the perpendicular force on the compressive stress block, including the compressive force required to equilibrate the tensile force in the flexura! reinforcement. Dowel action should not be included. 8.3.4.1.2.1 Nominal masonry shear strength as governed by web-shear cracking - Equations 8-13a and 8-13b were developed based on observed web shear cracking in shear walls tested at the University of Texas at Austin 8 · 2 • 8 · 4 and Hebel AG8 · 9 in Gerrnany. During testing at the University of Texas at Austin, flexur-shear cracking of AAC shear walls was observed, as predicted, in 6 shear wall tests8 · 1 • 8 · 2 • 8 · 3 • The presence offlexur-shear cracks did not reduce the strength or stiffness of tested AAC shear walls. Another AAC shear wall tested by Cancino8 · 8 performed in a similar manner. The results in both testing efforts indicate the
- 198. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-185 CODE VnAAC =0.661"' ~ ~ ~~ C ]+ ~ 2. ~~ AC 1,. t (Equation 8-13b) For AAC masonry not laid in running bond, nominal masonry shear strength as govemed by web-shear cracking, VnAAC, shall be computed using Equation 8-13c: VnAAC =0.9 ~ f~ c A11 +0.05Pu (Equation 8-13c) 8.3.4.1.2.2 Nominal shear strength as governed by crushing of diagonal compressive strut - For walls with M,/(V11 dv) < 1.5, nominal shear strength, VnAAC, as governed by crushing of a diagonal strut, shall be computed as follows: ' h·l 2 VnAAC = 0.17j AAC t 2 3w 2 h +(-;¡ lw) (Equation 8-14) For walls with M,/(Vudv) equal to or exceeding 1.5, capacity as governed by crushing of the diagonal compressive strut need not be calculated. 8.3.4.1.2.3 Nominal shear strength provided by shear reinforcement - Nominal shear Strength prOVided by reinfO rCement, V11s, Shall be computed as follows: Vns = O.s(~v )fydv (Equation 8-15) Nominal shear strength provided by reinforcement, Vns, shall inelude only deformed reinforcement embedded in grout for AAC shear walls. COMMENTARY hysteretic behavior was not changed after the formation of flexure-shear cracks. Thus, flexure-shear cracking does not constitute a limit state in AAC masonry and design equations are not provided. Masonry units not laid in running bond may exhibit discontinuities at head joints. The nominal masonry shear strength calculation for AAC masonry not laid in running bond considers the likelihood ofvertical discontinuities at head joints and is based on test results for AAC walls made of vertical panels with open vertical joints between sorne panels. 8.3.4.1.2.2 Nominal shearstrength as governed by crushing of diagonal compressive strut - This mechanism limits the shear strength at large levels of axial load. It was based on test results8 · 2 , using a diagonal strut width of0.251,. based on test observations. 8.3.4.1.2.3 Nominal shear strength provided by shear reinforcement - Equation 8-15 is based on Equation 3-24. Equation 3-24 was developed based on results of reversed cyclic load tests on masonry wall segments with horizontal reinforcement distributed over their heights. The reason for the 0.5 efficiency factor is the non-uniform distribution of tensile strain in the horizontal reinforcement over the height of the element. The formation of an inclined diagonal compressive strut from one comer of the wall segment to the diagonally opposite comer creates a strain field in which the horizontal shear reinforcement at the top and bottom of the segment may not yield. For that reason, not all of the horizontal shear reinforcement in the wall may be fully effective or efficient in resisting shear forces. AAC masonry walls differ from concrete masonry walls and clay masonry walls in that horizontal joint reinforcement is not used for horizontal shear reinforcement. For reasons of constructability, AAC walls are traditionally reinforced horizontally with deformed steel reinforcing bars in grout-filled bond beams. In addition, the strength ofthe thin set AAC mortar exceeds the strength of the AAC masonry units, which would suggest that AAC walls will behave in a manner similar to reinforced concrete. Assemblage testing conducted on AAC masonry walls also suggested that horizontal joint reinforcement provided in concrete bond beams could be fully effective in resisting shear. For this reason, earlier additions ofthe Code presented Equation 8-15 without the 0.5 efficiency factor, mimicking the reinforced concrete design equation for strength provided by shear reinforcement.
- 199. C-186 CODE 8.3.4.1.2.4 Nominal shear strength govemed by out-of-plane loading shall be computed as follows: VnAAC =0.8 Jj'AAC bd (Equation 8-16) 8.3.4.2 Beams - Design of beams shall meet the requirements of Section 1.13 and the additional requirements of Sections 8.3.4.2.1 through 8.3.4.2.5. 8.3.4.2.1 The factored axial compressive force on a beam shall not exceed 0.05 Anf ÁAc. 8.3.4.2.2 Longitudinal reinforcement 8.3.4.2.2.1 The variation in longitudinal reinforcing bars shall not be greater than one bar size. Not more than two bar sizes shall be used in a beam. 8.3.4.2.2.2 The nominal flexura! strength of a beam shall not be less than 1.3 multiplied by the nominal cracking moment of the beam, Mcr. The modulus of rupture, frAAc , for this calculation shall be determined in accordance with Section 8.1.8.3. 8.3.4.2.3 Transverse reinforcement Transverse reinforcement shall be provided where V,, exceeds rp VnAAC. The factored shear, Vu, shall include the effects of lateral load. When transverse reinforcement is required, the following provisions shall apply: (a) Transverse reinforcement shall be a single bar with a 180-degree hook at each end. (b) Transverse reinforcement shall be hooked around the longitudinal reinforcement. (e) The mínimum area of transverse reinforcement shall be 0.0007 bd•. (d) The first transverse bar shall not be located more than one-fourth ofthe beam depth, d. , from the end ofthe beam. (e) The maximum spacing shall not exceed the lesser of one-halfthe depth ofthe beam or 48 in. (1219 mm). 8.3.4.2.4 Construction - Beams shall be fully grouted. 8.3.4.2.5 Dimensionallimits - The nominal depth ofa beam shall not be less than 8 in. (203 mm). 8.3.4.3 Piers 8.3.4.3.1 The factored axial compression TMS 402-111ACI 530-111ASCE 5·11 COMMENTARY Although this appeared reasonable in the original judgment of the committee, no tests have been performed with AAC masonry walls having deformed horizontal reinforcement in concrete bond beams Until such testing is performed, the 0.5 efficiency factor is being included in Equation 8-15 to be consistent with design procedures associated with concrete masonry and elay masonry, and to provide a conservative design approach.
- 200. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-187 CODE force on the piers shall not exceed 0.3 Anf ÁAc . 8.3.4.3.2 Longitudinal reinforcement - A pier subjected to in-plane stress reversals shall be reinforced symmetrically about the geometric center ofthe pier. The longitudinal reinforcement of piers shall comply with the following: (a) At least one bar shall be provided in each end ce!l. (b) The mínimum area of longitudinal reinforcement shall be 0.0007 bd. 8.3.4.3.3 Dimensional limits - Dimensions shall be in accordance with the following: (a) The nominal thickness of a pier shall not be less than 6 in. ( 152 mm) and shall not exceed 16 in. (406 mm). (b) The distance between lateral supports of a pier shall not exceed 25 multiplied by the nominal thickness of a pier except as provided for in Section 8.3.4.3.3(c). (e) When the distance between lateral supports of a pier exceeds 25 multiplied by the nominal thickness of the pier, design shall be based on the provisions of Section 8.3.5. (d) The nominal length of a pier shall not be less than three multiplied by its nominal thickness nor greater than six multiplied by its nominal thickness. The clear height of a pier shall not exceed five multiplied by its nominal Iength. Exception: When the factored axial force at the location of maximum moment is less than 0.05f '.«c Ag, the length of a pier shall be permitted to be taken equal to the thickness ofthe pier. 8.3.5 Wall designfor out-ofplane Ioads 8.3.5.1 Scope - The requirements of Section 8.3.5 are for the design ofwalls for out-of-plane loads. 8.3.5.2 Maximum reinforcement The maximum reinforcement ratio shall be determined by Section 8.3.3.5. 8.3.5.3 Moment and deflection calculations - Moment and detlection calculations in Section 8.3.5.4 and 8.3.5.5 are based on simple support conditions top and bottom. For other support and fixity conditions, moments, and detlections shall be calculated using established principies ofmechanics. COMMENTARY 8.3.5.3 Moment and deflection calculations- This section only includes design equations based on walls having simple support conditions at the top and bottom of the walls. In actual design and construction, there may be varying support conditions, thus changing the curvature of the wall under lateral Ioading. Through proper calculation and using the principies of mechanics, the points of intlection can be determined and actual moments and deflection can be calculated under different support conditions. The designer should examine moment and deflection conditions to locate the critica] section using the assumptions outlined in Section 8.3.5.
- 201. C-188 CODE 8.3.5.4 Walls with factored axial stress of 0.20f ÁAc or less - The procedures set forth in this section shall be used when the factored axial load stress at the location of maximum moment satisfies the requirement computed by Equation 8-17. ( ;: } 0.20fÁAc (Equation 8-1 7) When the ratio of effective height to nominal thickness, hit, exceeds 30, the factored axial stress shall not exceed 0.05f ÁAc Factored moment and axial force shall be determined at the midheight of the wall and shall be used for design. The factored moment, Mu, at the midheight of the wall shall be computed using Equation 8-18. (Equation 8-18) Where: (Equation 8-19) The deflection due to factored loads (b;,) shall be obtained using Equations (8-24 and 8-25) and replacing Mser with M,, and 6:, with b;, . The design strength for out-of-plane wall loading shall be in accordance with Equation 8-20. (Equation 8-20) The nominal moment shall be calculated using Equations 8-21 and 8-22 if the reinforcing steel is placed in the center ofthe wall. Mn = (A sfy+Pu{d-~J (Pu +A sfy) a =...:....____..:;...;.. 0.85/ ~c b (Equation 8-21) (Equation 8-22) The nominal shear strength for out-of-plane loads shall be determined by Section 8.3.4.1.2.4. 8.3.5.5 Deflections - The horizontal midheight deflection, Os, under service lateral and service axial loads (without load factors) shall be limited by the relation: (Equation 8-23) P-delta effects shall be included in deflection calculation. The midheight deflection shall be computed using either Equation 8-24 or Equation 8-25, as applicable. (a) Where M ser < M cr TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY 8.3.5.4 Walls with factored axial stress of 0.20/'AAC or less - For hit ratios greater than 30, there is an additional limitation on the axial stress. There are currently no strength design provisions for axial stress greater than 0.20 f 'AAc . The required moment due to lateral loads, eccentricity of axial load, and lateral deformations are assumed maximum at mid-height of the wall. In certain design conditions, such as large eccentricities acting simultaneously with small lateral loads, the design maximum moment may occur elsewhere. When this occurs, the designer should use the maximum moment at the critica! section rather than the moment determined from Equation 8-18. The design formulas provide procedures for determining the nominal moment strength. These formulas take into account the effect of verticalloads increasing the capacity ofthe section.
- 202. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY t5 = 5M••,h 2 S 48EAACJg CODE (b) Where Mcr < Mser< M,. t5,.= 5Mcrh2 +5(Mser-Mcr)h2 48 EAAc fg 48EAAC]cr (Equation 8-24) (Equation 8-25) The cracking moment of the wall shall be computed using Equation 8-26, where J,.AAc is given by Section 8.1.8.3: Mcr =s,.(frAAC + ~) (Equation 8-26) lf the section of AAC masonry contains a horizontal leveling bed, the value of J,.AAc shall not exceed 50 psi (345 kPa). 8.3.6 Wa/1 designfor in-plane loads 8.3.6.1 Scope - The requirements of Section 8.3.6 are for the design ofwalls to resist in-plane loads. 8.3.6.2 Reinforcement - Reinforcement shall be in accordance with the following: (a) Reinforcement shall be provided perpendicular to the shear reinforcement and shall be at least equal to one-third Av . The reinforcement shall be uniformly distributed and shall notexceed a spacing of8 ft (2.44 m). (b) The maximum reinforcement ratio shall be determined in accordance with Section 8.3.3.5. 8.3.6.3 Flexura/ and axial strength - The nominal flexura( and axial strength shall be determined in accordance with Section 8.3.4.1.1. 8.3.6.4 Shear strength - The nominal shear strength shall be computed in accordance with Section 8.3.4.1.2. 8.3.6.5 Flexura/ cracking strength - The flexural cracking strength shall be computed in accordance with Equation 8-27, where J,.AAc is given by Section 8.1.8.3: V e r=~~ (frAAC + ~) (Equation 8-27) If the section of AAC masonry contains a horizontal leveling bed, the value of J,.AAc shall not exceed 50 psi (345 kPa). COMMENTARY C-189
- 203. C-190 CODE 8.3.6.6 The maximum reinforcement requirements of Section 8.3.3.5 shall not apply if a shear wall is designed to satisfy the requirements of Sections 8.3.6.6.1 through 8.3.6.6.4. 8.3.6.6.1 The need for special boundary elements at the edges of shear walls shall be evaluated in accordance with Section 8.3.6.6.2 or 8.3.6.6.3. The requirements of Section 8.3.6.6.4 shall also be satisfied. 8.3.6.6.2 This Section applies to walls bending in single curvature in which the flexura! limit state response is governed by yielding at the base of the wall. Walls not satisfying those requirements shall be designed in accordance with Section 8.3.6.6.3. (a) Special boundary elements shall be provided over portions of compression zones where: and e is calculated for the P, given by ASCE 7 Load Combination 5 (1.2D + l.OE +L + 0.2S) or the corresponding strength design load combination of the legally adopted building code, and the corresponding nominal moment strength, Mn, at the base critica! section. The load factor on L in Load Combination 5 is reducible to 0.5, as per exceptions to Section 2.3.2 of ASCE 7. (b) Where special boundary elements are required by Section 8.3.6.6.2 (a), the special boundary element reinforcement shall extend vertically from the critica! section a distance not less than the larger of !,. or M,/4V,,. 8.3.6.6.3 Shear walls not designed to the provisions of Section 8.3.6.6.2 shall have special boundary elements at boundaries and edges around openings in shear walls where the maximum extreme fiber compressive stress, corresponding to factored forces including earthquake effect, exceeds 0.2J'AAC. The special boundary element shall be perrnitted to be discontinued where the calculated compressive stress is less than 0.15f ÁAc . Stresses shall be calculated for the factored forces using a linearly elastic model and gross section properties. For walls with flanges, an effective flange width as defined in Section 1.9.4.2.3 shall be used. 8.3.6.6.4 Where special boundary elements are required by Section 8.3.6.6.2 or 8.3.6.6.3, (a) through (d) shall be satisfied and tests shall be perforrned to verify the strain capacity ofthe element: (a) The special boundary element shall extend horizontally from the extreme compression fiber a distance not less than the larger of (e - 0. 11,.) and c/2. TMS 402-11/AC1 530-11/ASCE 5-11 COMMENTARY 8.3.6.6 While requirements for confined boundary elements have not been developed for AAC shear walls, they have not been developed for conventional masonry shear walls either, and the monolithic nature of AAC shear walls favors possible applications involving boundary elements. Also see Commentary Section 3.3.6.5. 8.3.6.6.1 See Commentary Section 3.3.6.5.2. 8.3.6.6.2 SeeCommentary Section 3.3.6.5.3. 8.3.6.6.3 See Commentary Section 3.3.6.5.4. 8.3.6.6.4 See Commentary Section 3.3.6.5.5.
- 204. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY CODE (b) In flanged sections, the special boundary element shall include the effective flange width in compression and shall extend at least 12 in. (305 mm) into the web. (e) Special boundary element transverse reinforcement at the wall base shall extend into the support at least the development length of the largest longitudinal reinforcement in the boundary element unless the special boundary element terminates on a footing or mat, where special boundary element transverse reinforcement shall extend at least 12 in. (305 mm) into the footing or mat. (d) Horizontal shear reinforcement in the wall web shall be anchored to develop the specified yield strength, ¡;,,within the confined core ofthe boundary element. COMMENTARY C-191
- 205. C-192 TMS 402-11/ACI 530-11/ASCE 5-11 APPENDIXA Appendix A is intentionally left blank. In the previous edition ofthis standard, provisions for the design of AAC Masonry were included in Appendix A. Those provisions have been moved into Chapter 8 in this edition. As such, this Appendix has been maintained to redirect users to Chapter 8 for AAC Masonry provision.
- 206. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-193 APPENDIX B DESIGN OF MASONRY INFILL CODE 8 .1 - General B.l.l Scope This chapter provides mínimum requirements for the structural design of concrete and clay masonry infills, either non-participating or participating. Infills shall comply with the requirements of Chapter 1, Section B.!, and either Section B.2 or B.3. B.l.l.l Except as stated elsewhere in this Appendix, design of masonry infill shall comply with the requirements of Chapter 1, excluding Sections 1.12, 1.13, 1.14 and l. 15. B.l.l.2 Design of masonry infill shall comply with Section B.l and either Section B.2 or B.3. B.l.2 Requiredstrength Required strength shall be determined in accordance with the strength design load combinations of the legal!y COMMENTARY 8.1- General B.l.l Scope The provisions of Appendix B outline a basic set of design provisions for masonry infill based upon experimental research and anecdotal performance ofthese masonry assemblies. The provisions address both non- participating infills, which are structurally isolated from the lateral force-resisting system, as well as participating infills, which are used to resist in-plane forces due to wind and earthquake. While masonry infills have been a part of contemporary construction for nearly a century, research investigations into their performance, particularly during seismic events, is still ongoing. A comprehensive review of available research data on the performance of masonry infills is provided by Tucker8 · 11 • As with masonry systems designed by other chapters of the Code, masonry infill must also be designed per the applicable requirements of Chapter l. By reference to Chapter 1, masonry infill must comply with the prescriptive requirements of Section 1.18 for seismic design and detailing. This includes the prescriptive detailing requirements of Section 1.18.3.1 for non- participating infills and Section 1.18.3.2 for participating infills. Properly detailed masonry infills have shown considerable system ductility8 · 12 • When participating infills are used to resist in-plane loads as part ofa concrete or steel frame structure, a hybrid system is effectively created that may not otherwise be defined in Table 12.2-1 of ASCE 7 for seismic force-resistance. Until further research is completed, the Committee recommends using the smallest R and Cd value for the combination of the frame and masonry infill be used to design the system. Over time, masonry materials expand and contract due to fluctuations in temperature and moisture content as discussed in Code Commentary Sections 1.8.3, 1.8.4, and 1.8.5. Volumetric changes in the masonry infill will open and close the gap between the infill and the bounding frame, which can have a significant impact on the strength and performance of the infill assembly. Such volumetric changes must be considered as required by Section 1.7.5. The provisions and design equations of this Appendix are applicable only to clay and concrete masonry infill. These requirements have not been verified for their applicability to other infill materials, including AAC masonry. B.1.2 Required strength
- 207. C-194 CODE adopted building code. When the legally adopted building code does not provide load combinations, structures and members shall be designed to resist the combination of loads specified in ASCE 7 for strength design. B.1.3 Design strength Infills shall be proportioned so that the design strength equals or exceeds the required strength. Design strength is the nominal strength multiplied by the strength- reduction factor, q:í, as specified in Section B.l.4. B.1.4 Strength-reduction factors The value of q:í shall be taken as 0.60, and applied to the shear, flexure, and axial strength ofa masonry infill panel. B.l.S Limitations Partial infills and infills with openings shall not be considered as part of the lateral force- resisting system. Their effect on the bounding frame, however, shall be considered. 8.2 - Non-participating infills Non-participating infills shall comply with the requirements of Sections B.2.1 and B.2.2. B.2.1 In-plane isolation joints for non-participating infills B.2.1.1 In-plane isolation joints shall be designed between the infill and the sides and top of the bounding frame. B.2.1.2 In-plane isolation j oints shall be specified to be at least 3/8 in. (9.5 mm) wide in the plane of the infill, and shall be sized to accommodate the design displacements ofthe bounding frame. B.2.1.3 In-plane isolation joints shall be free of mortar, debris, and other rigid materials, and shall be permitted to contain resilient material, provided that the compressibility of that material is considered in establishing the required size ofthe joint. B.2.2 Design ofnon-participating infills for out-of- plane loads Connectors supporting non-part1c1pating infills against out-of-plane loads shall be designed to meet the requirements of Sections B.2.2.1 through B.2.2.4. The infill shall be designed to meet the requirements of Section B.2.2.5. B.2.2.1 The connectors shall be attached to the bounding frame. B.2.2.2 The connectors shall not transfer in- plane forces. TMS 402-11/ACI530-11 /ASCE 5-11 COMMENTARY B.1.4 Strength-reductionfactors See Code Commentary Section 3.1.4. The strength reduction factor applies only to the design of the masonry infill. The strength reduction factors for the anchorage (Section 3.1.4.1) and bearing (Section 3.1.4.2) remain unchanged. B.l.S Limitations Structures with partial-height infills have generally performed very poorly during seismic events. Partial- height infills create short columns, which attract additional load due to their increased stiffness. This has led to premature colurnn failure. Concrete columns bounding partial-height infills are particularly vulnerable to shear failure.8 · 1 8.2 - Non-participating infills B.2.1 Jn-plane isolation joints for non-participating infills To preclude the unintentional transfer of in-plane loads from the bounding frame to the non-participating infill, gaps are required between the top and sides of the masonry infill assembly. These gaps must be free of materials that could transfer loads between the infill and bounding frame and must be capable of accommodating frame displacements, including inelastic deformation during seismic events. B.2.2 Design of non-participating infills for out-of- plane loads Mechanical connection between the infill and bounding frame is required for out-of-plane support of the masonry. Masonry infill can be modeled as spanning vertically, horizontally, or both. Connectors are required only along the perimeter of the infill parallel to the direction ofthe design span.
- 208. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-195 CODE 8 .2.2.3 The connectors shall be designed to satiscy the requirements of ASCE 7. 8 .2.2.4 The connectors shall be spaced at a maximum of 4 ft (1.22 m) along the supported perimeter ofthe infill. 8.2.2.5 The infill shall be designed to resist out-of-plane bending between connectors in accordance with Section 3.2 for unreinforced infill or Section 3.3 for reinforced infill. 8 .3 - Participating infills Participating infills shall comply with the requirements ofSections B.3.1 through B.3.6. 8.3.1 General Infills with in-plane isolation joints not meeting the requirements of Section B.2.1 shall be considered as participating infills. For such infills the displacement shall be taken as the bounding frame displacement minus the specified width of the gap between the bounding column and infill. 8 .3.1.1 The maximum ratio of the nominal vertical dimension to nominal thickness of participating infills shall not exceed 30. 8 .3.1.2 Participating infills that are not constructed in contact with the bounding beam or slab adjacent to their upper edge shall be designed in accordance with Section B.3.1.2.1 or B.3.1.2.2. 8.3.1.2.1 Where the specified gap between the bounding beam or slab at the top ofthe infill is less than 3/8 in. (9.5 mm) or the gap is not sized to accommodate design displacements, the infill shall be designed in accordance with Sections B.3.4 and 8.3.5, except that the calculated stiffness and strength shall be multiplied by a factor of0.5. 8.3.1.2.2 lf the gap between the infill and the overlying bounding beam or slab is sized such that in- plane forces cannot be transferred between the bounding beam or slab and the infill, the infill shall be considered a partial infill and shall comply with Section B.1.5. 8.3.2 ln-plane connection requirements for participating infil/s Mechanical connections between the infill and the bounding frame shall be permitted provided that they do not transfer in-plane forces between the infill and the bounding frame. COMMENTARY 8.3 - Participating infills 8.3.1 General Flanagan and Bennett (1999a)8 2 tested an infilled frame with a 1.0-inch gap between the infill and column. Once the gap was closed, the specimen performed like an infilled frame with no gap. 8 .3.1.1 The maximum permitted ratio of height to thickness is based on practica! conditions for stability. 8.3.1.2.1 Dawe and Seah (1989a) 8 .3 noted a slight decrease in stiffness and strength when a bond breaker (a polyethylene sheet) was used at the top interface. Riddington (1984) 8 .4 showed an approximate 50% decrease in stiffuess but little reduction in peak load with a top gap that was 0.1% of the height of the infill. Dawe and Seah ( 1989a) 8 · 3 showed an approximate 50% reduction in stiffness and a 60% reduction in strength with a top gap that was 0.8% of the height of the infill. A top gap that is in compliance with Section 8.2.1.2 is generally Jess than 0.5% of the infill height. Thus, a 50% reduction in strength and stiffness seems appropriate. 8 .3.1.2.2 In cases where the gap at the top of the infill is sufficiently large so that forces cannot be transferred between the bounding frame or beam and the masonry infill, the infill is considered to be partial infill and not permitted to considered part of the lateral force- resisting system. 8.3.2 Jn-plane connection requirements for participating infil/s The modeling provisions of Appendix B for participating infills assume that in-plane Joads are resisted by the infill by a diagonal compression strut, which does not rely upon mechanical connectors to transfer in-plane load. While mechanical connections, including the use of
- 209. C-196 CODE B.3.3 Out-of-plane connection requirements for participating infills B.3.3.1 Participating infills shall be supported out-of-plane by connectors attached to the bounding frame. B.3.3.2 Connectors providing out-of-plane support shall be designed to satisfY the requirements of ASCE 7. B.3.3.3 Connectors providing out-of-plane support shall be spaced at a maximum of 4 ft (1.22 m) along the supported perimeter ofthe infill. B3 .4 Design ofparticipating infillsfor in-planeforces B.3.4.1 Unless the stiffness of the infill is obtained by a more comprehensive analysis, a participating infill shall be analyzed as an equivalent strut, capable of resisting compression only; whose width is calculated using Equation B-1; whose thickness is the specified thickness of the infill; and whose elastic modulus is the elastic modulus of the infill. 0.3 (Equation B-1) W;n¡ where (Equation B-2) B.3.4.2 Design forces in equivalent struts, as defined in Section 8.3.4.1, shall be determined from an elastic analysis of a braced frame including such equivalent struts. B.3.4.3 V,,;n¡shall be the smallest of(a), (b), and (e): (a) (6.0 in.)tnetinff'm (Equation B-3) (b) the calculated horizontal component of the force in the equivalent strut at a horizontal racking displacement of 1.0 in. (25 mm) (e) ~ 1.5 (Equation B-4) where Vn is the smallest nominal shear strength from Section 3.2.4, calculated along a bed j oint of the TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY reinforcement, are permitted, they must be detailed to preclude load transfer between the infill and bounding frame. This is because mechanical connectors between the infill and frame can cause premature damage along the boundaries of the infill under in-plane loading 8 .3. This damage actually reduces the out-of-plane capacity of the infill, as the ability of the infill to have arching action is reduced. B.3.3 Out-of-plane connection requirements for partícipating infills B.3.4.3 The capacity of the infill material is often referred to as comer crushing, although the failure may occur elsewhere as well. Flanagan and Bennett (1999a) 8 · 2 compared six methods for determining the strength of the infill material to experimental results ofstructural clay tile infills in steel frames. The method given in the Code is the simplest method, and also quite accurate, with a coefficient of variation of the ratio of the measured strength to the predicted strength of the infill of 24%. Flanagan and Bennett (2001) 8 5 examined the performance of this method for predicting the strength of 58 infill tests reported in the literature. Clay tile, clay brick, and concrete masonry infills in both steel and
- 210. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C·197 CODE equivalent frame. B.3.5 Design offrame elements with participating infillsfor in-plane loads B.3.5.1 Design each frame member not in contact with an infill for shear, moment, and axial force not less than the results from the equivalent strut frame analysis. B.3.5.2 Design each bounding column and beam or slab in contact with an infill for shear and moment equal to not less than 1.1 times the results from the equivalent strut frame analysis, and for axial force not less than the results from that analysis. In addition, augment the design shear at each end ofthe column by the horizontal component of the equivalent strut force acting on that end under design loads. B.3.5.3 Design each beam in contact with an infill for shear and moment equal to not less than 1.1 times the results from the equivalent strut frame analysis, and for an axial force not less than the results from that analysis. In addition, augment the design shear at each end ofthe beam by the vertical component of the equivalent strut force acting on that end under design loads. B.3.6 Design ofparticipating infillsfor out-ofplane forces The nominal out-of-plane flexura) capacity to resist out-of-plane forces of the infill per unit area shall be determined as: 1os( r' )o.1s 2 ( aarch Parch ) q, ¡nr = Jm l;nr ~+~ mr mf (Equation B-5) where: COMMENTARY concrete bounding frames were examined. For the 58 tests considered, the coefficient of variation of the ratio of measured to predicted strength ofthe infill was 21%. Flanagan and Bennett ( 1999a) 8 2 determined that in- plane displacement is a better indicator of infill performance than in-plane drift (displacement divided by height). This was based on comparing the results of approximately 8-ft high (2.4 m) infill tests to 24-ft (7.3 m) high infill tests on similar material. Thus, a displacement limit rather than a drift limit is given in the Code. As a general rule, the strength ofthe infill is reached at smaller displacements for stiffer columns. For more flexible columns, the strength of the infill is controlled by the displacement limit of 1.0 inch (25 mm). Equation B-4 is intended to address shear failure along a bed joint. The use of a formula from Section 3.2 is not intended to imply that infills are necessarily unreinforced. Shear resistance along a bed joint is similar for the equations of Section 3.2 and Section 3.3, and the former are more clearly related to failure along a bed joint. B.3.6 Design ofparticipating infills for out-ofplane forces lt is not appropriate to calculate the out-of-plane flexura) capacity of unreinforced masonry infills using values for flexura) tensile capacity. The predominant out- of-plane resisting mechanism for masonry infills is arching. Even infills with dry-stacked block have been shown to have significant out-of-plane strength (Dawe and Seah, 1989b)8 7 • The out-of-plane resistance of masonry infill as calculated by Equation B-5 is based upon an arching
- 211. C-198 CODE (Equation B-6) f3arch = - 1 - (Ebb fbb l¡~f ) 025 < 35 /inf (Equation B-7) In Equation B-5, f;n¡ shall not be taken greater than 118 hn¡ . When colurnns of different cross-sectional properties are used on either side of the infill, average properties shall be used to calculate this capacity. When beams of different cross-sectional properties are used above and below the infill, average properties shall be used to calculate this capacity. In the case of a single story frame, the cross-sectional properties ofthe bounding beam above the infill shall be used to calculate this capacity. When a side gap is present, a.arch shall be taken as zero. When a top gap is present, f3arch shall be taken as zero. TMS 402-11/ACI 530-11/ASCE 5-11 COMMENTARY model of the infill in the bounding frame and therefore neglects the contribution ofany reinforcement that may be present in the infill in determining the out-of-plane flexura! strength ofparticipating infill. Masonry infill may require reinforcement, however, to resist out-of-plane flexure between points of connection with the bounding frame, or to meet the prescriptive seismic detailing requirements of Section 1.17. The thickness used in computations of out-of-plane flexura! resistance is limited because infills with low height-to-thickness ratios are less influenced by membrane compression and more influenced by plate bending. The out-of-plane flexura! capacity of the masonry infill is determined based on the work of Dawe and Seah s.7 • They first developed a computer program based on a modified yield line analysis that included the flexibility of the bounding frame. The program coincided quite well with their experimental results, with an average ratio of observed to predicted capacity of 0.98 and a coefficient of variation of6%. Dawe and Seah then used the program for an extensive parametric study that resulted in the empírica) equation given here. Two other equations are available. The first, proposed by Abrams et al. (1993) s.6 , is used in ASCE 416 · 10 • The second was proposed by Klingner et al. (1997) 6 · 9 . In Flanagan and Bennell (1999b) 68 , ea<.:h of these three proposed equations is checked against the results of 31 experimental tests from seven different test programs including clay brick infills in concrete frames, clay tite infills in steel frames, clay brick infills in steel frames, and concrete masonry infills in steel frames. Flanagan and Bennett (1999b) s.s determined that Dawe and Seah's equation is the best predictor of out-of-plane strength, with an average ratio of observed to predicted strength of 0.92, and a coefficient of variation of 0.28. The coefficient of variation of observed to predicted capacity was 28%. Results are summarized in Figure CC-BJ-1. The experimental tests involved infills with height-to-thickness ratios ranging from 6.8 to 35.3. Sorne infills had joint reinforcement, but this did not affect the results. Two ofthe specimens had a top gap. Arching still occurred, but was one-way arching. The code equation is thus quite robust.
- 212. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY 2 1.8 1.6 a; ti 1.4 ~ 1.2 o.. ....... 1 4> 0.8 ~ o 0.6 0.4 0.2 o 3 5 7 9 COMMENTARY 11 13 15 17 19 21 23 25 27 29 31 Test Number Figure CC-B. J-1: Ratios ofobserved to predictedstrengths[fY infills loaded out-ofplane (Flanagan and Bennett 1999b) .a C-199
- 213. C-200 TMS 402-11/ACI 530-11/ASCE 5-11 This page is intentionally left blank.
- 214. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY Code Equation No. or Section No. 1.8.2.2.1 1.8.2.3.1 1.8.2.4 (1-1) (l-2a) (l-2b) (l-3a) (1-3b) (1-4) (1-5) (2-1) (2-2) (2-3) (2-4) (2-5) CONVERSION OF INCH-POUND UNITS TO SI UNITS The equations in this Code are for use with the specified inch-pound units only. The equivalent units for use with SI units follow. SI Unit Units Equivalent Equation E., =700f'., for clay masonry f'., in MPa E., =900 f'm for concrete maSOf!l)' EAAC=887.8 lf'AAC ) 06 f'AAc in MPa 5 00 !~ /'gin MPa 1.17 = ~ .( : : r+ /"H ::)}~. I.ffin mm4 111 in mm4 lcr in mm 4 Me, in N-mm M0 in N-mm '·lf Z =0.2(lejf + 2dV) leffin mm (l ) When 1~- < 2 d,, inmm d. z in mm ' '·lf leffin mm (2) When - < 1 z = 0.6/eff d. in mm d. ' z inmm '·lf Z =0.2{¡eff + 1.5d v) leffin mm (1) When 1 ~-<3 d. in mm d. ' zinmm t.IJ l,ffin mm (2) When - < 1 Z =0.5/eff d,, inmm dv ' zinmm AP, =.,.t; Ap 1 in mm• lbin mm A = 1r ti. A . 2 pv mmm pv 2 !be in mm Ap1 in mm2 Bab =0.11AP,g B06 in Newtons ..J1: in MPa A6 in mm2 B., =0.6A6 f y Bas in Newtons /y in MPa Ap1 in mm2 Bab = 0.11AP, g Bahin Newtons fJ:: inMPa f'., inMPa Bap =0.6/'m e6 d6 + 0.83tr(/6 + e6 + d6 )d6 e6 in mm d6 in mm h in mm Bap in Newtons A6 in mm2 B0 , =0.6 Ab/y Bas in Newtons J;, inMPa C-201
- 215. C-202 TMS 402-11/ACI 530-11/ASCE 5-11 Code Equation No. SI Unit Units or Section No. Equivalent Equation Apv in mml (2-6) Bab = 0.1 1AP,,.¡;: Bab in Newtons Rz in MPa Bab = 1072VJ~ ,Ab Bah in Newtons (2-7) ~ f~A b in Newtons Bvpry = 2.0Bab = 2.5Apl.¡;: Ap1in mml (2-8) Babin Newtons Bvpry in Newtons Rz in MPa Ahin mm¿ (2-9) B,s = 0.36Abfy Bas in Newtons fv inMPa ba in Newtons (2-10) .!!_g_+ .!2..~ 1 b"in Newtons Ba Bv Ba in Newtons Bv in Newtons 2.1.5.2.2(e) 0.108 ~ spec i fie d unit compressive strength of header in MPa db in mm (2-11) Id =0.22ddFs Fs in MPa Id in mm Av~ 0.4{~: J Av in mm2 b.., inmm s in mm 2.1.7.4.1.5(b) /y inMPa s~(~J dinmm 8/}b ~ b is dimensionless dbin mm 2 Rz inMPa Id= I.Sdb /yY (2-12) Kg /y in MPa Kin mm Id in mm I l.59A,c 11.59A Asein mm2 (2-13) ~ = 1.0- where d 2S se ~ 1.0 d2.5 dbin mm b b Fa in MPa (2-14) fa + fb~ 1 Fbin MPa Fa Fb la in MPa Ji, in MPa (2-15) P ~ (X)P, P in Newtons P, in Newtons Fo·(Y.lr+-c.:J] Fa inMPa (2-16) f'm in MPa h in mm rinmm ( J Fa in MPa _ 1 , 70r f'm in MPa (2-17) Fa-(X)J m h hin mm r inmm (2-1 8) Fb =(X)¡,;, F bin MPa f'm in MPa
- 216. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-203 Code Equation No. SI Unit Units or Section No. Equivalent Equation E, in MPa e in mm (2-19) P. r/E,,l, ( 1- 0.577::_r hin mm h2 r / in mm4 Pe in Newtons r inmm binmm VQ fv in MPa (2-20) /., =-¡¡; 1, in mm4 " Q in mm3 V in Newtons 2.2.5.2(a) 0. 125¡¡;; R, inMPa Answer in MPa A, in mm2 2.2.5.2(c) 255 + 0.45 N.,!A, Nv in Newtons Answer in k.Pa A, in mm2 2.2.5.2(d) 255 + 0.45 Nv!A, Nv in Newtons Answer in k.Pa A, in mm' 2.2.5.2(e) 414 + 0.45 N.,!A, Nv in Newtons Answer in k.Pa A, in mm2 A51 in mm2 Pa = (0.25/~A, + 0.65A s ,F s { l -c:~r r] Fs in MPa (2-21) f', in MPa hin mm Pa in Newtons rinmm A, in mm' As1 in mm2 Pa=(0.25 ü, . An + 0.65 Ast F s) C~r r Fs in MPa (2-22) f', in MPa hin mm Pain Newtons r inmm nf,;, ¡;, in MPa Pmax = 2/y(n+f~) f', inMPa (2-23) !,, V b, in mm (2-24) f.,=- d., in mm A,., fv in MPa V in Newtons Fv in MPa (2-25) Fv =F.,,+ F.,, F,., in MPa F,,5 inMPa
- 217. C-204 TMS 402-11/ACI 530-11/ASCE 5-11 Code Equation No. SI Unit Units or Section No. Equivalent Equation d inmm F,,in MPa (2-26) Fv ~ 0.25.¡¡:: For MI(Vd) :S 0.25 M in Newton-mm V in Newtons .¡¡::: in MPa dinmm FvinMPa (2-27) Fv = 0.18.¡¡:: For MI(Vd) ?. 1.0 M in Newton-mm V in Newtons .¡¡::: in MPa An in mm 2 d inmm Fvm =0.042[(4.0- 1. 75(~))~]+0.25 ~ F,., in MPa (2-28) M in Newton-mm P in Newtons V in Newtons .¡¡::: inMPa An in mm 2 d inmm F., = 0.02{(4.0-1.75(~))~]+0.25 ~ F,., in MPa (2-29) M in Newton-mm P in Newtons V in Newtons .¡¡::: inMPa Anin mm2 Avin mm 2 (2-30) ( AvFsd) dinmm Fvs= 0.5 - - F, in MPa A11 s Fvs in MPa s mmm A . ::< p1 mmm (3-1) Banb = 0.33Aptg .¡¡::: inMPa Banb in Newtons (3-2) Bans =Ab/y Abin mm2 /y in MPa Ban.• in Newtons A . ~ z p1 mmm (3-3) Banb =0.33Aptg .¡¡::: inMPa Banb in Newtons f'., in MPa Banp =1.5/', e6d6 +2.071f(16 +e6 +d6 )d6 eb in mm (3-4) dbin mm hin mm B01,nin Newtons Abin mm 2 (3-5) Bans =Abfy /y in MPa Ba"' in Newtons Apvin mm 2 (3-6) Banb =0.33Apvg .¡¡::: inMPa Banb in Newtons
- 218. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-205 Code Equation No. SI Unit Units or Section No. Equivalent Equation Abin mm 2 (3-7) Bvnc =3216 Vf'm Ab Bl'llc in Newtons f'm in MPa ~ ¡,;,Ab in Newtons Ap1 in mm" (3-8) Bvnpry =2.0Banb =0.67Aptg .¡¡:: in MPa Banb in Newtons Bvn>rv in Newtons Ab in mm 2 (3-9) Bvns =0.6Ab/y ¡;, in MPa Bvn.r in Newtons boj bv¡ ba¡in Newtons (3- 10) bv¡in Newtons - - + - -5 1 (J Ban (J BV/1 8011 in Newtons 8 ,11 in Newtons Pnin Newtons P. o 0.80{0.80A. J~ [1-c:oJ]) h An in mm2 (3-11) For - 599 f'm in MPa r hin mm rmmm Pnin Newtons P. o oso(080A.J~C~' n h An in mm 2 (3-12) For ->99 f'm in MPa r hin mm rmmm (3-13) M e= 8M, Me in N-mm M, in N-mm Ó= 1 A11 in mm2 P, f'm in MPa (3-14) 1- A/' COrr P, in Newtons hin mm n m h rinmm 3.2.4(a) 0.33A11 .¡¡:: in N An in mm 2 f'm in MPa 3.2.4(b) 0.83A11 in N Anin mm 2 3.2.4(c) 0.26A11 +0.45N, in N Anin mm 2 N, in Newtons 3.2.4(d) 0.26A11 + 0.45N, in N A11 in mm2 N, in Newtons 3.2.4(e) 0.414A11 +0.45N, in N A11 in mm2 N,, in Newtons 3.2.4(f) O. l03A11 inN An in mm• (3-15) '· =13db l. in mm dbin mm dbin mm 2 .¡¡:: in MPa Id = l.5db / yY (3-16) K.¡¡: ¡;, in MPa K in mm ld in mm e;= 1.0- 11 .59Asc where l l.59Asc O Ase in mm 2 (3-17) dl.5 dl·5 :$ l. dbin mm
- 219. C-206 TMS 402-11/ACI530-11/ASCE 5-1 1 Code Equation No. SI Unit Units or Section No. Equivalent Equation A, in mm2 Ast in mm2 P . ~ 0.80 [0.80/~ (A. -A., )+f ,A.,l[1- e.:,n f', in MPa (3-18) /y in MPa P, in Newtons hin mm rin mm A, in mm2 As1 in mm2 p/1 = 0.80 [o.8o¡,;,(A,- AS/)+ !y As/1 (?~r r f', in MPa (3-19) /y in MPa P, in Newtons hin mm rmmm V,., in Newtons (3-20) V,= v,m +V/IS V,5 in Newtons V,, in Newtons Anv in mm M,, in N-mm V,, in Newtons (3-21) Vn ~ 0 . 5A ,. g For Mu O d. in mm -- ~ .25. Vudv V, in Newtons ..JY:: inMPa A,. in mm M,, in N-mm V11 ~ 0.33A,• .¡¡;: M u ~ LOO . V" in Newtons (3-22) For d. in mm Vudv V, in Newtons ..JY:: inMPa A,. in mm M11 inN-mm V,, in Newtons (3-23) v,m =0.083[4.0- 1.7{ MI/ )]AII.g,+0.25?,, d. in mm V/IdV P, in Newtons V,, in Newtons ..JY:: inMPa A. in mm' v"s = o.5( ~· )1y d. /y inMPa (3-24) d. in mm s in mm Vn.• in Newtons [ ;; )~ 0.20/ ~ P11 in Newtons (3-25) Agin mm2 f'm in MPa hin mm w, in N/mm w,h 2 p e, p 0 P,1 in Newtons (3-26) M" e, in mm =-8 - + •if2+ . 11 11 P, in Newtons ó,, in mm M11 in N-mm P11 in Newtons (3-27) P,, = puw +pu f P,1 in Newtons P,"' in Newtons
- 220. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES (TMS 402/ACI 530/ASCE 5) C-207 Code Equation No. SIUnit Units or SectionNo. EquivalentEquation (3-28) tSS ~ 0.007 h Ós in mm hin mm t5, in mm hin mm 2 (3-29) t5 = 5M5crh For M scr~ M cr Emin MPa 5 48Emfg fg in mm4 M.e, in N-mm Mc, in N-mm t5, in mm t5 5Mcrh2 5(Mser-Mcr)b2 h in mm S= + ~n i nMPa (3-30) 48Emfg 48Emfcr 1 8 in mm4 Mser in N-mm For Mcr <Mser <Mil Mc, inN-mm Mn in N-mm le, in mm4 le, in mm 4 A , in mm2 J ={ r!,+ ¡; 1 'P }d-c)2 +be' Puin Newtons (3-31) fsp in mm cr f 2d 3 t; in MPa y d inmm e in mm b in mm e in mm A,. f y + pu A , in mm2 (3-32) e= t; in MPa 0.64 f'mb Puin Newtons Fmin MPa b in mm Pu ~ 0. 10 A 8 f ~ Puin Newtons 3.3.6.5.1 A 8 in mm2 Pu ~ 0.05 A 8 f~n f;u in MPa M . ~ 1.0 Muin N-mm 3.3.6.5.1 Vuin Newtons V.d, lwin mm A n in mm 2 ~ ~ 0 .25~ .rz: and M. ~ 3.0 f'm in MPa 3.3.6.5.1 ~.d , lwin mm Muin N-mm v;,in Newtons e inmm 3.3.6.5.3 (a) e~ Jw hwin mm 600 (Cdt5nef h.v} lw in mm Óne in mm ain mm f,, in MPa A . 2 f psAps + J_;,A,. +P¡J ps lnmm (4-1) a t; in MPa 0.8 f ;J b A 5 in mm2 Puin Newtons f~ 1 in MPa bin mm
- 221. C-208 BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES (TMS 402/ACI 530/ASCE 5) Code Equation No. SIUnit Units or Section No. EquivalentEquation Mn in N-mm f,, in MPa A . 2 Mn = (rpsAps + fyAs + Pu{ d ~) ps mmm (4-2) fy in MPa A , in mm2 Pu in Newtons dinmm a mmm ¡;,, in MPa f.e in MPa dinmm (4-3) F ~ F +{6,900{~ lt'f "" ~"' l IPin mm ps se 1 bdf J;,u in MPa p m A . 2 ps mmm b inmm f ~, inMP a f, =0.2 ~ /AAC /¡'inMPa (8-1) ~ IAAc in MPa (8-2) f v =0.15 f~A C f., in MPa f ÁAcin MPa hin mm P,, ~ oso{oss~ , r.,cH ,~ J]) rinmm (8-3) An inmm 2 FAAcinMPa Pn in Newtons hin mm P. ~ oso[o•,..., ,AA~ 7 ~')'] rinmm (8-4) An in mm2 fÁAcin MPa Pn in Newtons (8-5) le= 13db l. in mm dbin mm Id, in mm 1.5d/ fyy dbinmm Id= KAAc inmm (8-6) K AAcR fy in MPa ~ 1g in MPa hin mm rinmm P. = o .so[o.ss1._.,(A, - A,)+ fA,[1-c~J l A n in mm 2 (8-7) A ,1 in mm2 fy in MPa fÁAc in MPa Pn in Newtons hin mm rinmm Anin mm2 (8-8) ~ . {70rr Ast in mm 2 Pn = 0.80 0.85 fAA c(An- A51 ) + fy A51 h fy in MPa fÁAcin MPa Pn in Newtons Vn in Newtons (8-9) ~ = ~1AA C + ~ s vnAAc in Newtons Vns in Newtons
- 222. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES (TMS 402/ACI 530/ASCE 5) C-209 Code EquationNo. SIUnit Units or Section No. Equivalent Equation (8-1O) ~ =f.lAACpu Vnin Newtons P,, in Newtons ~ i n Newtons (8-1 1) ~~ $ 0.5An ~ f'.vtc ~ /AAC in MPa Anin mm2 Vnin Newtons (8-12) ~ $ 0 . 33A 11 ~ f~AC ~ !AAC in MPa A, in mm2 VnAAc in Newtons ¡-¡;:::: pu Puin Newtons (8-13a) VnAAc= 0.08 /IV t 1+ ¡-¡;:::: ~ /AAC in MPa V 0.2 [AAC /IV t fwin mm t inmm ~AA C in Newtons V¡"L4AC= 0.055/IV ~ ~ ~A C ' p Puin Newtons (8-13b) 1+ /1 ~ .{,¡AC in MPa 0.2 ~ fAAC Jw t lwin mm t in mm ~AA c in Newtons VnAAC=0.075 ~ i::Uc An +0.05Pu Puin Newtons (8-13c) ~ .{,¡AC in MPa Anin mm2 VnAAcin Newtons 1 [ h(l,.)' f'.4Ac in MPa (8-14) tin m in m ~ A AC= 170000 AACt 2 hin mm ,i +e~v) lwin mm Vns in Newtons ~ s = O.s(A; )f ydv t; in MPa (8-15) s in mm dvin mm A vin mm2 VnAACin Newtons (8-16) VnAAC= 0,066 ~ ~A c bd ~ fAAC in MPa binmm dinmm P,, P,, in Newtons (8-17) ~0 . 2f~ c f'.4Ac inMPa Ag A01 in mm2 Puin Newtons Pufin Newtons wuh2 eu t5 h in mm (8-18) euin mm M" = - 8-+~,f 2 +~, " buin mm W uin N/mm Muin N-mm Puin Newtons (8-19) ~ / =~/I V+ P,¡{ Puw in Newtons P,1rin Newtons
- 223. C-210 BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES (TMS 402/ACI 530/ASCE 5) Code Equation No. SIUnit Units or SectionNo. Equivalent Equation (8-20) Mu :5;if> Mn Muin N-mm M11 in N-mm Puin Newtons ainmm (8-2 1) M n = (AJy + P,,{d -f) dinmm Asin mm2 t; in MPa M,, in N-mm a in mm (As fy+ Pu) Pu in Newtons (8-22) a= binmm 0.85 IAAc b As in mm2 fA.4c inMPa f. in MPa (8-23) os :5; 0.0007h O s in mm hin mm O s in mm O = 5Mcrh2 fg in mm4 (8-24) hin mm S 48EAAC¡g EAAc in MPa Me, in N-mm O s in mm 1 8 in mm4 O = 5Mcr/¡2 5(Mser- Mcr) h 2 fe, in mm4 (8-25) + hin mm S 48EAAC¡g 48EAAC/ cr EAAc in MPa Mcr in N-mm M.., in N-mm S 11 in mmJ M cr =S"(J;.AAC+ ~) A11 in mm2 (8-26) f;.AAc in MPa Pin Newtons Mcr in N-mm. Sn in mm3 An in mm2 (8-27) S" ( f P) hin mm ~ r =- rAAc+ - I;AAc in MPa h A11 Pin Newtons Ver in Newtons c inmm 8.3.6.6.2 (a) e ;?: 1.., hwin mm 600 (edone1!Jw) lwin mm 0," in mm 0.3 W,:nrin. mm (B-1) H'inf = Bsrror in degrees Asuur COS BSlrut Asrrur =mm·! Asrrur = mm"1 Ebe in MPa Em tnerinr sin28smll EminMPa (8-2) Astro/ = 4 h,:nrin mm 4 Ebe 1be h.nr /be in mm4 lnerinf in mm eslrol in degrees (8-3) (l50mm) fnetinf (n rm in MPa lnetinf in mm
- 224. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES (TMS 402/ACI 530/ASCE 5) C-211 Code Equation No. SIUnit Units or Section No. EquivalentEquation (B-4) ~ V,, in N - 1.5 % inrin Pa t'm in MPa 729100 ( r )0.75 2 ( a.m:h jJarch ) h¡,rin mm (B-5) qninf = m f¡nf ~ +- -2.-5 1¡-,,inmm /inf hinf l¡nr in mm Ctarch in N°. 25 /3. · No25 arch In · 1 ( 1 12 ) 0.25 o Ctarch in ~.25 (B-6) aarch =- - E be be 1¡nr < 5 Ebc in MPa h¡nf h,,in mm !be in mm 4 fJ 1 p 0.25 o f3arch in N° 25 (B-7) arch =-(Ebb/bb inf ) <5 Ebb in MPa l¡nf /,-,, in mm I hb in mm 4
- 225. C-212 BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES (TMS 402/ACI 530/ASCE 5) This page is intentionally left blank.
- 226. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-213 REFERENCES FOR THE CODE COMMENTARY References, Chapter 1 1.1. "Giossary of Terms Relating to Brick Masonry," Technical Notes on Brick Construction, No. 2 (Revised), Brick lndustry Association, Reston, VA, 1999, 4 pp. 1.2. "Giossary of Concrete Masonry Terms," NCMA TEK Bulletin No. 145, National Concrete Masonry Association, Herndon, VA, 1985, 4 pp. 1.3. "The Masonry Glossary," International Masonry Institute, Washington, DC, 1981, 144 pp. 1.4. Structural Design ofTal! Concrete and Masonry Buildings, Monograph on Planning and Design of Tall Buildings, V. CB, Council on Tall Buildings and Urban Habitat!American Society ofCivil Engineers, New York, NY, 1978, 960 pp. 1.5. Wolde-Tinsae, A.M., Atkinson, R.H. and Hamid, A.A., "State-of-the-Art: Modulus of Elasticity," 6th North American Masonry Conference. Philadelphia, PA, June 1993, pp. 1209-1220, The Masonry Society, Boulder, CO. 1.6. Colville, J., Miltenberger, M.A., and Wolde- Tinsae (Amde), A.M. "Hollow Concrete Masonry Modulus of Elasticity," 6th North American Masonry Conference, Philadelphia, PA, June 1993, pp. 1195- 1208, The Masonry Society, Boulder, CO. 1.7. Copeland, R.E., "Shrinkage and Temperature Stresses in Masonry," ACI Journal, Proceedings V. 53, No. 8, American Concrete Institute, Detroit MI, Feb. 1957, pp. 769-780. 1.8. Plummer, H.C., Brick and Tile Engineering, Brick fnstitute of America (now Brick Industry Association), Reston, VA, 1962, 736 pp. 1.9. Grimm, C.T., "Probabilistic Design ofExpansion Joints in Brick Cladding," Proceedings, V. 1, 4th Canadian Masonry Symposium, University of Fredericton, 1986, pp. 553-568. 1.10. Kalouseb, L., "Relation of Shrinkage to Moisture Content in Concrete Masonry Units," Paper No. 25, Housing and Home Finance Agency, Washington, DC, 1954. 1.11. "Autoclaved Aerated Concrete Properties, Testing and Design, " RJLEM Recommended Practice, RILEM Technical Committees 78-MCA and 51-ALC. Edited by: S. Aroni, G.J. de Grood, M.F. Robinson, G. Svanholm and F.H. Wittman, E & FN SPON, London, 1993. 1.12. Smith, R.G., "Moisture Expansion of Structural Ceramics - Long Term Unrestrained Expansion of Test Bricks," Journal of the British Ceramic Society, Stoke- on-Trent, England, Jan. 1973, pp. 1-5. 1.13. "Crack Control in Concrete Masonry Walls," NCMA TEK 10-1 A, National Concrete Masonry Association, Herndon, VA, 200 1, 4 pp. 1.14. "Control Joints for Concrete Masonry Walls," NCMA TEK 10-2A, National Concrete Masonry Association, Herndon, VA, 1998, 6 pp. 1.15. "AII Weather Concrete Masonry Construction," NCMA TEK 3-1C, Nationa1 Concrete Masonry Association, Herndon, VA, 2002, 4 pp. 1.16. Lenczner, D., and Salahuddin, J., "Creep and Moisture Movements in Masonry Piers and Walls," Proceedings, 1st Canadian Masonry Symposium, University ofCalgary, June 1976, pp. 72-86. 1.17. Post-Tensioning Institute. "Chapter 2-Post- Tensioning Systems," Post-Tensioning Manual, 5th Edition, Phoenix, AZ, 1990, pp. 51-206. 1.18. "Section Properties for Concrete NCMA-TEK 14-1, National Concrete Association, Herndon, VA, 1990. Masonry," Masonry 1.19. He, L., and Priestley, M.J.N., Seismic Behavior of Flanged Masonry Shear Walls -Final Report, TCCMAR Report No. 4.1-2, November 1992, 279 pp. 1.20. Dickey, W. and Maclntosh, A., "Results of Variation of b' or Effective Width in Flexure in Concrete Block Panels," Masonry Institute of America, Los Angeles, CA, 1971. 1.21. Arora, S.K. ( 1988). "Performance of masonry walls under concentrated load." Proceedings of the British Masonry Society, (2), 50-55. 1.22. Page, A.W., and Shrive, N.G., "Concentrated loads on hollow masonry - load dispersion through bond beams," TMS Journal, V. 6, No. 2, T45-T51 pp, The Masonry Society, Boulder, CO, 1987. 1.23. Hansell, W. and Winter, G. (1959). "Lateral Stability of Reinforced Concrete Beams." ACI Journal, Proceedings V. 56, No. 5, pp. 193-214. 1.24. Revanthi, P. and Menon, D. (2006). "Estimation of Critica( Buckling Moments in Slender Reinforced Concrete Beams." ACIStructural Journal, V. 103, No. 2, pp. 296-303. 1.25. Galambos, T.V., and Ellingwood, B. (1986). "Serviceability limit states: deflection." Journal of Structural Engineering, ASCE, 112(1), 67-84. 1.26. Design of Masonry Structures, CSA S304.1-04, Canadian Standards Association, 2004.
- 227. C-214 1.27. Branson, D.E., "Instantaneous and Time- Dependent Detlections on Simple and Continuous Reinforced Concrete Beams." HPR Report No. 7, Part 1, Alabama Highway Department, Bureau of Public Roads, August, 1965, pp. 1-78. 1.28. Horton, R.T., and Tadros, M.K. (1990). " Deflection of reinforced masonry members." ACI Structural Journal, 87(4), 453-463. 1.29. Lee, R., Longworth, J., Warwaruk, J. (1983). "Behavior of restrained masonry beams." 3rd Canadian Masonry Symposium, Edmonton, Alberta, 3711-16. 1.30. Bennett, R.M., McGinley, W.M., and Bryja, J. (2007). "Detlection Criteria for Masonry Beams." Journal of ASTM International, 4 (1), Paper ID: JAI100442. 1.31. Park , Robert and Paulay, Thomas. Reinforced Concrete Structures, John Wiley & Sons, 1975. 1.32. ACI Committee 318, Building Code Requirementsfor Structural Concrete (ACI 318-08) and Commentary (ACI 318R-08), American Concrete lnstitute, Farrnington Hills, MI, 2008. 1.33. CEB-FIP Model Code 1990: Design Code. Comité Euro-lnternational du Béton (Euro-International Committee for Concrete, CEB) and the Fédération International de la Précontrainte (International Federation tor Prestressing, FIP), Thomas Telford Ltd, 1993. 1.34. Mínimum Design Loads for Building and Other Structures, ASCE Standard ASCE/SEI 7-05, American Society ofCivil Engineers, Reston, VA, 2005. 1.35. Roark, Raymond J. and Young, Warren C.. Formulas for Stress and Strain, 5th ed. McGraw- Hill Companies, 1985. 1.36. Drysdale, Robert G. and Hamid, Ahmad A., Masonry Structures: Behavior and Design, Third Edition, Boulder, CO: The Masonry Society, 2008. 1.37. Code of practice for the use of masonry. Structural use of reinforced and prestressed masonry. BS 5628-2:2005, British Standards Institution, 2005. 1.38. Pfister, J.F., "lntluence of Ties on the Behavior of Reinforced Concrete Columns," ACI Journal, Proceedings V. 61, No. 5, American Concrete lnstitute, Detroit, MI, May 1964, pp. 521-537. 1.39. ACI Committee 318, "Building Code Requirements for Reinforced Concrete (ACI 318-83)," American Concrete lnstitute, Detroit, MI 1983, 111 pp. TMS 402-11/ACI530-11/ASCE 5-11 1.40. Priestley, M.J.N., and Bridgeman, D.O., "Seismic Resistance of Brick Masonry Walls," Bulletin, New Zealand National Society for Earthquake Engineering (Wellington), V. 7, No. 4, Dec. 1974, pp. 167-187. 1.41. Dickey, W.L., "Joint Reinforcement and Masonry," Proceedings, 2nd North American Masonry Conference, College Park, MD, Aug. 1982, The Masonry Society, Boulder, CO. 1.42. Rad, F. N, Winnen, J., M., and Mueller, W. H., "An Experimental Study on the Strength of Grouted Anchors in Masonry Walls," Report submitted to the Masonry & Ceramic Tite Institute ofOregon, Portland State University, Portland, OR, 1998. 1.43. Tubbs, J. B., Pollock, D. G. and McLean, D. l., "Testing of Anchor Bolts in Concrete Block Masonry," TMS Journal, V. 18, No. 2, pp. 75-88, The Masonry Society, Boulder, CO, 2000. 1.44. Brown, R.H. and Whitlock, A.R., "Strength of Anchor Bolts in Concrete Masonry," Journal of the Structural Division, V. 109, No. 6, pp. 1362-1374, American Society of Civil Engineers, New York, NY, 1983. 1.45. Allen, R., Borchelt, J. G., Klingner, R. E. and Zobel, R., "Proposed Provisions for Design of Anchorage to Masonry," TMS Journal, V. 18, No. 2, pp. 35-59, The Masonry Society, Boulder, CO, 2000. 1.46. Gulkan, P., Mayes, R.L., and Clough, R.W., "Shaking Table Study of Single-Story Masonry Houses Volumes 1 and 2," Report No. UCB/EERC-79/23 and 24, Earthquake Engineering Research Center, University ofCalifornia, Berkeley, CA, Sept. 1979. 1.47. Chrysler, J., "Reinforced Concrete Masonry Construction Inspector's Handbook", ih Edition, Masonry Institute of America and International Code Council, Torrance, CA, 201 O. 1.48. "Inspection and Testing of Concrete Masonry Construction", National Concrete Masonry Association and International Code Council, Herndon, VA, 2008. 1.49. "Technical Notes 39, "Testing for Engineered Brick Masonry-Brick and Mortar'', Brick lndustry Association, Reston, VA, Nov. 200 l. 1.50. "Technical Notes 39B, "Testing for Engineered Brick Masonry-Quality Controf', Brick lndustry Association, Reston, VA, Mar. 1988. 1.51. ASTM Cl093-95 (reapproved 2001), "Standard Practice for Accreditation of Testing Agencies for Unit Masonry," ASTM, West Conshohocken, Pennsylvania.
- 228. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-215 References, Chapter 2 2.1. Ellifrit, D.S., "The Mysterious 1 / 3 Stress Increase," EngineeringJouma/, ASIC, 4th Quarter, 1977. 2.2. Minimum Design Loads for Buildings and Other Structures, ASCE Standard ASCE/SEI 7-10, American Society ofCivil Engineers, Reston, VA. 2.3. International Building Code 2012, International Code Council, Washington, OC. 2.4. McCarthy, J.A., Brown, R.H., and Cousins, T.E., "An Experimental Study of the Shear Strength of Collar Joints in Grouted and Slushed Composite Masonry Walls," Proceedings, 3rd North American Masonry Conference, Arlington, TX, June 1985, pp. 39-1 through 39-1 6, The Masonry Society, Boulder, CO. 2.5. Williams, R. and Geschwinder, L., "Shear Stress Across Collar Joints in Composite Masonry," presented at Proceedings, 2nd North American Masonry Conference, College Park, MD, 1982, Paper No. 8, The Masonry Society, Boulder, CO. 2.6. Colville, J., Matty, S.A., and Wolde-Tinsae, A.M., "Shear Capacity of Mortared Collar Joints," Proceedings, 4th North American Masonry Conference, Los Angeles, CA, Aug. 1987, V. 2 pp. 60-1 through 60-15, The Masonry Society, Boulder, CO. 2.7. Porter, M.L., Wolde-Tinsae, A.M., and Ahmed, M.H., "Strength Analysis of Composite Walls," Advances in Ana/ysis ofStructural Masonry, Proceedings of Structures Congress '86, American Society of Civil Engineers, New York, NY, 1986. 2.8. Porter, M.L., Wolde-Tinsae, A.M., and Ahmed, M.H., "Strength Design Method for Brick Composite Walls," Proceedings, 4th International Masonry Conference, London, Aug. 1987. 2.9. Wolde-Tinsae, A.M., Porter, M.L., and Ahmed, M.H., "Shear Strength of Composite Brick-to-Brick Panels," Proceedings, 3rd North American Masonry Conference, Arlington, TX, June 1985, pp. 40-1 through 40-13, The Masonry Society, Boulder, CO. 2.10. Wolde-Tinsae, A.M., Porter, M.L., and Ahmed, M.H., "Behavior of Composite Brick Walls," Proceedings, 7th International Brick Masonry Conference, Melbourne, New South Wales, Feb. 1985, V. 2, pp. 877-888. 2.11. Ahmed, M.H., Porter, M.L., and Wolde-Tinsae, A.M., "Behavior of Reinforced Brick-to-Biock Walls," Ph.D. dissertation, M. H. Ahmed, lowa State University, Ames, lA, 1983, Part 2A. 2.12. Ahmed, M.H., Porter, M.L., and Wolde-Tinsae, A.M., "Behavior of Reinforced Brick-to-Biock Walls," Ph.D. dissertation, M. H. Ahmed, lowa State University, Ames, lA, 1983, Part 2B. 2.13. Anand, S.C. and Young, D.T., "A Finite Element Model for Composite Masonry," Proceedings, American Society of Civil Engineers, V. 108, ST12, New York, NY, Dec. 1982, pp. 2637-2651. 2.14. Anand, S.C., "Shear Stresses in Composite Masonry Walls," New Analysis Techniquesfor Structural Masonry, American Society of Civil Engineers, New York, NY, Sept. 1985, pp. 106-127. 2.15. Stevens, O.J. and Anand, S.C., "Shear Stresses in Composite Masonry Walls Using a 2-0 Modes," Proceedings, 3rd North American Masonry Conference, Arlington, TX, June 1985, p. 41 -1 through 40-1 5, The Masonry Society, Boulder, CO. 2.16. Anand, S.C. and Rahman, M.A., "Temperature and Creep Stresses in Composite Masonry Walls," Advances in Analysis ofStructural Masonry, American Society of Civil Engineers, New York, NY, 1986, pp. 111-133. 2.17. "Anchors and Ties for Masonry," NCMA TEK 12-l, National Concrete Masonry Association, Herndon, VA, 1995,6 pp. 2.18. "Connectors for Masonry," (CAN 3-A370-M84), Canadian Standards Association, Rexdale, Ontario, 1984. 2.19. "Development of Adjustable Wall Ties," ARF Project No. 8869, Illinois lnstitute of Technology, Chicago, IL, Mar. 1963. 2.20. Gallagher, E.F., "Bond Between Reinforcing Steel and Brick Masonry," Brick and C/ay Record, V. 5, Cahners Publishing Co., Chicago, IL, Mar. 1935, pp. 86-87. 2.21. Richart, F.E., "Bond Tests Between Steel and Mortar," Structural Clay Products lnstitute (now Brick Tndustry Association), Reston, VA, 1949. 2.22. Treece, R.A., "Bond Strength of Epoxy-Coated Reinforcing Bars," Masters Thesis, Department of Civil Engineering, University of Texas at Austin, Austin, TX, May, 1987. 2.23. Ferguson, P. M., and Matloob, F. N., "Effect of Bar Cutoff on Bond and Shear Strength of Reinforced Concrete Beams," ACI Journal, Proceedings, V. 56, No. 1, American Concrete lnstitute, Detroit, Ml, July 1959, pp. 5-24.
- 229. C-216 2.24. Joint PCI/WRI Ad Hoc Committee on Welded Wire Fabric for Shear Reinforcement, "Welded Wire Fabric for Shear Reinforcement," Journal, Prestressed Concrete Tnstitute, V. 25, No. 4, Chicago, TL, July-Aug. 1980, pp. 32-36. 2.25. ACI Committee 318, "Commentary on Building Code Requirements for Reinforced Concrete (ACI 318- 83)," American Concrete Institute, Oetroit, MJ, 1983, 155 pp. 2.26. National Concrete Masonry Association, "Effects of Confinement Reinforcement on Bar Splice Performance - Summary of Research and Oesign Recommendations", MR33, Research Report, Hemdon VA, July, 2009. 2.27. Mjelde, Z., McLean, O.T., Thompson, J. J. and McGinley, W. M., "Performance ofLap Splices in Concrete Masonry Shear Walls," TMS Journal, V. 27, No. 1, The Masonry Society. Boulder, CO, 2009. 2.28. ACI Committee 531, "Building Code Requirements for Concrete Masonry Structures {ACI 531-79) (Revised 1983)," American Concrete Institute, Oetroit, MI, 1983, 20 pp. 2.29. Colville, J., "Simplified Oesign of Load Bearing Masonry Walls," Proceedings, 5th Intemational Symposium on Loadbearing Brickwork, Publication No. 27, British Cerarnic Society, London, Oec. 1978, pp. 2171- 2234. 2.30. Colville, J., " Stress Reduction Design Factors for Masonry Walls," Proceedings, American Society of Civil Engineers, V. 105, STlO, New York, NY, Oct. 1979,pp.2035-2051 . 2.31. Yokel, F.Y., "Stability and Load Capacity of Members with no Tensile Strength," Proceedings, American Society of Civil Engineers, V. 97, SD, New York, NY, July 1971, pp. 1913-1926. 2.32. Colville, J., "Service Load Design Equations for Unreinforced Masonry Construction." TMS Journal, V. 11, No. 1, pp. 9-20, The Masonry Society, Boulder, CO, 1992. 2.33. Hatzinikolas, M., Longworth, J., and Warwaruk, J., "Concrete Masonry Walls," Structural Engineering Report No. 70, Oepartment of Civil Engineering, University ofAlberta, Canada, Sept. 1978. 2.34. Fattal, S.G. and Cattaneo, L.E., "Structural Performance of Masonry Walls Under Compression and Flexure," Building Science Series No. 73, National Bureau of Standards, Washington, DC, 1976, 57 pp. 2.35. Yokel, F.Y., and Oikkers, R.O., " Strength of Load-Bearing Masonry Walls," Proceedings, American Society of Engineers, V. 97, ST5, New York, NY, 'May 1971, pp. 1593-1609. TMS 402-11/ACI 530-11/ASCE 5-11 2.36. Yokel, F.Y., and Dikkers, R.O., Closure to "Strength of Load-Be3ring Masonry Walls," Proceedings, American Society of Engineers, V. 99, ST5, New York, NY, May 1973, pp. 948-950. 2.37. Kim, Y.S. and Bennett, R.M., "Flexura! Tension in Unreinforced Masonry: Evaluation of Current Specifications." TMS Journal, V. 20, No. 1, pp. 23-30, The Masonry Society, Boulder, CO, 2002. 2.38. Ellingwood, B., Galambos, T.V., MacGregor, J.G., and Cornell, C.A., "Development of a Probability Based Load Criteria for American National Standard A58," NBS Special Publication 577, National Bureau of Standards, 1980. 2.39. Stewart, M. G. and Lawrence, S., "Bond Strength Variability and Structural Reliability of Masonry Walls in Flexure," Proc. 12th International Brick/Block Masonry Conf., Madrid, Spain, 2000. 2.40. Melander, J.M. and Ghosh, S.K., "Development of Specifications for Mortar Cement," Masonry: Esthetics, Engineering and Economy, STP 1246, D. H. Taubert and J.T. Conway, Ed., American Society for Testing and Materials, Philadelphia, 1996. 2.41. Hedstrom, E.G., Tarhini, K.M., Thomas, R.O., Dubovoy, V.S., Klingner, R.E., and Cook, R.A., "Flexura! Bond Strength of Concrete Masonry Prisms using Portland Cement and Hydrated Lime Mortars." TMS Journal, V. 9 No. 2, pp. 8-23, The Masonry Society, Boulder, CO, 1991. 2.42. Borchelt, J.G. and J.A. Tann. "Bond Strength and Water Penetration of Low IRA Brick and Mortar," Proceedings of the Seventh North American Masonry Conference, 1996, South Bend, IN, pp. 206-216, The Masonry Society, Boulder, CO. 2.43. Brown, R. and Palm, B., "Flexura( Strength ofBrick Masonry Using the Bond Wrench," Proceedings, 2nd North American Masonry Conference, College Park, MD, Aug. 1982, The Masonry Society, Boulder, CO. 2.44. Hamid, A.A., "Bond Characteristics of Sand-Molded Brick Masonry," TMS Journal, V. 4, No. 1, pp. T-18,1-22, The Masonry Society, Boulder, CO, 1985. 2.45. Ribar, J., "Water Permeance of Masonry: A Laboratory Study," Masonry: Properties and Performance, STP-778, ASTM, Philadelphia, PA, 1982. 2.46. Hamid, A.A., "Effect of Aspect Ratio of the Unit on the Flexura( Tensile Strength of Brick Masonry," TMS Journal, V. 1, No. 1, The Masonry Society, Boulder, CO, 1981. 2.47. Drysdale, R.G. and Hamid, A.A., "Effect of Grouting on the Flexura( Tensile Strength of Concrete Block Masonry," TMS Journal, V. 3, No. 2, pp. T-1 ,T-9, The Masonry Society, Boulder, CO, 1984.
- 230. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-217 2.48. Brown, R.H. and Melander, J.M., "Flexura! Bond Strength of Unreinforced Grouted Masonry using PCL and MC Mortars," Proceedings of the 8th North American Masonry Conference, The Masonry Society, 1999. 2.49. Woodward, K. and Ranking, F., "Influence of Vertical Compressive Stress on Shear Resistance of Concrete Block Masonry Walls," U.S. Department of Commerce, National Bureau of Standards, Washington, D.C., Oct. 1984, 62 pp. 2.50. Pook, L.L., Stylianou, M.A., and Dawe, J.L., "Experimental Investigation of the Influence of Compression on the Shear Strength of Masonry Joints," Proceedings, 4th Canadian Masonry Symposium, Fredericton, New Brunswick, June 1986, pp. 1053-1062. 2.51. Nuss, L.K., Noland, J.L., and Chinn, J., "The Parameters Influencing Shear Strength Between Clay Masonry Units and Mortar," Proceedings, North American Masonry Conference, University of Colorado, Boulder, CO, Aug. 1978. 2.52. Hamid, A.A., Drysda1e, R.G., and Heidebrecht, A.C., "Shear Strength of Concrete Masonry Joints," Proceedings, American Society of Civil Engineers, V. 105, ST7, New York, NY, July 1979, pp. 1227-1240. 2.53. "Recommended Practices for Engineered Brick Masonry," Brick Institute of America (now Brick Industry Association), Reston, VA, pp. 337, 1969. 2.54. Davis, C.L. Evaluation ofDesign Provisions for In- Plane Shear in Masonry Walls. Master of Science Thesis, Washington State University, 2008. References, Chapter 3 3.1. Brown, R.H. and Whitlock, A.R., "Strength of Anchor Bolts in Concrete Masonry," Joumal of the Structural Division, American Society of Civil Engineers, New York, NY, V. 109, No. 6, June, 1983, pp. 1362-1 374. 3.2. Hatzinikolos, M., Longworth, J., and Warwaruk, J., "Strength and Behavior ofAnchor Bolts Embedded in Concrete Masonry," Proceedings, 2nd Canadian Masonry Conference, Carleton University, Ottawa, Ontario, June, 1980. pp. 549-563. 3.3. Rad, F.N., Muller, W.H. and Winnen, J.M., "An Experimental Study on the Strength of Grouted Anchors in Masonry Walls," Report to the Masonry & Ceramic Tile lnstitute of Oregon, Portland State University, Portland, Oregon, October 1998. 3.4. Tubbs, J.B., Pollock, D.G., Jr., McLean, D.I. and Young, T.C. (1999), "Performance of Anchor Bolts in Concrete Block Masonry", Proceedings, 8th North American Masonry Conference, Austin, Texas, June 6-9, 1999. 3.5. Allen, R., Borchelt, J.G., K lingner, R.E. and Zobel, R., "Proposed Provisions for Design of Anchorage to Masonry," TMS Journal, V. 18, No. 2, pp. 35-59, The Masonry Society, Boulder, CO, 2000. 3.6. Brown, R. H ., Borchelt, J. G., and Burgess, R. E., "Strength of Anchor Bolts in the Top of Clay Masonry Walls," Proceedings of the 9th Canadian Masonry Symposium, Fredericton, New Brunswick, Canada, June 2001 . 3.7. Weigel, T.A., Mohsen, J.P., Burke, A., Erdmann, K. and Schad, A., "Tensile Strength of Headed Anchor Bolts in Tops of CMU Walls," TMS Journal, V. 20, No. 1, pp 6 1-70, The Masonry Society, Boulder, CO, 2002. 3.8. ACI Committee 3 18, "Building Code Requirements for Structural Concrete (ACI 318-05) and Commentary (ACI 318R-05)", American Concrete lnstitute, Farmington Hills, MI. 3.9. Malik, J.B., Mendonca, J.A., and Klingner, R.E., "Effect of Reinforcing Details on the Shear Resistance of Short Anchor Bolts under Reversed Cyclic Loading," Joumal of the American Concrete lnstitute, Proceedings, V. 79, No. 1, January-February 1982, pp. 3-1 1. 3.10. Davis, C.L., " Evaluation of Design Provisions for In-Plane Shear in Masonry Walls," Master of Science Thesis, Washington State University, 2008. 3.11. The following Technical Coordinating Committee for Masonry Research (TCCMaR) task reports not specifically cited in this Chapter provide the substantiating data for the strength design criteria presented. ReportNo. l.l-1: Atkinson and Kingsley, Comparison of the Behavior of C/ay & Concrete Masonry in Compression, September 1985, 15 1 pp. Report No. 1.2(a)-l: Hamid, A. A., Assis, G.F., and Harris, H.G., Material Models for Grouted BlockMasonry, August 1988, 67 pp. Report No. 1.2(a)-2: Assis, G. F., Hamid, A.A., and Harris, H.G., Material Models for Grouted Block Masonry, August 1989, 134 pp. Report No. 1.2(b)-l: Young, J. M., and Brown, R.H., Compressive Stress Distribution of Grouted Hollow Clay Masonry Under Strain Gradient, May 1988, 170 pp. Report No. 1.3-1: Atkinson, R.H., An Assessment of Curren/ Material Test Standards for Masonry Limit States Design Methods, June 1991, 38 pp. ReportNo. 2. 1- 1: Hart, G., and Basharkhah, M., Slender Wall Structural Engineering Analysis Computer Program (Shwall, Version l. 01), September 1987. 68 pp.
- 231. C-218 Report No. 2. 1-2: Hart, G., and Basharkhah, M., Shear Wa/l Structural Engineering Analysis Computer Program (Shwall, Version 1.01), September 1987, 75 pp. ReportNo. 2.1-3: Nakaki, D., and G. Hart, Uplifting Response of Structures Subjected to Earthquake Motions, August 1987, 200 pp. Report No. 2. 1-4: Hart, G., Sajjad, N., and Basharkhah, M., 1nelastic Column Analysis Computer Program (1NCAP, Version 1.01), March 1988. Report No. 2.1-5: Hong, W.K., Hart, G.C., and Englekirk, R.E., Force-Deflection Evaluation and Models for University of Colorado Flexura) Walls, December 1989. ReportNo. 2.1-6: Hart, G. C., Jaw, J.W., and Low, Y.K., SCM Model for University of Colorado Flexura/ Walls, December 1989,31 pp. ReportNo. 2.1 -7: Hart, G.C., Sajjad, N., and Basharkhah, M., 1nelastic Masonry Flexura! Shear Wall Analysis Computer Program, February 1990, 41 pp. Report No. 2.1-8: Hart, G.C., Englekirk, R.E., Srinivasan, M., Huang, S.C., and Drag, D.J., Seismic Performance Study, DPC Gymnasium, Elastic Time History Analysis Using SAP90, February 1992, 4 1 pp. Report No. 2. 1-9: Hart, G.C., Englekirk, R.E., Srinivasan, M., Huang, S.C., and Drag, D.J., Seismic Performance Study, TMS Shopping Center, Elastic Time History Analysis Using SAP90, February 1992, 42 pp. Report No. 2.1-10: Hart, G.C., Englekirk, R.E., Jaw, J.W., Srinivasan, M., Huang, S.C., and Drag, D.J., Seismic Performance Study, RCJ Hotel, February 1992, 51 pp. Report No. 2. 1-11: Hart, G.C., Englekirk, R.E., Srinivasan, M., Huang, S.C., and Drag, D.J., Performance Study, 2-Story Masonry Wall-Frame Building, February 1992, 112 pp. Report No. 2.1-12: Hart, G.C., Englekirk, R.E., Jaw, J.W., Srinivasan, M., Huang, S.C., and Drag, D.J., Seismic Perf ormance Study, Designed by Tentative Limit Sates Design Standard, February 1992, 75 pp. Report No. 2.2-1: Ewing, R.O., A. El- Mustapha, and Kariotís, J., FEM/1 - A Finite Element Computer Program for the Nonlinear Static Analysis of Reinforced Masonry Building Components, December 1987 (Revísed June 1990), 124 pp. TMS 402-11/ACI 530-11/ASCE 5-11 Report No. 2.2-2: Ewing, R. D., Parametric Studies on Reinforced Masonry Shear Walls Using FEM/1, A Nonlinear Finite Element Analysis Program, March 1992. Report No. 2.2-3: Ewing, R.D., Finite Element Analysis of Reinforced Masonry Building Components Designed by a Tentative Masonry Limit States Design Standard, March 1992, 48 pp. Report No. 2.3-1: Ewing, R., J. Kariotis, and A. EI-Mustapha, LPM/1, A Computer Program for the Nonlinear, Dynamic Analysis of Lumped Parameter Models, August 1987, 200 pp. Report No. 2.3-2: Kariotis, J., El-Mustapha, A., and Ewing, R., 1njluence of Foundation Model on the Uplifting ofStructures, July 1988, 50 pp. Report No. 2.3-3: Kariotis, J., Rahman, A., and EI-Mustapha, A., 1nvestigation of Curren/ Seismic Design Provisions for Reinf orced Masonry Shear Walls, January 1990, 48 pp. Report No. 2.3-4: Kariotis, J., Rahman, A., Waqfi, 0., and Ewing, R., Version 1.03 LPM/1- A Computer Program for the Nonlinear, Dynamic Analysis of Lumped Parameter Models, February 1992, 227 pp. Report No. 2.3-5: Kariotis, J., Waqfi, 0 ., and Ewing, R., A Computer Program Using Beam Elements for the Nonlinear, Dynamic Analysis of LumpedParameter Models, February 1992, 96 pp. Report No. 2.3-6: Kariotis, J., and Waqfi, 0., Comparison ofthe Dynamic Response ofa Damped MDOF Nonlinear Beam Model with an Equivalen/ SDOF Hysteretic Model, April 1992, 88 pp. Report No. 2.3-7: Kariotis, J., and Waqfi, 0., Recommended Procedure for Calculation of the BalancedReinforcement Ratio, February 1992, 73 pp. Report No. 2.4(b)-1: Button, M.R., and Mayes, R.L., Out-ofPlane Seismic Response ofReinforced Masonry Walls: Correlation ofFuli-Scale Test and AnalyticalModel Results, March 1991,65 pp. Report No. 3.1(a)-1: Scrivener, J., Summary of Findings ofCyclic Tests on Masonry Piers, June 1986, 7 pp. Report No. 3.1(a)-2: Shing, P.B., Noland, J., Spaeh, H., Klamerus, E., and Schuller, M., Response of Single-Story Reinforced Masonry Shear Walls to 1n- PlaneLatera!Loads, January 1991, 136 pp. ReportNo. 3.l(b)-l: Seible, F., and LaRovere, H., Summary of Pseudo Dynamic Testing, February 1987, 46pp.
- 232. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES AND COMMENTARY C-219 Report No. 3.1(b)-2: lgarashi, A., Seible, F., and Hegemier, G., Development of the Generated Sequential displacement Procedure and the Simulated Seismic Testing of the TCCMaR Three-Story In-Piane Walls, June 1993. Report No. 3.1 (c)-1: Merryman, K., Leiva, G., Antrobus, B., and Klingner, R., In-Plane Seismic Resistance ofTwo-Story Concrete Masonry Coupled Shear Walls, September 1989, 176 pp. ReportNo.3.1(c)-2: Leiva, G., and Klingner, R., In-plane Seismic Resistance of Two-story Concrete Masonry Shear Walls with Openings, August 1991,326 pp. Report No. 3.2(a)-1: Hamid, A., Abboud, B., Farah, M., Hatem, K., and Harris, H., Response of Reinforced Block Masonry Walls to Out-of-Plane Static Loads, September 1989, 120 pp. Report No. 3.2(b)-1: Agbabian, M., Adham, S., Masri, S., Avanessian, V., and Traína, V., Out-of- Plane Dynamic Testing ofConcrete Masonry Walls, V. 1 and 2, July 1989, 220 pp. Report No. 3.2(b)-2: Blondet, M., and Mayes, R.L., The Transverse Response of Clay Masonry Walls Subjected to Strong Motion Earthquakes, V. 1: General!nformation, April 1991, 172 pp. Report No. 3.2(b)-2: Blondet, M., and Mayes, R.L., The Transverse Response of Clay Masonry Walls Subjected to Strong Motion Earthquakes, V. 2: Walls No. 4 and 6 (Group 1), Aprill991, 267 pp. Report No. 3.2(b)-2: Blondet, M., and Mayes, R.L., The Transverse Response of Clay Masonry Walls Subjected to Strong Motion Earthquakes, V. 3: Walls No. 8, 9, JO and Il (Group 2), April1991 , 310 pp. ReportNo. 3.2(b)-2: Blondet, M., and Mayes, R.L., The Transverse Response ofClay Masonry Walls Subjected to Strong Motion Earthquakes, V. 4: Walls No. 3, 5, and 7 (Group 3), Apri11991, 256 pp. Report No. 4. 1-1 : He, L., and Priestley, M.J.N., Seismic Behavior ofFlanged Masonry Shear Walls, May 1988, 119 pp. Report No. 4. 1-2: He, L., and Priestley, M.J.N., Seismic Behavior ofFlanged Masonry Shear Walls -FinalReport, November 1992, 279 pp. Report No. 4.2-1: Hegemier, G., and Murakami, H., On the Behavior of Floor-to-Wall Intersections in Concrete Masonry Construction: Part 1: Experimental. Report No. 4.2-2: Hegemier, G., and Murakami, H., On the Behavior of Floor-to-Wall Intersections in Concrete Masonry Construction: Part JI: Theoretical. Report No. 5.1-1: Porter, M., and Sabri, A., Plank Diaphragm Characteristics, July 1990, 226 pp. ReportNo. 5.2-1: Porter, M., Yeomans, F., and Johns, A., Assembly of Existing Diaphragm Data, July 1990, 142 pp. Report No. 6.2-1: Scrivener, J., Bond of Reinforcement in Grouted Hollow Unit Masonry: A State-of-the-Art, June 1986, 53 pp. Report No. 6.2-2: Soric, Z., and Tulin, L., Bond Splices in Reinforced Masonry, August 1987, 296 pp. Report No. 7.1-1: Paulson, T., and Abrams, D., Measured lnelastic Response of Reinforced Masonry Building Structures to Earthquake Motions, October 1990,294 pp. ReportNo. 8.1-1: Hart, G., A Limit State Design Methodfor ReinforcedMasonry, ]une 1988. Report No. 8.1-2: Hart, G., Expected Value Design in the Context of a Limit Sate Design Methodology, February 1990. Report No. 8.2-1: Hart, G., and Zorapapel, G.T., Reliability of Concrete Masonry Wall Structures, December 1991,229 pp. Report No. 8.2-2: Hart, G., and Sajjad, N., Conjinement in Concrete Masonry, December 1990. Report No. 8.2-3: Hart, G., and Jang, J., Seismic Performance of Masonry Wall Frames, December 1991. Report No. 9.1-1: Kariotis, J.C., and Johnson, A.W., Design of Reinforced Masonry Research Building, September 1987, 42 pp. Report No. 9.1-2: Kariotis, J.C., and Waqfi, O.M., Tria! Designs Made in Accordance with Tentative Limit States Design Standards for Reinforced Masonry Buildings, February 1992, 184 pp. Report No. 9.2-1: Seible, F., Report on Large Structures Testing Facilities in Japan, September 1985, 120 pp. Report No. 9.2-2: Seible, F., Design and Construction of the Charles Lee Powell Structural Systems Laboratory, November 1986, 65 pp. Report No. 9.2-3: Seible, F., The Japanese Five-story Full Sea/e Reinforced Masonry Building Test, January 1988, 100 pp.
- 233. C-220 Report No. 9.2-4: Seible, F., Hegemier, G.A., Priestley, M.J.N., Kingsley, G.R., Kurkchubasche, A., and Igarashi, A. The U.S. - TCCMAR Five-story Full Sea/e Masonry Research Building Test - Preliminary Report, October 1992, 58 pp. Report No. 11.1-1: TCCMaR, Summary Report: U. S. Coordinated Program for Masonry Building Research,September 1985 to August 1986, 190 pp. Report No. 11.1-2: TCCMaR, Status Report - U.S. Coordinated Program for Masonry Building Research, November 1988, 170 pp. 3.12. Mirza, S.A., Lee, P.M., and Morgan, D.L. (1987). "ACI stability resistance factor for RC columns." Joumal of Structural Engineering, ASCE, 113(9), 1963-1976. 3.13. MacGregor, J.G., Breen, J.E., and Pfrang, E.O. (1970). "Design of slender concrete columns." ACI Joumal, 67(1), 6-28. 3.14. Assis, G.F. and Hamid, A.A., Compression Behavior of Concrete Masonry Prisms Under Strain Gradient, TMS Journal, V. 9, No. lThe Masonry Society, Boulder, CO, 1990. 3.15. Brown, R.H., Compressive Stress Distribution of Grouted Hollow Clay Masonry Under Strain Gradient, TMS Joumal, V. 6, No. 1, The Masonry Society, Boulder, CO, 1987. 3.16. National Concrete Masonry Association, "Evaluation of Reinforcing Bar Splice Criteria for Hollow Clay Brick and Hollow Concrete Block Masonry," Hemdon, VA, May, 1999. 3.17. Thompson, J.J., "Behavior and Design of Tension Lap Splices in Reinforced Concrete Masonry," Masters Thesis, Department of Civil and Environmental Engineering, Washington State University, Pullman, Washington, 1997. 3.18. Hammons, M.l., Atkinson, R.H., Schuller, M.P., Tikalsky, P.J., "Masonry Research for Limit-States Design," Construction Productivity Advancement Research Program Technical Report, CPAR-SL-94-1 , October 1994, 136 pp. 3.19. Borchelt, J.G. and J.L. Elder, "Reinforcing Bar Splices in Hollow Brick Masonry," Proceedings of the 11th lntemational Brick/Block Masonry Conference, Tongji University, Shanghai, China, October 1997, pp. 306-316. 3.20. National Concrete Masonry Association, "Effects of Confinement Reinforcement on Bar Splice Performance - Summary of Research and Design Recommendations", MR33, Research Report, Hemdon VA, July, 2009. 3.21. Mjelde, Z., McLean, D.l., Thompson, J. J. and McGinley, W. M., "Performance ofLap Splices in Concrete Masonry Shear Walls," TMS Journal, V. 27, No. 1, The Masonry Society. Boulder, CO, 2009. TMS 402-11/ACI 530-11/ASCE 5-11 3.22. Schultz, A. E. , "An Evaluation of Reinforcing Bar Splice Requirements for Strength Design ofMasonry Structures," Council for Masonry Research, Herndon, VA, December, 2005, 94 pp. 3.23. Schultz, A. E. (2004). "A Reevaluation of Reinforcing Bar Splice Requirements for Masonry Structures according to the 2002 MSJC Strength Design Provisions," lnternational Masonry lnstitute, Annapolis, MD, May, 2004, 37 pp. 3.24. Blake, J. D. , "Lap Splice Behavior in Concrete Masonry Walls under Flexura! Loading," M.S. thesis, Department of Civil and Environmental Engineering, Washington State University, Pullman, WA, 1993, 160 pp. 3.25. Blake, J. D., Marsh, M. L., and McLean, D. L. "Lap Splices in Flexurally Loaded Masonry Walls." TMS Journal, V. 13, No. 2, pp. 22-36, The Masonry Society. Boulder, CO, 1995. 3.26. National Concrete Masonry Association, "Evaluation of the Effects of Concrete Masonry Structural Cover over Spliced Reinforcing Bars," Herndon, VA, December, 1995, 65 pp. 3.27. Soric, Z., Tulin, L. G.. "Bond Stress and Slip in Masonry Reinforced with Spliced Reinforcement." TMS Journal, V. 6, No. 1, pp. T13-T27, The Masonry Society. Boulder, CO, 1987. 3.28. Suter, G. T., Fenton, G. A.. "Splice Length Tests of Reinforced Concrete Masonry Walls." The Masonry Society, June 1985, p. 14. 3.29. National Concrete Masonry Association, "Effects of Confinement Reinforcement on Bar Splice Performance - Summary of Research and Design Recommendations", Research Report, Herndon VA, February, 2009. 3.30. Hogan, M.B., Samblanet, P.J., and Thomas, R.D., "Research Evaluation of Reinforcing Bar Splices in Concrete Masonry," Proceedings of the 11th lntemational Brick/Block Masonry Conference, Tongji University, Shanghai, China, October 1997, pp. 227-238 3.31. Amrhein, J.E., and Lee, D.E., "Design of Reinforced Masonry Tall Slender Walls", 1984, Westem States Clay Products Association, 46 pp. 3.32. Wallace, J.W. and Orakcal, K., "ACI 318-99 Provisions for Seismic Design of Structural Walls," ACI Structural Journal, V. 99, No. 4, July-August 2002. 3.33. Paulay, T., "The Design of Ductile Reinforced Concrete Structural Walls for Earthquake Resistance," Earthquake Spectra, EERI, V. 2, No. 4, 1986, pp. 783-823. 3.34. Wallace, J.W., "A New Methodology for Seismic Design of RC Shear Walls," Journal of Structural Engineering, ASCE, V. 120, No. 3, 1994, pp. 863-884.
- 234. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES ANO COMMENTARY C-221 3.35. Wallace, J.W. and Moehle, J.P., "Ductility and Detailing Requirements of Bearing Wall Buildings," Journal of Structural Engineering, ASCE, V. 118, No. 6, 1992, pp. 1625-1 644. References, Chapter 4 4.1. Schultz, A.E. and Scolforo, M.J., "An Overview ofPrestressed Masonry," TMS Journal, V. 10, No. 1, pp. 6-21, The Masonry Society, Boulder, CO, 1991. 4.2. Woodham, D.B. and Hamilton lll, H.R., "Monitoring Prestress Losses in Post-Tensioned Concrete Masonry," Proceedings, 9th North American Masonry Conference, Clemson, South Carolina, June 2003. 4.3. Code ofPracticefor the Use ofMasonry, Part 2: Reinforced and Prestressed Masonry, BS 5628, British Standards lnstitution, London, England, 1985. 4.4. Phipps, M.E., "The Codification of Prestressed Masonry Design," Proceedings, Sixth Canadian Masonry Symposium, Saskatoon, Saskatchewan, Canada, June 1992, pp. 561-572. 4.5. Schultz, A.E. and Sco1foro, M.J., "Engineering Design Provisions for Prestressed Masonry, Part 1: Masonry Stresses," TMS Journal, V. 1O , No. 2, pp. 29- 47, The Masonry Society, Boulder, CO, 1992. 4.6. Schultz, A.E., and Scolforo, M.J., "Engineering Design Provisions for Prestressed Masonry, Part 2: Steel Stresses and Other Considerations," TMS Journal, V. 10, No. 2, pp. 48-64, The Masonry Society, Boulder, CO, 1992. 4.7. Post-Tensioned Masonry Structures, VSL Intemational Ltd., VSL Report Series, Beme, Switzerland, 1990, 35 pp. 4.8. Curtin, W.G., Shaw, G., and Beck, J.K., Design ofReinforced and Prestressed Masonry, Thomas Telford Ltd., London, England, 1988,244 pp. 4.9. Phipps, M.E. and Montague, T.I., "The Design of Prestressed Concrete Blockwork Diaphragm Walls," Aggregate Concrete Block Association, England, 1976, 18 pp. 4.10. Building Code Requirements for Reinforced Concrete, ACI 318-08, American Concrete Institute, Farmington Hills, Ml, 2008. 4.11. "Recommendations for Estimating Prestress Losses," Report of PCI Committee on Prestress Losses, Journal ofthe Prestressed Concrete Institute, V. 20, No. 4, Chicago, IL, July-August 1975, pp. 43-75. 4.12. Lenczner, D., "Creep and Stress Relaxation in Stack-Bonded Brick Masonry Prisms, A Pilot Study," Department of Civil Engineering, Clemson University, Clemson, SC, May 1985, 28 pp. 4.13. Lenczner, D., "Creep and Loss of Prestress in Stack Bonded Brick Masonry Prisms, Pilot Study · Stage ll," Department of Civil Engineering, University of lllinois, Urbana-Champaign, IL, August 1987, 29 pp. 4.14. Shrive, N.G., "Effects of Time Dependen! Movements in Composite and Post-Tensioned Masonry," Masonry International, V. 2, No. 1, British Masonry Society, London, England, Spring 1988, pp. 1-34. 4.15. ASTM A416-06, Standard Specificationfor Steel Strand, Uncoated Seven-Wire for Prestressed Concrete, American Society for Materials and Testing, West Conshohocken, PA. 4.16. ASTM A421.-05, Standard Specification for Uncoated Stress-Relieved Steel Wire for Prestressed Concrete, American Society for Materials and Testing, West Conshohocken, PA. 4.17. ASTM A722-07, Standard Specification for Uncoated High-Strength Steel Bars for Prestressing Concrete, American Society for Materials and Testing, West Conshohocken, PA. 4.18. Hamilton Ill, H.R. and Badger, C.C.R., "Creep Losses in Post-Tensioned Concrete Masonry," TMS Journal, V. 18, No. 1, pp. 19-30, The Masonry Society, Boulder, CO, 2000. 4.19. Biggs, D.T. and Ganz, H.R., "The Codification of Prestressed Masonry in the United States", Proceedings, Fifth International Masonry Conference, London, UK, October 1998, pp. 363-366. 4.20. NCMA TEK-1 4-20A, "Post-tensioned Concrete Masonry Wall Design", National Concrete Masonry Association. 4.21. Stierwalt, D.D. and Hamilton lll, H.R., "Restraint Effectiveness in Unbonded Tendons for Post- tensioned Masonry," ACI Structural Journal, Nov/Dec 2000, V. 97, No. 6, pp. 840-848. 4.22. Scolforo, M.J. and Borchelt, J.G., "Design of Reinforced and Prestressed Slender Masonry Walls," Proceedings, Innovative Large Span Structures, The Canadian Society of Civil Engineers, Montreal, Canada, July 1992, pp. 709-720. 4.23. Schultz, A.E., Bean, J.R., and Stolarski, H. K., "Resistance of Slender Post-Tensioned Masonry Walls with Unbonded Tendons to Transverse Loading", Proceedings, 9th North American Masonry Conference, Clemson, South Carolina, June 2003.
- 235. C-222 4.24. Bean, J.R. and Schultz A.E., "Flexura! Capacity of Post-Tensioned Masonry Walls:Code Review and Recommended Procedure", PTI Joumal, V. 1, No. 1, January 2003, pp. 28-44. 4.2S. Bean Popehn, J. R. and Schultz, A.E., "Design Provisions for Post-Tensioned Masonry Walls Subject to Lateral Loading", Proceedings, 14th International Brick and Block Masonry Conference, Sydney, Australia, February 2008. 4.26. Bean Popehn, Jennifer R. "Mechanics and Behavior of Slender, Post-Tensioned Masonry Walls to Transverse Loading", Ph.D. dissertation, University of Minnesota, 2007. 4.27. "Guide Specifications for Post-Tensioning Materials," Post-Tensioning Manual, 5th Edition, Post- Tensioning lnstitute, Phoenix, AZ, 1990, pp. 208-216. 4.28. Sanders, D.H., Breen, J.E., and Duncan, R.R. lll, "Strength and Behavior of Closely Spaced Post- Tensioned Monostrand Anchorages," Post-Tensioning Institute, Phoenix, AZ, 1987, 49 pp. References, Chapter 5 S.l. Baker, LO., A Treatise on Masonry Construction, University oflllinois, Champaign, IL, 1889, 1899, 1903. Also, 10th Edition, John Wiley & Sons, New York, NY, 1909, 745 pp. S.2. "Recommended Mínimum Requirements for Masonry Wall Construction," Publication No. BH6, National Bureau ofStandards, Washington, DC, 1924. S.3. "Modifications in Recommended Mínimum Requirements for Masonry Wall Construction," National Bureau of Standards, Washington, DC, 1931. S.4. "American Standard Building Code Requirements for Masonry," (ASA A 41.1 ), American Standards Association, New York, NY, 1944. S.S. "American Standard Building Code Requirements for Masonry," (ANSI A 41.1), American National Standards lnstitute, New York, NY, 1953 (1970). S.6. "Standard Specifications and Load Tables for Steel Joists and Joist Girders", Steel Joist lnstitute, Myrtle Beach, SC, 2002. TMS 402-111AC1530-111ASCE 5-11 References, Chapter 6 6.1. Brown, R.H. and Arumula, J.O., "Brick Veneer with Metal Stud Backup - An Experimental and Analytical Study," Proceedings Second North American Masonry Conference, The Masonry Society, Boulder, CO, August 1982, pp. 13-1 to 13-20. 6.2. "Brick Veneer 1 Steel Stud Walls," Technical Note on Brick Construction No. 28B, Brick Industry Association, Reston, VA, December2005. 6.3. Grimm, C.T. and Klingner, R.E., "Crack Probability in Brick Veneer over Steel Studs," Proceedings Fifth North American Masonry Conference, The Masonry Society, Boulder, CO, June 1990, pp. 1323- 1334. 6.4. Kelly, T., Goodson, M., Mayes, R., and Asher, J., "Analysis ofthe Behavior ofAnchored Brick Veneer on Metal Stud Systems Subjected to Wind and Earthquake Forces," Proceedings Fifth North American Masonry Conference, The Masonry Society, Boulder, CO, June 1990, pp. 1359-1370. 6.5. "Structural Backup Systems for Concrete Masonry Veneers," NCMA TEK 16-3A, National Concrete Masonry Association, Herndon, VA, 1995. 6.6. NCMA TEK 5-2A: Clay and Concrete Masonry Banding Details, National Concrete Masonry Association, Hemdon, VA, 2002. 6.7. BIA E&R Digest on Combinations of Materials, Brick Industry Association, Reston, VA. 6.8. BIA Technical Notes ISA Accommodating Brickwork Expansion, Brick Industry Association, Reston, VA, November 2006. 6.9. "The Permanent Wood Foundation System," Technical Report No. 7, Nationa1 Forest Products Association (now the American Forest and Paper Association), Washington, DC, January 1987. 6.10. "Connectors for Masonry," CAN3-A370-M84, Canadian Standards Association, Rexdale, Ontario, Canada, 1984. 6.11. "Brick Veneer - New Frame Construction, Existing Frame Construction," Technical Notes on Brick and Tile Construction No. 28, Structural Clay Products Institute (now Brick Industry Association), Reston, VA, August 1966. 6.12. National Building Code, Building Officials and Code Administrators, Country Club Hills, JL, 1993. 6.13. Standard Building Code, Southem Building Code Congress Intemational, Birmingham, AL, 1991.
- 236. BUILDING CODE REQUIREMENTS FOR MASONRY STRUCTURES AND COMMENTARY C-223 6.14. Uniform Building Code, Intemational Conference ofBuilding Officials, Whittier, CA, 1991. 6.15. Drysdale, R.G. and Suter, G.T., "Exterior Wall Construction in High-Rise Buildings: Brick Veneer on Concrete, Masonry or Steel Stud Wall System," Canada Mortgage and Housing Corporation, Ottawa, Ontario, Canada, 1991. 6.16. Klingner, R. E., Shing, P. B., McGinley, W, M., McLean, D. M., Okail, H. and Jo, S., "Seismic Performance Tests of Masonry and Masonry Veneer", ASTM Masonry Symposium, June 2010. 6.17. Reneckis, D., and LaFave, J. M., "Seismic Performance of Anchored Brick Veneer," Newmark Structural Laboratory Report Series No. NSEL-0 16, University ofillinois, Urbana, IL, August 2009. 6.18. "Handbook for Ceramic Tile Installation," Tile Council ofAmerica, Anderson, SC, January 1996. 6.19. Dickey, W.L., "Adhered Veneer in Earthquake, Storm, and Prefabrication," Proceedings, 2nd North American Masonry Conference, College Park, MD, The Masonry Society, Boulder, CO, August 1982. 6.20. Guide to Portland Cement Plastering, ACI 524R- 93, American Concrete lnstitute, Farmington Hills, MI, 1993. References, Chapter 7 7.1. "Fire Resistance Directory - Volume 3," File No. R2556, Underwriters Laboratories, lnc., Northbrook, IL, 1995. 7.2. "PC Glass Block Products," Installation Brochure (GB-185), Pittsburgh Coming Corp., Pittsburgh, PA, 1992. 7.3. "WECK Glass Blocks," Glashaus Inc., Arlington Heights, IL, 1992. 7.4. Smolenski, Chester P., "A Study of Mortared PCC Glass Block Panel Lateral Load Resistance (Historical Perspective and Design Implications)," Pittsburgh Coming Corporation, Pittsburgh, PA, 1992. 7.5. Structural lnvestigation of Pittsburgh Corning Glass Block Masonry, National Concrete Masonry Association Research and Development Laboratory, Hemdon, VA, August 1992. References, Chapter 8 8.1. Varela, J.L., Tanner, J.E. and Klingner, R.E., "Development of Seismic Force-Reduction and Displacement Amplification Factors for AAC Structures," EERISpectra, V. 22, No. 1, February 2006, pp. 267-286. 8.2. Tanner, J.E., Varela, J.L., Klingner, R.E., Brightman M. J. and Cancino, U., "Seismic Testing of Autoclaved Aerated Concrete (AAC) Shear Walls: A Comprehensive Review," Structures Journal, American Concrete Institute, Farmington Hills, Michigan, V. 102, No. 3, May - June 2005, pp. 374-382. 8.3. Tanner, J.E., Varela, J.L., Klingner, R.E., "Design and Seismic Testing of a Two-story Full-scale Autoclaved Aerated Concrete (AAC) Assemblage Specimen," Structures Journal, American Concrete Institute, Farmington Hills, Michigan, V. 102, No. 1, January- February 2005, pp. 114-119. 8.4. Argudo, Jaime, "Evaluation and Synthesis of Experimental Data for Autoclaved Aerated Concrete," MS Thesis, Department of Civil Engineering, The University ofTexas at Austin, August 2003. 8.5. ASTM C78-02 Test Method for Flexura! Strength of Concrete (Using Simple Beam with Third- Point Loading), American Society for Materials and Testing, West Conshohocken, PA. 8.6. Fouad, Fouad; Dembowski, Joel; Newman, David, "Material Properties and Structural Behavior of Plain and Reinforced Components," Department of Civil and Environmental Engineering at The University of Alabama at Birmingham, February 28, 2002. 8.7. Kingsley, G.R., Tulin, L. G. and Noland, J.L., "The Influence of Water Content and Unit Absorption Properties on Grout Compressive Strength and Bond Strength in Hollow Clay Unit Masonry," Proceedings, Third North American Masonry Conference, Arlington, Texas, 1985. 8.8. Cancino, Ulises, "Behavior of Autoclaved Aerated Concrete Shear Walls with Low-Strength AAC," MS Thesis, Department of Civil Engineering, The University ofTexas at Austin, December, 2003. 8.9. Vratsanou, V., Langer, P., "Untersuchung des Schubtragverhaltens von Wanden aus Porenbeton- Piansteinmauerwerk" (Research on Shear Behavior of Aerated Concrete Masonry Walls), Mauerwerk, V. 5, No. 6, 2001, pp. 210-215.
- 237. C-224 References, Appendix B B.l. Chiou, Y., Tzeng, J., and Liou, Y., (1999). "Experimental and Analytical Study of Masonry Infilled Frames." Journal of Structural Engineering, 125(10), 1109-1117. B.2. Flanagan, R.D., and Bennett, R.M. (l999a). "ln- plane behavior of structural clay tile infilled frames." J. Struct. Engrg., ASCE, 125(6), 590-599. B.3. Dawe, J.L, and Seah, C.K. (1989a). "Behavior of masonry infilled steel frames." Can. J Civ. Engrg., Ottawa, 16, 865-876. B.4. Riddington, J.R. (1984). "The influence of initial gaps on infilled frame behavior." Proc. Jnstn. Civ. Engrs., 77,295-310. B.S. Flanagan, R.D., and Bennett, R.M. (2001). "In- plane analysis of masonry infill materials." Practice Periodical on Structural Design and Construction, ASCE, 6(4), 176-182. B.6. Abrams, D. P., Angel, R., and Uzarski, J. (1993), Transverse Strength of Damaged URM Infills," Proceedings of the Sixth North American Masonry Conference, Philadelphia, PA, 347-358. TMS 402-11/ACI 530-11/ASCE 5-11 B.7. Dawe, J.L., and Seah, C.K. (1989b). "Out-of- plane resistance of concrete masonry infilled panels." Can. J. Civ. Engrg., Ottawa, 16, 854-864. B.S. Flanagan, R.D., and Bennett, R.M. (1999b). "Arching of masonry infilled frames: comparison of analytical methods." Practice Periodical on Structural Design and Construction, ASCE, 4(3), 105-110. B.9. Klingner, R. E., Rubiano, N. R., Bashandy, T. and Sweeney, S., "Evaluation and Analy1ical Verification of Infilled Frame Test Data," TMS Journal, V. 15, No. 2, The Masonry Society, Boulder, CO, 1997. B.lO. ASCE 41-06, Seismic Rehabilitation of Existing Buildings, Structural Engineering lnstitute of the American Society of Civil Engineers, Reston, VA, 2006. B.ll. Tucker, C. (2007). "Predicting the In-plane Capacity of Masonry Infilled Frames." Ph.D. Dissertation, Tennessee Technological University. B.12. Henderson, R. C., Porter, M.L., Jones, W.D., Burdette, E.G. (2006). "Prior Out-of-plane Damage on the In-plane Behavior of Masonry Infilled Frames" TMS Journal, TMS, V. 24, No. 1, pp. 7 1-82, The Masonry Society, Boulder, CO, 2006.
- 240. Specification for Masonry Structures (TMS 602-11/ACI530.1-11/ASCE 6-11) TABLE OF CONTENTS SYNOPSIS AND KEYWORDS, pg. S-iii PREFACE, S-1 PART 1 - GENERAL, pg. S-3 1.1- Summary .................................................................................................................................................................. S-3 1.2 - Definitions ................................................................................................................................................................ S-3 1.3 - Reference standards .................................................................................................................................................. S-8 1.4 - System description ................................................................................................................................................. S-13 1.5 - Submitta1s ............................................................................................................................................................... S-20 1.6 - Qua1ity assurance ................................................................................................................................................... S-21 1.7 - Delivery, storage, and handling .............................................................................................................................. S-26 1.8 - Project conditions ................................................................................................................................................... S-26 PART 2 - PRODUCTS, pg. S-31 2. 1- Mortar materials ..................................................................................................................................................... S-31 2.2- Grout materials ....................................................................................................................................................... S-34 2.3 - Masonry unit materials ........................................................................................................................................... S-34 2.4 - Reinforcement, prestressing tendons, and metal accessories .................................................................................. S-37 2.5 - Accessories ............................................................................................................................................................. S-44 2.6 - Mixing .................................................................................................................................................................... S-46 2.7 - Fabrication .............................................................................................................................................................. S-48 PART 3 - EXECUTION, pg. S-51 3.1- lnspection ............................................................................................................................................................... S-51 3.2- Preparation ....................................................,........................................................................................................ S-52 3.3 - Masonry erection .................................................................................................................................................... S-53 3.4 - Reinforcement, tie, and anchor installation ............................................................................................................ S-58 3.5 - Grout placement ..................................................................................................................................................... S-65 3.6 - Prestressing tendon installation and stressing procedure ........................................................................................ S-69 3.7 - Field quality control ............................................................................................................................................... S-70 3.8 - Cleaning ................................................................................................................................................................. S-70 FOREWORD TO SPECIFICATION CHECKLISTS, pg. S-71 M'andatory Requirements Checklist .................................................................................................................................. S-72 Optional Requirements Checklist....................................................................................................................................... S-74 REFERENCES FOR TOE SPECIFICATION COMMENTARY, pg. S-77
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- 242. SPECIFICATION FOR MASONRY STRUCTURES Specification for Masonry Structures (TMS 602-11/ACI 530.1-11/ASCE 6-11) SYNOPSIS This Specification for Masonry Structures (TMS 602-11/ACI 530.1-1 1/ASCE 6-11) is written as a master specification and is required by Building Code Requirements for Masonry Structures (TMS 402-111ACl 530-11/ASCE 5- 11) to control materials, labor, and construction. Thus, this Specification covers mínimum construction requirements for masonry in structures. lncluded are quality assurance requirements for materials; the placing, bonding, and anchoring of masonry; and the placement of grout and of reinforcement. This Specification is meant to be referenced in the Project Manual. Individual project requirements may supplement the provisions ofthis Specification. Keywords: AAC masonry, anchors; autoclaved aerated concrete (AAC) masonry, clay brick; clay tite; concrete block; concrete brick; construction; construction materials; curing; grout; grouting; inspection; joints; masonry; materials handling; mortars (material and placement); quality assurance and quality control; reinforcing steel; specifications; ties; tests; tolerances. S-iii
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- 244. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY S-1 SPECIFICATION COMMENTARY PREFACE INTRODUCTION Pl. This Preface is included for explanatory purposes only; it does not forrn a part of Specification TMS 602- l l/ACJ 530.1 -11 /ASCE 6- 11. P2. Specification TMS 602-I 1/ACI 530.1-1 1/ASCE 6- 11 is a reference standard which the Architect/Engineer may cite in the contract documents for any project, together with supplementary requirements for the specific project. P3. Specification TMS 602-11/ACT 530.1-1 1/ASCE 6-11 is written in the three-part section format of the Construction Specifications Institute, as adapted by ACL The 1 anguage is generally imperative and terse. P4. Specification TMS 602-1 1/ACI 530.1-1 1/ASCE 6-1 1 is intended to be used in its entirety by reference in the project specifications. Individual sections, articles, or paragraphs should not be copied into the project specifications since taking them out ofcontext may change their meaning. PS. These mandatory requirements should designate the specific qualities, procedures, materials, and performance criteria for which alternatives are permitted or for which provisions were not made in this Specification. Exceptions to this Specification should be made in the project specifications, ifrequired. P6. A statement such as the following wi11 serve to make Specification lMS 602-11/ACI 530.1 -11/ASCE 6-11 an official part ofthe project specifications: Masonry construction and materials shall conforrn to the requirements of "Specification for Masonry Structures (lMS 602-11/ACI 530.1-11/ASCE 6-11)," published by The Masonry Society, Boulder, Colorado; the American Concrete Institute, Farmington Hills, Michigan; and the American Society of Civil Engineers, Reston, Virginia, except as modified by the requirements ofthese contract documents. Chapter 1 of the Building Code Requirements for Masonry Structures (TMS 402-11/ACI 530-11/ASCE 5- 11) makes the Specificationfor Masonry Structures (TMS 602-11/ACI 530.1-11/ASCE 6-11 ) an integral part of the Code. TMS 602-11/ACI 530.1-1 1/ASCE 6-11 Specification sets mínimum construction requirements regarding the materials used in and the erection of masonry structures. Specifications are written to set mínimum acceptable levels of performance for the contractor. This commentary is directed to the Architect/Engineer writing the project specifications. This Commentary covers sorne of the points that the Masonry Standards Joint Committee (MSJC) considered in developing the provisions of the Code, which are written into this Specification. Further explanation and documentation of sorne of the provisions of this Specification are included. Comments on specific provisions are made under the corresponding part or section and article numbers ofthis Code and Specification. As stated in the Preface, Specification TMS 602- 11/ACI 530.1-11/ASCE 6-11 is a reference standard which the Architect/Engineer may cite in the contract documents for any project. Owners, through their representatives (Architect/Engineer), may write requirements into contract documents that are more stringent than those of TMS 602-111ACI 530.1-11/ASCE 6-11. This can be accomplished with supplemental specifications to this Specification. The contractor should not be required through contract documents to comply with the Code or to assume responsibility regarding design (Code) requirements. The Code is not intended to be made a part of the contract documents. The Preface and the Foreword to Specification Checklists contain information that exp1ains the function and use ofthis Specification. The Checklists are a summary ofthe Articles that require a decision by the Architect/Engineer preparing the contract documents. Project specifications should include the inforrnation that relates to those Checklist items that are pertinent to the project. Each project requires response to the mandatory requirements.
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- 246. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY S-3 PART 1 -GENERAL SPECIFICATION 1.1- Summary 1.1 A. This Specification covers requirements for materials and construction of masonry structures. SI values shown in parentheses are provided for information only and are not part ofthis Specification. 1.1 B. The Specification supplements the legally adopted building code and govems the construction of masonry elements designed in accordance with the Code, except where this Specification is in conflict with requirements in the legally adopted building code. This Specification defines the mínimum acceptable standards ofconstruction practice. 1.1 C. This article covers the furnishing and construction of masonry including the following: l. Furnishing and placing masonry units, grout, mortar, masonry lintels, sills, copings, through-wall flashing, and connectors. 2. Furnishing, erecting and maintaining of bracing, forming, scaffolding, rigging, and shoring. 3. Furnishing and installing other equipment for constructing masonry. 4. Cleaning masonry and removing surplus material and waste. 5. lnstalling lintels, nailing blocks, inserts, window and door frames, connectors, and construction items to be built into the masonry, and building in vent pipes, conduits and other items furnished and located by other trades. 1.2- Definitions A. Acceptable, accepted - Acceptable to or accepted by the Architect/Engineer. B. Architect!Engineer - The architect, engineer, architectural firm, engineering firm, or architectural and engineering firm, issuing drawings and specifications, or administering the work under project specifications and project drawings, or both. C. Area, gross cross-sectional- The area delineated by the out-to-out dimensions of masonry in the plane under consideration. D. Area, net cross-sectional - The area of masonry units, grout, and mortar crossed by the plane under consideration based on out-to-out dimensions. E. Autoclaved aerated concrete - low-density cementitious product of calcium silicate hydrates. COMMENTARY 1.1- Summary 1.1 C. Tbe scope of the work is outlined in this article. Al! of these tasks and materials will not appear in every project. 1.2 - Definitions For consisten! application of this Specification, it is necessary to define terms that have particular meaning in this Specification. The definitions given are for use in application of this Specification only and do not always correspond to ordinary usage. Definitions have been coordinated between the Code and Specification.
- 247. S-4 SPECIFICATION 1.2 - Definitions (Continued) F. Autoclaved aerated concrete (AAC) masonry - Autoclaved aerated concrete units, manufactured without reinforcement, set on a mortar leveling bed, bonded with thin-bed mortar, placed with or without grout, and placed with or without reinforcement. G. Bond beam - A horizontal or sloped element that is fully grouted, has longitudinal bar reinforcement, and is constructed within a masonry wall. H. Bonded prestressing tendon - Prestressing tendon that is encapsulated by prestressing grout in a corrugated duct that is bonded to the surrounding masonry through grouting. l. Cleanouts - Openings that are sized and spaced to allow removal of debris from the bottom ofthe grout space. J. Collarjoint - Vertical longitudinal space between wythes of masonry or between masonry and back up construction, which is permitted to be filled with mortar or grout. K. Compressive strength of masonry - Maximum compressive force resisted per unit of net cross-sectional area of masonry, determined by testing masonry prisms; or a function of individual masonry units, mortar and grout in accordance with the provisions ofthis Specification. L. Contract Documents - Documents establishing the required Work, and including in particular, the Project Drawings and Project Specifications. M. Contractor - The person, firm, or corporation with whom the Owner enters into an agreement for construction ofthe Work. N. Cover, grout - thickness of grout surrounding the outer surface ofembedded reinforcement, anchor, or tie. O. Cover, masonry - thickness of masonry units, mortar, and grout surrounding the outer surface of embedded reinforcement, anchor, or tie. P. Cover, mortar - thickness of mortar surrounding the outer surface ofembedded reinforcement, anchor, or tie. Q. Dimension, nominal - The specified dimension plus an allowance for the joints with which the units are to be laid. Nominal dimensions are usually stated in whole numbers. Thickness is given first, followed by height and then length. R. Dimensions, specified - Dimensions specified for the manufacture or construction ofa unit,joint, or element. S. G/ass unit masonry - Non-load-bearing masonry composed of glass units bonded by mortar. TMS 602-111ACI 530.1-111ASCE 6-11 COMMENTARY G. Bond beam - This reinforced member is usually constructed horizontally, but may be sloped to match an adjacent roof, for example. Q & R. The permitted tolerances for units are given in the appropriate materials standards. Permitted tolerances for joints and masonry construction are given in this Specification. Nominal dimensions are usually used to identify the size ofa masonry unit. The thickness or width is given first, followed by height and length. Nominal dimensions are normally given in whole numbers nearest to the specified dimensions. Specified dimensions are most often used for design calculations.
- 248. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY SPECIFICATION 1.2- Definitions (Continued) T. Grout - (1) A plastic mixture of cementitious materials, aggregates, and water, with or without admixtures, initially produced to pouring consistency without segregation of the constituents during placement. (2) The hardened equivalen! of sueh mixtures. U. Grout, self-consolidating - A highly fluid and stable grout typically with admixtures, that remains homogeneous when placed and does not require puddling or vibration for consolidation. V. Grout lift - An increment ofgrout height within a total grout pour. A grout pour consists ofone or more grout lifts. W. Grout pour - The total height of masonry to be grouted prior to erection of additional masonry. A grout pour consists ofone or more grout lifts. X. Inspection, continuous- The lnspection Agency's full-time observation of work by being present in the area where the work is being perforrned. Y. Inspection, periodic ~ The Inspection Agency's part-time or intermittent observation of work during construction by being present in the area where the work has been or is being performed, and observation upon completion ofthe work. Z. Masonry unit, hollow - A masonry unit with net cross-sectional area of less than 75 percent of its gross cross-sectional area when measured in any plane parallel to the surface containing voids. AA. Masonry unit, solid - A masonry unit with net cross-sectional area of75 percent or more ofits gross cross- sectional area when measured in every plane parallel to the surface containing voids. AB. Mean daily temperature - The average daily temperature of temperature extremes predicted by a local weather bureau for the next 24 hours. AC. Mínimum daily temperature - The low temperature forecast by a local weather bureau to occur within the next 24 hours. AD. Minimum!maximum (not less than . . . not more than) - Mínimum or maximum values given in this Specification are absolute. Do not construe that tolerances allow lowering a mínimum or increasing a maximum. AE. Otherwise required - Specified differently in requirements supplemental to this Specification. AF. Owner - The public body or authority, corporation, association, partnership, or individual for whom the Work is provided. S-5 COMMENTARY X & Y. The lnspection Agency is required to be on the project site whenever masonry tasks requiring continuous inspection are in progress. During construction requiring periodic inspection, the lnspection Agency is only required to be on the project site intermittently, and is required to observe completed work. The frequency of periodic inspections should be defined by the Architect/Engineer as part of the quality assurance plan, and should be consisten! with the complexity and size ofthe project.
- 249. S-6 SPECIFICATION 1.2- Definitions (Continued) AG. Partition wall- An interior wall without structural function. AH. Post-tensioning - Method of prestressing in which prestressing tendons are tensioned after the masonry has been placed. Al. Prestressed masonry - Masonry in which interna! compressive stresses have been introduced by prestressed tendons to counteract potential tensile stresses resulting from applied loads. AJ. Prestressing grout - A cementitious mixture used to encapsulate bonded prestressing tendons. AK. Prestressing tendon - Steel element such as wire, bar, or strand, or a bundle of such elements, used to impart prestress to masonry. AL. Pretensioning - Method of prestressing in which prestressing tendons are tensioned before the transfer of stress into the masonry. AM. Prism - An assemblage of masonry units and mortar, with or without grout, used as a test specimen for determining properties ofthe masonry. AN. Project Drawings - The Drawings that, along with the Proj ect Specifications, complete the descriptive information for constructing the Work required or referred to in the Contract Documents. AO. Project Speci.fications - The written documents that specify requirements for a project in accordance with the service parameters and other specific criteria established by the Owner or his agent. AP. Quality assurance - The administrative and procedural requirements established by the Contract Documents to assure that constructed masonry is in compliance with the Contract Documents. AQ. Reiriforcement - Nonprestressed steel reinforcement. AR. Running bond - The placement of masonry units such that head joints in successive courses are horizontally offset at least one-quarter the unit length. AS. Slump jlow - The circular spread of plastic self- consolidating grout, which is evaluated in accordance with ASTM Cl 611/Cl611M. AT. Speci.fied compressive strength of masonry, f ~. - Mínimum compressive strength, expressed as force per unit of net cross-sectional area, required of the masonry used in construction by the Project Specifications or Project Drawings, and upon which the project design is based. TMS 602-11/ACI530.1-11/ASCE 6-11 COMMENTARY
- 250. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY SPECIFICATION 1.2- Definitions (Continued) AU. Stone masonry - Masonry composed of field, quarried, or cast stone units bonded by mortar. l . Stone masonry, ashlar - Stone masonry composed of rectangular units having sawed, dressed, or squared bed surfaces and bonded by mortar. 2. Stone masonry, rubble - Stone masonry composed of irregular shaped units bonded by mortar. AV. Submit, submitted - Submit, submitted to the Architect/Engineer for review. AW. Tendon anchorage - In post-tensioning, a device used to anchor the prestressing tendon to the masonry or concrete member; in pretensioning, a device used to anchor the prestressing tendon during hardening of masonry mortar, grout, prestressing grout, or concrete. AX. Tendon coupler - A device for connecting two tendon ends, thereby transferring the prestressing force from end to end. AY. Tendonjackingforce- Temporary force exerted by device that introduces tension into prestressing tendons. AZ. Unbonded prestressing tendon - Prestressing tendon that is not bonded to masonry. BA. Veneer, adhered - Masonry veneer secured to and supported by the backing through adhesion. BB. Visual stability index (VSI) - An index, defined in ASTM Cl6l l/C1611M, that qualitatively indicates the stability ofself-consolidating grout BC. Wall- A vertical element with a horizontal length to thickness ratio greater than 3, used to enclose space. BD. Wall, load-bearing - A wall supporting vertical loads greater than 200 lb per lineal foot (2919 N/m) in addition to its own weight. BE. Wall, masonry bonded hollow - A multiwythe wall built with masonry units arranged to provide an air space between the wythes and with the wythes bonded together with masonry units. BF. When required - Specified in requirements supplemental to this Specification. BG. Work - The furnishing and performance of equipment, services, labor, and materials required by the Contract Documents for the construction ofmasonry for the project or part ofproject under consideration. BH. Wythe- Each continuous vertical section ofa wall, one masonry unit in thickness. S-7 COMMENTARY
- 251. S-8 SPECIFICATION 1.3 - Reference standards Standards referred to in this Specification are listed below with their serial designations, including year of adoption or revision, and are declared to be part of this Specification as if fully set forth in this document except as modified here. American Concrete Institute A. ACI 117-06 Standard Specifications for Tolerances for Concrete Construction and Materials (Reapproved 2002) American National Standards Institute B. ANSI A 137.1-08 Standard Specification for Ceramic Tile ASTMInternational C. ASTM A36/A36M-08 Standard Specification for Carbon Structural Steel D. ASTM A82/A82M-07 Standard Specification for Steel Wire, Plain, for Concrete Reinforcement E. ASTM AI23/Al23M-09 Standard Specification for Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products F. ASTM AI53/Al53M-09 Standard Specification for Zinc Coating (Hot-Dip) on Iron and Steel Hardware G. ASTM Al85/A185M-07 Standard Specification for Steel Welded Wire Reinforcement, Plain, for Concrete H. ASTM A240/A240M-09a Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications l. ASTM A307-07b Standard Specification for Carbon Steel Bolts and Studs, 60,000 PSI Tensile Strength J. ASTM A416/A416M-06 Standard Specification for Steel Strand, Uncoated Seven-Wire for Prestressed Concrete K. ASTM A42l/A421M-05 Standard Specification for Uncoated Stress-Relieved Steel Wire for Prestressed Concrete L. ASTM A480/A480M-09 Standard Specification for General Requirements for Flat-Rolled Stainless and Heat-Resisting Steel Plate, Sheet, and Strip M. ASTM A496/A496M-07 Standard Specification for Steel Wire, Deformed, for Concrete Reinforcement TMS 602-11/ACI530.1-11/ASCE 6-11 COMMENTARY 1.3 - Reference standards This list of standards includes material specifications, sampling, test methods, detailing requirements, design procedures, and classifications. Standards produced by ASTM Intemational (ASTM) are referenced whenever possible. Material manufacturers and testing laboratories are familiar with ASTM standards that are the result of a consensus process. In the few cases not covered by existing standards, the committee generated its own requirements. Specific dates are given since changes to the standards alter this Specification. Many of these standards require compliance with additional standards. Contact information for these organizations is given below: American Concrete Institute 38800 Country Club Drive Farmington Hills, MI 48331 www.aci-int.org American National Standards Institute 25 West 43rd Street, New York, NY 10036 www.ansi.org ASTM Intemational 100 Barr Harbor Drive West Conshohocken, PA 19428-2959 www.astm.org American Welding Society 550 N.W. LeJeune Road Miami, Florida 33126 www.aws.org Federal Test Method Standard from: U.S. Army General Material and Parts Center Petroleum Field Office (East) New Cumberland Army Depot New Cumberland, PA 17070
- 252. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY SPECIFICATION 1.3- Reference standards (Continued) N. ASTM A497/A497M-07 Standard Specification for Steel Welded Wire Reinforcement, Deformed, for Concrete O. ASTM A510-08 Standard Specification for General Requirements for Wire Rods and Coarse Round Wire, Carbon Steel P. ASTM A580/A580M-08 Standard Specification for Stainless Steel Wire Q. ASTM A615/A615M-09 Standard Specification for Deformed and P1ain Carbon-Steel Bars for Concrete Reinforcement R. ASTM A641 /A641M-09a Standard Specification for Zinc-Coated (Galvanized) Carbon Steel Wire S. ASTM A653/A653M-08 Standard Specification for Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy-Coated (Galvanealed) by the Hot-Dip Process T. ASTM A666-03 Standard Specification for Annealed or Cold-Worked Austenitic Stainless Steel Sheet, Strip, Plate, and Flat Bar U. ASTM A706/A706M-08a Standard Specification for Low-Alloy Steel Deformed and Plain Bars for Concrete Reinforcement V. ASTM A722/A722M-07 Standard Specification for Uncoated High-Strength Steel Bars for Prestressing Concrete W. ASTM A767/A767M-05 Standard Specification for Zinc-Coated (Galvanized) Steel Bars for Concrete Reinforcement X. ASTM A775/A775M-07b Standard Specification for Epoxy-Coated Steel Reinforcing Bars Y. ASTM A884/A884M-06 Standard Specification for Epoxy-Coated Steel Wire and Welded Wire Reinforcement Z. ASTM A899-91{2007) Standard Specification for Steel Wire, Epoxy-Coated AA. ASTM A95 1/A95 1M-06 Standard Specification for Steel Wire Masonry Joint Reinforcement AB. ASTM A996/A996M-09 Standard Specification for Raii-Steel and Axle-Steel Deformed Bars for Concrete Reinforcement AC. ASTM A1008/AI008M-09 Standard Specification for Steel, Sheet, Cold-Rolled, Carbon, Structural, High- Strength Low-Ailoy, High-Strength Low-Ailoy with Improved Formability, Solution Hardened, and Bake Hardenable AD. ASTM B117-07 Standard Practice for Operating Salt Spray (Fog) Apparatus S-9 COMMENTARY
- 253. S-10 SPECIFICATION 1.3- Reference standards (Continued) AE. ASTM C34-03 Standard Specification for Structural Clay Load-Bearing Wall Tile AF. ASTM C55-06el Standard Specification for Concrete Building Brick AG. ASTM C56-05 Standard Specification for Structural Clay Nonloadbearing Tile AH. ASTM C62-08 Standard Specification for Building Brick (Solid Masonry Units Made from Clay or Shale) Al. ASTM C67-08 Standard Test Methods for Sampling and Testing Brick and Structural Clay Tile AJ. ASTM C73-05 Standard Specification for Calcium Silicate Brick (Sand-Lime Brick) AK. ASTM C90-08 Standard Specification for Loadbearing Concrete Masonry Units AL. ASTM CI09/C I09M-08 Standard Test Method for Compressive Strength ofHydraulic Cement Mortars (Using 2-in. or [50-mm] Cube Specimens) AM. ASTM C126-09 Standard Specification for Ceramic Glazed Structural Clay Facing Tile, Facing Brick, and Solid Masonry Units AN. ASTM C129-06 Standard Specification for Nonloadbearing Concrete Masonry Units AO. ASTM C143/C143M-08 Standard Test Method for Slump ofHydraulic-Cement Concrete AP. ASTM C144-04 Standard Specification for Aggregate for Masonry Mortar AQ. ASTM CIS0-07 Standard Specification for Portland Cement AR. ASTM C212-00 (2006) Standard Specification for Structural Clay Facing Tile AS. ASTM C216-07a Standard Specification for Facing Brick (Solid Masonry Units Made from Clay or Shale) AT. ASTM C270-08 Standard Specification for Mortar for Unit Masonry AU. ASTM C476-09 Standard Specification for Grout for Masonry AV. ASTM C482-02 (2009) Standard Test Method for Bond Strength of Ceramic Tite to Portland Cement Paste AW. ASTM C503-08a Standard Specification for Marble Dimension Stone AX. ASTM C568-08 Standard Specification for Limestone Dimension Stone TMS 602-11/ACI530.1-11/ASCE 6-11 COMMENTARY
- 254. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY SPECIFICATION 1.3- Reference standards (Continued) AY. ASTM C615-03 Standard Specification for Granite Dimension Stone AZ. ASTM C616-08 Standard Specification for Quartz- Based Dimension Stone BA. ASTM C629-08 Standard Specification for Slate Oimension Stone BB. ASTM C652-09 Standard Specification for Hollow Brick (Hollow Masonry Units Made from Clay or Shale) BC. ASTM C744-08 Standard Specification for Prefaced Concrete and Calcium Silicate Masonry Units BD. ASTM C901-04 Standard Specification for Prefabricated Masonry Panels BE. ASTM C920-08 Standard Elastomeric Joint Sealants Specification for BF. ASTM C 1006-07 Standard Test Method for Splitting Tensile Strength of Masonry Units BG. ASTM C 1O19-09 Standard Test Method for Sampling and Testing Grout BH. ASTM Cl072-06 Standard Standard Test Method for Measurement of Masonry Flexura! Bond Strength BI. ASTM Cl 088-09 Standard Specification for Thin Veneer Brick Units Made from Clay or Shale BJ. ASTM Cl3 14-07 Standard Test Method for Compressive Strength ofMasonry Prisms BK. ASTM C1386-07 Standard Specification for Precast Autoclaved Aerated Concrete (AAC) Wall Construction Units BL. ASTM C l405-08 Standard Specification for Glazed Brick (Single Fired, Brick Units) BM. ASTM Cl532-06 Standard Practice for Selection, Removal and Shipment of Masonry Assemblage Specimens from Existing Construction BN. ASTM Cl6ll/Cl611M-09 Standard Test Method for Slump Flow ofSelf-Consolidating Concrete BO. ASTM 0 92-05a Standard Test Method for Flash and Fire Points by Cleveland Open Cup Tester BP. ASTM D95-05el Standard Test Method for Water in Petroleum Products and Bituminous Materials by Oistillation BQ. ASTM 0512-04 Standard Test Methods for Chloride Ion in Water BR. ASTM 0 566-02(2009) Standard Test Method for Dropping Point ofLubricating Grease BS. ASTM 0 610-08 Standard Practice for Evaluating Oegree ofRusting on Painted Steel Surfaces S-11 COMMENTARY
- 255. S-12 SPECIFICATION 1.3- Reference standards (Continued) BT. ASTM D638-08 Standard Test Method for Tensile Properties ofPlastics BU. ASTM D994-98 (2003) Standard Specification for Preforrned Expansion Joint Filler for Concrete (Bituminous Type) BV. ASTM Dl056-07 Standard Specification for Flexible Cellular Materials - Sponge or Expanded Rubber BW. ASTM Dl187-97 (2002)e1 Standard Specification for Asphalt-Base Emulsions for Use as Protective Coatings for Metal BX. ASTM Dl227-95 (2007) Standard Specification for Emulsified Asphalt Used as a Protective Coating for Roofing BY. ASTM D2000-08 Standard Classification System for Rubber Products in Automotive Applications BZ. ASTM D2265-06 Standard Test Method for Dropping Point of Lubricating Orease Over Wide Temperature Range CA. ASTM D2287-96 (2001) Standard Specification for Nonrigid Vinyl Chloride Polymer and Copolymer Molding and Extrusion Compounds CB. ASTM D4289-03 (2008) Standard Test Method for Elastomer Compatibility ofLubricating Oreases and Fluids CC. ASTM E72-05 Standard Test Methods of Conducting Strength Tests ofPanels for Building Construction CD. ASTM E328-02 (2008) Standard Test Methods for Stress Relaxation Tests for Materials and Structures CE. ASTM E5 18-09 Standard Test Methods for Flexura] Bond Strength ofMasonry CF. ASTM E519-07 Standard Test Method for Diagonal Tension (Shear) in Masonry Assemblages CG. ASTM F959M-07 Standard Specification for Compressible-Washer-Type Direct Tension Indicators for Use with Structural Fasteners [Metric] American Welding Society CH. AWS D 1.4-05 Structural Welding Code - Reinforcing Steel Federal Test Method Standard CI. FTMS 791B (1974) Oil Separation from Lubricating Orease (Static Technique). Federal Test Method Standard from the U.S. Army General Material and Parts Center, Petroleum Field Office (East), New Cumberland Army Depot, New Cumberland, PA 17070 TMS 602-11/ACI530.1-11/ASCE 6-11 COMMENTARY
- 256. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY SPECIFICATION 1.4 - System description 1.4 A. Compressive strength requirements - Compressive strength of masonry in each masonry wythe and grouted collar joint shall equal or exceed the applicable f ~ or f ÁAc. For partially grouted masonry, the compressive strength of both the grouted and ungrouted masonry shall equal or exceed the applicable f ~ .. At the transfer of prestress, the compressive strength ofthe masonry shall equal or exceedf ~,;. 1.4 B. Compressive strength determina/ion l. Alternatives for determination of compressive strength - Determine the compressive strength for each wythe by the unit strength method or by the prism test method as specified here. 2. Unit strength method a. Clay masonry - Use Table 1 to determine the compressive strength of clay masonry based on the strength of the units and the type of mortar specified. The following requirements apply to masonry: 1)Units are sampled and tested to verifY conformance with ASTM C62, ASTM C2 16, or ASTMC652. 2)Thickness of bed joints does not exceed 5 / 8 in. (15.9 mm). 3)For grouted masonry, the grout meets one of the following requirements: a) Grout conforms to Article 2.2. b) Grout compressive strength equals or exceeds f 'm but compressive strength is not less than 2,000 psi (13.79 MPa). Determine compressive strength of grout in accordance with ASTM C1019. S-13 COMMENTARY 1.4 - System description 1.4 A. Compressive strength requirements - Design is based on a certain f ~. or f ÁAc and this compressive strength value must be achieved or exceeded. In a multiwythe wall designed as a composite wall, the compressive strength of masonry for each wythe or grouted collarjoint must equal or exceedf ~. orf ÁAc. 1.4 B. Compressive strength determination l. Alternatives for determination of compressive strength - There are two separate methods to determine compressive strength ofmasonry. The unit strength method eliminates the expense of prism tests but is more conservative than the prism test method. The unit strength method was generated by using prism test data as shown in Figures SC-1 and SC-2. The Specification permits the contractor to select the method of determining the compressive strength of masonry unless a method is stipulated in the Project Specifications or Project Drawings. 2. Unit strength method - Compliance with the requirement for f ~, based on the compressive strength of masonry units, grout, and mortar type, is permitted instead of prism testing. The influence of mortar joint thickness is noted by the maximum joint thickness. Grout strength greater than or equal tof 'm fulfills the requirements of Specification Article 1.4 A and Code Section 1.19.6.1. a. Clay masonry - The values of net area compressive strength of clay masonry in Table l were derived using the following equation taken from Reference 1.1 : f~ = A(400+Bf.) where A 1 (inspected masonry) B 0.2 for Type N portland cement-lime mortar, 0.25 for Type Sor M portland cement-lime mortar f,, average compressive strength of clay masonry units, psi f ~. = specified compressive strength ofmasonry Rearranging terms and letting A = 1.0 1" = ~~ -400 Ju B (These equations are for inch-pound units only.) These values were based on testing of solid clay masonry units11 and portland cement-lime mortar. Further testingt.2 has shown that the values are applicable for hollow clay masonry units and for both types of clay
- 257. S-14 TMS 602-11/ACI530.1-11/ASCE 6-11 SPECIFICATION COMMENTARY 1.4 B.2a. Clay masonry (Continued) masonry units with all mortar types. A plot of the data is shown in Figure SC-1. Reference 1.1 uses a height-to-thickness ratio offive as a basis to establish prism compressive strength. The Code uses a different method to design for axial stress so it was necessary to change the basic prism hit ratio to two. This corresponds to the hit ratio used for concrete masonry in the Code and for all masonry in other codes. The net effect is to increase the net area compressive strength of brick masomy by 22 percent over that in Reference l.l. Table 1 - Compressive strength of masonry based on the compressive strength of clay masonry units and type of mortar used in construction Net area compressive strength of Net area compressive clay masonry units, psi (MPa) strength of masonry, psi (MPa) Type M or S mortar Type N mortar 1,700 (11.72) 2,100 (14.48) 1,000 (6.90) 3,350 (23.10) 4,150 (28.61) 1,500 (10.34) 4,950 (34.13) 6,200 (42.75) 2,000 (13.79) 6,600 (45.5 1) 8,250 (56.88) 2,500 (17.24) 8,250 (56.88) 10,300 (71.02) 3,000 (20.69) 9,900 (68.26) - 3,500 (24. 13) 11,500 (79.29) - 4000 (27.58)
- 258. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY SPECIFICATION 1.4 8.2. Unit strength method(Continued) b. Concrete masomy - Use Table 2 to determine the compressive strength of concrete masonry based on the strength of the unit and type of mortar specified. The following Articles must be met: 1)Units are sampled and tested to verizy conformance with ASTM C55 or ASTM C90. 2)Thickness of bed joints does not exceed 5 / 8 in. (15.9 mm). 3)For grouted masonry, the grout meets one of the following requirements: a) Grout conforms to Article 2.2. b) Grout compressive strength equals or exceeds f'm but compressive strength is not less than 2,000 psi (13.79 MPa). Determine compressive strength of grout in accordance with ASTM C1019. 5-15 COMMENTARY b. Concrete masonry - In building codesu·1.4 prior to this Code, the compressive strength of concrete masonry was based on the net cross-sectional area of the masonry unit, regardless of whether the prism was constructed using full or face shell mortar bedding. Furthermore, in those previous codes, the designer was required to base axial stress calculations on the net area of the unit regardless of the type of mortar bedding. This Code, in contras!, computes the compressive strength of masonry based on the mínimum cross-sectional area of that masonry. If the masonry is fully grouted, masonry strength is based on the specified cross-sectional area, including the grouted area; if it is ungrouted but fully bedded, masonry strength is based on the specified net cross-sectional area ofthe unit; and if it is ungrouted and face-shell bedded only, masonry strength is based on the specified area ofthe face shells only. According to ASTM Cl314, compliance with the specified compressive strength of masonry is now determined using a fully bedded prism either grouted or ungrouted to match the specified construction. While each of these changes makes this Code and this Specification easier to use, a recalibration of earlier hollow unit prism test data was required to account for diffcrences between the compressive strength of prisms with full bedding and the compressive strength ofprisms with face-shell bedding. Table 2 lists compressive strength of masonry as related to concrete masonry unit strength and mortar type. These relationships are plotted in Figure SC-2 along with data from 329 testsl.5 • 1 11 • The curves in Figure SC-2 are shown to be conservative when masonry strength is based on unit strength and mortar type. In order to use face shell bedded prism data in determining the unit strength to masonry compressive strength relationship used in the Specification, a correlation factor between face shell prisms and full bedded prisms was developed. Based on 125 specimens tested with full mortar bedding and face shell mortar bedding, the correlation factor was determined to be 1.291.5 · 17 ' u z. The face shell bedded prism strength multiplied by this correlation factor determines the full mortar bedded prism strength which is used in the Code. The unit height will affect the compressive strength of masonry. The lateral expansion ofthe unit dueto unit and mortar incompatibility increases with reduced unit heightl.l3. A reduction factor in the compressive strength of masonry is required for masonry constructed of units less than 4 in. (102 mm) in height, but need not be applied to masonry in which occasional units are cut to fit.
- 259. S-16 TMS 602-11/ACI530.1-11/ASCE 6-11 Table 2- Compressive strength of masonry based on the compressive strength of concrete masonry units and type of mortar used in construction Net area compressive strength of Net area compressive concrete masonry units, psi (MPa) strength of masonry, psi1 (MPa) Type M or S mortar Type N mortar - 1,900 (13.10) 1,350 (9.31) 1,900 (13.10) 2,150 (14.82) 1,500 (10.34) 2,800 (19.31) 3,050 (21.03) 2,000 (13.79) 3,750 (25.86) 4,050 (27.92) 2,500 (17.24) 4,800 (33.10) 5,250 (36.20) 3,000_(_20.69) 1 For units ofless than 4 in. (1 02 mm) height, 85 percent ofthe values listed. ·¡¡; "" • E = Ol e !!! Cií Q) > ·¡¡; (1) !!! a. E o (.) E (1) & ·¡¡; "" • E .... = Ol e ~Q) > ·¡¡; (1) !!! a. E o (.) E (1) ·e Q. COMMENTARY Brick Compressive Strength, fu , MPa 7 o 14 28 41 55 69 83 97 11o 124 6 5 4 3 2 o o o 7 6 5 4 3 2 o o O o o o 00 8 p : 80 o o o ~·: a !· • o o o o 11 o o o o o 1 .. o 1' •l:t ' V r- o o 08.,. o V o• ~""e: ~~ !.a/ ~ 11' ... Assumed f'r, 2 4 6 8 10 12 14 16 18 Brick Compressive Strength, fu , ksi (a) Prism Strength vs. Brick Strength (Type S Mortar, Commercial Laboratories) Brick Compressive Strength, fu , MPa 14 28 41 55 69 83 97 110 124 o o o 1 8 8 ~.~ 8 o 1 8 o o o o _IL o o• .. : 8 o a 8 1" o 1~8 8 o o 8 A r .. V o ,./ • ~ ~ ~ Assumed f'c,. A. 2 4 6 8 10 12 14 16 18 Brick Compressive Strength, fu , ksi (b) Prism Strength vs. Brick Strength (Type S Mortar, SCPI Laboratory) 138 48 41 ro Q. ~ 34 .S::. o, e !!! 28 Cií Q) > ·¡¡; 21 (1) !!! a. E o 14 (.) E (1) ·e Q. 7 o 20 138 48 41 ro Q. ~ 34 = Ol e Q) 28 ~ Q) > ·¡¡; (1) 21 !!! a. E o 14 (.) E (1) ·e Q. 7 o 20 Figure SC-1 - Compressive strength ofmasonry versus clay masonry unit strength
- 260. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY S-17 COMMENTARY Compressive Strength of Concrete Masonry Units, MPa 7 21 5000 rn~TrnnTTrn~Tn~Trnn~Mn~rn~irnn~rn~rn~Trnn o o Type M or S Morlar O Type N Mortar ~o o 4000 flO 28 ll Grouted ll o 8 go o <ti ·¡¡; a.. o. 00 o :::! i- ll ~ o i- e o o e "' o o <ti 3000 "' :::! 21 <ti o :::! .e o o, .e e o, ~ e ~ U5 U5 (1) > 2000 14 (1) ·¡¡; > "' ·¡¡; ~ "' o. ~ E o. o E ü o ü 1000 7 Compressive Strength of Concrete Masonry Units, psi Figure SC-2 - Compressive strength ofconcrete masonry versus.compressive strength ofconcrete.masonry units SPECIFICATION 1.4 B.2. Unit strength method(Continued) c. AAC masonry- Detennine the compressive strength ofmasonry based on the strength ofthe AAC masonry unit only. The following requirements apply to the masonry: 1) Units conform to Article 2.3 E. 2) Thickness of bed joints does not exceed 1/8 in. (3.2 mm). 3) For grouted masonry, the grout meets one of the following requirements: a) Grout confonns to Article 2.2. b) Grout compressive strength equals or exceeds J'AAC but compressive strength is not less than 2,000 psi (13.79 MPa). Determine compressive strength of grout in accordance with ASTM C IOI9. COMMENTARY c. AAC masonry- The strength of AAC masonry, f 'Me, is controlled by the strength class of the AAC unit as defined by ASTM C1386. The strength of the thin-bed mortar and its bond in compression and shear will exceed the strength ofthe unit.
- 261. S-18 SPECIFICATION 1.4 B. Compressive strength determination (Continued) 3.Prism test method - Determine the compressive strength of clay masonry and concrete masonry by the prism test method in accordance with ASTM CI314. 4. Testing prisms from constructed masonry - When approved by the building official, acceptance of masonry that does not meet the requirements of Article 1.4 B.2 or 1.4 B.3 is permitted to be based on tests ofprisms cut from the masonry construction. a. Prism sampling and removal - For each 5,000 square feet (465 m2 ) of wall area in question, saw- cut three prisms from masonry that is at least 28 days old. Obtain a mínimum of three prisms from the project. Select, remove and transport prisms in accordance with ASTM Cl 532. Determ ine the length, width and height dimensions of the prism and test in accordance with ASTM Cl 314. TMS 602-11/ACI 530.1-11/ASCE 6-11 COMMENTARY 3. Prism test method - The prism test method described in ASTM Cl314 was selected as a uniform method oftesting elay masonry and concrete masonry to determine their compressive strengths. Masonry design is based on the compressive strength established at 28 days. The prism test method is used as an altemative to the unit strength method. ASTM C1314 provides for testing masonry prisms at 28 days or at any designated test age. Therefore, a shorter time period, such as a 7-day test, could be used to estímate the 28-day strength based on a previously established relationship between the results of tests conducted at the shorter time period and results of the 28 day tests. Materials and workmanship of the previously established relationship must be representative ofthe prisms being tested. Compliance with the specified compressive strength of masonry can be determined by the prism method instead of the unit strength method. ASTM Cl314 uses the same materials and workmanship to construct the prisms as those to be used in the structure. References 1.14 through 1.18 discuss prism testing. Many more references on the prism test method parameters and results could be added. The adoption of ASTM Cl314 alleviates most of the concems stated in the above references. ASTM C1314 replaced ASTM E447, which was referenced in editions of the Specification prior to 1999. 4. Testing prisms from constructed masonry - While uncommon, there are times when the compressive strength of masonry determined by the unit strength method or prism test method may be questioned or may be lower than the specified strength. Since low strengths could be a result of inappropriate testing procedures or unintentional damage to the test specimens, prisms may be saw-cut from the completed masonry wall and tested. This section prescribes procedures for such tests. Such testing is difficult, requires masonry walls to be constructed at least 28 days before the test, and requires replacement of the sampled wall area. Therefore, concerted efforts should be taken so that strengths determined by the unit strength method or prism test method are adequate. a. Prism sampling and removal - Removal of prisms from a constructed wall requires care so that the prism is not damaged and that damage to the wall is minimal. Prisms must be representative of the wall, yet not contain any reinforcing steel, which would bias the results. As with a prism test taken during construction, a prism test from existing masonry requires three prism specimens.
- 262. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY SPECIFICATION 1.4 B.4. Testing prismsfrom constructed masonry (Continued) b. Compressive strength calculations Calculate the compressive strength of prisms in accordance with ASTM CI3l4. c. Compliance - Strengths determined from saw-cut prisms shall equal or exceed the specified compressive strength of masonry. Additional testing of specimens cut from construction in question is permitted. 1.4 C.Adhered veneer requirements - When adhered veneer is not placed in accordance with Article 3.3 C, determine the adhesion of adhered veneer unit to backing in accordance with ASTM C482. S-19 COMMENTARY b. Compressíve strength calculations Compressive strength calculations from saw-cut specirnens must be based on the net mortar bedded area, or the net mortar bedded area plus the grouted area for grouted prisms. The net area must be determined by the testing agency before the prism is tested. 1.4 C.Adhered veneer requírements - Adhesion should be verified if a form release agent, an applied coating, or a smooth surface is present on the backing.
- 263. S-20 SPECIFICATION 1.5- Submittals 1.5 A. Obtain written acceptance of submittals prior to the use ofthe materials or methods requiring acceptance. 1.5 B. Submit the following: l . Mix designs and test results a. One of the following for each mortar mix, excluding thin-bed mortar for AAC: l)Mix designs indicating type and proportions of ingredients in compliance with the proportion specification ofASTM C270, or 2)Mix designs and mortar tests performed m accordance with the property specification of ASTMC270. b. One ofthe following for each grout mix: l)Mix designs indicating type and proportions of the ingredients according to the proportion requirements ofASTM C476, or 2)Mix designs and grout strength test performed in accordance with ASTM C476, or 3)Compressive strength tests performed in accordance with ASTM Cl019, and slump flow and Visual Stability Index (VSI) as deterrnined by ASTM Cl 611/Cl611M. 2. Material certificates - Material certificates for the following, certifying that each material is in compliance. a. Reinforcement b. Anchors, ties, fasteners, and metal accessories c. Masonry units d. Mortar, thin-bed mortar for AAC, and grout materials e. Self-consolidating grout 3. Construction procedures a. Cold weather construction procedures b. Hot weather construction procedures TMS 602-11/ACI 530.1-11/ASCE 6-11 COMMENTARY 1.5- Submittals Submittals and their subsequent acceptance or rejection on a timely basis will keep the project moving smoothly. If the specifier wishes to require a higher leve! ofquality assurance than the mínimum required by this Specification, submittals may be required for one or more of the following: shop drawings for reinforced masonry and lintels; sample specimens of masonry units, colored mortar, each type of movement joint accessory, anchor, tie, fastener, and metal accessory; and test results for masonry units, mortar, and grout.
- 264. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY S-21 SPECIFICATION COMMENTARY 1.6- Quality assurance 1.6- Quality assurance 1.6 A. Testing Agency's services and duties l. Sample and test in accordance with Table 3, 4, or 5, as specified for the project. 2. Unless otherwise required, report test results to the Architect/Engineer, Inspection Agency, and Contractor promptly after they are performed. lnclude in test reports a summary of conditions under which test specimens were stored prior to testing and state what portion ofthe construction is represented by each test. 3. When there is reason to believe that any material furnished or work performed by the Contractor fails to fulfill the requirements of the Contract Documents, report such discrepancy to the Architect/Engineer, Inspection Agency, and Contractor. 4. Unless otherwise required, the Owner will retain the Testing Agency. Table 3- Level A Quality Assurance Quality assurance consists of the actions taken by an owner or owner's representative, including establishing the quality assurance requirements, to provide assurance that materials and workmanship are in accordance with the contract documents. Quality assurance includes quality control measures as well as testing and inspection to verify compliance. The term quality control was not used in the Specification because its meaning varíes with the perspective of the parties involved in the project. The owner and Architect/Engineer may require a testing laboratory to provide sorne or all of the tests mentioned in Specification Tables 3, 4, and 5. The quality objectives are met when the building is properly designed, completed using materials complying with product specifications using adequate construction practices, and is adequately maintained. Inspection and testing are important components of the quality assurance program, which is used to meet the objective ofquality in construction. Laboratories that comply with the requirements of ASTM CI093 are more likely to be familiar with masonry materials and testing. Specifying that the testing agencies comply with the requirements of ASTM C1093 is suggested. 1.6 A. Testing Agency's services and duties - Implementation of testing and inspection requirements contained in the Quality Assurance Tables requires detailed knowledge of the appropriate procedures. Comprehensiveu 9 • 1. 20 • ·1. 21 • 1. 22 and summaryl.23 • 1. 24 testing and inspection procedures are available from recognized industry sources which may be referenced for assistance in complying with the specified Quality Assurance program. MINIMUM TESTS None MINIMUM INSPECTION Verify compliance with the approved submittals
- 265. S-22 TMS 602-11/ACI 530.1-11/ASCE 6-11 Table 4- Level 8 Quality Assurance MINIMUM TESTS Verification ofSiump flow and Visual Stability Index (VSI) as delivered to the project site in accordance with Article 1.5 B.1.b.3 for self-consolidating grout Verification of/ '.. and!'AAe in accordance with Article 1.4 B prior to construction, except where specifically exempted by the Code. MINIMUM INSPECTION Inspection Task Frequency <•> Reference for Criteria TMS 402/ TMS 602/ Continuous Periodic ACI 530/ ACI 530.1/ ASCE5 ASCE6 l. Verify compliance with the approved submittals X Art. 1.5 2. As masonry construction begins, verify that the following are in compliance: a. Proportions ofsite-prepared mortar X Art. 2. 1, 2.6 A b. Construction ofmortarjoints X Art. 3.3 B c. Grade and size of prestressing tendons and X Art. 2.4 B, anchorages 2.4 H d. Location ofreinforcement, connectors, and X Art. 3.4, 3.6 A prestressing tendons and anchorages e. Prestressing technique X Art. 3.6 B f. Properties ofthin-bed mortar for AAC masonry x<b> x<c) Art. 2.1 e 3. Prior to grouting, verify that the following are in compliance: a. Grout space X Art. 3.2 D, 3.2 F b. Grade, type, and size of reinforcement and X Sec. 1.16 Art. 2.4, 3.4 anchor bolts, and prestressing tendons and anchorages c. Placement ofreinforcement, connectors, and X Sec. 1.1 6 Art. 3.2 E, 3.4, prestressing tendons and anchorages 3.6A d. Proportions ofsite-prepared grout and X Art. 2.6 B, prestressing grout for bonded tendons 2.4 G. l.b e. Construction ofmortarjoints X Art. 3.3 B
- 266. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY S-23 Table 4- Level B Quality Assurance (Continued) MINIMUM INSPECTION Inspection Task Frequency <•> Reference for Criteria TMS 402/ TMS 602/ eontinuous Periodic Ael 530/ Ael530.1/ ASeE5 ASeE6 4. Verify during construction: a. Size and location of structural elements X Art. 3.3 F b. Type, size, and location of anchors, including X Sec. 1.16.4.3, other details ofanchorage of masonry to 1. 17. 1 structural members, frames, or other construction c. Welding ofreinforcement X Sec.2.1.7.7.2, 3.3.3.4 (e), 8.3.3.4(b) d. Preparation, construction, and protection ofmasonry X Art. 1.8 e, 1.8 D during cold weather (temperature below 40°F (4.4°e)) or hot weather (temperature above 90°F (32.2°C)) e. Application and measurement ofprestressing X Art. 3.6 B force f. Placement ofgrout and prestressing grout for X Art. 3.5, bonded tendons is in compliance 3.6 e g. Placement ofAAe masonry units and x<b> x<c ) Art. 3.3 B.8 construction ofthin-bed mortar joints 5. Observe preparation ofgrout specimens, mortar X Art. 1.4 B.2.a.3, specimens, and/or prisms 1.4 B.2.b.3, 1.4 B.2.c.3, 1.4 8.3, 1.4 B.4 (a) Frequency refers to the frequency of mspect1on, wh1ch may be contmuous dunng the task hsted or penod1cally dunng the listed task, as defined in the table. (b) Required for the first 5000 square feet (465 square meters) ofAAe masonry. (e) Required after the first 5000 square feet (465 square meters) ofAAe masonry.
- 267. S-24 TMS 602-11/AC1530.1-11/ASCE 6-11 Table 5- Level C Quality Assurance MINIMUM TESTS Verification off'm andf'AAC in accordance with Article 1.4 B prior to construction and for every 5,000 sq. ft (465 sq. m) during construction Verification ofproportions ofmaterials in premixed or preblended mortar, prestressing grout, and grout other than self-consolidating grout as delivered to the project site Verification of Slump flow and Visual Stability Tndex (VSI) as delivered to the project site in accordance with Article 1.5 B.l.b.3 for self-consolidating grout MINIMUM INSPECTION Inspection Task Frequency <•J Reference for Criteria TMS 402/ TMS 602/ Continuous Periodic ACI 530/ ACI 530.1/ ASCE5 ASCE6 l. Verify compliance with the approved submittals X Art. 1.5 2. Verify that the following are in compliance: a. Proportions ofsite-mixed mortar, grout, and X Art. 2.1, 2.6 A, prestressing grout for bonded tendons 2.6 s, 2.6 e, 2.4 G.l.b b. Grade, type, and size ofreinforcement and anchor X Sec. 1.16 Art. 2.4, 3.4 bolts, and prestressing tendons and anchorages c. Placement ofmasonry units and construction of X Art. 3.3 8 mortar joints d. Placement of reinforcement, connectors, and X Sec. 1.16 Art. 3.2 E, 3.4, prestressing tendons and anchorages 3.6 A e. Grout space prior to grouting X Art. 3.2 D, 3.2 F f. Placement ofgrout and prestressing grout for X Art. 3.5, 3.6 e bonded tendons g. Size and location of structural elements X Art. 3.3 F h. Type, size, and location ofanchors including X Sec. l.l6.4.3, other details ofanchorage ofmasonry to 1.17.1 structural members, frames, or other construction l. Welding ofreinforcement X Sec. 2.1.7.7.2, 3.3.3.4 (e), 8.3.3.4(b) j. Preparation, construction, and protection of X Art. 1.8 C, 1.8 D masonry during cold weather (temperature below 40°F (4.4°C)) or hot weather (temperature above 90°F (32.2°C)) l. Application and measurement ofprestressing X Art. 3.6 8 force m. Placement ofAAC masonry units and X Art. 3.3 8.8 construction ofthin-bed mortar joints n. Properties ofthin-bed mortar for AAC masonry X Art. 2.1 C.! 3. Observe preparation of grout specimens, mortar X Art. 1.4 B.2.a.3, specimens, and/or prisms 1.4 8.2.b.3, 1.4 8.2.c.3, 1.4 BJ, 1.4 8.4 (a) Frequency rcfers to the rrequency ofmspect1on, wh1 ch may be contmuous dunng the task hsted or penod1cally dunng the hsted task, as defined mthe table.
- 268. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY SPECIFICATION 1.6 B. Inspection Agency's services and duties l. lnspect and evaluate in accordance with Table 3, 4, or 5, as specified for the project. 2. Unless otherwise required, report inspection results to the Architect!Engineer, and Contractor promptly after they are performed. Include in inspection reports a summary of conditions under which the inspections were made and state what portion of the construction is represented by each inspection. 3. Furnish inspection reports to the Architect!Engineer and Contractor. 4. When there is reason to believe that any material furnished or work performed by the Contractor fails to fulfill the requirements ofthe Contract Documents, report such discrepancy to the Architect!Engineer and to the Contractor. 5. Submit a final signed report stating whether the Work requiring inspection was, to the best of the Inspection Agency's knowledge, in conformance. Submit the final report to the Architect!Engineer and Contractor. 6. Unless otherwise required, the Owner will retain the lnspection Agency. 1.6 C. Contractor's services and duties l. Permit and facilitate access to the construction sites and the performance ofactivities for quality assurance by the Testing and lnspection Agencies. 2. The use of testing and inspection services does not relieve the Contractor of the responsibility to furnish materials and construction in full compliance. 3. To facilitate testing and inspection, comply with the following: a. Furnish necessary labor to assist the designated testing agency in obtaining and handling samples at the Project. b.Advise the designated Testing Agency and Inspection Agency sufficiently in advance of operations to allow for completion of quality assurance measures and for the assignment ofpersonnel. c. Provide masonry materials required for preconstruction and construction testing. 4. Provide and maintain adequate facilities for the sole use of the testing agency for safe storage and proper curing oftest specimens on the Project Site. 5.ln the submittals, include the results of testing performed to qualify the materials and to establish mix designs. S-25 COMMENTARY 1.6 B. Jnspection Agency's services and duties - The Code and this Specification require that masonry be inspected. The allowable stresses used in the Code are based on the premise that the work will be inspected, and that quality assurance measures will be implemented. Minimum testing and minimum inspection requirements are given in Specification Tables 3, 4, and 5. The Architect!Engineer may increase the amount oftesting and inspection required. The method of payment for inspection services is usually addressed in general conditions or other contract documents and usually is not govemed by this article. 1.6 C. Contractor's services and duties - The contractor establishes mix designs, the source for supply of materials, and suggests change orders. The listing of duties of the inspection agency, testing agency, and contractor provide for a coordination of their tasks and a means of reporting results. The contractor is bound by contract to supply and place the materials required by the contract documents. Perfection is obviously the goal, but factors of safety included in the design method recognize that sorne deviation from perfection w ill exist. Engineering judgment must be used to evaluate reported discrepancies. Tolerances listed in Specification Article 3.3 F were established to assure structural performance and were not based on aesthetic criteria.
- 269. S-26 SPECIFICATION 1.6 D. Sample panels l. For masonry governed by Leve! B or C Quality Assurance (Table 4 or Table 5), construct sample panels ofmasonry walls. a. Use materials and procedures accepted for the Work. b. The mínimum sample panel dimensions are 4 ft by 4ft (1.22 m by 1.22 m). 2. The acceptable standard for the Work is established by the accepted panel. 3. Retain sample panels at the project site until Work has been accepted. 1.6 E. Grout demonstration panel - Prior to masonry construction, construct a grout demonstration panel if proposed grouting procedures, construction techniques, or grout space geometry do not conform to the applicable requirements ofArticles 3.5 C, 3.5 D, and 3.5 E. 1.7- Delivery, storage, and handling 1.7 A. Do not use damaged masonry units, damaged components ofstructure, or damaged packaged material. 1.7 B. Protect cementitious materials for mortar and grout from precipitation and groundwater. l.7 C. Do not use masonry materials that are contaminated. 1.7 D. Store different aggregates separately. 1.7 E. Protect reinforcement, ties, and metal accessories from permanent distortions and store them offthe ground. 1.8 - Project conditions 1.8 A. Construction loads - Do not apply construction Ioads that exceed the safe superimposed load capacity ofthe masonry and shores, ifused. 1.8 B. Masonry protection - Cover top of unfinished masonry work to protect it from the weather. 1.8 C. Cold weather construction - When ambient air temperature is below 40°F (4.4°C), implement cold weather procedures and comply with the following: l. Do not (ay glass unit masonry. 2.Preparation Comply with the following requirements prior to conducting masonry work: a. Do not lay masonry units having either a temperature below 20°F (-6.7°C) or containing frozen moisture, visible ice, or snow on their surface. b. Remove visible ice and snow from the top surface of existing foundations and masonry to receive new construction. Heat these surfaces above freezing, using methods that do not result in damage. TMS 602-11/ACI530.1-11/ASCE 6-11 COMMENTARY 1.6 D. Sample panels - Sample panels should contain the fu(( range of unit and mortar color. Each procedure, including cleaning and application ofcoatings and sealants, should be demonstrated on the sample panel. The effect of these materials and procedures on the masonry can then be determined before large areas are treated. Since it serves as a comparison ofthe finished work, the sample panel should be maintained until the work has been accepted. The specifier has the option of permitting a segment of the masonry construction to serve as a sample panel or requiring a separate stand-alone panel. 1.7- Delivery, storage, and handling The performance of masonry materials can be reduced by contamination by dirt, water, and other materials during delivery or at the project site. Reinforcement and metal accessories are less prone than masonry materials to damage from handling. 1.8 - Project conditions 1.8 C. Cold weather construction - The procedure described in this article represents the committee's consensus of current good construction practice and has been framed to generally agree with masonry industry recommendations1 ' 25 . The provisions of Article 1.8 C are mandatory, even if the procedures submitted under Article 1.5 B.3.a are not required. The contractor has severa) options to achieve the results required in Article 1.8 C. The options are available because ofthe climatic extremes and their duration. When the air temperature at the project site or unit temperatures fall below 40° F (4.4° C), the cold weather protection plan submitted becomes mandatory. Work stoppage may be justified ifa short cold spell is anticipated. Enclosures and heaters can be used as necessary.
- 270. SPECIFICATION FOR MASONRY STRUCTURES AND COMMENTARY SPECIFICATION 1.8 C. Coldweather construction (Continued) 3. Construction - These requirements apply to work in progress and are based on ambient air temperature. Do not heat water or aggregates used in mortar or grout above 140°F (60°C). Comply with the following requirements when the following ambient air temperatures exist: a. 40°F to 32°F (4.4°C to 0°C): 1) Heat sand or mixing water to produce mortar temperature between 40°F (4.4°C) and l20°F (48.9°C) at the time of mixing. 2) Heat grout materials when the temperature ofthe materials is below 32°F (0°C). b. Below 32°F to 25°F (0°C to -3.9°C): 1) Heat sand and mixing water to produce mortar temperature between 40°F (4.4°C) and l20°F (48.9°C) at the time of mixing. Maintain mortar temperature above freezing until used in masonry. 2) Heat grout aggregates and mixing water to produce grout temperature between 70°F {21.1°C) and l20°F (48.9°C) at the time of mixing. Maintain grout temperature above 70°F (21.1°C) at the time of grout placement. 3) Heat AAC units to a mínimum temperature of 40°F (4.4°C) before installing thin-bed mortar. c. Below 25°F to 20°F (-3.9°C to -6.7°C): Comply with Article 1.8 C.3.b and the following: 1) Heat masonry surfaces under construction to 40°F (4.4°C) and use wind breaks or enclosures when the wind velocity exceeds 15 mph (24 km/h). 2) Heat masonry to a mínimum temperature of 40°F (4.4°C) prior to grouting. d. Below 20°F (-6.7°C): Comply with Article 1.8 C.3.c and the following: Provide an enclosure and auxiliary heat to maintain air temperature above 32°F (0°C) within the enclosure. S-27 COMMENTARY Temperature of the masonry mortar may be measured using a metal tip immersion thermometer inserted into a sample ofthe mortar. The mortar sample may be mortar as contained in the mixer, in hoppers for transfer to the working face of the masonry or as available on mortar boards currently being used. The critica! mortar temperatures are the temperatures at the mixer and mortar board locations. The ideal mortar temperature is 60°F to 80°F (15.6°C to 26.7°C). Temperature ofthe masonry unit may be measured using a metallic surface contact thermometer. Temperature ofthe units may be below the ambient temperature if the requirements ofArticle 1.8 C.2.a are met. The contractor may choose to endose the entire area rather than make the sequential materials conditioning and protection modifications. Ambient temperature conditions apply while work is in progress. Minimum daily temperatures apply to the time after grouted masonry is placed. Mean daily temperatures apply to the time after ungrouted masonry is placed. Grout made with Type lii portland cement gains strength more quickly than grout mixed with Type l portland cement. This faster strength gain eliminates the need to protect masonry for the additional 24 hr period. Construction experience, though not formally documented, suggests that AAC thin-bed mortar reaches full strength significantly faster . than masonry mortar; however, it is more sensitive to cold weather applications. AAC masonry also holds heat considerably longer than concrete masonry. Cold weather requirements are therefore different for thin-bed mortar applications as compared to conventional mortar. Cold weather requirements for leveling course mortar and grout remain the same as for other masonry products.
- 271. S-28 SPECIFICATION 1.8 C.4 Cold weather construction (Continued) 4. Protection - These requirements apply after masonry is placed and are based on anticipated mínimum daily temperature for grouted masonry and anticipated mean daily temperature for ungrouted masonry. Protect completed masonry in the following manner: a. Maintain the temperature of glass unit masonry above 40°F (4.4°C) for the first 48 hr after construction. b. Maintain the temperature ofAAC masonry above 32°F (0°C ) for the first 4 hr after thin-bed mortar application. c. 40°F to 25°F (4.4°C to -3 .9°C): Protect newly constructed masonry by covering with a weather- resistive membrane for 24 hr after being completed. d. Below 25°F to 20°F (-3.9°C to -6.7°C): Cover newly constructed masonry completely with weather-resistive insulating blankets, or equal protection, for 24 hr after completion of work. Extend time period to 48 hr for grouted masonry, unless the only cement in the grout is Type lil portland cement. e. Below 20°F (-6.7°C): Maintain newly constructed masonry temperature above 32°F (0°C) for at Jeast 24 hr after being completed by using heated enclosures, electric heating blankets, infared lamps, or other acceptable methods. Extend time period to 48 hr for grouted masonry, unless the only cement in the grout is Type III portland cement. TMS 602-111ACI530.1-111ASCE 6-11 COMMENTARY
- 272. SPECIFICATION FOR MASONRY STRUCTURES AND COMMENTARY SPECIFICATION 1.8 D. Hot weather construction - Implement approved hot weather procedures and comply with the following provisions: l .Preparation- Prior to conducting masonry work: a. When the ambient air temperature exceeds 100°F (37.8°C), or exceeds 90°F (32.2°C) with a wind velocity greater than 8 mph (12.9 km/hr): l)Maintain sand piles in a damp, loose condition. 2)Provide necessary conditions and equipment to produce mortar having a temperature below 120°f (48.9°C). b. When the ambient temperature exceeds Jl5°F (46.1°C), or exceeds 105°F (40.6°C) with a wind velocity greater than 8 mph (12.9 km/hr), implement the requirements of Article 1.8 D.l.a and shade materials and mixing equipment from direct sunlight. 2. Construction - While masonry work is in progress: a. When the ambient air temperature exceeds l00°F (37.8°C), or exceeds 90°F (32.2°C) with a wind velocity greaterthan 8 mph (12.9 km/hr): 1) Maintain temperature of mortar and grout below 120°F (48.9°C). 2) Flush mixer, mortar transport container, and mortar boards with cool water before they come into contact with mortar ingredients or mortar. 3) Maintain mortar consistency by retempering with cool water. 4) Use mortar within 2 hr of initial mixing. 5) Spread thin-bed mortar no more than four feet ahead ofAAC masonry units. 6) Set AAC masonry units within one minute after spreading thin-bed mortar. b. When the ambient temperature exceeds ll5°F (46.1°C), or exceeds 105°F (40.6°C) with a wind velocity greater than 8 mph (12.9 km/hr), implement the requirements of Article 1.8 D.2.a and use cool mixing water for mortar and grout. Ice is permitted in the mixing water prior to use. Do not permit ice in the mixing water when added to the other mortar or grout materials. 3.Protection - When the mean daily temperature exceeds 100°F (37.8°C) or exceeds 90°F (32.2°C) with a wind velocity greater than 8 mph (12.9 krn/hr), fog spray newly constructed masonry until damp, at least three times a day until the masonry is three days old. S-29 COMMENTARY 1.8 D. Hot weather construction - High temperature and low relative humidity increase the rate of moisture evaporation. These conditions can lead to "dryout" (drying ofthe mortar or grout before sufficient hydration has taken place) of the mortar and grout.l.26 Dryout adversely affects the properties of mortar and grout because dryout signals improper curing and associated reduction of masonry strength development. The preparation, construction, and protection requirements in the Specification are mínimum requirements to avoid dryout of mortar and grout and to allow for proper curing. They are based on industry practicel.27 • 1. 29 . More stringent and extensive hot weather practices may be prudent where temperatures are high, winds are strong, and humidity is low. During hot weather, shading masonry materials and equipment reduces mortar and grout temperatures. Scheduling construction to avoid hotter periods ofthe day should be considered. See Specification Commentary Article 2.1 for considerations in selecting mortar materials. The most effective way of reducing mortar and grout batch temperatures is by using cool mixing water. Small batches of mortar are preferred over larger batches to minimize drying time on mortar boards. Mortar should not be used after a maximum of2 hr after initial mixing in hot weather conditions. Use of cool water to retemper, when tempering is permitted, restores plasticity and reduces the mortar temperaturel.25 ·1. 27 '1. 28 . Most mason's sand is delivered to the project in a damp, loose condition with a moisture content ofabout 4 to 6 percent. Sand piles should be kept cool and in a damp, loose condition by sprinkling and by covering with a plastic sheet to limit evaporation. Research suggests that covering and moist curing of concrete masonry walls dramatically improves flexura! bond strength compared to walls not covered or moist cured130 .
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- 274. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY S-31 PART 2- PRODUCTS SPECIFICATION 2.1 - Mortar materials 2.1 A. Provide mortar of the type and color specified, and conforming with ASTM C270. COMMENTARY 2.1 - Mortar materials ASTM C270 contains standards for materials used to make mortar. Thus, component material specifications need not be listed. The Architect/Engineer may wish to include only certain types of materials, or exclude others, to gain better control. There are two methods of specifying mortar under ASTM C270: proportion and property. The proportion specification directs the contractor to mix the materials in tbe volumetric proportions given in ASTM C270. These are repeated in Table SC-1. The property specification instructs the contractor to develop a mortar mix that will yield the specified properties under laboratory testing conditions. Table SC-2 contains tbe required results outlined in ASTM C270. The results are submitted to the Architect/Engineer and the mix proportions developed in the laboratory are maintained in the field. Water added in the field is determined by the mason for both methods of specifying mortar. A mortar mixed in accordance with the proportion requirements of Table SC-1 may have different physical properties than ofa mortar ofthe same type (i.e. Type M, S, N, or O) mixed in accordance with proportions established by laboratory testing to meet the property specification requirements of Table SC-2. Higher lime content increases workability and water retentivity. ASTM C270 has an Appendix with information that can be useful in selecting mortar. Either proportions or properties, but not both, should be specified. A good rule ofthumb is to specify the weakest mortar that will perform adequately, not the strongest. Excessive amounts of pigments used to achieve mortar color may reduce both the compressive and bond strength of the masonry. Conformance to the maximum percentages indicated will limit the loss of strength to acceptable amounts. Due to the fine particle size, the water demand of the mortar increases when coloring pigments are used. Admixtures containing excessive amounts of chloride ions are detrimental to steel items placed in mortar or grout. ASTM C270 specifies mortar testing under laboratory conditions only for acceptance of mortar mixes under the property specifications. Field sampling and testing of mortar is conducted under ASTM C780 and is used to verify consistency of materials and procedures, not mortar strength. ASTM Cl586 provides guidance on appropriate testing ofmortar for quality assurance.
- 275. S-32 TMS 602-11/ACI530.1-11/ASCE 6-11 COMMENTARY Table SC-1 - ASTM C270 mortar proportion specification requirements Proportions by volume cementitious materials) Portland Mortar Masonry Aggregate ratio Mortar Type cement or cement cement Hydrated lime (measured in damp, blended M S N M S N or lime putty loose conditions) cement Cement-lime M 1 - - - - - - Y-1 S 1 - - - - - - over Y-1 to ~ N 1 - - - - - - over ~ to 1Y-t o 1 - - - - - - over 1Y-1 to 2~ Mortar cement M 1 - - 1 - - - - M - 1 - - - - - - Not less than 2 Y-1 S 12 - - 1 - - - - and not more than S 1 - 3 times the sum of - - - - - - N 1 the separate - - - - - - - volumes of o - - - 1 - - - - cementitious Masonry cement M 1 - - - - - 1 - materials. M - - - - 1 - - - S ~ - - - - - 1 - S - - - - - 1 - - N - - - - - - 1 - o - - - - - - 1 - Two atr entrammg matenals shall not be combmed m mortar. Table SC-2- ASTM C270 property specification requirements for laboratory prepared mortar Average Mortar Type compressive Water retention Air content max, Aggregate ratio (measured strength at 28 min, percent percent in damp, loose conditions) days, psi (MPa) Cement-lime M 2500 (17.2) 75 12 S 1800 (12.4) 75 12 N 750 (5.2) 75 141 o 350 (2.4) 75 141 Mortar cement M 2500 (17.2) 75 12 Not less than 2Y-t and not S 1800 (12.4) 75 12 more than 3~ times the sum ofthe N 750 (5.2) 75 141 separate volumes of o 350 (2.4) 75 141 cementitious materials Masonry cement M 2500 (17.2) 75 18 S 1800 (12.4) 75 18 N 750 (5.2) 75 202 o 350 (2.4) 75 202 When structural reinforcement is incorporated in cement-lime or mortar cement mortar, the maximum air content shall be 12 percent. 2 When structural reinforcement is incorporated in masonry cement mortar, the maximum air content shall be 18 percent.
- 276. SPECIFICATION FOR MASONRY STRUCTURES AND COMMENTARY SPECIFICATION 2.1 B.Glass unit masonry - For glass unit masonry, provide Type Sor N mortar that conforrns to Article 2.1 A. 2.1 C. AAC Masonry l. Provide thin-bed mortar specifically manufactured for use with AAC masonry. Testing to verify mortar properties shall be conducted by the thin-bed mortar manufacturer and confirmed by an independent testing agency. a. Provide thin-bed mortar with compressive strength that meets or exceeds the strength of the AAC masonry units. Conduct compressive strength tests in accordance with ASTM Cl09/Cl09M. b. Provide thin-bed mortar with shear strength that meets or exceeds the strength ofthe AAC masonry units. Conduct shear strength tests in accordance with ASTM E519. Cure the gypsum capping for at least 6 hours prior to testing. c. For each specified strength class, provide thin-bed mortar with flexura! tensile strength that is not less than the smaller of: the maximum value specified in the goveming building code; and the modulus of rupture ofthe masonry units. Conduct flexura! strength tests in accordance with ASTM E72, ASTM E518 Method A or ASTM C1072. 1) For conducting flexura! strength tests in accordance with ASTM E518, construct at least five test specimens as stack-bonded prisms at least 32 in. (810 mm) high. Use the type of mortar specified by the AAC unit manufacturer. 2) For flexura! strength tests in accordance with ASTM Cl072, construct test specimens as stack-bonded prisms comprised ofat least 3 bed joints. Test a total of at least 5 joints. Use the type of mortar specified by the AAC unit manufacturer. d. Perform splitting tensile strength tests m accordance with ASTM C l006. S-33 COMMENTARY 2.1 B. Glass unit masonry - ln exterior applications, certain exposure conditions or panel sizes may warrant the use of mortar type with high bond strength. Type S mortar has a higher bond strength than Type N mortar. Portland cement-lime mortars and mortar-cement mortars have a higher bond strength than sorne masonry cement mortars of the same type. The performance of locally available materials and the size and exposure conditions of the panel should be considered when specifying the type of mortar. Manufacturers of glass units recommend using mortar containing a water-repellen! admixture or a cement containing a water-repellen! addition.21 23 A workable, highly water-retentive mortar is recommended for use when conditions of high heat and low relative humidity exist during construction. 2.1 C.AAC masonry - ASTM E72 measures the flexura! strength of a full-sized panel, whereas ASTM E518 and ASTM C1072 measure the flexura! strength of small scale test specimens. ASTM E72 was developed to provide the most realistic assessment of a wall's performance under flexuralloading.
- 277. S-34 SPECIFICATION 2.1 C. AACMasonry (Continued) 2. Mortar for leveling course shall be Type M or S. Conform to the requirements of Article 2.1A. 2.2 - Grout materials 2.2 A. Unless otherwise required, provide grout that conforms to: l . the requirements of ASTM C476, or 2. the material requirements of ASTM C476; attains the specified compressive strength or 2,000 psi (13.79 MPa), whichever is greater, at 28 days when tested in accordance with ASTM CI019; has a slump flow of 24 in to 30in. (610 to 762 mm) as determined by ASTM C161 1/Cl611M; and has a Visual Stability Index (VSI) less than or equal to 1 as determined in accordance with ASTM C16 11/C1611M, Appendix X.l. 2.2 B. Provide a grout demonstration panel, meeting the requirements of Article 1.6 E, when grout conforming to article 2.2 A.2 will be used with AAC masonry. 2.2 C. Do not use admixtures unless acceptable. Field addition of admixtures is not permitted in self-consolidating grout. 2.3- Masonry unit materials 2.3 A. Provide concrete masonry units that conform to ASTM C55, C73, C90, C l29, or C744 as specified. TMS 602-11/ACI 530.1 -11/ASCE 6-11 COMMENTARY 2.2 - Grout materials ASTM C476 contains standards for materials used to make grout. Thus, component material specifications need not be listed. Admixtures for grout include those to increase flow and to reduce shrinkage. Since self-consolidating grouts include admixtures and are delivered to the project site premixed or preblended and certified by the manufacturer, the addition of admixtures in the field is not permitted. Self-consolidating grout meets the material requirements in ASTM C476. Because the mix is highly fluid, traditional slump cone tests for masonry grout are not applicable. The material is qualified by measuring its slump flow and determining its Visual Stability Index (VSI) using ASTM Cl611/Cl611 M. This article does not apply to prestressing grout; see Article 2.4 G.l.b. 2.3- Masonry unit materials 2.3 A. Concrete masonry units are made from lightweight and normal weight aggregate, water, and cement. The units are available in a variety of shapes, sizes, colors, and strengths. Since the properties of the concrete vary with the aggregate type and mix proportions, there is a range of physical properties and weights available in concrete masonry units. Masonry units are selected for the use and appearance desired, with m1mmum requirements addressed by each respective ASTM standard. When particular features are desired such as surface textures for appearance or bond, finish, color, or particular properties such as weight classification, higher compressive strength, fire resistance, therrnal or acoustical performance, these features should be specified separately by the purchaser. Local suppliers should be consulted as to the availability ofunits having the desired features. Concrete brick specified in ASTM C55 and sand- lime brick specified in ASTM C73 are specified by grade. ASTM C55 designates two grades: Grade N and Grade S. Grade N units are for general use, such as in exterior walls above or below grade, which may or may not be exposed to the weather. Grade S units are limited to use above grade in exterior walls with weather- protective coatings and in walls not exposed to weather.
- 278. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY SPECIFICATION 2.3 B. Provide clay or shale masonry units that conform to ASTM C34, C56, C62, Cl26, C212, C216, C652, Cl088, or Cl405 orto ANSI A 137.1, as specified. S-35 COMMENTARY 2.3 A. (Continued) ASTM C73 designates sand-lime brick as either Grade SW or Grade MW. Grade SW brick are intended for use where they will be exposed to freezing temperatures in the presence of moisture. Grade MW brick are limited to applications in which they may be subjected to freezing temperature but in which they are unlikely to be saturated with water. Table SC-3 summarizes the requirements for various concrete masonry units given in the referenced standards. ASTM C744 covers the properties ofunits that have a resin facing on them. The units must meet the requirements ofone ofthe other referenced standards. 2.3 B. Clay or shale masonry units are formed from those materials and referred to as brick or tite. Clay masonry units may be molded, pressed, or extruded into the desired shape. Physical properties depend upon the raw materials, the method of forming, and the firing temperature. Incipient fusion, a melting and joining of the clay particles, is necessary to develop the strength and durability of clay masonry units. A wide variety of unit shapes, sizes, colors, and strengths is available. The intended use determines which standard specification is applicable. Generally, brick units are smaller than ti te, tite is always cored, and brick may be solid or cored. Brick is normally exposed in use and · most tile is covered. Grade or class is determined by exposure condition and has requirements for durability, usually given by compressive strength and absorption. Dimensional variations and allowable chips and cracks are controlled by type. Table SC-4 sumrnarizes the requirements given in the referenced standards. Table SC-3- Concrete masonry unit requirements ASTM Specification Unit Strength Weight Type Grade C55 Concrete brick yes yes yes yes C73 Sand-lime brick yes no no yes C90 Load-bearing units yes yes yes no Cl29 Non-load-bearing units yes yes yes no C744 Prefaced units - - - -
- 279. S-36 SPECIFICATION 2.3 C. Provide stone masonry units that conform to ASTM C503, C568, C615, C616, or C629, as specified. 2.3 D. Provide hollow glass units that are partially evacuated and have a mínimum average glass face thickness of 3 116 in. (4.8 mm). Provide solid glass block units when required. Provide units in which the surfaces intended to be in contact with mortar are treated with polyvinyl butyral coating or latex-based paint. Do not use reclaimed units. T bl SC-4 Cl a e - . k d . ay brtc an t1le requirements TMS 602-11/ACI530.1-11/ASCE 6-11 COMMENTARY 2.3 C. Stone masonry units are typically selected by color and appearance. The referenced standards classify building stones by the properties shown in Table SC-5. The values given in the standards serve as mínimum requirements. Stone is often ordered by a particular quarry or color rather than the classification method in the standard. 2.3 D. Hollow glass masonry units are formed by fusing two molded halves of glass together to produce a partía! vacuum in the resulting cavity. The resulting glass block units are available in a variety of shapes, sizes, and pattems. Underwriters Laboratories inspects the manufacturing and quality control operations of glass block production on a regular basis for UL- approved units. The mínimum face thickness is part of that inspection24 . The block edges are usually treated in the factory with a coating that can be clear or opaque. The primary purpose of the coating is to provide an expansion/contraction mechanism to reduce stress cracking and to improve the mortar bond. Mínimum ASTM % Grade Specification Unit solid Strength Weight Type C34 Load-bearing wall tile a yes yes no C56 Non-load-bearing wall tile b no yes no C62 Building brick (solid) 75 yes yes no Cl26 Ceramic glazed units e yes no yes C212 Structural facing tile b yes no yes C216 Facing brick (solid) 75 yes yes yes C652 Hollow brick a yes yes yes Notes: a. A mínimum percent is given in this specification. The percent solid is a function of the requirements for size and/or number ofcelis as well as the mínimum shell and web thicknesses. b. No mínimum percent solid is given in this specification. The percent solid is a function of the requirements for the number ofcelis and weights per square foot. c. Solid masonry units mínimum percent solid is 75 percent. Hollow masonry units- no mínimum percent solid is given in this specification. Their percent solid is a function of the requirements for number of cells and the mínimum shell and web thicknesses. r bl ses s a e - - tone reqUirements ASTM Compressive Modulus Abrasion Acid Specification Stone Absorption Density strength ofrupture resistance resistance C503 Marble mínimum range mtmmum mínimum mmtmum none C568 Limestone range range range range range none C615 Granite mmtmum mínimum mínimum mínimum mmtmum none C616 Sandstone range range range range range none C629 Slate range none none mínimum mínimum range
- 280. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY 5-37 SPECIFICATION 2.3 E. Provide AAC masonry units that conform to ASTM C1386 for the strength class specified in the Contract Documents. 2.4- Reinforcement, prestressing tendons, and metal accessories 2.4 A. Reinforcing steel - Provide deformed reinforcing bars that conform to one of the following as specified: 1. ASTM A615/A615M 2. ASTMA706/A706M 3. ASTM A767/A767M 4. ASTM A775/A775M 5. ASTM A996/A996M Table SC-6 - Reinforcement and metal accessories ASTM specification Material Use A36/A36M Structural steel Connectors COMMENTARY 2.3 E. AAC masonry units are specified by both compressive strength and density. Various density ranges are given in ASTM Cl386 for specific compressive strengths. Generally, the density is specified based on consideration of thermal, acoustical, and weight requirements. While ASTM Cl386 provides both mínimum compressive strength and corresponding average compressive strength values, AAC masonry is structurally designed based on the specific mínimum compressive strength of the AAC material as determined by ASTM Cl386. 2.4 - Reinforcement, prestressing tendons, and metal accessories See Table SC-6 for a summary ofproperties. Yield strength, Yield stress, ksi (MPa) MPa 36 (248.2) 250 A82/A82 M Steel wire Joint reinforcement, ties 70 (482.7) 485 A167 Stainless steel Bolts, reinforcement, ties 30 (206.9) 205 A185/A185 M Steel welded wire Welded wire reinforcement 75 (517.1) 485 reinforcement A307 Carbon steel Connectors a - A366/A366M Carbon steel Connectors - - A496/A496M Steel wire Reinforcement 75 (517.1) 485 A497/A497M Steel welded wire Reinforcement, welded 70 (482.7) 485 reinforcement wire reinforcement A615/A615M Carbon-steel Reinforcement 40,60 (275.8, 413.7) 300,420 A996/A996M Rail and axle steel Reinforcement 40, 50, 60 (275.8, 344.8, 413.7) 300,350, 420 A706/A706M Low-alloy steel Reinforcement 60 (413.7) - a. ASTM does not define a yteld strength value for ASTM A307, Grade A anchor bolts.
- 281. S-38 SPECJFICATION 2.4 B. Prestressing tendons l. Provide prestressing tendons that conform to one of the following standards, except for those permitted in Articles 2.4 B.2 and 2.4 B.3: a. Wire .....................................ASTM A42JIA421M b. Low-relaxation wire .............ASTM A4211A421M c. Strand ...................................ASTM A416/A4.16M d. Low-relaxation strand ..........ASTM A4!6/A416M e. Bar........................................ASTM A722/A722M 2. Wire, strands, and bars not specifically Iisted in ASTM A416/A416M, A421/A421M, or A722/A722M are permitted, provided that they conform to the mínimum requirements in ASTM A416/A416M, A421/A421M, or A722/A722M and are approved by the Architect/Engineer. 3.Bars and wires of less than 150 ksi (1034 MPa) tensile strength and conforming to ASTM A82/A82M, A510/A510M, A615/A6 15M, A996/A996M, or A706/A706M are permitted to be used as prestressed tendons, provided that the stress relaxation properties have been assessed by tests according to ASTM E328 for the maximum permissible stress in the tendon. 2.4 C.Joint reinforcement l. Provide joint reinforcement that conforms to ASTM A951. Maximum spacing of cross wires in Jadder- type joint reinforcement and of points of connection of cross wires to longitudinal wires of truss-type joint reinforcement shall be 16 in. (400 mm). 2. Deformed reinforcing wire - Provide deformed reinforcing wire that conforms to ASTM A496/A496M. 3. Welded wire reinforcement- Provide welded wire reinforcement that conforms to one of the following specifications: a. Plain ....................................ASTM A185/A185M b. Deformed .............................ASTM A497/A497M 2.4 D.Anchors, ties, and accessories- Provide anchors, ties, and accessories that conform to the following specifications, except as otherwise specified: l. Plate and bent-bar anchors..........ASTM A36/A 36M 2. Sheet-metal anchors and ties ..................................... .............................................ASTM AI008/AI008M 3. Wire mesh ties .........................ASTM Al85/Al85M 4. Wire ties and anchors ..................ASTM A82/A82M 5. Headed anchor bolts ..............ASTM A307, Grade A TMS 602-11/AC1530.1-11/ASCE 6-11 COMMENTARY 2.4 B. Prestressing tendons - The constructibility aspects of prestressed masonry favor the use of rods or rigid strands with mechanical anchorage in ungrouted construction. Mild strength steel bars have been used in prestressed masonry installations in the United States25 • The stress-relaxation characteristics of mild strength bars (ofless than 150 ksi [1034 MPa]) should be determined by tests and those results should be documented.
- 282. SPECIFICATION FOR MASONRY STRUCTURES AND COMMENTARY S-39 SPECIFICATION 2.4 D.Anchors, ties, andaccessories (Continued) 6. Panel anchors (for glass unit masonry) - Provide 13 /4-in. (44.5-mm) wide, 24-in. (6 10-mm) long, 20-gage steel strips, punched with three staggered rows ofelongated holes, galvanized after fabrication. 2.4 E. Stainless steel -Stainless steel items shall be AlSl Type 304 or Type 316, and shall conform to the following: l .Joint reinforcement ..................ASTM A580/A580M 2. Plate and bent-bar anchors......................................... .................... ASTM A480/A480M and ASTM A666 3. Sheet-metal anchors and ties ..................................... .......ASTM A480/A480M and ASTM A240/A240M 4. Wire ties and anchors ..............ASTM A580/A580M 2.4 F. Coatings for corrosion protection - Unless otherwise required, protect carbon steel joint reinforcement, ties, anchors, and steel plates and bars from corrosion by galvanizing or epoxy coating in conformance with the following minimums: l. Galvanized coatings: a. Mili galvanized coatings: 1) Joint reinforcement ........................................ ASTM A641/A641M (0.1 oz/ft2 ) (0.031 kg/m2 ) 2) Sheet-metal ties and sheet-metal anchors ...... ASTM A653/A653M Coating Designation 060 b. Hot-dip galvanized coatings: 1) Joint reinforcement, wire ties, and wire anchors ASTM Al53/Al53M (1.50 oz/ft2 ) (458 g/m2 ) 2) Sheet-metal ties and sheet-metal anchors ......... .......................... ASTM A153/A153M Class B 3) Steel plates and bars (as applicable to size and form indicated)................ASTM A123/A123M ..................... or ASTM A153/Al53M, Class B 2. Epoxy coatings: a. Joint reinforcement ................................................ ............................... ASTM A884/A884M Class A .................................... Type 1- 7 mils (175 J..lm) b. Wire ties and anchors ............................................. ASTM A899/A899M Class C- 20 mils (508 ~tm) c. Sheet-metal ties and anchors.................................. .................................20 mils (508 J..lm) per surface ............................. or manufacturer's specification COMMENTARY 2.4 E. Stainless steel- Corrosion resistance ofstainless steel is greater than that of the other steels listed. Thus, it does not have to be coated for corrosion resistance. 2.4 F. Coatings for corrosion protection - Amount of galvanizing required increases with severity of exposure26 - 2 · 8 • Project documents should specify the level of corrosion protection as required by Code Section 1.16.4.
- 283. S-40 SPECIFICATION 2.4 G. Corrosion protection for tendons - Protect tendons from corrosion when they are in exterior walls exposed to earth or weather or walls exposed to a mean relative humidity exceeding 75 percent (corrosive environment). Select corrosion protection methods for bonded and unbonded tendons from one ofthe following: l.Bonded tendons - Encapsulate bonded tendons in corrosion resistant and watertight corrugated ducts complying with Article 2.4 G. l.a. Fill ducts with prestressing grout complying with Article 2.4 G.l.b. a. Ducts High-density polyethylene or polypropylene. 1) Use ducts that are mortar-tight and non- reactive with masonry, tendons, and grout. 2) Provide ducts with an inside diameter at least 114 in. (6.4 mm) larger than the tendon diameter. 3) Maintain ducts free of water if members to be grouted are exposed to temperatures below freezing prior to grouting. 4) Provide openings at both ends of ducts for grout injection. b. Prestressing grout 1) Select proportions of materials for prestressing grout using either of the following methods as accepted by the Architect/Engineer: a) Results of tests on fresh and hardened prestressing grout - prior to beginning grouting operations, or b) Prior documented experience with similar materials and equipment and under comparable field conditions. 2) Use portland cement conforming to ASTM Cl 50, Type I, II, or III, that corresponds to the type upon which selection of prestressing grout was based. 3) Use the mínimum water content necessary for proper pumping of prestressing grout; however, limit the water-cement ratio to a maximum of0.45 by weight. 4) Discard prestressing grout that has begun to set due to delayed use. 5) Do not use admixtures, unless acceptable to the Architect/Engineer. 6) Use water that is potable and free of materials known to be harmful to masonry materials and reinforcement. TMS 602-11/ACI530.1-11/ASCE 6-11 COMMENTARY 2.4 G. Corrosion protection for tendons - The specified methods of corrosion protection for unbonded prestressing tendons are consistent with corrosion protection requirements developed for single-strand prestressing tendons in concrete2.9. Masonry cover is not sufficient corrosion protection for bonded prestressing tendons in a corrosive environment. Therefore, complete encapsulation into plastic ducts is required. This requirement is consistent with corrosion protection for unbonded tendons. Altemative methods of corrosion protection, such as the use of stainless steel tendons or galvanized tendons, are permitted. Evidence should be provided that the galvanizing used on the tendons does not cause hydrogen embrittlement ofthe prestressing tendon. Protection of prestressing tendons against corrosion is provided by a number of measures. Typically, a proprietary system is used that includes sheathing the prestressing tendon with a waterproof plastic tape or duct. Discussion of the various corrosion-protection systems used for prestressed masonry is available in the literature210 • One example of a corrosion- protection system for the prestressing tendon is shown in Figure SC-3. Chlorides, fluorides, sulfites, nitrates, or other chemicals in the prestressing grout may harm prestressing tendons and shóuld not be used in harmful concentrations. Historically, aggregates have not been used in grouts for bonded, post-tensioned concrete construction. Prestressing Tendon Permanent Corrosion Preventive Grease Plastic Sheath Galvanized Steel or Plastic Pipe Figure SC-3- An example ofa corrosion-protection systemfor an unbonded tendon
- 284. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY SPECIFICATION 2.4 G. Corrosion protection for tendons (Continued) 2. Unbonded tendons - Coat unbonded tendons with a material complying with Article 2.4 G.2b and covered with a sheathing complying with Article 2.4 G.2a. Acceptable materials include a corrosion-inhibiting coating material with a tendon covering (sheathing). a. Provide continuous tendon sheathing over the entire tendon length to prevent loss of coating materials during tendon installation and stressing procedures. Provide a sheathing of medium- density or high-density polyethylene or polypropylene with the following properties: 1) Sufficient strength to withstand damage during fabrication, transport, installation, and tensioning. 2) Water-tightness over the entire sheathing length. 3) Chemical stability without embrittlement or softening over the anticipated exposure temperature range and service life of the structure. 4) Non-reactive with masonry and the tendon corrosion-inhibiting coating. 5) In normal (non-corrosivc) environments, a sheathing thickness ofnot Jess than 0.025 in. (0.6 mm). In corrosive environments, a sheathing thickness ofnot less than 0.040 in. (1.0 mm). 6) An inside diameter at Jeast 0.010 in. (0.3 mm) greater than the maximum diameter of the tendon. 7) For applications in corrosive environments, connect the sheathing to interrnediate and flXed anchorages in a watertight fashion, thus providing a complete encapsulation of the tendon. b. Provide a corrosion-inhibiting coating material with the following properties: 1) Lubrication between the tendon and the sheathing. 2) Resist flow from the sheathing within the anticipated temperature range ofexposure. 3) A continuous non-brittle film at the lowest anticipated temperature ofexposure. 4) Chemically stable and non-reactive with the tendon, sheathing material, and masonry. 5) An organic coating with appropriate polar- moisture displacing and corrosion-preventive additives. S-41 COMMENTARY
- 285. 5-42 SPECIFICATION 2.4 G.2.b. (Continued) 6) A minimum weight not less than 2.5 lb of coating material per 100 ft (37.2 g of coating material per m) of 0.5-in. (12.7-mm) diameter tendon and 3.0 lb ofcoating material per 100ft (44.6 g of coating material per m) of 0.6-in. (15.2-mm) diameter tendon. Use a sufficient amount of coating material to ensure filling of the annular space between tendon and sheathing. 7) Extend the coating over the entire tendon length. 8) Provide test results in accordance with Table 6 for the corrosion-inhibiting coating material. 3. Alternative methods of corrosion protection that provide a protection leve! equivalent to Articles 2.4 G.l and 2.4 G.2 are permitted. Stainless steel prestressing tendons or tendons galvanized according to ASTM A153/A153M, Class B, are acceptable altemative methods. If galvanized, further evidence must be provided that the coating will not produce hydrogen embrittlement of the steel. 2.4 B. Prestressiflg anchorages, couplers, undend blucks 1. Provide anchorages and couplers that develop at least 95 percent of the specified breaking strength of the tendons or prestressing steel when tested in an unbonded condition, without exceeding anticipated set. 2. Place couplers Architect/Engineer. permits anticipated during stressing. where accepted by Enclose with housing that movements of the couplers 3. Protect anchorages, couplers, and end fittings against corrosion 4. Protect exposed anchorages, couplers, and end fittings to achieve the fire-resistance rating required for the element by the legally adopted building code. TMS 602-11/ACI530.1·11/ASCE 6-11 COMMENTARY 2.4 H.Prestressing anchorages, couplers, and end blocks - Typical anchorage and coupling devices are shown in Figure SC-4. Strength ofanchorage and coupling devices should be provided by the manufacturer. Protection of anchorage devices typically includes filling the opening of bearing pads with grease, grouting the recess in bearing pads, and providing drainage of cavities housing prestressing tendons with base flashing and weep holes. When anchorages and end fittings are exposed, additional precautions to achieve the required tire ratings and mechanical protection for these elements must be taken.
- 286. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY S-43 Table 6- Performance specification for corrosion-inhibiting coating Test Test Method Acceptance Criteria Oropping Point, op CC) ASTM 0566 or Mínimum 300 (148.9) ASTM 0 2265 Oil Separation @ 160°F (71.1°C) FTMS 79IB Maximum 0.5 % by weight Method 321.2 Water,% maximum ASTM095 0.1 Flash Point, °F (0 C) ASTM 092 Mínimum 300 (148.9) (Refers to oil component) Corrosion Test ASTM BI 17 For normal environments: Rust Grade 7 or better after 5% Salt Fog@ 100°F (37.8°C) 720 hr of exposure according to ASTM 0 610. For 5 mils (0.13 mm), mínimum hours corrosive environments : Rust Grade 7 or better after (Q Panel type S) 1000 hr of exposure according to ASTM 0610.1 Water Soluble Ions2 a. Chlorides, ppm maximum ASTM 0 512 10 b. Nitrates, ppm maximum 10 c. Sulfides, ppm maximum 10 Soak Test 5% Salt Fog at 100°F (37.8°C) ASTM B117 No emulsification of the coating after 720 hr of 5 mils (0.13 mm) coating, Q panels, (Modified) exposure type S. Immerse panels 50% in a 5% salt solution and expose to salt fog Compatibility with Sheathing a. Hardness and volume change of ASTM04289 Permissible change in hardness 15% polymer after exposure to grease, Permissible change in volume JO% 40 days@ 150°F (65.6°C). b. Tensile strength change of polymer ASTM 0 638 Permissible change in tensile strength 30% after exposure to grease, 40 days @ 150°F (65.6°C). Extension of exposure time to 1000 hours for greases used in corrosive environments requires use of more or better corrosion-inhibiting additives. 2 Procedure: The inside (bottom and sides) of a 33.8 oz (1L) Pyrex beaker, approximate O.D. 4.1 in. (105 mm), height 5.7 in. (145 mm), is thoroughly coated with 35.3 ± 3.5 oz (1 00 ± 10 g) corrosion-inhibiting coating material. The coated beaker is filled with approximately 30.4 oz (900 ce) of distilled water and heated in an oven at a controlled temperature of l00°F ± 2°F (37.8°C ± 1°C) for 4 hours. The water extraction is tested by the noted test procedures for the appropriate water soluble ions. Results are reported as ppm in the extracted water.
- 287. S-44 SPECIFICATION 2.5- Accessories 2.5 A. Unless otherwise required, provide contraction (shrinkage) joint material that conforms to one of the following standards: l. ASTM D2000, M2AA-805 Rubber shear keys with a mínimum durometer hardness of 80. 2. ASTM D2287, Type PVC 654-4 PVC shear keys with a mínimum durometer hardness of 85. 3. ASTM C920. 2.5 B. Unless otherwise required, provide expansionjoint material that conforms to one ofthe following standards: l.ASTM C920. 2.ASTM D994. 3.ASTM Dl056, Class 2A 2.5 C.Asphalt emulsion - Provide asphalt emulsionas follows: l. Metal surfaces.................... ASTM D1187, Type JI 2. Porous surfaces ... ASTM Dl227, Type III, Class 1 STRESSING ANCHORAGE Prefabricated Reinforced Concrete Capping Element Galvanized Steel or Plastic Pipe Threaded Sleeve Tendon Cavity Grouted Salid with Lateral Restraints Required Reinforced Concrete Foundation as Required Prestressing Tendon in Plastic Sheath SELF-ACTIVATING DEAD END ANCHORAGE TMS 602-11/ACI530.1-11/ASCE 6-1 1 COMMENTARY 2.5 - Accessories 2.5 A. and B. Movement joints are used to allow dimensional changes in masonry, minimize random wall cracks, and other distress. Contraction joints (also called control joints or shrinkage joints) are used in concrete masonry to accommodate shrinkage. These joints are free to open as shrinkage occurs. Expansion joints permit clay brick masonry to expand. Material used in expansion joints must be compressible. Placement of movement joints is recommended by severa! publications2 11 • 2 .1 4 • Typical movement joints are illustrated in Figure SC-5. Shear keys keep the wall sections on either side of the movement joint from rnoving out of plane. Proper configuration must be available to fit properly. ASTM C920 covers elastomeric joint sealants, either single or multi-component. Grade NS, Class 25, Use M is applicable to masonry construction. Expansion joint fillers must be compressible so the anticipated expansion of the masonry can occur without imposing stress. Threaded Prestressing Tendon Load lndicator Washer Steel Bearing Plate Special Bearing Masonry Unit Corrosion Protection for Prestressing Tendon Not Shown Tendon Coupler Reinforced Concrete Foundation as Required Figure SC-4 - Typical anchorage and coupling devicesfor prestressed masonry
- 288. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY S-45 COMMENTARY Out-of-Piane Restraint Preformed Gasket Sash Block Units Gasket Type Double Wvthe Masonrv Compressible Material Control Joint Unit Control Block Rake Joint Approx. :V. in. (19 mm) and Caulk Raked Joint _e;;._traction Joint J:l[lmp~""' """"" Single Wvthe Masonrv Grouted Multiwythe Masonrv Figure SC-5 - Movement joints SPECIFICATION 2.5 D. Masonry cleaner l . Use potable water and detergents to clean masonry unless otherwise acceptable. 2. Unless otherwise required, do not use acid or caustic solutions. 2.5 E. Joint fillers - Use the size and shape of joint fillers specified. COMMENTARY 2.5 D. Masonry cleaner- Adverse reactions can occur between certain cleaning agents and masonry units. Hydrochloric acid has been observed to cause corrosion of metal ties. Care should be exercised in its use to minimize this potential problem. Manganese staining, efflorescence, "buming" of the units, white scum removal of the cement paste from the surface of the joints, and damage to metals can occur through improper cleaning. The manufacturers of the masonry units should be consulted for recommended cleaning agents.
- 289. S-46 SPECIFICATION 2.6- Mixing 2.6 A. Mortar J.Mix cementitious materials and aggregates between 3 and 5 minutes in a mechanical batch mixer with a sufficient amount of water to produce a workable consistency. Unless acceptable, do not hand mix mortar. Maintain workability ofmortar by remixing or retempering. Discard mortar which has begun to stiffen or is not used within 2 1 / 2 hr after initial mixing. 2. Limit the weight of mineral oxide or carbon black pigments added to project-site prepared mortar to the following maximum percentages by weight of cement: a. Pigmented portland cement-lime mortar 1) Mineral oxide pigment 2) Carbon black pigment JO percent 2 percent b. Pigmented mortar cement mortar 1) Mineral oxide pigment 2) Carbon black pigment 5 percent 1 percent c. Pigmented masonry cement mortar 1) Mineral oxide pigment 2) Carbon black pigment 5 percent 1 percent Do not add mineral oxide or carbon black pigment to preblended colored mortar or colored cement without the approval of the Architect/Engineer. 3. Do not use admixtures containing more than 0.2 percent chloride ions. 4. Glass unit masonry - Reduce the amount of water to account for the lack of absorption. Do not retemper mortar after initial set. Discard unused mortar within 11 / 2 hr after initial mixing. TMS 602-11/AC1530.1-11/ASCE 6-11 COMMENTARY 2.6- Mixing 2.6 A. Mortar - Caution must be exercised when adding color pigment in field-prepared mortar so that the proportions comply with the Specification requirements. Preblended products are typically certified to the applicable ASTM Standard and the addition of color at the project site may impact mortar performance.
- 290. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY SPECIFICATION 2.6 B. Grout l.Except for self-consolidating grout, mix grout in accordance with the requirements ofASTM C476. 2. Unless otherwise required, mix grout other than self- consolidating grout to a consistency that has a slump between 8 and 11 in. (203 and 279 mm). 3. Proportioning of self-consolidating grout at the project site is not permitted. Do not add water at the project site except in accordance with the self-consolidating grout manufacturer's recommendations. S-47 COMMENTARY 2.6 B. Grout - The two types ofgrout are fine grout and coarse grout, which are defined by aggregate size. ASTM C476 requires the grout type to be specified by proportion or strength requirements, but not by both methods. ASTM proportion requirements are given in Table SC-7. Specified grout compressive strength requirements are based on a mix design that provides the required strength at 28 days, where the required strength must be at least 2,000 psi (14.4 MPa). The permitted ranges in the required proportions of fine and coarse aggregates are intended to accommodate variations in aggregate type and gradation. As noted in Specification Table 7, the selection of the grout type depends on the size of the space to be grouted. Fine grout is selected for grout spaces with restricted openings. Coarse grout specified under ASTM C476 has a maximum aggregate size that will pass through a 3/8 in. (9.5 mm) opening. Larger aggregate, conforming to ASTM C33, can be specified if the grout is placed in areas of unobstructed dimensions greater than 6 in. ( 152 mm). Grout meeting the proportion specifications ofASTM C476 typically has compressive strength ranges shown in Table SC-8 when measured by ASTM C1019. Grout compressive strength is influenced by the water cement ratio, aggregate content, and the type ofw1its used. Since grout is placed in an absorptive form made of masonry units, a high water content is required. A slump of at least 8 in. (203 mm) provides a mix fluid enough to be properly placed and supplies sufficient water to satisfy the water demand ofthe masonry units. Small cavities or cells require grout with a higher slump than larger cavities or cells. As the surface area and unit shell thickness in contact with the grout decrease in relation to the volume of the grout, the slump of the grout should be reduced. Segregation of materials should not occur. The grout in place will have a lower water-cement ratio than when mixed. This concept ofhigh slump and absorptive forms is different from that ofconcrete. Proportioning of self-consolidating grout at the project site is not permitted since the mixes can be sensitive to variations in proportions, and tighter quality control on the mix is required than can be achieved in the field. Typically, self-consolidating grout comes ready mixed from the manufacturer. Self- consolidating grout may also be available as a preblended dry mix requiring the addition of water at the project site. Manufacturers provide instructions on proper mixing techniques and amount of water to be added. Slump values for self-consolidating grout are expressed as a slump tlow because they exceed the 8 in. to 11 in. (203 to 279 mm) slump range for non-self- consolidating grouts.
- 291. S-48 TMS 602-11/ACI530.1-11/ASCE 6-11 COMMENTARY a e - - rou propo T bl se 1 G t rf 1ons b 1y vo ume Aggregate damp, loose1 Grout_ type Cement Lime Fine Coarse Fine 1 Oto 1110 2Y4 to 3 - Coarse 1 Oto 1/10 2Y4 to 3 1 to 2 1 T1mes the sum ofthe volumes ofthe cementitious materials T bl se s G t t th a e -- rou s reng1 s Compressive strength, psi (MPa) Grout type Location Low Mean High Reference Coarse Lab 1,965 (13.55) 3,106 (21.41) 4,000 (27.58) 2.15 Coarse Lab 3,611 (24.90) 4,145 (28.58) 4,510 (31.10) 2.16 Coarse Lab 5,060 (34.89) 5,455 (37.61) 5,940 (40.96) 2.17 SPECIFICATION COMMENTARY 2.6 C. Thin-bed mortar for AAC- Mix thin-bed mortar for AAC masonry as specified by the thin-bed mortar manufacturer. 2.7- Fabrication 2.7 A. Reinforcement l.Fabricate reinforcing bars in accordance with the fabricating tolerances ofACI 117. 2.Unless otherwise required, bend bars cold and do not heat bars. 3. The mínimum inside diameter of bend for stirrups shall be five bar diameters. 4. Do not bend Grade 40 bars in excess of 180 degrees. The mínimum inside diameter of bend is five bar diameters. 5.The mínimum inside bend diameter for other bars is as follows: a. No. 3 through No. 8 (M#1Othrough 25) ..................... ............................................................ 6 bar diameters b.No. 9 through No. 11 (M#29 through 36) ................... ............................................................8 bar diameters 6. Provide standard hooks that conform to the following: a. A standard 180-degree hook: 180-degree bend plus a mínimum extension of 4 bar diameters or 21 / 2 in. (64 mm), whichever is greater. b. A standard 90-degree hook: 90-degree bend plus a mínimum extension of 12 bar diameters. c. For stirrups and tie hooks for a No. 5 (M#l6) bar and smaller: a 90- or 135-degree bend plus a mínimum of 6 bar diameters or 21 / 2 in. (64 mm), whichever is greater. 2.7- Fabrication 2.7 A. Reinforcement - ACI 117 Specifications for Tolerances for Concrete Construction and Materials and Commentary contains fabrication tolerances for steel reinforcement. Recommended methods and standards for preparing design drawings, typical details, and drawings for the fabrications and placing of reinforcing steel in reinforced concrete structures are given in ACI 3152 · 18 and may be used as a reference in masonry design and construction.
- 292. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY SPECIFICATION 2.7 B. Prefabricatedmasonry l. Unless otherwise required, provide prefabricated masonry that conforms to the provisions of ASTM C901. 2. Unless otherwise required, provide prefabricated masonry lintels that have an appearance similar to the masonry units used in the wall surrounding each lintel. 3.Mark prefabricated masonry for proper location and orientation. S-49 COMMENTARY 2.7 B.Prefabricated masonry - ASTM C901 covers the requirements for prefabricated masonry panels, including materials, structural design, dimensions and variations, workmanship, quality control, identification, shop drawings, and handling.
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- 294. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY S-51 PART 3- EXECUTION SPECIFICATION 3.1 - lnspection 3.1 A.Prior to the start of masonry construction, the Contractor shall verify: l. That foundations are constructed within a leve) alignment tolerance of ± 1 / 2 in. (12.7 mm). 2. That reinforcing dowels are positioned in accordance with the Project Drawings. 3.1 B. If stated conditions are not met, notify the Architect/Engineer. Top of Foundation Specified Grade or Elevation -- Maximum Variation (+) --- --- --- Maximum Variation(·) COMMENTARY 3.1 - lnspection 3.1 A. The tolerances in this Article are taken from Reference 3.l. The dimensional tolerances of the supporting concrete are important since they control such aspects as mortar joint thickness and bearing area dimensions, which influence the performance of the masonry. Tolerances for variation in grade or elevation are shown in Figure SC-6. The specified width of the foundation is obviously more critica! than its specified length. A foundation wider than specified will not normally cause structural problems. --- --- --- --- Y. in. (6.4 mm) Maximum Variation from Scale: Horizontal1 in. (25.4 mm) = 10ft (3.0 m) Vertical1 in. (25.4 mm) = 1 in. (25.4 mm) Level or Grade ---- Figure SC-6 - Tolerancefor variation in grade or elevation
- 295. S-52 SPECIFICATION 3.2- Preparation 3.2 A. Clean reinforcement and shanks of anchor bolts by removing mud, oil, or other materials that will adversely affect or reduce bond at the time mortar or grout is placed. Reinforcement with rust, mili scale, or a combination of both are acceptable without cleaning or brushing provided that the dimensions and weights, including heights of deformations, of a cleaned sample are not less than required by the ASTM specification covering this reinforcement in this Specification. 3.2 B. Prior to placing masonry, remove laitance, loose aggregate, and anything else that would prevent mortar from bonding to the foundation. 3.2 C. Wetting masomy units l. Concrete masonry- Unless otherwise required, do not wet concrete masonry or AAC masonry units before laying. Wet cutting is permitted. 2. Clay or shale masonry - Wet clay or shale masonry units having initial absorption rates in excess of 1 g per min. per in.2 (0.0016 g per min. per mm2 ), when measured in accordance with ASTM C67, so the initial rate of absorption will not exceed 1 g per min. per in.2 (0.0016 g per min. per mm2 ) when the units are used. Lay wetted units when surface dry. Do not wet clay or shale masonry units having an initial absorption rate less than 0.2 g per min. per in.Z (0.00031 g per min. per mm2 ). 3.2 D. Debris - Construct grout spaces free of mortar dropping, debris, loose aggregates, and any material deleterious to masonry grout. 3.2 E. Reinforcement - Place reinforcement and ties in grout spaces prior to grouting. 3.2 F. Cleanouts - Provide cleanouts in the bottom course of masonry for each grout pour when the grout pour height exceeds 5 ft 4 in. (1.63 m). l. Construct cleanouts so that the space to be grouted can be cleaned and inspected. In solid grouted masonry, space cleanouts horizontally a maximum of32 in. (813 mm) on center. 2. Construct cleanouts with an opening of sufficient size to permit removal of debris. The mínimum opening dimension shall be 3 in. (76.2 mm). 3. After cleaning, close cleanouts with closures braced to resist grout pressure. TMS 602-11/ACI530.1-11/ASCE 6-11 COMMENTARY 3.2 - Preparation 3.2 C. Wetting masonry units - Concrete masonry units increase in volume when wetted and shrink upon subsequent drying. Water introduced during wet cutting is localized and does not significantly affect the shrinkage potential of concrete masonry. Clay masonry units with high absorption rates dry the mortar/unit interface. This may result in a lower extent of bond between the units and mortar, which may create paths for moisture intrusion. Selection of compatible units and mortar can mitigate this effect. 3.2 D. Debris - Continuity in the grout is critica! for uniform stress distribution. A reasonably clean space to receive the grout is necessary for this continuity. Cells need not be vacuumed to achieve substantial cleanliness. Inspection of the bottom of the space prior to grouting is critica! to ensure that it is substantially clean and does not have accumulations of deleterious materials that would prevent continuity ofthe grout. 3.2 E. Reiriforcement - Loss of bond and misalignment of the reinforcement can occur ifit is not placed priorto grouting. 3.2 F. Cleanouts - Cleanouts can be constructed by removing the exposed face shell of units in hollow unit grouted masonry or individual units when grouting between wythes. The purpose of cleanouts is to allow the grout space to be adequately cleaned prior to grouting. They can also be used to verify reinforcement placement and tying.
- 296. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY 5-53 SPECIFICATION 3.3 - Masonry erection 3.3 A. Bond pattern - Unless otherwise required, !ay masonry in running bond. 3.3 B. Placing mortar and units l. Bed and head joints - Unless otherwise required, construct 3 / 8-in. (9.5-mm) thick bed and head joints, except at foundation or with glass unit masonry. Construct bed joint of the starting course of foundation with a thickness not less than 1 / 4 in. (6.4 mm) and not more than 3 /4 in. (19.1 mm). Provide glass unit masonry bed and head joint thicknesses in accordance with Article 3.3 B.6.c. Constructjoints that also conforrn to the following: a. Fill holes not specified in exposed and below grade masonry with mortar. b. Unless otherwise required, too! joint with a round jointer when the mortar is thumbprint hard. · c. Remove masonry protrusions extending 1 / 2 in. (12.7 mm) or more into cells or cavities to be grouted. 2. Collarjoints - Unless otherwise required, solidly fill collar joints less than 3 /4 in. (19.1 mm) wide with mortar as the project progresses. 3. Hollow units - Place hollow units so: a. Face shells ofbed joints are fully mortared. b. Webs are fully mortared in: 1) al! courses ofpiers, columns and pilasters; 2) when necessary to confine grout or insulation. c. Head joints are mortared, a mínimum distance from each face equal to the face shell thickness ofthe unit. d. Vertical cells to be grouted are aligned and unobstructed openings for grout are provided in accordance with the Project Drawings. 4. So/id units - Unless otherwise required, solidly fill bed and head joints with mortar and: a. Do not fill head joints by slushing with mortar. b. Construct head joints by shoving mortar tight against the adjoining unit. c. Do not deeply furrow bed joints. COMMENTARY 3.3 - Masonry erection 3.3 B. Placing mortar and units - Article 3.3 B applies to masonry construction in which the units support their own weight. Face shell mortar bedding of hollow units is standard, except in locations detailed in Article 3.3 B.3.b. Figure SC-7 shows the typical placement of mortar for hollow-unit masonry walls. In partially grouted walls, however, cross webs next to cells that are to be grouted are usually mortared. If fui! mortar beds throughout are required for structural capacity, for example, the specifier must so stipulate in the Project Specifications or Project Drawings. Figure SC-7 -Mortarplacement ofhollow units in walls
- 297. S-54 SPECIFICATION 3.3 B. Placing mortar and units (Continued) 5. Open-end units with beveled ends - Fully grout open- end units with beveled ends. Head joints of open-end units with beveled ends need not be mortared. At the beveled ends, form a grout key that permits grout within 5/8 inch (15.9 mm) ofthe face of the unit. Tightly butt the units to prevent leakage ofgrout. 6. Glass units a. Apply a complete coat ofasphalt emulsion, not exceeding 1 / 8 in. (3.2 mm) in thickness, to panel bases. b. Lay units so head and bed joints are filled solidly. Do not furrow mortar. c. Unless otherwise required, construct head and bed joints of glass unit masonry 1 /4-in. (6.4-mm) thick, except that vertical joint thickness ofradial panels shall not be less than 1 / 8 in. (3.2 mm). The bed-joint thickness tolerance shall be minus 1 / 16 in. (1.6 mm) and plus 1 / 8 in. (3.2 mm). The head-joint thickness tolerance shall be plus or minus 1 / 8 in. (3.2 mm). d. Do not cut glass units. 7. Al! units a. Place clean units while the mortar is soft and plastic. Remove and re-lay in fresh mortar any unit disturbed to the extent that initial bond is broken after initial positioning. b. Except for glass units, cut exposed edges or faces of masonry units smooth, or position so that exposed faces or edges are unaltered manufactured surfaces. c. When the bearing of a masonry wythe on its support is less than two-thirds of the wythe thickness, notify the Architect/Engineer. TMS 602-11/ACI 530.1-11/ASCE 6-11 COMMENTARY
- 298. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY S-55 SPECIFICATION 3.3 B. Placing mortar and units (Continued) 8. AAC masonry a. Place mortar for leveling bed joint in accordance with the requirements of Article 3.3 B. l. b. Lay subsequent courses using thin-bed mortar. Use special notched trowels manufactured for use with thin-bed mortar to spread thin-bed mortar so that it completely fills the bed joints. Unless otherwise specified in the Contract Documents, similarly fill the head joints. Spread mortar and place the next unit before the mortar dries. Place each AAC unit as close to head joint as possible before lowering the block onto the bed joint. Avoid excessive movement along bed joint. Make adjustments while thin-bed mortar is still soft and plastic by tapping to plumb and bring units into alignment. Set units into final position, in mortar joints approximately 1116-in. (1.5-mm) thick, by striking on the end and top with a rubber mallet. c. Lay units in alignment with the plane of the wall. Align vertically and plumb using the first cuurst: for reference. Make minor adjustments by sanding the exposed faces of the units and the bed joint surface with a sanding board manufactured for use with AAC masonry. 3.3 C. Placing adhered veneer l . Brush a paste of neat portland cement on the backing and on the back ofthe veneer unit. 2. Apply Type S mortar to the backing and to the veneer unit. 3. Tap the veneer unit into place, completely filling the space between the veneer unit and the backing. Sufficient mortar shall be used to create a slight excess to be forced out between the edges of the veneer units. The resulting thickness of the mortar in back of the veneer unit shall not be less than 3 / 8 in. (9.5 mm) nor more than l Y. in. (31.8 mm). 4. Tool the mortar joint with a round jointer when the mortar is thumbprint hard. COMMENTARY 3.3 B.8 AAC Masonry- AAC masonry can be cut, shaped and drilled with tools that are capable of cutting wood; however, saws, sanding boards, and rasps manufactured for use with AAC are recommended for field use. Since thin-bed mortar joints do not readily allow for plumbing of a wall, the ability of AAC masonry to be easily cut and shaped allows for field adjustment to attain required tolerances. 3.3 C Placing adhered veneer- Article 3.3 C applies to adhered veneer in which the backing supports the weight of the units. This basic method has served satisfactorily since the early 1950s. Properly filled and tooled joints (3.3 C.4) are essential for proper performance of adhered veneer.
- 299. S-56 SPECIFICATION 3.3 D. Embedded items and accessories - lnstall embedded items and accessories as follows: l. Construct chases as masonry units are laid. 2. Install pipes and conduits passing horizontally through nonbearing masonry partitions. 3. Place pipes and conduits passing horizontally through piers, pilasters, or columns. 4. Place horizontal pipes and conduits in and parallel to plane ofwalls. 5. Install and secure connectors, flashing, weep holes, weep vents, nailing blocks, and other accessories. 6. Install movementjoints. 7. Aluminum - Do not embed aluminum conduits, pipes, and accessories in masonry, grout, or mortar, unless effectively coated or covered to prevent chemical reaction between aluminum and cement or electrolytic action between aluminum and steel. 3.3 E. Bracing of masonry - Design, provide, and install bracing that will assure stability of masonry during construction. 3.3 F. Site tolerances - Erect masonry within the following tolerances from the specified dimensions. l. Dimension ofelements a. In cross section or elevation ...... ........ ....- 1 / 4 in. (6.4 mm), +1 / 2 in. (12.7 mm) b. Mortar joint thickness bed ...........................................± 1 / 8 in. (3.2 mm) head ...........- 1 / 4 in. (6.4 mm), + 3 / 8 in. (9.5 mm) collar...........-1 / 4 in. (6.4 mm), + 3 / 8 in. (9.5 mm) glass unit masonry .............see Article 3.3 B.6.c c. Grout space or cavity width, except for masonry walls passing framed construction .......... ......... . - 1 / 4 in. (6.4 mm),+ 3 / 8 in. (9.5 mm) TMS 602-11IAC1530.1-11IASCE 6-11 COMMENTARY 3.3 E. Bracing ofmasonry- For guidance on bracing of masonry walls for wind, consult Standard Practice for Bracing Masonry Walls Under Construction32 . 3.3 F. Site tolerances - Tolerances are established to limit eccentricity of applied load. Since masonry is usually used as an exposed material, it is subjected to tighter dimensional tolerances than those for structural frames. The tolerances given are based on structural performance, not aesthetics. The provisions for cavity width shown are for the space between wythes ofnon-composite masonry. The provisions do not apply to situations where masonry extends past floor slabs, spandrel beams, or other structural elements. The remaining provisions set the standard for quality of workmanship and ensure that the structure is not overloaded during construction.
- 300. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY SPECIFICATION 3.3 F. Site tolerances (Continued) 2. Elements a. Variation from leve!: bed joints ....................± 1 / 4 in. (6.4 mm) in JO ft (3.05 m) ............................± 1 / 2 in. ( 12.7 mm) maximum top surface of bearing walls ....................± 1 / 4 in. (6.4 mm) in 10ft (3.05 m) ............................± 1 / 2 in. (12.7 mm) maximum b. Yariation from plumb ....................± 1 / 4 in. (6.4 mm) in JO ft (3.05 m) ....................±3 / 8 in. (9.5 mm) in 20ft (6.10 m) ............................± 1 / 2 in. ( J2.7 mm) maximum c. True to a line ....................±1 /4 in. (6.4 mm) in JO ft (3.05 m) ....................± 3 / 8 in. (9.5 mm) in 20ft (6.JO m) ............................± 1 / 2 in. (12.7 mm) maximum d. Alignment ofcolumns and walls (bottom versus top) ...................................... ±1 / 2 in. (12.7 mm) for bearing walls and columns .......... ± 3 / 4 in. (19.1 mm) for nonbearing walls 3. Location of e1ements a. lndicated in plan ..................± 1 / 2 in. (12.7 mm) in 20ft (6.10 m) ............................±3 / 4 in. (19.1 mm) maximum b. lndicated in elevation .......................± 1 / 4 in. (6.4 mm) in story height ............................±3 /4 in. (19.1 mm) maximum 4.lf the above conditions cannot be met due to previous construction, notify the Architect/Engineer. S-57 COMMENTARY
- 301. S-58 SPECIFICATION 3.4- Reinforcement, tie, and anchor installation 3.4 A.Basic requirements - Place reinforcement, wall ties, and anchors in accordance with the sizes, types, and locations indicated on the Project Drawings and as specified. Do not place dissimilar metals in contact with each other. 3.4 B. Reinforcement l. Support reinforcement to prevent displacement caused by construction loads or by placement of grout or mortar, beyond the allowable tolerances. 2. Completely embed reinforcing bars in grout in accordance with Article 3.5. 3. Maintain clear distance between reinforcing bars and the interior of masonry unit or formed surface of at least 1 /4 in. (6.4 mm) for fine grout and 1 /2 in. (12.7 mm) for coarse grout, except where cross webs of hollow units are used as supports for horizontal reinforcement. 4. Place reinforcing bars maintaining the following mínimum cover: a. Masonry face exposed to earth or weather: 2 in. (50.8 mm) for bars larger than No. 5 (M#I6); IYz in. (38.1 mm) forNo. 5 (M#l6) bars or smaller. b. Masonry not exposed to earth or weather: 1Yz in. (38.1 mm). 5. Maintain mm1mum clear distance between parallel bars of the nominal bar size or 1 in. (25.4 mm), whichever is greater. 6. In columns and pilasters, maintain mínimum clear distance between vertical bars ofone and one-half times the nominal bar size or 1Yz in. (38.1 mm), whichever is greater. 7. Splice only where indicated on the Project Drawings, unless otherwise acceptable. When splicing by welding, provide welds in conformance with the provisions ofAWS D 1.4. 8. Unless accepted by the Architect/Engineer, do not bend reinforcement after it is embedded in grout or mortar. 9. Noncontact lap splices- Position bars spliced by noncontact lap splice no farther apart transversely than one-fifth the specified length of lap nor more than 8 in. (203 mm) TMS 602-11/ACI530.1-11/ASCE 6-11 COMMENTARY 3.4- Reinforcement, tie, and anchor installation The requirements given ensure that: a. galvanic action is inhibited, b. location is as assumed in the design, c. there is sufficient clearance for grout and mortar to surround reinforcement, ties, and anchors so stresses are properly transferred, d. corrosion is delayed, and e. compatible lateral deflection of wythes is achieved. Tolerances for placement of reinforcement in masonry first appeared in the 1985 Uniform Building Code33 . Reinforcement location obviously influences structural performance ofthe member. Figure SC-8 illustrates severa! devices used to secure reinforcement. Figure SC-8- Typical reinforcing barpositioners 9. Noncontact lap splices - Lap splices may be constructed with the bars in adjacent grouted cells if the requirements ofthis section are met.
- 302. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY S-59 SPECIFICATION 3.4 B. Reinforcement (Continued) 10. Joint reinforcement a. Place joint reinforcement so that longitudinal wires are embedded in mortar with a minimum cover of 1 / 2 in. (12.7 mm) when not exposed to weather or earth and 5 / 8 in. (15.9 mm) when exposed to weather or earth. b. Provide minimum 6-in. (152-mm) lap splices for joint reinforcement. c. Ensure that all ends of longitudinal wires ofjoint reinforcement are embedded in mortar at laps. 11. Placement tolerances a. Place reinforcing bars in walls and flexura! elements within a to1erance of ± 1 / 2 in. (12.7 mm) when the distance from the centerline of reinforcing bars to the opposite face of masonry, d, is equal to 8 in. (203 mm) or less, ± 1 in. (25.4 mm) for d equal to 24 in. (610 mm) or less but greater than 8 in. (203 mm), and ± 11 / 4 in. (31.8 mm) for d greater than 24 in. (610 mm). b. Place vertical bars within: 1) 2 in. (50.8 mm) of the required location along the length of the wall when the wall segment length exceeds 24 in. (610 mm). 2) 1 in. (25.4 mm) ofthe required location along the length of the wall when the wall segment length does not exceed 24 in. (61 Omm) c. If it is necessary to move bars more than one bar diameter or a distance exceeding the tolerance stated above to avoid interference with other reinforcing steel, conduits, or embedded items, notify the ArchitecúEngineer for acceptance of the resulting arrangement of bars. COMMENTARY 3.4 B.ll.a. Ways to measure d distance in various common masonry elements are shown in Figures SC-9 through SC-113.4. The maximum permissible tolerance for placement of reinforcement in a wall, beam, and column is based on the d dimension ofthat element. In masonry walls, the d dimension is measured perpendicular to the length ofthe wall and is defmed in the Specification as the distance from the center of the reinforcing bar to the compression face of masonry. The distance, d, to the compression face is normally the larger distance when reinforcing bars are offset from the center of the wall, as shown in Figure SC-9. The d dimension in masonry columns will establish the maximum allowable tolerance for placement ofthe vertical reinforcement. As shown in Figure SC-1O, two dimensions for each vertical bar must be considered to establish the allowable tolerance for placement of the vertical reinforcement in each primary direction. The d dimension in a masonry beam will establish the maximum allowable tolerance for placement of the horizontal reinforcement within the depth of the beam. As shown in Figure SC-11, the distance to the top of beam is used to establish the allowable tolerance for placement of the reinforcement. b The tolerance for placement of vertical reinforcing bars along the length of the wall is shown in Figure SC-9. As shown, the allowable tolerance is +/- 2 in., except for wall segments not exceeding 24 in. where the allowable tolerance is decreased to +/- 1 inch. This tolerance applies to each reinforcing bar relative to the specified location in the wall. An accumulation oftolerances could result in bar placement that interferes with cross webs in hollow masonry units.
- 303. S-60 ~ - o -o e w Specified location ± 1 in. (25.4 mm) TMS 602-11/ACI 530.1-11/ASCE 6-11 COMMENTARY when d s 8 In. (203 mm). lolerance = ± Y. In. (12.7 mm) when 8 in. (203 mm) < d s 24 in. (61 Omm), tolerance =± 1 in. (25.4 mm) when d > 24 in. (610 mm), tolerance = ± 1 Y. in. (31 .8 mm) ... . -· . ..·~ ·.~ .· .. . 1 • .. ' · . . ..·: o10:, . ···' .. 1 , . • •' ,. • · : "' • o 1 ' · ·l . • ,' 1 ' ... : . ..·...·..·.· . When wall segment s 24 In. (610 mm) Acceptab le range of placement -2 in. (50.8 mm) -H+-- +2 in. (50.8 mm) Speclfied location when wall segment exceeds 24 in. (610 mm) Figure SC-9 - Typical 'd' distance in a wall d d r--1-------, - r- d d Figure SC-10 - Typical 'd ' distance in a column
- 304. SPECIFICATION FOR MASONRY STRUCTURES AND COMMENTARY S-61 SPECIFICATION d. Foundation dowels that interfere with unit webs are permitted to be bent to a maximum of 1 in. (25.4 mm) horizontally for every 6 in. (152 mm) of vertical height. COMMENTARY 3.4 B.ll (d) Misaligned foundation dowels may interfere with placement of the masonry units. Interfering dowels may be bent in accordance with this provision (see Figure SC-12) 3 · 5 • 3 · 6 • Removing a portion of the web to better accommodate the dowel may also be acceptable as long as the dowel is fully encapsulated in grout and masonry cover is maintained. 'it> 4 •tr ~) d 4 •tp ~ '1:' ~ Section A-A Figure SC-11- Typical 'd' distance in a beam A y y .. 6 .. ~ .... .. . .. • • ., A. 1 A. • .· .·: . . ·. ..·.. 4 ·· ~ . : • • • A. ..· ~ · • ... •.. • Figure SC-12 - PermittedBending ofFoundation Dowels
- 305. S-62 SPECIFICATION 3.4 C. Wall ties l. Embed the ends of wall ties in mor1ar joints. Embed wall tie ends at least 1 /2 in. (12.7 mm) into the outer face shell of hollow units. Embed wire wall ties at least 1 1 / 2 in. (38.1 mm) into the mortar bed of solid masonry units or solid grouted hollow units. 2. Unless otherwise required, bond wythes not bonded by headers with wall ties as follows: Wire size Minimum number of wall ties required Wl.7 (MWll) W2.8 (MW18) One per 2.67 ft2 (0.25 m2 ) One per 4.50 ft2 (0.42 m2 ) The maximum spacing between ties is 36 in. (914 mm) horizontally and 24 in. (610 mm) vertically. 3. Unless accepted by the Architect/Engineer, do not bend wall ties after being embedded in grout or mortar. 4. Unless otherwise required, install adjustable ties in accordance with the following requirements: a. One tie for each 1.77 ft2 (0.16 m2 ) ofwall area. b. Do not exceed 16 in. (406 mm) horizontal or vertical spacing. c. The maximum misalignment ofbedjoints from one wythe to the other is 11 1 4 in. (31.8 mm). d. The maximum clearance between connecting parts ofthe ties is 1 / 16 in. (1.6 mm) e. When pintle anchors are used, provide ties with one or more pintle leg made ofwire size W2.8 (MW18). 16 in. (406 mm) Max. Vert. Spacing 1.77 Sq. Ft. (0.16 m2) Maximum Wall Surface Area Per Tie -¡, '¡-;:::;!ion J- "-16 in. (406 mm) Max. Horiz. Spacing Spacing of Adjustable Ties TMS 602-11/ACI530.1-11/ASCE 6-11 COMMENTARY 3.4 C. Wall ties- The Code does not permit the use of cavity wall ties with drips, nor the use of Z-ties in ungrouted, hollow unit masonry. The requirements for adjustable ties are shown in Figure SC-13. Vertical Section PlanView 1-t ~.~x . Clear. .~in . (1 .6 mm) Figure SC-13 - Adjustable ties
- 306. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY S-63 SPECIFICATION 3.4 C. Wall ties (Continued) 5. Install wire ties perpendicular to a vertical line on the face of the wythe from which they protrude. Where one-piece ties or joint reinforcement are used, the bed joints ofadjacent wythes shall align. 6. Unless otherwise required, provide additional unit ties around openings larger than 16 in. (406 mm) in either dimension. Space ties around perimeter of opening at a maximum of 3 ft (0.91 m) on center. Place ties within 12 in. (305 mm) ofopening. 7. Unless otherwise required, provide unit ties within 12 in. (305 mm) ofunsupported edges at horizontal or vertical spacing given in Article 3.4 C.2. 3.4 D. Anchor bolts l. Embed headed and bent-bar anchor bolts larger than 4 in. (6.4 mm) diameter in grout that is placed in accordance with Article 3.5 A and Article 3.5 B. Anchor bolts of 4 in. (6.4 mm) diameter or less are permitted to be placed in grout or mortar bed joints that have a specified thickness of at least Yz in. (12.7 mm) thickness. 2. For anchor bolts placed in the top of grouted celis and bond beams, maintain a clear distance between the bolt and the face of masonry unit of at Jeast 4 in. (6.4 mm) when using fine grout and at least Yz in. (12.7 mm) when using coarse grout. 3. For anchor bolts placed through the face shell of a hollow masonry unit, drill a hole that is tight-fitting to the bolt or provide minimum clear distance that conforms to Article 3.4 D.2 around the bolt and through the face shell. For the portien of the bolt that is within the grouted cell, maintain a clear distance between the bolt and the face of masonry unit and between the head or bent leg of the bolt and the formed surface of grout of at least 4 in. (6.4 mm) when using fine grout and at least Yz in. (12.7 mm) when using coarse grout. 4. Place anchor bolts with a clear distance between parallel anchor bolts not less than the nominal diameter of the anchor bolt, nor less than 1 in. (25.4 mm). COMMENTARY 3.4 D. Anchor bolts 3. Quality assurance/control (QA/QC) procedures should assure that there is sufficient clearance around the bolts prior to grout placement. These procedures should also include observation during grout placement to assure that grout completely surrounds the bolts, as required by the QA Tables in Article 1.6.A The clear distance requirement for grout to surround an anchor bolt does not apply where bolt fits tightly in the hole of the face shell, but is required where the bolt is placed in an oversized hole in the face shell and where grout surrounds the anchor bolt in a grouted cell or cavity. See Figure SC-14.
- 307. S-64 TMS 602-11/ACI530.1-11/ASCE 6-11 COMMENTARY Minimum Y. in. (12.7 mm) for coarsegrout orY. in. (6,4mm) forfinegrout AnchorboH AnchorboH Bond beam Figure SC-14 -Anchor bolt clearance requirementsfor headed anchor bolts - bent-bars are similar SPECIFICATION 3.4 E. Veneer anchors - Place corrugated sheet-metal anchurs, sht:ct-mt:lal am:hurs, and wire anchors as follows: l . With solid units, embed anchors in mortar joint and extend into the veneer a mínimum of 1~ in. (38.1 mm), with at least 5 / 8 in. (15.9 mm) mortar cover to the outside face. 2. With hollow units, embed anchors in mortar or grout and extend into the veneer a mínimum of 1 ~ in. (38.1 mm), with at least 5 / 8 in. (15.9 mm) mortar or grout cover to outside face. 3. lnstall adjustable anchors in accordance with the requirements ofArticles 3.4 C.4.c, d, ande. 4. Provide at least one adjustable two-piece anchor, anchor of wire size W 1.7 (MWII), or 22 gage (0.8 mm) corrugated sheet-metal anchor for each 2.67 ft2 (0.25 m2 ) ofwall area. 5. Provide at least one anchor of other types for each 3.5 ft2 (0.33 m2 ) ofwall area. 6. Space anchors at a maximum of 32 in. (813 mm) horizontally and 25 in. (635 mm) vertically, but not to exceed the applicable requirement of Article3.4 E.4 or 3.4 E.5. 7. Provide additional anchors around openings larger than 16 in. (406 mm) in either dimension. Space anchors around the perimeter of opening at a maximum of 3 ft (0.9 m) on center. Place anchors within 12 in. (305 mm) ofopening. COMMENTARY 3.4 E. Veneer anchors - Mínimum embedment requirements have been established for each ofthe anchor types to ensure load resistance against push-through or pullout ofthe mortarjoint.
- 308. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY SPECIFICATION 3.4 F. Glass unit masonry panel anchors - When used instead of channel-type restraints, install panel anchors as follows: l. Unless otherwise required, space panel anchors at 16 in. (406 mm) in both thejambs and across the head. 2. Embed panel anchors a mínimum of 12 in. (305 mm), except for panels less than 2 ft (0.6 1 m) in the direction of embedment. When a panel dimension is Jess than 2 ft (0.61 m), embed panel anchors in the short direction a mínimum of 6 in. (152 mm), unless otherwise required. 3. Provide two fasteners, capable of resisting the required loads, per panel anchor. 3.5 - Grout placement 3.5 A. Placing time - Place grout within 11 / 2 hr from introducing water in the mixture and prior to initial set. l. Discard site-mixed grout that does not meet the specified slump without adding water after initial mixing. 2. For ready-mixed grout: a. Addition of water is permitted at the time of discharge to adjust slump. b. Discard ready-mixed grout that does not meet the specified slump without adding water, other than the water that was added at the time ofdischarge. The time limitation is waived as long as the ready-mixed grout meets the specified slump. 3.5 B. Conjinement - Confine grout to the areas indicated on the Project Drawings. Use material to confine grout that permits bond between masonry units and mortar. S-65 COMMENTARY 3.5 - Grout placement Grout may be placed by pumping or pouring from Jarge or small buckets. The amount of grout to be placed and contractor experience influence the choice of placement method. The requirements of this Article do not apply to prestressing grout. 3.5 A. Placing time - Grout placement is often limited tol 12 hours after initial mixing, but this time period may be too long in hot weather (initial set may occur) and may be unduly restrictive in cooler weather. One indicator that the grout has not reached initial set is a stable and reasonable grout temperature. However, sophisticated equipment and experienced personnel are required to determine initial set with absolute certainty. Article 3.5 A.2 permits water to be added to ready- mixed grout to compensate for evaporation that has occurred prior to discharge. Replacement of evaporated water is not detrimental to ready-mixed grout. However, water may not be added to ready-mixed grout after discharge. 3.5 B. Confinement - Certain locations in the wall may not be grouted in order to reduce dead loads or allow placement of other materials such as insulation or wiring. Cross webs adjacent to cells to be grouted can be bedded with mortar to confine the grout. Metal lath, plastic screening, or other items can be used to plug cells below bond beams.
- 309. S-66 TMS 602-11/ACI 530.1-11/ASCE 6-11 SPECIFICATION COMMENTARY 3.5 C.Grout pour height - Do not exceed the maximum grout pour height given in Table 7. 3.5 C. Grout pour height - Table 7 in the Specification has been developed as a guide for grouting procedures. The designer can impose more stringent requirements if so desired. The recommended maximum height ofgrout pour (see Figure SC-15) corresponds with the least clear dimension of the grout space. The mínimum width of grout space is used when the grout is placed between wythes. The mínimum cell dimensions are used when grouting cells of hollow masonry units. As the height of the pour increases, the mínimum grout space increases. The grout space dimensions are clear dirnensions. See the Commentary for Section 1.19.1 of the Code for additional information. T bl 7 G a e - rout t space reqUiremen s G rout type' Maxim um grout pour height, ft (m) Fine 1 (0.30) Fine 5.33 (1.63) Fine 12.67 (3.86) Fine 24 (7.32) Coarse 1 (0.30) Coarse 5.33 (1.63) Coarse 12.67 (3.86) Coarse 24 (7.32) 1 Fine and coarse grouts are defined in ASTM C476. 2 For grouting between masonry wythes. Grout pour heights and mínimum dimensions that meet the requirements of Table 7 do not automatically mean that the grout space will be filled. Grout spaces smaller than specified in Table 7 have been used successfuJly in some areas. When the contractor asks for acceptance of a grouting procedure that does not meet the limits in Table 7, construction of a grout demonstration panel is required. Destructive or non- destructive evaluation can confirm that filling and adequate consolidation have been achieved. The Architect/Engineer should establish criteria for the grout demonstration panel to assure that critica! masonry elements included in the construction will be represented in the demonstration panel. Because a single grout demonstration panel erected prior to masonry construction cannot account for all conditions that may be encountered during construction, the Architect/Engineer · should establish inspection procedures to verif)r grout placement during construction. These inspection procedures should include destructive or non-destructive evaluation to confmn that filling and adequate consolidation have been achieved. Mínimum clear width M inimum clear grout space dimensions for of grout space,2.3 grouting cells of hollow units,3 • 4 • 5 in. (mm) in. x in. (mm x mm) (19.1) ! 1 / 2 x2(38.1 x50.8) 2 (50.8) 2 X 3 (50.8 X 76.2) il2 (63.5) 2 1 /2 X 3 (63.5 X 76.2) 3 (76.2) 3 X 3 (76.2 X 76.2) 11 / 2 (38.1) 11 /2 X 3 (38.1 X 76.2) 2 (50.8) zl/2 X 3 (63.5 X 76.2) 21 / 2 (63.5) 3 X 3 (76.2 X 76.2) 3 (76.2) 3 X 4 (76.2 X 102) 3 Minimum clear width of grout space and minimum clear grout space dimension are the net dimension ofthe space determined by subtracting masonry protrusions and the diameters ofhorizontal bars from the as-built cross-section ofthe grout space. Select the grout type and maximum grout pour height based on the minimum clearspace. 4 Area ofvertical reinforcement shall not exceed 6 percent of the area ofthe grout space. 5 Minimum grout space dimension for AAC masonry units shall be 3 in. (76.2 mm) x 3 in. (76.2 mm) ora 3 in. (76.2 mm) diameter ce!l.
- 310. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY S-67 SPECIFICATION 3.5 D. Grout lifi height l . For grout conforming to Article 2.2 A. l: a. Where the following conditions are met, place grout in lifts not exceeding 12 ft 8 in. (3.86 m). i. The masonry has cured for at least 4 hours. 11. The grout slump is maintained between 1O and 11 in. (254 and 279 mm). m. No intermediate reinforced bond beams are placed between the top and the bottom ofthe pour height. b. When the conditions of Articles 3.5 D.l.a.i and 3.5 D.l.a.ii are met but there are intermediate bond beams within the grout pour, limit the grout lift height to the bottom of the lowest bond beam that is more than 5 ft 4 in. (1.63 m) above the bottom of the lift, but do not exceed a grout lift height of 12ft 8 in. (3.86 m). c. When the conditions of Article 3.5 D.l.a.i or Article 3.5 D.l.a.ii are not met, place grout in lifts not exceeding 5 ft 4 in. (1.63 m). 2. For self-consolidating grout conforming to Article 2.2: a. When placed in masonry that has cured for at least 4 hours, place in lifts not exceeding the grout pour height. b. When placed in masonry that has not cured for at least 4 hours, place in lifts not exceeding 5 ft 4 in. (1.63 m) 3.5 E. Consolidation l . Consolidate grout at the time ofplacement. a. Consolidate grout pours 12 in. (305 mm) or less in height by mechanical vibration or by puddling. b. Consolidate pours exceeding 12 in. (305 mm) in height by mechanical vibration, and reconsolidate by mechanical vibration after initial water loss and settlement has occurred. 2. Consolidation or reconsolidation is not required for self-consolidating grout. COMMENTARY 3.5 D. Grout lifi height - A lift is the height to which grout is placed into masonry in one continuous operation (see Figure SC-15). After placement of a grout lift, water is absorbed by the masonry units. Following this water loss, a subsequent lift may be placed on top of the still plastic grout. Grouted construction develops fluid pressure in the grout space. Grout pours composed of severa! lifts may develop this fluid pressure for the full pour height. The faces of hollow units with unbraced ends can break out. Wythes may separate. The wire ties between wythes may not be sufficient to prevent this from occurring. Higher lifts may be used with self-consolidating grout because its fluidity and its lower initial water-cement ratio result in reduced potential for fluid pressure problems. The 4-hour time period is stipulated for grout lifts over 5 ft 4 in. (1.63 m) to provide sufficient curing time to minimize potential displacement of units during the consolidation and reconsolidation process. The 4 hours is based on typical curing conditions and may be increased based on local climatic conditions at the time of construction. For example, during cold weather construction, consider increasing the 4-hour curing period. When a wall is to be grouted with self-consolidating grout, the grout lift height is not restricted by intermediate, reinforced bond beam locations because self-consolidating grout easily flows around reinforcing bars3 · 7 • 3 · 8 3.5 E. Consolidation - Except for self-consolidating grout, consolidation is necessary to achieve complete filling of the grout space. Reconsolidation returns the grout to a plastic state and eliminates the voids resulting from the water loss from the grout by the masonry units. It is possible to have a height loss of 8 in. (203 mm) in 8 ft (2.44 m). Consolidation and reconsolidation are normally achieved with a mechanical vibrator. A low velocity vibrator with a 14 in. (19.1 mm) head is used. The vibrator is activated for one to two seconds in each grouted cell of hollow unit masonry. When double open-end units are used, one cell is considered to be formed by the two open ends placed together. When grouting between wythes, the vibrator is placed in the grout at points spaced 12 to 16 in. (305 to 406 mm) apart. Excess vibration does not improve consolidation and may blow out the face shells of hollow units or separate the wythes when grouting between wythes.
- 311. S-68 TMS 602-11/ACI530.1-11/ASCE 6-11 COMMENTARY Cleanout (required when the g height is greater than 5 ft 4 in. Dowels if required by Cleanout (required when the rout pour (1.63 m)) typ. design grout pour _) height is greater than 5 ft 4 in. (1.53 m)) typ. .11 v, ' 1 . : ~ N ;:g S e (!) UJ ~ ;:g S e (!) o ~ ;:g S e (!) (.) ~ ;:g S e (!) CD ~ ;:g S e (!) ~ ~ ;:g :; e (!) Grout (typ) N :; o a. S e (!) ~ :; o a. S e (!) Masonry constructed to the height of Pour 1 and then grouted in lifts Notes: 1. Alter completing grouting for Pour 1, construct masonry to the height of Pour 2 and then grout in lifts. 2. Adhere to the pour height limitations shown in Specification Table 7 and the lift height limitations of Specification Article 3.5 D unless other construction procedures are documented as producing acceptable results vía an approved grout demonstration panel. Figure SC-15 - Groutpour height andgrout /ift height SPECIFICATION 3.5 F. Grout key - When grouting, form grout keys between grout pours. Form grout keys between grout lifts when the first lift is permitted to set prior to placement of the subsequent lift l. Form a grout key by terminating the grout a mínimum of 112 in.(38.1 mm) below a mortarjoint. 2. Do not form grout keys within beams. 3. At beams or lintels laid with closed bottom units, terminate the grout pour at the bottom of the beam or lintel without forming a grout key. 3.5 G.Alternate groutplacement - Place masonry units and grout using construction procedures employed in the accepted grout demonstration panel. 3.5 H. Groutfor AAC masonry- Use grout conforming to ASTM C476. Wet AAC masonry thoroughly before grouting to ensure that the grout flows to completely fill the space to be grouted. Grout slump shall be between 8 in. and 11 in. (203 and 279 mm) when determined in accordance with ASTM C143/C143M. COMMENTARY 3.5 F. Grout key - The top of a grout pour should not be located at the top ofa unit, but at a minimum of 1Yz in. (38 mm) below the bedjoint. If a lift of grout is permitted to set prior to placing the subsequent lift, a grout key is required within the grout pour. This setting normally occurs if the grouting is stopped for more than one hour. 6" MIN. ACI530-08
- 312. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY S-69 SPECIFICATION 3.6- Prestressing tendon installation and stressing procedure 3.6 A. Site tolerances l . Tolerance for prestressing tendon placement in the out-of-plane direction in walls shall be ± 1 / 4 in. (6.4 mm) for masonry cross-sectional dimensions less than nominal 8 in. (203 mm) and ± 3 / 8 in. (9.5 mm) for masonry cross-sectional dimensions equal to or greater than nominal 8 in. (203 mm). 2. Tolerance for prestressing tendon placement in the in-plane direction of walls shall be ± 1 in. (25.4 mm). 3. If prestressing tendons are moved more than one tendon diameter or a distance exceeding the tolerances stated in Articles 3.6 A. l and 3.6 A.2 to avoid interference with other tendons, reinforcement, conduits, or embedded items, notify the Architect/Engineer for acceptance of the resulting arrangement ofprestressing tendons. 3.6 B. Application and measurement of prestressing force l . Determine the prestressing force by both of the following methods: a. Measure the prestressing tendon elongation and compare it with the required elongation based on average load-elongation curves for the prestressing tendons. b. Observe the jacking force on a calibrated gage or load cell or by use of a calibrated dynamometer. For prestressing tendons using bars of less than 150 ksi (1034 MPa) tensile strength, Direct Tension lndicator (DTI) washers complying with ASTM F959M are acceptable. 2. Ascertain the cause of the difference in force determined by the two methods described in Article 3.6 B.l. when the difference exceeds 5 percent for pretensioned elements or 7 percent for post-tensioned elements, and correct the cause of the difference. 3. When the totalloss of prestress dueto unreplaced broken prestressing tendons exceeds 2 percent of total prestress, notify the Architect!Engineer. COMMENTARY 3.6 - Prestressing tendon installation and stressing procedure Installation oftendons with the specified tolerances is common practice. The methods of application and measurement ofprestressing force are common techniques for prestressed concrete and masonry members. Designer, contractor, and inspector should be experienced with prestressing and should consult the Post-Tensioning Institute's Field Procedures Manual for Unbonded Single Strand Tendons3 9 or similar literature before conducting the Work. Critica) aspects of the prestressing operation that require inspection include handling and storage ofthe prestressing tendons and anchorages, installation of the anchorage hardware into the foundation and capping members, integrity and continuity of the corrosion- protection system for the prestressing tendons and anchorages, and the prestressing tendon stressing and grouting procedures. The design method in Code Chapter 4 is based on an accurate assessment of the leve) of prestress. Tendon elongation and tendon force measurements with a calibrated gauge or load cell or by use of a calibrated dynamometer have proven to provide the required accuracy. For tendons using steels of less than 150 ksi (1034 MPa) strength, Direct Tension lndicator (DTI) washers also provide adequate accuracy. These washers have dimples that are intended to compress once a predetermined force is applied on them by the prestressing force. These washers were first developed by the steel industry for use with high-strength bolts and have been modified for use with prestressed masonry. The designer should verify the actual accuracy of DTI washers and document it in the design. Buming and welding operations in the vicinity of prestressing tendons must be carefully performed since the heat may lower the tendon strength and cause failure of the stressed tendon.
- 313. S-70 SPECIFICATION 3.6 C. Grouting bonded tendons l . Mix prestressing grout in equipment capable of continuous mechanical mixing and agitation so as to produce uniform distribution of materials, pass through screens, and pump in a manner that will completely fill tendon ducts. 2. Maintain temperature ofmasonry above 35°F (1.7°C) at time of grouting and until field-cured 2 in. (50.8 mm) cubes of prestressing grout reach a mínimum compressive strength of 800 psi (5.52MPa). 3. Keep prestressing grout temperatures below 90°F (32.2°C) during mixing and pumping. 3.6 D. Burning and welding operations - Carefully perform buming and welding operations in the vicinity of prestressing tendons so that tendons and sheathings, if used, are not subjected to excessive temperatures, welding sparks, or grounding currents. 3.7- Field quality control 3.7 A. Verifyf'm andf:.Uc in accordance with Article 1.6. 3.7 B. Sample and test grout as required by Articles 1.4 B and 1.6. 3.8 - Cleaning Clean exposed masonry surfaces of stains, efflorescence, mortar or grout droppings, and debris. TMS 602-11/ACI530.1-11/ASCE 6-11 COMMENTARY 3.7- Field quality control 3.7 A. The specified frequency oftesting must equal or exceed the mínimum requirements of the quality assurance tables. 3.7B. ASTM Cl019 requires a mold for the grout specimens made from the masonry units that will be in contact with the grout. Thus, the water absorption from the grout by the masonry units is simulated. Sampling and testing frequency may be based on the volume of grout to be placed rather tban the wall area.
- 314. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY S -71 FOREWORD TO SPECIFICATION CHECKLISTS SPECIFICATION Fl. This Foreword is included for explanatory purposes only; it does not form a part of Specification TMS 602- 11/ACI 530.1-11/ASCE 6-11. F2. Specification TMS 602-1 1/ACI 530.1- 11/ASCE 6- 11 may be referenced by the Architect/Engineer in the Project Specification for any building project, together with supplementary requirements for the specific project. Responsibilities for project participants must be defined in the Project Specification. F3. Checklists do not form a part of Specification TMS 602-1 1/ACl 530.1-11/ASCE 6-11. Checklists assist the Architect/Engineer in selecting and specifying project requirements in the Project Specification. The checklists identify the Sections, Parts, and Articles of the reference Specification and the action required or available to the Architect/Engineer. F4. The Architect/Engineer must make adjustments to the Specification based on the needs of a particular project by reviewing each of the items in the checklists and including the items the Architect/Engineer se1ects as mandatory requirements in the Project Specification. FS. The Mandatory Requirements Checklist indicates work requirements regarding specific qualities, procedures, materials, and performance criteria that are not defined in Specification TMS 602-11/ACI 530.1-1 1/ASCE 6-11 or requirements for which the Architect/Engineer must define which ofthe choices apply to the project. F6. The Optional Requirements Checklist identifies Architect!Engineer choices and alternatives. COMMENTARY Fl. No Commentary F2. Building codes (of which this standard is a part by reference) set mínimum requirements necessary to protect the public. Project specifications may stipulate requirements more restrictive than the mínimum. Adjustments to the needs of a particular project are intended to be made by the Architect/Engineer by reviewing each of the items in the Checklists and then including the Architect/Engineer's decision on each ítem as a mandatory requirement in the project specifications. F3. The Checklists are addressed to each ítem of this Specification where the Architect/Engineer must or may make a choice of alternatives; may add provisions if not indicated; or may take exceptions. The Checklists consist of two columns; the first identifies the sections, parts, and articles of the Specification, and the second column contains notes to the Architect/Engineer to indicate the type ofaction required by the Architect!Engineer.
- 315. S-72 TMS 602-11/ACI530.1-11/ASCE 6-11 MANDATORY REQUIREMENTS CHECKLIST Section/Part/Article Notes to the Architect/Engineer PART 1 -GENERAL 1.4 A Compressive strength requirements Specifyf 'm andf ÁAc, except for veneer, glass unit 1.4 B.2 Unit strength method 1.6 Quality assurance 1.6 A.l Testing Agency's services and duties 1.6 B.l Inspection Agency's services and duties PART 2- PRODUCTS 2.1 Mortar materials 2.3 Masonry unit materials 2.4 Reinforcement, prestressing tendons, and metal accessories 2.4 C.3 Welded wire reinforcement 2.4 E Stainless steel 2.4 F Coating for corrosion protection 2.4 G Corrosion protection for tendons 2.4 H Prestressing anchorages, couplers, and end blocks 2.5 E Joint fillers 2.7 B Prefabricated masonry masonry, and empirically designed masonry. Specifyf 'mi for prestressed masonry. Specify when strength ofgrout is to be determined by test. 1 Define the submittal reporting and review procedure. Specify which ofTables 3, 4, or 5 applies to the project. Specify which portions of the masonry were designed in accordance with the empírica!, veneer, or glass unit masonry provisions of this Code and are, therefore, exempt from verification off'm. Specify which ofTables 3, 4, or 5 applies to the project. Specify which portions of the masonry were designed in accordance with the empírica!, veneer, or glass unit masonry provisions of this Code and are, therefore, exempt from verification off'm. Specify type, color, and cementitious materials to be used in mortar and mortar to be used for the various parts of the project and the type of mortar to be used with each type of masonry unit. Specify the masonry units to be used for the various parts ofthe projects. Specify type and grade of reinforcement, tendons, connectors, and accessories. Specify when welded wire reinforcement is to be plain. Specify when stainless steel joint reinforcement, anchors, ties, and/or accessories are required. Specify the types ofcorrosion protection that are required for each portien ofthe masonry construction. Specify the corrosion protection method. Specify the anchorages and couplers and their corrosion protection. Specify size and shape ofjoint fillers. Specify prefabricated masonry and requirements in supplement ofthose of ASTM C90l .
- 316. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY MANDATORY REQUIREMENTS CHECKLIST (Continued) Section/Part/Article PART 3- EXECUTION 3.3 D.2-4 Pipes and conduits 3.3 D.S Accessories 3.3 D.6 Movementjoints 3.4 B.ll Placement tolerances 3.4 E Veneer anchors Notes to the Architect/Engineer Specify sleeve sizes and spacing. Specify accessories not indicated on the project drawings. Indicate type and location of movementjoints on the project drawings. Indicate d distance for beams on drawings or as a schedule in the project specifications. Specify type ofanchor required. S-73
- 317. 5-74 TMS 602-11/ACI530.1-11/ASCE 6-11 OPTIONAL REQUIREMENTS CHECKLIST 1.5 B 1.6 2.2 Section/Part/Article PART 1 -GENERAL Quality assurance PART 2- PRODUCTS 2.5 A Movement joint and 2.5 B 2.5 D Masonry cleaner 2.6 A Mortar 2.6 B.2 Grout consistency PART 3- EXECUTION 3.2 C Wetting masonry units 3.3 A Bond pattern 3.3 B.l Bed and head joints 3.3 B.2 Collar joints 3.3 B.3 Hollow units 3.3 8.4 Solid units 3.3 8.6 Glass units 3.3 B.8.b AAC Masonry Notes to the Architect!Engineer 1 Specify additional required submittals. 1 Define who will retain the Testing Agency and Inspection Agency, if other than the Owner. 1 1 Specify grout requirements at variance with TMS 602/ACI 530.1/ASCE 6. Specify admixtures. Specify requirements at variance with TMS 602/ACI 530.1/ASCE 6. Specify where acid or caustic solutions are allowed and how to neutralize them. 1 Specify if hand mixing is allowed and the method of measurement of material. 1 Specify requirements at variance with TMS 602/ACI 530.1/ASCE 6 1 1 Specify when units are to be wetted. 1 Specify bond pattern if not running bond. 1 Specify thickness and tooling differing from TMS 602/ACI 530.1/ASCE 6. Specify the filling ofcollar joints less than 3 /4 in. (19.1 mm) thick differing from TMS 602/ACI 530.1/ASCE 6. 1 Specify when cross webs are to be mortar bedded. 1 Specify mortar bedding at variance with TMS 602/ACI 530.1/ASCE 6. Specify mortar bedding at variance with TMS 602/ACI530.1/ASCE 6. Specify when mortar may be omitted from AAC running bond masonry head joints that are less than 8 in. (200 mm) (nominal) tall. 3.3 D.2 Embedded items and accessories Specify locations where sleeves are required for pipes or 3.4 C.2, 3, and 4 conduits. Specify requirements at variance with TMS 602/ACI 530.1/ASCE 6.
- 318. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY S-75 This page is intentionally left blank.
- 319. S-76 TMS 602-11/ACI530.1-11/ASCE 6-11 This page is intentionally left blank.
- 320. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY S-77 REFERENCES FOR THE SPECIFICATION COMMENTARY References, Part 1 1.1. "Recommended Practice for Engineered Brick Masonry," Brick Institute ofAmerica (formerly Structural Clay Products Association), Reston, VA, 1969. 1.2. Brown, R.H., and Borchelt, J.G., "Compression Tests of Hollow Brick Units and Prisms," Masonry Components to Assemblages, ASTM STP 1063, J.H. Matthys, editor, American Society for Testing and Materials, Philadelphia, PA, 1990, pp. 263 - 278. 1.3. ACI Committee 531 , Building Code Requirements for Concrete Masonry Structures (ACI 531 -79) (Revised 1983)," American Concrete Institute, Detroit, MI, 1983, 20 pp. 1.4. "Specification for the Design and Construction of Load Bearing Concrete Masonry," (TR-75B), National Concrete Masonry Association, Herndon, VA, 1976. 1.5. Redmond, T.B., "Compressive Strength of Load Bearing Concrete Masonry Prisms," National Concrete Masonry Association Laboratory Tests, Herndon, VA, 1970, Unpublished. 1.6. Nacos, C.J., "Comparison of Fully Bedded and Face-Shell Bedded Concrete Block," Report No. CE- 495, Colorado State University, Fort Collins, CO, 1980, Appendix p. A-3. 1.7. Maurenbrecher, A.H.P., "Effect of Test Procedures on Compressive Strength of Masonry Prisms," Proceedings, 2nd Canadian Masonry Symposium, Carleton University, Ottawa, June 1980, pp. 119-132. 1.8. Self, M.W., "Structural Properties of Loading Bearing Concrete Masonry," Masonry: Past and Present, STP-589, ASTM, Philadelphia, PA, 1975, Table 8, p. 245. 1.9. Baussan, R., and Meyer, C., "Concrete Block Masonry Test Program," Columbia University, New York, NY, 1985. 1.10. Seaman, J.C., " Investigation of the Structural Properties of Reinforced Concrete Masonry," National Concrete Masonry Association, Herndon, YA, 1955. 1.11. Hamid, A.A., Drysdale, R.G., and Heidebrecht, A.C., "Effect ofGrouting on the Strength Characteristics of Concrete Block Masonry," Proceedings, North American Masonry Conference, Un iversity of Colorado, Boulder, CO, Aug. 1978, pp. J1-1 through 11-17. 1.12. Hatzinikolas, M., Longworth, J., and Warwaruk, J., "The Effect of Joint Reinforcement on Vertical Load Carrying Capacity of Hollow Concrete Block Masonry," Proceedings, North American Masonry Conference, University ofColorado, Boulder, CO, Aug. 1978. 1.13. Drysdale, R.G., Hamid, A.A., and Baker, L.R. "Masonry Structures: Behavior and Design." 2"d edition, The Masonry Society, Boulder, CO 1999. 1.14. Atkinson, R.H., and Kingsley, G.R., "A Comparison of the Behavior of Clay and Concrete Masonry in Compression," Atkinson-Noland & Associates, Inc., Boulder, CO, Sept. 1985. 1.15. Priestley, M.J.N., and Elder, D.M., "Stress-Strain Curves for Unconfined and Confined Concrete Masonry," ACJ JOURNAL, Proceedings V. 80, No. 3, Detroit, MI, May-June 1983, pp. 192-201. 1.16. M iller, D.E.; Noland, J.L.; and Feng, C.C., "Factors Influencing the Compressive Strength of Hollow Clay Unit Prisms," Proceedings, 5th International Brick Masonry Conference, Washington DC, 1979. 1.17. Noland, J.L., "Proposed Test Method for Determining Compressive Strength of Clay-Unit Prisms," Atkinson-Noland & Associates, Inc., Boulder, CO, June 1982. 1.18. Hegemier, G.A., Krishnamoorthy, G., Nunn, R.O., and Moorthy, T.V., "Prism Tests for the Compressive Strength of Concrete Masonry," Proceedings, North American Masonry Conference, University ofColorado, Boulder, CO, Aug. 1978, pp. 18- 1 through 18-17. 1.19. Chrysler, J., "Reinforced Concrete Masonry Construction Inspector's Handbook", 7'h Edition, Masonry Institute of America and International Code Council, Torrance, CA, 20 1O. 1.20. "lnspection and Testing of Concrete Masonry Construction", National Concrete Masonry Association and International Code Council, Herndon, VA, 2008. 1.21. "Technical Notes 39, "Testing for Engineered Brick Masonry-Brick and Mortar", Brick Industry Association, Reston, VA, Nov. 200 l. 1.22. "Technical Notes 398 , "Testing for Engineered Brick Masonry-Quality Controf', Brick lndustry Association, Reston, VA, Mar. 1988.
- 321. S-78 1.23. "CodeMaster, Special Inspection for Masonry", Structures & Codes Institute and Masonry Institute of America, Torrance, CA, 2006 1.24. "CodeMaster, Masonry Materials", Structures & Codes Institute and Masonry Institute of America, Torrance, CA, 2006. 1.25. "Recommended Practices and Guide Specifications for Cold Weather Masonry Construction," International Masonry Industry All-Weather Council, Washington, DC, 1973. 1.26. Tomasetti, A.A., "Problems and Cures in Masonry" ASTM STP 1063, Masonry Components to Assemblages, ASTM, Philadelphia. PA ,1990, 324-338. 1.27. "All Weather Construction" Technical Notes on Brick Construction Number 1 Revised, Brick Institute of America, Restan, VA, March 1992 1.28. "Hot Weather Masonry Construction," Trowel Tips, Portland Cement Association, Skokie, IL, 1993 1.29. Panarese, W.C., S.H. Kosmatka, and F.A. Randall Jr "Concrete Masonry Handbook for Architects, Engineers, and Builders," Portland Cement Association, Skokie, IL, 1991, pp. 121-123. 1.30. "Research Evaluation of Flexura! Tensile Strength of Concrete Masonry," National Concrete Masonry Association, Herndon, VA, 1994. References, Part 2 2.1. "PC Glass Block Products," (GB 185), Pittsburgh Corning Corp., Pittsburgh, PA, 1992. 2.2. "WECK Glass Blocks," Glashaus Inc., Arlington Heights, IL, 1992. 2.3. Beall, C., "Tips on Designing, Detailing, and Specifying Glass Block Panels," The Magazine of Masonry Construction, 3-89, Addison, IL, pp 92- 99. 2.4. "Follow up Service Procedure," (File R2556), Underwriters Laboratories, Inc., Northbrook, IL, 111.1, Sec.1,Vol.1. 2.5. Schultz, A.E. and Scolforo, M.J., 'An Overview of Prestressed Masonry," The Masonry Society Journal, V. LO, No. l, The Masonry Society, Boulder, CO, August 1991, pp. 6-21. 2.6. Grimm, C.T., "Corrosion of Steel in Brick Masonry," Masonry: Research, Application, and Problems, STP-871, ASTM, Philadelphia, PA, 1985, pp. 67-87. TMS 602-11/ACI530.1-11/ASCE 6-11 2.7. Catani, M.J., "Protection of Embedded Steel in Masonry," Construction Specifier, V. 38, No. 1, Construction Specifications Jnstitute, Alexandria, VA, Jan. 1985, p. 62. 2.8. "Steel for Concrete Masonry Reinforcement," NCMA TEK 12-4A, National Concrete Masonry Association, Herndon, VA, 1995, 6 pp. 2.9. "Specifications for Unbonded Single Strand Tendons," Post-Tensioning Manual, 5th Edition, Post- Tensioning Jnstitute, Phoenix, AZ, 1990, pp. 217-229. 2.10. Garrity, S.W., "Corrosion Protection of Prestressing Tendons for Masonry," Proceedings, Seventh Canadian Masonry Symposium, McMaster University, Hamilton, Ontario, June 1995, pp. 736-750. 2.11. Grimm, C.T., "Masonry Cracks: A Review ofthe Literature," Masonry: Materials, Design, Construction, and Maintenance, STP-992, ASTM, Philadelphia, PA, 1988. 2.12. "Volume Changes - Analysis and Effects of Movement," Technical Notes on Brick Construction 18, Brick Industry Association, Reston, VA, Oct. 2006, 9 pp. 2.13. "Accommodating Expansion of Brickwork", Technical Notes on Brick Construction 18A, Brick Industry Association, Restan, VA, Oct. 2006, 11 pp. 2.14. "Control Joints for Concrete Masonry Walls- Empirical Method," NCMA TEK l0-2B, National Concrete Masonry Association, Hemdon, VA, 2005, 4 pp. 2.15. ACI-SEASC Task Committee on Slender Walls, "Test Report on Slender Walls," ACI Southern California Chapter/Structural Engineers Association of Southern California, Los Angeles, CA, 1982, 125 pp. 2.16. Li, D., and Neis, V.V., "The Performance of Reinforced Masonry Beams Subjected to Reversa] Cyclic Loadings," Proceedings, 4th Canadian Masonry Symposium, Fredericton, New Brunswick, Canada, June 1986, V. 1, pp. 351-365. 2.17. Unpublished Field Test Report, File 80-617, B'Nai B'Rith Housing, Associated Testing Laboratories, Houston, TX, 1981. 2.18. "Details and Detailing of Concrete Reinforcement", ACI 315-99, American Concrete Institute, Farmington Hills, MI.
- 322. SPECIFICATION FOR MASONRY STRUCTURES ANO COMMENTARY References, Part 3 3.1. ACT Committee 11 7, "Standard Specifications for Tolerances for Concrete Construction and Materials (ACI 117-90)," American Concrete lnstitute, Detroit, MI, 198 1, 10 pp. 3.2. Council for Masonry Wall Bracing, Standard Practice for Bracing Masonry Walls Under Construction, Mason Contractors Association of America, 2001, 52 pgs. 3.3. Uniform Building Code, International Conference ofBuilding Officials, Whittier, CA, 1985. 3.4. Reinforced Concrete Masomy Construction Inspector's Handbook, 7'11 Edition, Masonry lnstitute of America!Intemational Code Council, Torrance, CA, 2009, pp. 167-168. 3.5. Stecich, J.P, Hanson, John M. and Rice, Paul F., "Bending and Straightening of Grade 60 Reinforcing Bars" Concrete lntemational, August 1984, Volume 6, lssue 8, pp. 14-23. S-79 3.6. "Grouting Concrete Masonry Walls", NCMA TEK 3-2A, National Concrete Masonry Association, Herndon, VA, 2005, 6 pp. 3.7. "Self-Consolidating Grout Investigation: Compressive Strength, Shear Bond, Consolidation and Flow, (MR29)". National Concrete Masonry Association, 2006, 82 pp. 3.8. "Self-Consolidating Grout Investigation: Making and Testing Prototype SCG Mix Designs - Report of Phase U Research, (MR31)". National Concrete Masonry Association, 2007, 224 pp. 3.9. Field Procedures Manual for Unbonded Single Strand Tendons, 2nd Edition, Post-Tensioning Institute, Phoenix, AZ, 1994, 62 pp.
- 323. S-80 TMS 602-11/ACI530.1 -11/ASCE 6-11 This page is intentionally left blank.
- 324. JNDEX A AAC masonry.........C-1 , C-5- 13, C-17- 19, C-23- 25, ..........C-32, C-35, C-39, C-54- 57, C-60- 75, C-143, ............ C- 160, C-1 75-193, C-201, C-208-2 10, S-4, ........................ S-11, S-13, S-17, S-20-24, S-27- 29, .............. S-33, S-34, S-37, S-48, S-52, S-55, S-66, S68 anchor bolts in......................................... C-176, C-177 coefficients ofthermal expansion ......................... C-25 compressive strength requirements.....S-13, S-17, S-72 construction...................C-19, C-25, C-70, C-71 , C-72, ................................................. C-1 76, S-22- 24, S-28 creep coefficient...................................................... C-9 definition........................................................ C-13, S-4 design...................................................... C-175, C-192 empírica! 1veneer Iimitations................................ C-55 modulus ofelasticity ............................C-7, C-23, C-24 mortar for ..........................C-70, C-72, S-20-24, S-48 protection in cold weather......................................S-28 protection in hot weather .......................................S-29 seismic requirements............................................. C-60 shear walls ................. ........C-54-66, C-175, C-178, .....................................................C-1 80, C-184, C-1 89 shrinkage coefficient............................................. C-25 Acceptable, accepted - definition ................................S-3 Adhered veneer...C-157- 160, C-167, C-1 68, S-19, S-55 adhesion requirements ...............................C-167, S-19 definition ........................................................ C-20, S-7 placement..................................................... S-19, S-55 thickness, maximum ........................................... C-167 Adhesion .... see Adhered veneer, adhesion requirements Adjustable anchors/ties............C-81-83, C-163-165, .................................................................... S-62, S-64 Admixtures for grout.......................... C-1 5, C-177, S-5, S-34, S-74 for mortar ..................................................... S-31, S-46 Allowable forces, load, strengths, and stresses anchor bolts..........................................C-6, C-77, C-78 compression, axial and flexural. ....... C-6, C-1O, C-39, .........................................................C-90, C-93, C-136 empírica! requirements.................C-143, C-148, C-149 notations.................................................................. C-6 prestressing tendon ................................... C-1 34-139 reinforced masonry ..........................C-60, C-97, C-101 shear.......................C-6, C-8, C-78, C-79, C-96, C-100 steel reinforcement................................................ C-97 tension................................................. C-8, C-83, C-86 unreinforced masonry ........................................... C-90 Allowable stress design method ............ C-1, C-12, C-23, .... C-40, C53,C-60,C-63, C-77-103,C- 125,C- 134 Anchor(s)....................C-9, C-14, C-20, C-45-49, C-71, ............................C-72, C-106, C-1 08, C-155-C-166, ..........................C-176, C-1 77, S-20, S-23, S-24, S-38, ..............................S-52, S-58, S62- S-65, S-72, S-73 adjustable ........................... see Adjustable anchors/ties bolts.................................................. see Anchor bolt(s) corrugated sheet metal ..................... C-162- 165, S-64 definition............................................................... C-13 installation.................................................... S-58, S-69 material specifications ...........................................S-20 panel anchors, for glass unit masonry ..............C-172, ..................................................................... S-39, S-65 pintle .............................................. C-1 63, C-164, S-62 protection ...............................................................S-39 pullout..............C-6, C-48, C-51, C-78, C-105, C-107, .............................. C-108, C-1 65, C-166, C-176, S-64 tests ............................................................. C-47, C-49 veneer.................................C-1 57- 162, C-165, C-166 wire .......................................C-1 63, C-165, S-39, S-64 Anchor bolts ...(see also Bent-bar anchors and Headed anchor bolts) .............................................C-47, C-48, C-51, C-78, .............................C-1 07, S-22, S-24, S-37, S-62, S-63 AAC masonry provisions........................ C-1 76, C-177 ASD provisions..................................................... C-77 embedment length..................C-10, C-51, C-52, C-156 in columns, seismic requirements ......................... C-66 material specifications ...........................................S-20 SD provisions...................................................... C-106 test requirements ......................................... C-47, C-49 Anchorage details...................................................................... C-3 empirical design.................................................. C-155 seismic ................................................................ C-143 tendon ...see Tendon anchorages, couplers, end blocks Anchored veneer....................C-157-162, C-165, C-166 definition ............................................................... C-20 seismic requirements............................... C-165, C-166 Architect, definition.....................................................S-3 Area bearing ................................. ..C-6, C-29, C-30, C-32, ............................................. C-82, C-1 08, C-1 78, S-49 bearing, for AAC masonry.................................. C-178 cross-sectional......................... see Cross-sectional area definition............................................................... C-13 net cross-sectional ................... see Cross-sectional area net shear................................................................ C-1 3 projected ................................................... C-47-C-49 section properties .................................................. C-26 transformed ........................................................... C-26 wall, per tie .......................... C-82, C-153, C-154, S-62 • AAC - Autoclaved Aerated Concrete, ASD - Allowable Stress Design, MSW- Masonry Shear Wall, SD - Strength Design
- 325. 1-2 Ashlar stone masonry allowable compressive stress (empirical design) .C-149 bonding ............................................................... C-155 definition........................................................ C-19, S-7 Autoclaved aerated concrete............... see AAC masonry definition........................................................ C-13, S-4 Axial compression empirically designed masonry ............................ C-143 prestressed masonry ............................................ C-136 reinforced AAC masonry .......................... C-97, C-186 reinforced masonry (ASD).................................... C-97 reinforced masonry (SD)..................................... C-123 unreinforced AAC masonry ...............C-90, C-91, C-94 unreinforced masonry (ASD)................................ C-90 unreinforced masonry (SD)................................. C-110 Axial tension anchor bolts......................................C-47, C-79, C-1 08 prestressed masonry ............................................ C-139 reinforced masonry (ASD).................................. C-100 unreinforced masonry ....................C-96, C-113, C-180 B Backing concrete................................................... C-165, C-167 definition............................................................... C-13 deflection ................................................ C-161, C-167 design requirements ............................................ C-160 masonry............................................................... C-165 steel stud ............................................................. C-159 wood ....................................................... C-164, C-166 Bar, reinforcing .... C-2, C-3, C-6, C-19, C31, C-42-47, ................C-59, C-60, C-83, C-87, C-88, C-114- 122, ............C-181-186, S-9, S-37, S-48, S-58, S-59, S-67 Base surface treatment, glass unit masonry ............ C-174 Beams .............C-2-4, C-7, C-14, C-28- 35, C-38-42, ..C-47, C-56, C-60, C-65, C-101, C-102, C-121-123, ....C-1 78, C-181- 186, C-198, S-56, S-59, S-68, S-73 ASD requirements................................... C-101, C-102 AAC masonry ..............................C-178, C-184, C-185 cantilevered ......................................................... C-121 deflection .............................................................. C-39 strength design .................................................... C-121 Bearing AAC masonry ........................................... C-176- 179 area................................................................ C-29-32 concentrated loads................................................. C-29 notation ................................................................... C-6 empirical requirements........................................ C-151 length for reinforced beams .................................. C-38 nominal strength ..................................... C-108, C-178 INDEX prestressed masonry ................................ C-139, C-140 strength design .................................................... C-1 08 strength-reduction factor .............. C-37, CC-55, CC-93 stress ........................................................... C-31, C-49 Bearing walls, (Loadbearing walls) definition ........................................................C-16, S-7 empirical requirements.......................C-53, C-54, C-55 tolerances ............................................................... S-57 Bedjoint anchors ................................................................ C-161 construction.................................................... S-53-55 definition ............................................................... C-13 reinforcement in glass unit masonry ..........C-174, S-51 reinforcement, seismic requirements .................... C-64 thickness .......................................... C-164, S-53, S-54 tolerances ............................................................... S-57 Bend, minimum diameter ......................................... C-47 Bent-bar anchors ........................... see also Anchor bolts AAC masonry ......................................... C-176, C-177 ASD provisions........................................... C-77, C-78 embedment length..............................C-10, C-51, C-52 material specifications ........................................... S-1 8 placement .............................................................. C-47 strength design .......................................... C-106-108 speciftcations ............................................... S-37, S-3R Bond empírica! design ........................................ C-153-155 headers ...................................................... see Headers optional specification requirement......................... S-74 pattern ................................................ C-17, S-53, S-74 running ..............................................see Running bond stack ...................................................... see Stack bond stone, empirical design........................................ C-155 wall intersections .................................................. C-20 wall ties ........................C-79, C-153, see also Wall ties Bond beam...............C-13, C-28-35, C-43, C-47, C-48, . ................................C-58, C-60, C-133, C-156, C-181, ...................................... C-184- 186, S-4, S-64-S-67 definition .......................................................C-13, S-4 Bonded prestressing tendon................C-14, C-1 7, C-133, ........................................ C-139, C-1 41, S-4, S-6, S-40 corrosion protection ...............................................S-40 definition........................................................ C-14, S-4 grouting...........................................................C-14, S- seismic requirements................................... C-61, C-62 Bonder................................C-15, C-155, see also Header definition............................................................... C-15 Bounding frame .........................C-14, C-16, C-193-198 definition............................................................... C-14 * AAC = Autoclaved Aerated Concrete, ASO - Allowable Stress Design, MSW - Masonry Shear Wall, SD - Strength Design
- 326. INDEX Bracing ............................................................. S-3, S-56 Brick ................ ......C-27, C-32, C-34, C44, C-79, C80, ....................C-94, C-95, C-148, C-159, C-166, C-1 96, .................... C-198, S-10, S-11, S-14, S-34- 36, S-44, ...................................................see also Clay masonry calcium silicate ......................................................S-1O clay or shale...... C-32, C-196, C-198, S-10, S-35, S-52 concrete ........................................... C-148, S-34, S-35 Buckling, Euler............................................................ C-1O , C-91 notation ................................................................. C-1O Building code, general................................................ C-1 Building official, definition ...................................... C-14 Bundling ofreinforcing bars....................... C-120, C-183 prohibition against for AAC masonry and SD .... C-120 e Calculations............C-3, C-13, C-23, C-24, C-49, C-50, ..........................C-65, C-77, C-78, C-89, C-98, C-106, ................... Cl07, C-121- 126, C-136, C-139, C-147, .................. C-176--178, C- 183--188, S-4, S-15, S-19 Camber ...................................................................C-140 Cantilevered beams/members.....................C-43, C-102, ................................................................ C-121, C-151 Cast stone .................................. C-19, C-149, C-155, S-7 Cavity wall definition .............................................................. C-14 Cavity width ..........................................C-73, C-81, S-56 Channel-type restraints...................... C-172, C-173, S-65 Chases.................................... C-147, C-1 56, C-172, S-56 Clay masonry coefficient of moisture expansion ........................... C-9 coefficients ofthermal expansion ......................... C-25 compressive strength.......................... C-108, S-13--18 creep coefficient.................................................... C-25 modulus of elasticity ............................................. C-23 unit specifications ............................ C-201, S-10, S-Il wetting ......................................................... S-52, S-74 Cleaning ......................C-73, S-3, S-26, S-45, S-52, S-70 Cleanouts........................................................... S-4, S-52 definition.................................................................. S-4 1-3 Coatings for corrosion protection ... S-8, S-12, S-39, S-41 Coefficient(s) creep........................................................................ C-9 expansion .............................................................. C-25 friction .................................................................. C-12 response modification ............C-11, C-57, C-62, C-138 shrinkage for concrete masonry .................... C-9, C-25 Cold weather construction .............. S-20, S-23-28, S-67 Collarjoints ...........C-14, C-43, C-73, C-79- 82, C-88, ...... C-102, C-1 14, C-1 81, S-4, S-13, S-53, S-56, S-74 allowable shear in ................................................. C-79 definition........................................................ C-14, S-4 construction............................................................ S-53 Column(s)........ ...C-3, C-4, C-7, C-9, C-14, C-21, C-34, ......................C-41--45, C-56, C-64-66, C-74, C-89, ........................C-97-99, C-121- 123, C-1 31, C-1 33, ................C-152, C-183, C-194- 198, S-53, S-56- 59 AAC masonry ..................................................... C-183 allowable stress design.........................C-89, C-97- 99 construction.................................................. C-74, S-53 definition............................................................... C-14 eccentricity............................................................ C-99 effective height ..................................... C-9, C-41--43 lateral ties ........ C-42, C-64, C-66, see also Lateral ties load transfer .................................................. C-3, C-21 reinforcement placement.....................................C-41 seismic requirements............................C-56, C-64--66 strength design .......................................... C-121- 123 thickness ............................................................... C-41 Composite action .......................C-14, C-23, C-26, C-79, .........................................................C-81, C-96, C-159 definition ............................................................... C-14 Composite masonry....................C-14, C-79, C-80, C-82, ........................................... C-102, C-146, C-147, S-56 definition .............................................................. C-14 Compression area, width .......................................... C-31 Compression, axial ...................... see Axial compression Compressive strength .. C-1 , C-3, C-8, C-14, C19, C-23, ......................... C-24, C-73, C-77, C-92, C-98, C-100, ................C-108, C-114, C-116, C-121, C-125, C-134, ...............C-136, C-143, C-148, C-177, S-4, S-10-20, ........................................ , S-32- 37, S-47, S-48, S-72 .... see also Specified compressive strength of masonry AAC masonry .................................. C-1 77, S-13, S-1 7 acceptance.................................................... C-73, S-18 axial, nominal...............................C-121, C-125, C-136 compliance ............................................................ C-73 definition ................................................ C-14, S-4, S-6 determination ............................................... C-73, S-13 • AAC =Autoclaved Aerated Concrete, ASD =Allowable Stress Design, MSW =Masonry Shear Wall, SD - Strength Design
- 327. 1-4 INOEX Compressive strength (continued) Construction loads........................................... S-26, S-58 empirical requirements............................ C-143, C-148 notation ................................................................... C-8 Contrae! documents ...........C-3, C-14, C-17, C-19, C-67, ofgrout....... C-177, S-13, S-17, S-20, S-34, S-47, S-48 ......................... C-69, S-1, S-4, S-21, S-25, S-37, S-53 ofunits ...........................................................S-13--17 definition ........................................................C-14, S-4 prism strength method............................................S-18 SD requirements ..........................C-1 08, C-114, C-125 Contraction (shrinkage) joint........................... S-44, S-45 shown on drawings ........................................ S-6, S-20 tests ......................... C-116, S-13--20, S-24, S-32-34 Contractor, definition .................................................. S-4 unit strength method ......................................S-13---17 Contractor's services and duties ................................S-25 Compressive strength ofmasonry definition ....................................................... C-14, S-4 Control joints................................................... S-44, S-45 Compressive stress Conversion oflnch-pound units to SI units ............ C-201 . allowable..........C-8, C-93, C-97, C-136, C-147, C-148 axial............................................................... C-90- 94 Corbels ....................................C-36, C-86, C-175, C-179 bearing ........................................................ C-38, C-89 empírica) requirements.......................... C-147-C-148 Corrosion/ corrosion protection........C-45, C-137, C-140, prestressed masonry ................... C-17, C-23, C-31, S-6 ..............................C-141, C-159, C-161, C-164-166, for reinforced masonry.............................. C-97, C-184 .......................................... S-39-44, S-56, S-69, S-72 for unreinforced masonry........................ C-11O, C-113 coatings for protection ................................. S-39, S-72 notations.................................................................. C-8 joint reinforcement....................................... C-45, S-39 steel reinforcement................................................ C-97 nails 1screws ............................................. C-45, C-166 prestressing tendons ..............C-140, C-141, S-40, S-44 Concentrated loads ....................C-29-33, C-133, C-147 reinforcement..................................... C-45, S-58, S-72 steel framing ....................................................... C-165 Concrete masonry ties, anchors and inserts ........................................ C-45 coefficient ofshrinkage........................................... C-9 coefficients ofthermal expansion ........................... C-9 compressive strength...................................... S-15- 17 Corrugated sheet metal anchors........... C-162-165, S-64 creep coefficient............................................ C-9, C-25 modulus of elasticity ................................... C-16, C-23 Coupled shear walls.................................................. C-21 modulus ofrigidity...................................... C-16, C-23 Cover unit specifications ............. S-10, S-15- 17, S-34, S-35 definitions ......................................................C-14, S-4 wetting ...................................................................S-52 grout................................... C-140, C-163, C-182, S-64 Conduits masonry. C-45, C-84, C-115, C-141, S-40,, S-58, S-61 mortar...................................... C-163, C-164,S-4, S-64 embedded ............................................. C-3, C-74, S-56 specification requirements ....................S-3, S-56, S-73 Creep ..................................C-3, C-9, C-11, C-21, C-22, Confinement.................C-12, C-29, C-65, C-88, C-116, ...................................C-25, C-34, C-39, C-135, C-140 ............................... C-120, C-127, C-128, C-131, S-65 Creep coefficient ........................................................ C-9 Confinement ofgrout ...................................... S-53, S-65 Cross-sectional area Connectors/connections definition .............................................................. C-14 load transfer .............................................. C-194- 196 placement........................ C-70, C-72, S-22, S-24, S-56 seismic requirements................................... C-56, C-64 shown on drawings ................................................. C-3 definition, net ........................................................ C-13 transformed ........................................................... C-26 gross cross-sectional area............C-6, C-9, C-26, C-41, ...............................C-59, C-66, C-67, C147-149, S-5 net cross-sectional area ..............C-6, C-9, C-11, C-13, ..............C-14, C-19, C-26, C-27, C-177, S-3-6, S-15 notation ................................................................... C-6 Consolidation ofgrout......................... C-115, S-66, S-67 Continuous inspection ..................... C-13, S-5, S-22- 24 • AAC - Autoclaved Aerated Concrete, ASO - Allowable Stress Design, MSW- Masonry Shear Wall, SO - Strength Design
- 328. INDEX D Dead load, definition ................................................ C-16 Deep beam .........................C-10, C-12, C-15, C-40, C-41 definition............................................................... C-15 Definitions ........................................... C-13- 20, S-3- 7 Deflection backing, for veneer ............................................. C-158 beams and lintels................................................... C-39 design story drift ................................................... C-15 lateral ........................... C-21, C-55, C-81, C-125, S-56 members supporting glass unit masonry ............. C-172 members supporting veneer .......................C158-167, prestressed masonry ............................................ C-140 reinforced AAC masonry .................................... C-177 renforced masonry (SD)...................................... C-106 structural frames ................................................... C-34 unrienforced (plain) AAC masonry .................... C-106 unrenforced (plain) masonry (SD) ...................... C-176 Deformation.................C-1, C-3, C-21, C-34, C-54--58, ..............................C-106, C-120, C-124--128, C-135, ............................... C-137, C-176, C-188, C-194, S-52 Delivery ofmaterials/products .................................. S-26 Demonstration panel........... C-73, S-26, S-34, S-66, S-68 Depth, definition....................................................... C-15 Depth of backfill (empírica! requirements) ............ C-152 Design......................................................................... C-1 see AAC masonry, Allowable stress design, Empírica! design, Glass unit masonry, Prestressed masonry design, Seismic design, Strength design, Veneer Design story drift.................................C-15, C-56, C-1 38 Design strength...............C-1 , C-15, C-19, C-77, C-105, .............................C-107, C-110, C-175, C-188, C-194 Detailed plain (unreinforced) AAC MSW..... C-17, C-54, ...........................................................C-55, C-57, C-60 Detailed plain (unreinforced) MSW............... C-18, C-57 Development bonded tendons ................................................... C-141 reinforcement, AAC masonry................................. C-9 reinforcement, ASO .............................C-83-87, C-92 reinforcement, SO................................... C-115, C-116 1-5 Diaphragm......................C-15, C-17, C-21, C-55, C-60, ................................C-64, C-65, C-125, C-145, C-147, .................................................... C-1 51, C-155, C-156 anchorage, AAC.......................................... C-60, C-64 definition............................................................... C-15 empírica! requirements........................... C-145, C-147, .....................................................C-151, C-155, C-156 Differential movement........C-3, C-11, C-21, C-34, C-55, ............. C-80, C-81 , C-90, C-159--161, C-167, C-169 Dimension nominal, definition......................................... C-15, S-4 specified, definition ....................................... C-16, S-4 Dimension stone .................................. C-160, S-1O, S-11 Dimensional changes.........................................C-3, S-44 Dimensional tolerances ............................ see Tolerances Drawings content, including anchorage, conduits, connectors, pipes, sleeves, reinforcement and specified compressive, strength ofmasonry..............C-3, C-14, ......................................... C-17, C-77, S-6, S-13, S-20, .......................................... S-48--53, S-58, S-65, S-73 definition, project...........................................C-1 7, S-6 Drift limits ...................................................... C-54, C-55 Dryout........................................................................ S-29 E Earthquake ..... see also Seismic load and Seismic design loads ....................................................C-20, C-53-56 Eccentricity.........................C-8, C-21, C-91, C-92, C-99, ................... C-112, C-121, C-124, C-1 37, C-188, S-56 Effective compressive width .................................... C-31 Effective height..........................C-9, C-15, C-41, C-43, .....................................................C-121, C-124, C-188 Effective prestress .......C-15, C-62, C-135, C-136, C-139 Elastic deformation..............................C-3, C-127, C-135 Elastic moduli.............................................. C-23, C-26, ....................................... see also Modulus ofelasticity Embedded items ...... S-56, S-58, S-59, , S-62, S-69, S-74 * AAC =Autoclaved Aerated Concrete, ASD =Allowable Stress Design, MSW =Masonry Shear Wall, SD- Strength Design
- 329. 1-6 Embedment length anchor bolts............................C-10, C-51, C-52, C-156 anchors ................................................................ C-156 hooks................................................C-10, C-87, C-182 notation ................................................................. C-1O reinforcement ...................................C-43, C-87, C-115 Empírica! design ...................C-1, C-2, C-54, C-57, C-63, .......................................................C-143-156, C-169 End-bearing splices .................................................. C-89 Engineer definition.................................................................. S-3 Epoxy-coating ............................... C-45, C-46, S-9, S-39 Euler buckling ............................................... C-10, C-91 notation ................................................................. C-1O Expansion ...............C-9, C-21, C-22, C-25, C-34, C-90, .... C-90, C-1 06, C-135, C-172-174, S-15, S-36, S-44 Expansionjoints ............................C-165, C-172, C-174, ............................................................ S-12, S-44, S-45 F Fabrication.............................................. S-39, S-41, S-48 Field quality control .................................................. S-70 Flanges, ofintersecting walls ..Cc21, C-28, C-129, C-190 Flexura) reinforcement ................C-40, C-41, C-84-88, .........................................C-114, C-125, C-181, C-1 84 Flexura) tension reinforced masonry ............................................... C-97 unreinforced masonry ......................................... C-11O Flexure prestressed masonry .................................. C-136- 139 reinforced AAC masonry .................................... C-176 reinforced masonry, ASD ........................... C-28, C-98 reinforced masonry, SD ...................................... C-106 stress allowable..................................................... C-97 notation ................................................................... C-8 unreinforced AAC masonry ................................ C-176 unreinforced masonry, ASD ................................. C-90 unreinforced masonry (SD)................................. C-11O veneer.................................................................. C-158 Floors/ floor diaphragms ...........C-21, C-54, C-60, C-96, .....................................................C-125, C-156, C-151 empírica! anchorage ................................ C-155, C-156 seismic anchorage ............................................... C-165 anchorage, AAC masonry ....C-60, C-64, C-178, C-179 INDEX Foundation(s)....................C-15, C-20, C-21, C-32, C-34, .................. C-54, C-125, C-125, C-140, C-143, C-144, .....................C-152, C-157, C-161, C-162, S-26, S-44, .................................................... S-51-53, S-61, S-69 support ofveneer ...........................C-20, C-161, C-162 Foundation dowel(s) ...............................................S-61 Foundation pier(s) .................C-15, C-143, C-144, C-152 definition............................................................... C-15 empírica) requirements........................................ C-152 Foundation wall(s) empírica) requirements............................ C-143, C-152 Frame, anchorage to ............................................... C-156 G Galvanized coatíngs/requirements.. C-45, C-46,S-8, S-39 Glass unit masonry ....................C-1, C-15, C-53, C-143, ..............................C-169-174, S-4, S-26, S-28, S-33, . , S-36, S-39, S-46, S-53, S-54, S-56, S-65, S-72, S-74 construction.................................................. S-33, S-54 definition ........................................................ C-15, S-4 empirical limitation............................................. C-143 mortar for ......................................... C-174, S-33, S-46 mortar joints..................................... C-173, S-53, S-54 panel anchors ................................... C-172, S-39, S-65 protection in cold weather............................ S-26, S-28 reinforcement ...................................................... C-174 support ................................................................ C-172 thickness ............................................................. C-169 unit specifications ........................................ S-36, S-52 Gross cross-sectional area definition ........................................................ C-13, S-3 Grout .........S-5, S-10, see also Grout lift and Grout pour admixtures..............................C-15, C-177, S-34, S-72 altemate placement procedures ..............................S-68 collar joint, allowable stress................. C-79-81, S-13 compressive strength.....................C-8, C-108, C-177, ............................................................S-13, S-16, S-17 compressive strength requirements for AAC masonry . ...............................................................................S-17 compressive strength requirements ..................C-177, .................................................................... S-16,S-17 confinement ................................................. S-53, S-65 consolidation .............................................. C-115, S-67 cover ..................C-14, C-140, C-163, C-182,S-4, S-64 demonstration panel........ C-73, S-26, S-34, S-66, S-68 materials.................................... S-20, S-27, S-29, S-34 mínimum dimensions of grout spaces................C-73, ..................................................................... C-75, S-66 mix designs .........................................S-20, S-47, S-48 mixing ......................................................... S-20, S-47, * AAC - Autoclaved Aerated Concrete, ASO = Allowable Stress Oesign, MSW = Masonry Shear Wall, SO= Strength Oesign
- 330. INDEX Grout (continued) modulus ofelasticity ................................... C-23, C-24 placement.........................C-47, C-73, S-27, S-65--68 protection in cold weather............................ S-27, S-28 protection in hot weather ............................. S-29, S-65 quality assurance.................C-71- 73, S-22-24, S-70 sampling....................................................... S-11, S-70 slump ..................................see Slump and Slump flow spaces/ space requirements.................... C-73, C-181, ........................................................... S-52, S-56, S-66 standards and specifications....... S-5, S-10, S-16, S-17, .................................................... S-34, S-47, S-65- 70 strength ................... see Grout - compressive strength testing......................................... S-1 1, S-22, S-24 S-34 Grout key......................................................... S-54, S-68 Grout lift ......................................... C-73, S-5, S-67, S-68 definition..................................................................S-5 Grout pour .................... C-73, C-75, S-5, S-52, S-66--68 definition..................................................................S-5 Grouting bonded tendons ......C-70- 72, S-22- 24, S-70 H Handling ofmaterials/products ...........C-67, C-69, C-73, ...................................... C-167, S-25, S-26, S-49, S-69 Headjoint construction.............................................. S-53 - S-56 definition............................................................... C-15 optional specification requirement......................... S-74 thickness ...................................................... S-53, S-56 Headed anchor bolts ......C-47, C-48, C-51, C-78, C-107, ..................... S-38, S-63, S-64 (see also Anchor bolts) ASD provisions..................................................... C-78 embedment length ................................................. C-51 material specificaitons ................................. S-38, S-63 placement .............................................................. C-47 strength design .................................................... C-107 specifications ............................................... S-38, S-63 Header (s) allowable stress ..................................C-26, C-79, C-80 composite action ................................................... C-79 definition............................................................... C-15 empírica! requirements.................C-150, C-1 53, C-1 54 Height effective...................................C-9, C-15, C-41, C-43, .....................................................C-121 , C-124, C-188 definition, effective height.................................... C-1 5 notation ................................................................... C-9 empírica! requirements, buildings....................... C-145 1-7 fill, unbalanced (empírica) requirements) .........C-145, ............................................................................ C-152 foundation walls (empírica! requirements) ......... C-152 height/thickness ratios (empírica! requirements) C-152 parapets (empírica! requirements)....................... C-151 grout pour (See Grout pour) ......... .....C-73, C-75, S-5, ............................................................. S-52, S-66--{)8 Hollow masonry unit, ..... ....C-47, C-120, C- 152, C-1 53, ......................................... S-Il , S-36, S-59, S-63, S-66 definition .............................................................. C-16 Hooks .................................................. see Standard hook Horizontal reinforcement seismic requirements............................................. C-67 for masonry not 1aid in running bond.......... C-3 1, C-35 Hot weather construction.....S-20, S-23, S-24, S-29, S-64 1 Impact........................................................... C-21, C-193 Inch-pounds translation table.................................. C-201 Tnfill definitions ................................................... C-15, C-16 design ......................................................... Appendix B non-participating ....................................... C-16, C-194 participating .....................................C-16, C-1 95- 198 Inserts, protection for...................................... C-45, C-46 lnspection ...........C-13, C-16, C-67-74, S-5, S-21-25, ............................. , S-51, S-52, S-66, S-69, S-72, S-74 definition ........................................................ C-16, S-5 1nspection Agency .......................C-13, C-16, S-5, S-21, ............................................................ S-25, S-72, S-74 fntermediate reinforced MSW ..............C-18, C-57, C-58, .........................................................C-61, C-64, C-1 18 lntersecting walls design.......................................................... C-21, C-28 empírica!, anchorage ........................................... C-155 J Jacking force, prestressed masonry ....... C-134, S-7, S-69 Joint .. see Bed joint, Collar joint, Head Joint, Expansion joint, Contraction joint, etc. Joint fillers.................................... S- 12, S-44, S-45, S-72 • AAC =Autoclaved Aerated Concrete, ASD =Allowable Stress Design, MSW =Masonry Shcar Wall, SD =Strength Design
- 331. 1-8 Joint reinforcement allowable stress ........................................... C-8 1, C-97 bonding, empirical design ................................... C-1 53 cover ..................................................................... C-45 cross wires ...........................C-43, C-80, C-81, C-153, ....................................................... C-163, C-174, S-38 for glass unit masonry......................................... C-174 material specifications .................. S-9, S-37- 39, S-72 mínimum wire size................................................ C-43 placement...............................................................S-59 protection .....................................................C-45, S-39 seismic design..................................................... C-165 veneer........................................................ C-163- 165 wire size.........................................C-43, C-1 63, C-1 66 L Lap splices .................C-88, C-89, C-11 5- 117, C-181, .............................................. S-58, S-59, (see Splices) Lateral force-resisting system.......................C-21, C-86, ...........................................C-143- 145, C-193, C-194 Lateral load distribution ........................................... C-21 Lateral stability, empirical design .......................... C-145 Lateral support..........C-1, C-15, C-21, C-38, C-41, C-42, ..........................................C-123, C-137, C-150- 152, .........................................C-155, C-156, C-172, C-1 87 empirical design.................C-150- 152, C-155, C-156 glass unit masonry .............................................. C-172 Lateral ties ...................................C-19, C-42, C-64, C-66 efinition................................................................. C-19 or columns .........................................C-42, C-64, C-66 seismic design ............................................. C-64, C-66 Laterally restrained prestressing tendon .................. C-16, .................................................................. C-134-139 Laterally unrestrained prestressing tendon .............C-16, .................................................................. C-136- 139 Lintels deflection .............................................................. C-39 empirical requirements............................ C-150, C-1 56 veneer.................................................................. C-162 Live load, definition ................................................. C-16 Load(s)/Loading allowable...................see Allowable forces, Loads, etc. combinations.................C-2, C-12, C-23, C-77, C-93, ....................................................C-105, C-125, C-134, .........................................C-138, C-175, C-193, C-194 concentrated ...............C-29, C-32, C-33, C-133, C-1 47 construction............................................................S-26 INDEX dead..............................C-7, C-62, C-96, C-136, C-1 37 definition ............................................................... C-16 distribution .................................................. C-21, C-81 drawings, shown on ................................................ C-3 empirical design, maximum .........C-143, C-149, C-150 glass unit masonry, maximum ............................ C-172 lateral ........................ ..C-21, C-35, C-56, C-81, C-84, .......................................................C-90, C-124, C-188 live .....................C-9, C-16, C-20, C-39, C-147, C-162 notation ................................................................... C-6 seismic .........C-21, C-23, C-53- 56, C-60, C-64--67, ...................C-93, C-120, C-143, C-147, C-165, C-166 service ...................C-1 , C-2, C-16, C-21, C-39, C-101 , .............................C-133, C-135, C-137, C-1 58, C-1 59 transfer ...............C-1, C-3, C-21, C-1 63, C-194, C-1 96 veneer, maximum................................................ C-161 wind .........................C- 11 , C-93, C-169, C-1 71, C-174 Load transfer......................C-1 , C-3, C-21, C-163, C-196 Load-bearing Wall definition........................................................C-20, S-7 empirical requirements........................................ C-155 tolerances ..........................,....................................S-55 Longitudinal reinforcement ......C-16, C-19, C-28, C-42, ................................C-87, C-88, C-101, C-116, C-118, ....... C-120-123, C-131, C- 182, C-186, C-187, C-190 M Masonry glass ..........................................see Glass unit masonry plain .................................... see Unreinforced masonry prestressed...............................see Prestressed masonry reinforced ................................ see Reinforced masonry unreinforced ........................ see Unreinforced masonry veneer...........................................................see Veneer Masonry bonded hollow waii ..............C-20, C-36, C-152 Masonry breakout, definition ............................ C- 16, S-7 Masonry cement..................................C-94, C-95, C-109 Masonry cleaners............................................. S-45, S-74 Masonry erection .......................................................S-53 cold weather construction .................... S-26- 28, S-67 field quality control................................................S-70 grout placement............... C-73, S-27, S-63, S-65, S-68 hot weather construction ............................ , S-29, S-65 placing mortar................................................S-53-55 preparation ............................................................. S-52 reinforcement installation ............................ S-58, S-69 site tolerances...................................... S-56, S-57, S-69 • AAC - Autoclaved Aerated Concrete, ASO - Allowable Stress Oesign, MSW- Masonry Shear Wall, SO = Strength Oesign
- 332. INDEX Masonry materials.......... C-69, C-114, C-193, S-8- 12, S-21, S-25, S-26, S-29, S-3 1-39 Material(s) certificates.............................................................. S-20 delivery .................................................................. S-26 handling ................................................................. S-26 properties ... C-22, C-105, C-108, C-131, C-176, C-177 samples .................................... S-20, S-26, S-27, S-52, seismic restrictions........................................ C-65--67 specifications ........................C-13, S-8- 12, S-31- 39 storage...................................... C-67, C-73, S-25, S-26 Maximum value, definition ......................................... S-5 Maximum wind pressure or speed empírica! design, maximum................................ C- 144 glass unit masonry, maximum .................. C-169- 171 veneer, maximum.................................... C-161, C-166 Mean daily temperature, definition .............................S-5 Mechanical connections/splices ........C-88, C-89, C-116, ...................................................... C-183, C-194- 196 Metal accessories.......C-43, C-45, S-20, S-26, S-37, S-72 Mínimum inside bend diameter for reinforcing bars..S-48 Mínimum thickness, empírica! design ........ C-1 51, C-152 Mínimum daily temperature, definition.......................S-5 Mínimum value, definition ..........................................S-5 Mix designs ........................ S-20, S-25, S-31, S-34, S-47 Mixing ..............S-27, S-29, S-46, S-47, S-65, S-70, S-74 Modulus ofelasticity ...........C-7, C-8, C-1 6, C-23- 26, .....................................................C-118, C-1 35, C-181 Modulus of rigidity........................C-8, C-16, C-23, C-24 Modulus of rupture.C-8, C-9, C-39, C-109- 111, C-122, ..................... C-125, C-177, C-178, C-186, S-33, S-36 Moisture.....................C-3, C-9, C-22, C-25, C-34, C-45, ..................................C-8l,C-90, C-135, C-167, C-193 .................................................. S-26, S-29, S-35, S-52 Moisture expansion ...........C-9, C-22, C-25, C-90, C-1 35 Moment of inertia........................C-9, C-27, C-39, C-91, .....................................................C-125, C-126, C-1 77 Moment, notation ..................................................... C-1 O 1 -9 Mortar admixtures..............................................................S-46 allowable flexura! tension..................................... C-94 cover ........................................................................S-4 empirical requirements.............................. C-147- 153 for glass unit masonry..........C-1 5, C-174, S-33, S-46, ............................................................S-53, S-54, S-56 inspection .................................. C-70, C-71, S-22-24. mandatory specifications .......................................S-72 materials..............................................S-31, S-32, S-72 mix designs ............................................................ S-20 mixing .................................................S-20, S-31, S-46 pigments....................................................... S-31, S-46 placing.................................................... S-3, S-53-55 protection in cold weather............................ S-27, S-28 protection in hot weather ....................................., S-29 retempering .................................................. S-29, S-46 seismic restrictions...................................... C-64, C-67 specifications ............................S-1O, S-31- 34, S-53, ............................................................S-56, S-72, S-74 thin-bed mortar .....................C-13, C-19, C-64, C-68, ...................................... C-70-72, C-178, C-184, S-4, ........................................ S-20, S-29, S-33, S-48, S-55 Movementjoints.. .... ...C-58, C-61, C-1 60, C-167, S-43, .......................................................... S-44, S-54, S-71, ....................see also Controljoint and Expansion joint design 1detailing adjacent to............................... C-160 specification requirements ........ S-44, S-45, S-73, S-74 submittals ...............................................................S-20 Multiwythe walls...C-36, C-79, C-80-82, C-147, C-150 empírica! design...................................... C-147, C-150 N Negative moment reinforcement .................... C-83, C-86 Net cross-sectional area, definition .......................... C-13 Nominal dimension, definition.......................... C-15, S-4 Nominal strength(s) ................C-2, C-6, C-8, C-15, C-17, .................... C-19, C-105-108, C-110, C-112, C-114, ...................C-121, C-1 75- 177, C-181 , C-1 83, C-1 94 anchor bolts............................................... C-105- 108 definition............................................................... C-17 Non-composite action............................................... C-81 Noncontact lap splices ......................... C-89, C-115, S-56 Non-participating infill definition............................................................... C-15 design.................................................................. C-194 Notation.............................................................. C-6-12 • AAC = Auloclaved Aerated Concrete, ASO = Allowable Stress Oesign, MSW = Masonry Shear Wall, SO= Strenglh Oesign
- 333. 1-10 o Ordinary plain (unreinforced) MSW ............. C-18, C-54, ........................... C-55, C-57, C-60, C-61, C-62, C-138 Ordinary reinforced MSW...C-18, C-54-61, C-64, C-66 Other than running bond (formerly stack bond)) bearing ...............................................C-29. C-32, C-33 reinforcement requirements, mínimum ....... C-31, C-35 seismic requirements................................... C-59, C-67 stress in masonry...............................C-93, C-94, C-96, .....................................................C-1 09, C-113, C-180 veneer, (for other than running bond) ................. C-165 Otherwise required, definition .....................................S-5 Owner definition..................................................................S-5 quality assurance.......................................... S-21, S-74 p Panel anchors for glass unit masonry .. C-172, S-39, S-65 Parapet walls empirical requirements............................ C-152, C-153 Participating infill definition............................................................... C-16 design .................................................... C-193--C-198 Partition walls, definition ........................................... S-6 Pigments .......................................................... S-3 1, S-46 Pier(s) .......C-15, C-17, C-56, C-65, C-121- 124, C-143, ......................C-144, C-152, C-183, C-186, S-51, S-54 AAC masonry ......................................... C-183, C-186 definition..................................................... C-15, C-17 foundation (empirical) .................C-143, C-144, C-152 SD requirements ..................................... C-183, C-186 Pilasters .................. ...C-9, C-21, C-43-45, C-56, C-65, .......................... C-74, C-151, C-152, S-53, S-56, S-58 load transfer .......................................................... C-21 reinforcement placement....................................... C-45 seismic requirements................................... C-56, C-65 Pintle anchors ....................................C-163, C-164, S-62 Pipes ...........C-3, C-74, S-3, S-40, S-44, S-56, S-73, S-74 Plain (unreinforced) masonry ... see Unreinforced (plain) masonry definition............................................................... C-20 INDEX Positive moment reinforcement................................ C-86 Post-tensioning, post-tensioned .........C-17, C-19, C-133, .......................................... C-141, S-6, S-7, S-40, S-69 definition ........................................................C-17, S-6 Prefabricated masonry ................ C-133, S-11, S-49, S-72 Prestressed masonry definition ........................................................C-17, S-6 deflection ............................................................ C-140 design .................................................................. C-134 inspection .........C-70-72, S-22-24, S-38, S-40, S-44 seismic design ............................................. C-62, C-63 shearwalls .............................................. C-139, C-140 strength requirements.............................. C-138, C-139 Prestressing grout.. ..........C-14, C-17, C-19, C-70- 72, .................... , S-6, S-22- 24, S-34, S-340, S-65, S-70 Prestressing steel ..... C-6, C-8, C-26, C-135, C-136, S-38 Prestressing tendon(s) allowable stresses................................................ C-134 bonded............................. C-139, C-141, S-4, S-6, S-40 corrosion protection ........................... C-140, S-40-43 definition ........................................................ C-17, S-6 inspection ..................................... C-70-72, S-22-24 installation............................................................ , S-69 Jaterally restrained........................C-16, C-136-C-138 laterally unrestrained....................C-16, C-136-C-138 materials.......................... C-62, C-70, S-38, S-70, S-72 seismic requirements............................................. C-62 specifications ............................ S-38, S-40-44, S-72 stressing ...........................................C-1 34- 136, S-69 unbonded, definition ......................................C-1 9, S-7 Prestressing tendon anchorages, couplers, and end blocks ............................................................................ C-140 Pretensioning definition ...........................................................C-1 7, S-6 Prism, .............................C-14, C-17, C-23, C-71, C-72, ............................................ C-134, S-4, S-6, S-11- 19 definition ........................................................... C-17, S-4 Prism test method ............... C-23, S-13, S-18, S-23, S-24 Project conditions......................................................S-26 Project drawings, definition.............................. C-17, S-6, ....................................................... see also Drawings Project specifications, definition ......................C-17, S-6, ................................................. see also Specifications * AAC = Autoclaved Aerated Concrete, ASO= Allowable Stress Design, MSW = Masonry Shear Wall, SD = Strength Design
- 334. INDEX Projected area for anchor bolts ................................ C-47 Protection corrosion ...........C-140, C-141, C-159, S-39-44, S-72 from weather .............................. C-71, C-72, S-23-29 of masonry and materials ......... C-71, C-72, S-23, S-24 prestressing tendons and accessories ......... C-140, S-40 reinforcement ........................................................ C-45 Q Quality assurance ...... C-3, C-13, C-17, C-47, C-67- 73, ...................................S-6, S-21- 26, S-63, S-72, S-74 definition........................................................ C-17, S-6 Quality control................... C-69, S-21, S-47, S-49, S-70 R Radius ofgyration .....................C-11, C-27, C-41, C-121 notation ................................................................. C-11 Reinforced AAC masonry ........C-18, C-57, C-61, C-64, .................................C-66, C-176, C-177, C-181-191 Reinforced masonry ASD ............................................................ C-97-103 strength <lesign .......................................... C-114--132 Reinforcement allowable stress............................................. C-97- 1O bend requirements......... C-93, C-122, S-48, S-58, S-61 bund1ing .................................................. C-120, C-183 cleaning................................................................. S-52, clearance between, minimum......................S-58, S-62 cover ..........................C-1 4, C-45, C-87, C-97, C-115, ................................................... C-116, S-4, S-58-61 cross-sectional area, notation .................................. C-6 definition........................................................C-17, S-6 details............................... C-3, C-43-47, C-181, S-48 details, on drawings ...............................................S-48 development.......................................see Development diameter ........................................................ C-7, C-43 diameter ofbend, minimum ......................... C-47, S-48 distance from extreme compression fiber, d ........... C-7 fabrication .............................................................. S-48 for glass unit masonry......................................... C-174 hook ................................................see Standard hooks installation.............................................................S-58, joint.......................................... see Joint reinforcement lap length ..................................................... see Splices lateral ties ...............................................see Lateral ties longitudinal, defination ......................................... C- 16 materials........................................... C-114, S-37, S-48 maximum area, (SD) ..........C-114, C-1 15, C-11&--120 maximum, AAC masonry ............C-183, C-187, C-189 modulus ofelasticity ............................................. C-23 embedment.......................................C-45, C-83, C-185 1-11 length, Id, notation ................................................ C-1O negative moment reinforcement.................. C-83, C-86 physical properties ................................................ C-44 placement requirements ..................C-45, C-70, C-72, .................................................... S-22-24, S-58, S-59 positive moment reinforcement ............................ C-86 prestressing ..................................see Prestressing steel protection .............................................................. C-45 seismic requirements..................................... C-58-62 for anchored veneer ............................................ C-163 shear....................................... see Shear, reinforcement shear wall............................................... see Shear wall size, limitations (SD) .......................................... C-114 size, maximum ....................................................C-43 size, minimum.....................................................C-43 spacing, notation ................................................... C-1 1 specifications .............................. S-37, S-48, S-58-65 splices ..........................................................see Splices stirrups ........................................................see Stirrups strength ................................................... C-1 09, C-178 stress ..................................................................... C-89 ties, lateral ..............................................see Lateral ties tolerances ....................................................... S-58- 61 transverse, defined ................................................ C-19 wire ...... C-87, C-88, C-184, S-8, S-9, S-37, S-38, S-72 yield strength notation,/y ........................................ C-9 Reinforcing steel..................................see Reinforcement Required strength ...............C-17, C-105, C-138, C-175, .......................................................C-193, C-194, S-47 Response modification factor ..................C-56--59, C-65 Retempering .................................................... S-29, S-46 Roof anchorage detailing .............................................................. C-1 55 empirical requirements........................................ C-1 55 seismic anchorage ................................................. C-63 Rubble stone masonry allowable compressive stress (empirical design) C-149 bonding ............................................................... C-155 definition ............................................................... C-19 minimum thickness (empirical design) ............... C-155 Running bond ............ .. .. ...C-17, C-28, C-29, C-31-33, ..........................C-35, C-59, C-67, C-93, C-96, C-109, ................ C-113, C-133, C-143, C-152, C-165, C-175, ...................................... C-180, C-185, S-6, S-53, S-74 definition........................................................ C-17, S-6 for empirically designed masonry........... C-143, C-152 seismic requirements................................... C-59, C-67 wall intersection.......................................... C-28, C-29 • AAC - Autoclaved Aerated Concrete, ASD- Allowable Stress Design, MSW - Masonry Shear Wall, SD - Strength Design
- 335. 1-12 S Sample panels ............................................................ S-26 Samples ............................... S-21, S-25, S-27, S-52, S-70 Sampling............ C-68, S-8, S-JO, S-11 , S-18, S-31, S-70 brick.......................................................................S-10 concrete masonry ...................................................S-1 O grout ......................................................................S-11 Sealant, specification.............................. S-11, S-26, S-44 Section properties ..........C-26, C-27, C-65, C-74, C-106, .............................C-129, C-140, C-176, C-177, C-1 90 Seismic design................C-42, C-5~7, C-131, C-143, .......................................................C-163--166, C-193 categories .............................................................. C-63 empírica! design restrictions ............................... C-143 limits for lightly loaded columns .......................... C-42 veneer requirements .................................. C-163--166 Seismic force-resisting system.....C-54--56, C-59, C-60, ........................................................ C-65, C-66, C-143 Seismic load (earthquake load, seismic force)........C-21, ................... C-23, C-53, C-54, C-56, C-60, C-64--67, .......... C-77, C-93, C120, C-143, C-147, C-165, C-166 Self-consolidating grout definition ........................................................ C-15, S-5 mixing ...................................... C-33, C-46, S-34, S-47 placement............................................................... S-67 submittals ............................................................... S-20 tests ............................. C-70, C-72, S-7, S-9, S-22-24 Service loads......................C-1, C-2, C-21, C-101, C-135 Settlement.................................. C-21, C-84, C-162, S-67 Shale masonry ...................................... see Clay masonry Shear AAC masonry .....C-54--66, C-175, C-178, C-1 80, C- 184, C-189 bolts....................................................................... C-49 force, notation ....................................................... C-11 reinforcement ........C-6, C-8, C-11, C-41, C-59, C-87, ....................C-88, C-1 00-102, C-115, C-122, C-123, .................C-126, C-132, C-1 82, C-185, C-189, C-191 prestressed masonry ................................ C-139, C-140 reinforced masonry ..................................... C-57, C-58 transfer at wall interfaces .......................... C-57, C-102 unreinforced .............................C-17, C-1 8, C-54, C-56 Shear stress composite action ......................C-14, C-26, C-79, C-96 reinforced members .................................. C-97, C-106 INDEX unreinforced members ............................ C-11 O , C-111 Shear wall(s) definition ..................................................... C-17, C-18 design for in-plane loads, AAC masonry........... C-1 89 detailed plain (unreinforced) AAC MSW ............ C-17, .................................................C-54, C-55, C-57, C-60 detailed plain (unreinforced) MSW ............ C-18, C-57 empírica] design .............................C-145-147, C-1 51 intermediate reinforced prestressed MSW ..........C-18, ...........................................................C-57, C-61, C-62 intermediate reinforced MSW.............. .....C-18, C-57, .........................................................C-61, C-64, C-118 intersections .................................................. C-28-30 lateral load distribution ......................................... C-21 ordinary plain (unreinforced) AAC MSW............C-18, ...........................................................C-54, C-55, C-60 ordinary plain (unreinforced) MSW .......... C-18, C-54, .........................................................C-55, C-57, C-138 ordinary plain (unreinforced) prestressed MSW ..C-18, .....................................................................C-61, C-62 ordinary reinforced AAC MSW ......C-18, C-54, C-55, ................................................. C-57, C-61, C-64, C-66 ordinary reinforced MSW ...............C-18, C-55, C-57, .................................................................... C-58, C-64 reinforced masonry, design................C-28, C-57--66, .............................C-100, C-101, C-118, C-126, C-130 seismic requirements..................................... C-54--66 specia1 reinforced MSW .........C-18, C-57--66, C-100, ................................................................ C-1O1, C-118 special reinforced prestressed MSW................... C-18, .................................................................... C-57, C-62 stiffness ................................................................. C-22 unreinforced .......................................................... C-56 Sheet-metal anchors............................C-45, C-162-165, ............................................................ S-38, S-39, S-64 Shrinkage .. .. .. ...C-3, C-5, C-9, C-1 1, C-21 , C-34, C-43, ......................... C-90, C-1 40, C-1 77, S-34, S-44, S-52 coefficient..................................................... C-9, C-25 deformation................................................... C-3, C-21 notation ......................................................... C-9, C-11 provisions, drawings ............................................... C-3 SI equivalents ............................................... C-201- 211 Site tolerances.........................................S-56, S-57, S-69 Sleeves.................................. C-3, C-74, S-44, S-73, S-74 Slump ................. S-6, S-10, S-34, S-47, S-65, S-67, S-68 Slump flow ................C-5, C-18, C-70, C-72, S-6, S-1 1, .................................................... S-20- 24, S-34, S-47 Solid masonry unit, .......... C-36, C-152, S-1 O, S-36, S-62 definition ............................................................... C-16 * AAC Autoclaved Aerated Concrete, ASO Allowable Stress Oesign, MSW - Masonry Shear Wall, SO- Strength Oesign
- 336. INDEX Span......................C-10, C-15, C-38, C-40, C-45, C-64, ......................C-81- 86, C-100, C-121, C-150, C-151, .........................................C-159, C-1 67, C-1 78, C-194 Special boundary elements ......C-18, C-126- 131, C-190 Special reinforced MSW ............C-18, C-57--66, C-100, ................................................................ C-1 O1, C-1 18 Special systems........................................C-4, C-61, C-62 Specifications for materials ............... S-8- 12, S-31--49 Specified compressive strength of masonry acceptance requirements ......................................... C-3 definition........................................................ C-19, S-6 limits for AAC masonry........................................ C-23 limits for SD.............................................. C-98, C-108 mandatory specifications ............................ S-13, S-72 methods to shown compliance with ..............S-' 13- 19 notation ................................................................... C-8 shown on drawings ................................................. C-3 Specified dimension, definition .........................C-15, S-4 Splices ofreinforcement........................................... C-88 Splitting tensile strength ofAAC masonry..... C-9, C-177 Stack bond ......................See Not Laid in Running Bond Stainless steel ........C-45, C-46, S-8, S-9, S-37-42, S-72 Standard hook(s)........................C-10, C-46, C-67, C-87, ....................................................... C-115, C-182, S-48 details.................................................................... C-46 fabrication ..............................................................S-48 seismic requirements............................................. C-67 Standards, cited ...................................................S-8- 12 Steel bars ................................................. see Reinforcement bolts.....................................................see Anchor bolts coatings ......................................... S-8, S-39- 42, S-72 fabrication ..............................................................S-48 stainless ..............C-45, C-46, S-8, S-9, S-36-41, S-70 wire ............................... C-5, S-8, S-9, S-37- 39, S-72 Steel reinforcement .............................see Reinforcement Steel piates and bars .............................. C-45, C-46, S-39 Stiffness .................C-12, C-20, C-21, C-27, C-39, C-56, ..........C-65, C-66, C-81, C-106, C-111 , C-112, C-121, ................C-125, C-153, C-1 59, C-161, C-163, C-167, .............................C-177, C-183, C-184, C-194, C-1 96 anchors, ties ........................................................ C-153 1-13 beams .............................................C-39, C-121, C-183 design ........................................................ C-81, C-1 06 laterai ...................................C-65, C-66, C-121, C-183 walls ........................................................ C-125, C-153 Stirrup(s)............... ...C-19, C-45--47, C-84- 89, C-11 5, ............................... C-116, C-122, C-182, C-183, S-48 Stone masonry allowable stress (empírica!) .................... C-149, C-155 ashlar, definition ............................................C-19, S-7 bond .................................................................... C-153 cast ...................................................................... C-149 definition........................................................ C-19, S-7 dimension...............................................................S-11 mínimum thickness ............................................. C-151 rubble, definition............................................C-19, S-7 specifications ..................................... S-1O, S-11, S-36 Storage ofmaterials/products .............C-67, C-73, S-25, ..................................................................... S-26, S-69 Strength bearing .................................................... C-108, C-178 design strength ............................... see Design strength bolts..................................................................... C-106 compressive .........................see Compressive strength nominal ........................................see Nominal strength required .......................................see Required strength specified ................see Specified compressive strength tensile .................... see Tension/tensile stress, strength Strength design ............................................. C-105-132 of elay and concrete masonry (Chapter 3) .................... ................................................................ C-1 11, C-128 ofAAC masonry ....................................... C-175-191 of prestressed masonry........................................ C-1 38 Strength reduction factor(s) .................C-12, C-15, C-17, ..................C-1 9, C-105, C-106, C-120, C-138, C-139, .....................................................C-175, C-176, C-194 definition............................................................... C-1 9 Stress allowable..... ...see Allowable forces, loads, strengths, and stresses bearing ...................................................... C-82, C-140 compressive ..........C-8, C-9, C-16, C-1 7, C-23, C-3 1, ........ C-38, C-89, C-100, C-110, C-114, C-129, C-136, .................. C-139, C-147-149, C-180, C- 181, C-190, computations ......................................................... C-26 flexura!................................................................ C-1 37 notation ................................................................... C-9 from prestressingjacking force...............C-19, C-134, ........................................................... C-140, S-7, S-69 reinforcement ........................................................ C-89 shear.....................C-8, C-9, C-ll, C-16, C-79, C-80, ........... C-86, C-96, C-100--102, C-126, C-150, C-167 * AAC Autoclaved Aerated Concrete, ASO Allowable Stress Oesign, MSW - Masonry Shear Wall, SO - Strength Oesign
- 337. 1-14 Stress (Continued) temperature change ............................................... C-90 tensile ........C-17, C-39, C-40, C-84, C-90--97, C-100, ..............................C-107-110, C-133, C-136, C-137, ................................. C-140, C- 150, C-161, C-167, S-6 Submit/ submitted/ submittals .......... S-7, S-20-26, S-72 T Temperature affects from changes ................C-21, C-25, C-45, C-90 ambient ................................................ C-25, S-26--29 cold weather.................. see Cold weather construction hot weather...................... see Hot weather construction mean daily ............................................. S-5, S-27-29 notation ................................................................. C-11 Tendon anchorage ................................. C-19, C-140, S-7 Tendon coup1er........................................ C-19, S-7, S-44 Tendon,jacking force .................. C-19, C-134, S-7, S-69 Tension/tensile (strength) axial bolts..................................................C-47, C-79, C-108 prestressed masonry............................................ C-139 reinforced masonry ............................................. C-1 00 unreinforceded masonry.................C-96, C-113, C-180 flexura! prestressed masonry.................................. C-136-139 reinforced masonry ............................................... C-97 unreinforceded masonry...................................... C-110 Test(s)/ testing agency .................... S-19, S-21, S-25, S-33, S-72, S-74 anchor bolts................................................. C-47, C-49 compressive strength............... C-116, S-13, S-18, S-20 field tests................................................................S-70 gr?ut............................................................. S-11, S-34 pnsms................................................. C-23, S-13, S-1 8 reporting....................................................... S-25, S-72 slump................................. C-70- 72, S-10, S-47, S-68 units.............................................................. S-10, S-13 Testing Agency's services and duties..... S-25, S-72, S-74 Thermal expansion ........................................... C-9, C-25 Thickness co1umns................................................................. C-41 empirical requirements............................ C-151, C-1 52 foundation walls (empírica! requirements).................. ................................................................ C-143, C-152 glass units............................................................ C-169 parapets (empírica! requirements)....................... C-151 veneer units......................................................... C-1 67 INDEX walls (empírica! requirements).............. C-143, C-147, ................................................................ C-150, C-152 Thin-bed mortar for AAC masonry ............... C-60, C-68, .........................................................C-70- 72, C-178, .......................................... S-20-24, S-33, S-48, S-55 definition............................................................... C-19 protection in cold weather............................ S-27, S-28 protection in hot weather ....................................... S-29 Ties adjustable ....................... see Adjustable anchors 1ties corrosion protection .............................................. C-45 definition ............................................................... C-19 fabrication .............................................................. S-39 hooks............................................................ C-46, S-48 installation................................. S-58, S-59, S-62, S-63 lateral .................................................. see Lateral ties material specifications ................................. S-38, S-39 specifications ............................................... S-38, S-39 wall tie .................................................... see Wall ties Tile ............................C-65, C-196, S-8, S-10, S-35, S-36 Tolerances ...................C-17, C-178, S-4, S-5, S-8, S-25, ................................. S-48, S-49, S-55- 60, S-69, S-73 concrete......................................................... S-8, S-48 masonry........................................................ S-56, S-57 foundations ............................................................ S-51 prestressing tendon placement ............................... S-69 reinforcement ...................................... S-48, S-59, S-60 units................................................................ C-13, S-4 Transfer, ofprestressing force .................. C-134--C-137 Transformed net cross-sectional area ....................... C-26 Transverse reinforcement, defined ........................... C-19 u Unbonded prestressing tendon .........C-19, C-133, C-138, .................................................. C-139, S-7, S-40, S-41 corrosion protection ..................................... S-40, S-41 definition ........................................................C-19, S-7 Unit strength method ............................... S-13-1 8, S-72 Units, translation table.................................. C-201-211 Unreinforced (plain) masonry AAC masonry ........................................... C-1 79- 180 allowable stress design.................................. C-90- 96 definition............................................................... C-20 strength design .......................................... C-11 0- 113 * AAC Autoclaved Aerated Concrete, ASD Allowable Stress Design, MSW Masonry Shear Wall, SO - Strength Design
- 338. INDEX V Veneer .......... C-20, C-53, C-157-168, S-64, S-72, S-73 ........... see also Adhered veneer and Anchored veneers anchors ................ C-20, C-157- 166, S-64, S-72. S-73 definition ........................................................C-20, S-7 seismic requirements......................C-53, C-165, C-166 Vertical support .......................C-39, C-65, C-161, C-172 anchored masomy veneer ................................... C-161 glass unit masonry .............................................. C-172 Visual stability index (VSI)...................C-20, C-70- 72, ...................................................... S-7, S-20-24, S-34 w Wall(s) anchorage ........................................................ C-3, C-4 cavity ................................................ see Cavity walls composite .............................. see Composite masonry definition........................................................C-20, S-7 design, ASD................................................ C-79, C-11 design for in-plane loads, AAC masonry............ C-189 design for in-plane loads (SD) ............................ C-126 design for out-of-plane loads (SD)...................... C-124 design for out-of-plane loads, AAC masonry ..... C-187 effective height ......................C-9, C-43, C-124, C-188 empírica! requirements...................C- 145, C-150- 153 flange ............. C-28, C-29, C-43, C-129, C-131, C-190 foundation ............................................... C-143, C-152 height, notation ....................................................... C-9 intersections..............C-21, C-28- 30, C-115, C-116, .....................................................C-155, C-182, C-183 intersecting empírica[ requirements ................... C-155 lateral support, empirical design ............. C-150, C-151 loadbearing .................................................... C-20, S-7 masonry bonded hollow ........... C-20, C-36, C-152, S-7 multiwythe ...................C-36, C-79-82, C-147, C-150 partition................................................ C-2, C-169, S-6 seismic anchorage ..............................C-54, C-64, C-67 shear .................................................... see Shear walls thickness (empiricai)........C-143, C-147, C-150, C-152 Wall tie(s) bonding ....................................................... ......C-153 definition............................................................... C-19 installation...........................................S-58, S-62, S-63 rnateriai .................................................................. S-38 protection .............................................................. C-45 1-15 Weather cold ......................... C-71, C-72, S-20, S-23-28, S-67 hot................ C-71, C-72, S-20, S-23, S-24, S-29, S-65 protection ................................... C-71, C-72, S-23-29 Welded splices.........................C-88, C-89, C-116, C-117 Welding ......................C-3, C-5, C-71, C-72, C-88, C-89, ........................ S-8, S-12, S-23, S-24, S-58, S-69, S-70 inspection requirements ........... C-71, C-72, S-23, S-24 Wetting masonry units..................................... S-52, S-74 When required, definition............................................S-7 Width cavity.................................................. C-73, C-81, S-56 definition ............................................................... C-20 diaphragm, empírica[ .............................. C-145, C-147 effective compressive............................................ C-31 flange .................................C-28, C-129, C-131, C-190 grout space ............................... C-73, C-75, S-56, S-66 notation ......................................................... C-7, C-1 1 panel, glass unit masonry .................................... C-169 Wind bracing ...................................................................S-56 cold weather requirements .....................................S-27 empiricallimitations ........................................... C-143 glass unit masonry .................................. C-170, C-171 hot weather requirements .......................................S-29 veneer limitations................................................ C-166 Wire anchors.............................C-163, C-165, S-39, S-64 Wire coatings............................................................ C-83 Wood backing for veneer .................................. C-164, C-166 support on glass unit masonry............................. C-172 support on, empirical requirements..................... C-156 support on, veneer............................................... C-164 Work, definition ..........................................................S-7 Wythe, definition ...............................................C-20, S-7 y Yield strength, notation ...................................... C-8, C-9 • AAC - Autoclaved Aerated Concrete, ASD - Allowable Stress Design, MSW - Masonry Shear Wall, SD - Strength Design