Building Materials & Construction Module - 3

BUILDING MATERIALS & CONSTRUCTION - 18CV34
ABHILASH B.L. M.Tech, IGBC-AP.
Assistant Professor,
Dept. of Civil Engineering,
VidyaVardhaka College of Engineering,
Mysuru – 570002.
Building Materials & Construction (18CV34)

Module-III
Chapter - 1 - Lintels and Arches
Definition, function and classification of lintels, Balconies, Chejja and canopy. Arches;
Elements and Stability of an Arch.
Floors and roofs
Floors; Requirement of good floor, Components of ground floor, Selection of flooring
material Procedure for laying of Concrete (VDF), Mosaic, Kota, Slate, Marble, Granite, Tile
flooring, Cladding of tiles.
Roof: Requirement of good roof, Types of roof, Elements of a pitched roof, Trussed roof,
King post Truss, Queen Post Truss, Steel Truss, Different roofing materials, R.C.C. Roof.

Lintels and Arches
 Placed across an opening to support the position of the structure
above it.
 Width will be equal to the width of the wall

Definition
 A lintel is a horizontal member which is placed across an opening to support
the position of the structure above it.
 A lintel is thus a sort of beam in which width will be equal to the width of
the wall, and the ends of which are built into the wall.
 The distance up to which it is inserted in the supporting wall, should be the
minimum on the following three considerations
1. 100mm
2. Height of lintel
3. 1/10th or 1/12th of the span of lintel

Classification of LINTEL
Based on the materials of construction
1.Timber lintels
2.Stone lintels
3.Brick lintels
4.Steel lintels
5.Reinforced concrete lintels

Building Materials & Construction Module - 3

Function of LINTEL
1.Lintel supports the walls above the openings like doors, windows, etc.
2.Lintels provide a safeguard of the windows and doors.
3.Lintel withstands the imposed loads coming from above bricks or block
including the roofing members.
4.The lintel is used to transfer all imposed loads to the side walls.
5.Sometimes lintels are used as a decorative architectural element.

Chejja

Balconies
Function of Balconies
1. Prevention against atmospheric actions
2. It is used for relaxation purpose.
3. It gives a good architectural appearance to a structure.

Canopy

Arches

Arches
Elements of an Arch

1. Intrados: This is the inner curve of the arch.
2. Extrados: This is the external curve of an arch.
3. Soffit: This is the inner surface of the arch.
4. Voussoirs: These are the wedge-shaped units forming the courses
of an arch.
5. Skewback: This is the inclined surface on the abutment which is so
prepared to receive the arch and from which the arch springs.

6. Crown: This is the highest point on the extrados.
7. Key: This is the wedge-shaped unit at the crown of an arch.
8. Springing points: These are the points from which the curve of an
arch springs.
9. Springing line: It is an imaginary line joining the springing points of
either end.

10. Abutment: This is the end support of an arch.
11. Piers: These are the intermediate supports of an arcade.
12. Span: This is the clear horizontal distance between the supports.
13. Rise: This is the clear vertical distance between the highest point on
the intrados and the springing line.
14. Centre: This is the geometrical center of the curve of an arch.

Stability of an Arch.
1. Crushing of the masonry
2. Rotation of some joint about an edge
3. Sliding of voussoir.
4. Uneven settlement of abutment or pier.

1. Crushing of the masonry
The compressive stress or thrust exceeds the safe crushing strength of
the materials and the arch fails due to crushing of the masonry.
The measures to avoid failure of arch due to this reason are as follows:
a) The material should be of adequate strength.
b) Voussoirs - To bear the thrust transmitted through them.
c) Voussoirs of variable heights may be provided
i,e less height near crown and max height at skewback.

2. Rotation of some joint about an edge
To prevent the rotation of joint, the line of resistance should be kept
within intrados and extrados.
The line of thrust should also be made to cross the joint away from the
edge so as to prevent the crushing of that edge.
It should fall within the middle third portion of the arch height.

3. Sliding of voussoir
To safeguard against the sliding of adjacent voussoirs due to transverse
shear, the voussoir of greater height should be provided.

4. Uneven settlement of abutment or pier.
a) The arch should be symmetrical so that unequal settlements of the two
abutments or abutment and pier are minimized.
b) The supports of arch should be strong enough to take or resist the thrust
as well as to bear all the loads transferred to them through the arc.
Semicircular arch test.mp4

Module-III
Chapter - 2 - Floors and roofs
Floors Requirement of good floor, Components of ground floor, Selection of flooring
material Procedure for laying of Concrete (VDF), Mosaic, Kota, Slate, Marble, Granite, Tile
flooring, Cladding of tiles.
Roof: Requirement of good roof, Types of roof, Elements of a pitched roof, Trussed roof,
King post Truss, Queen Post Truss, Steel Truss, Different roofing materials, R.C.C. Roof.

Floors
Requirement of good floor
1. Appearance
2. Cleanliness
3. Cost
4. Damp resistance
5. Durability
6. Fire resistance
7. Hardness
8. Maintenance
9. Thermal Insulation
10. Slipperiness

1. Appearance: A. Pleasing appearance B. Desired color effect and
architectural beauty.
Eg- Terrazzo, Mosaic, tiles and Marble give good appearance.
2. Cleanliness: A. capable of being cleaned easily B. non-absorbent.
C. Effective resistance against absorption of oil, grease etc.
3. Cost: Should be in conformity with the type of building,
Floor coverings of marble etc.

4. Damp resistance: Healthy environment is obtained in the building.
Flooring of concrete, terrazzo, mosaic etc are preferred
while flooring of wood, rubber, etc are not suitable for damp conditions.
5. Durability: Resistance to wear, temperature changes, disintegration with
time and decay so that long life is obtained.
Eg- flooring of marble, terrazzo, concrete etc are considered to be of best
type.

6. Fire resistance: This is more important for upper floors. Flooring material
should offer sufficient fire resistance so that fire barriers are obtained between
different levels of a building.
7. Hardness
8. Maintenance: the flooring material should require least maintenance.
However, whenever repairs are required, it should be such that repairs can be
done easily with least possible expenditure.

9. Thermal insulation: the flooring should offer reasonably good thermal
insulation so that comfort is imparted to the residents of the building.
10. Slipperiness: The surface of floor should be smooth but at the same time, it
should not be too slippery.

 FUNDAMENTALS FOR DEVELOPMENT OF
V D F…!!!
VALUE FOR
MONEY
LEVEL FLOOR,
HIGH FLATNESS
ACCURACY
IMPROVE WEAR
RESISTANCE
10

 NEED OF V D F…!!!
bleeding of concrete can caused for wear• Excessive
resistance.
• Thus the durability and service life of the flooring
element is in question.
• In hot and windy conditions it produce quality, durable
concrete.

 INSTRUMENTS USED IN V D F…!!!

Procedure for laying of Concrete (VDF)
• Preparation of sub base.
• Divide floor area into panels.
• Preparation of formwork using steel channels.
• Laying down of steel bars of specified size.
• Mix design of concrete.
• Placing of concrete and compacting.

 ADVANTAGES OF V D F…!!!
• Reduction in W/C ratio leads to early setting and high
strength.
• It removes the excess water of the concrete & an ideal
W/C ratio can be achieved.
• Increase in compressive strength of concrete by 40 – 70%.
• The surface hardness of the slab increase by 130%.

 ADVANTAGES OF V D F…!!!
• Water absorption is reduced enormously.
• Minimum dusts.
• Level floor, high flatness accuracy.
• Minimized crack formation, shrinkage reduced by 50%.
• Improved wear resistance.

 DISADVANTAGES OF V D F…!!!
• High initial cost.
for vacuum dewatering like
• Skilled Labour is needed.
• Need specific equipment
vacuum pump.
• Need power consumption during dewatering process.

Mosaic
• Small pieces of coloured stones, tiles, or glass
to render an artful design.
• A mosaic design is one that may consist of
geometric patterns

Slate
Rustic Black Slate Stone is a fine-grained, foliated, homogeneous
metamorphic rock derived from an original shale-type sedimentary
rock composed of clay or volcanic ash through low grade regional
metamorphism.

Marble

• Marble is a very popular natural stone used for tiles and slabs
for floors, countertops, and walls.
• It is a metamorphic rock that forms when a sedimentary stone, such
as limestone, is transformed under heat and pressure into a harder
stone with beautiful color and veined patterns.

Granite

Roof
A roof is defined as . . .
 Upper most part of a building,
 Provided as a structural covering, to protect the building from weather.
 The structural elements may be trusses, portals, beams, slabs, shells or
domes and the roof coverings may be A.C. sheets, G.I. sheets, wooden
shingles, tiles, slates etc.

Requirement of good roof
01. Weather Resistance:
The roof covering should have adequate resistance to resist the effect of
weather elements such as the wind, rain, sun, snow, etc.
02. Strength and Stability:
The roof structure should be strong and stable enough to take up the
anticipated loads safely including wind load.
03. Heat Protection:
The roof structure should provide adequate protection against heat. Both to
occupant and material used for construction.

Requirement of good roof
04. Sound Insulation:
The roof construction for all buildings should provide adequate degree of
insulation against sound from external sources.
05. Fire Resistance:
06. Day Lighting:
The roof designed according to may if provide daylight in buildings with large
floor area.

Types of roof
1. Flat roofs or terraced roofs
2. Pitched or sloping roofs
3. Curved roofs

Elements of a pitched roof

Trussed roof
Trussed rafter roofs, also known as roof trusses,
provide a structural framework to support the roof fabric, ceilings or floors of buildings in both domestic and
commercial structures
• “truss” describes a triangular design.
• A joint framed structure that sustained the inclined, vertical or horizontal
loads.
• A truss consist of angles, channels, plates and eye bars.
• It is a framework, typically consisting of rafters, posts, and struts,
supporting a roof, bridge or other structure.
• APPLICATION - You will find them supporting the roofs of auditoriums,
cinema halls, stadiums, railways, stations, airports and others.

King post Truss

Queen Post Truss

Use of trusses in buildings
• Trusses are used in a broad range of buildings, mainly where there is a requirement for
very long spans, such as in airport terminals, aircraft hangers, sports stadium roofs,
auditoriums and other leisure buildings.
• Trusses are also used to carry heavy loads and are sometimes used as transfer structures.
• The trusses are widely used to serve two main functions:
 Tocarry the roof load
 Toprovide horizontal stability.
2

WHY STEEL ROOF?
• There are numerous advantages to using steel trusses instead of traditional wood trusses but the main
reasons are simplicity and strength.
• Some prefer to use the metal roof truss because the building of a structure is all about precision and metal has
a more precise measurement than wood.
• This truss are extremely simple to install.
• You never have to worry about them rotting or deteriorating from the weather.
• You also get more usable space inside your building.
• Wood trusses are less expensive truss per truss but they require
you to install wood headers, the posts have to be closer
together and you have more trusses to install.
• You generally have to protect the wood from the weather.

Advantages of Metal Roof Truss Structures
1. Even though they are considered to be more expensive, metal roof trusses can span further than
wood.
2. Metal roof trusses can be manufactured to exact standards.
3. They are much more lightweight and this allows for larger shipments. This reduces the time it takes
to get to the project site.
4. Metal roof trusses are fire resistant.
5. They are compatible with almost all types of roofing systems.
6. No insect infestations can occur.
7. Chemical treatments are not necessary to maintain the trusses.
8. Metal roof trusses are recyclable and therefore environmentally friendly.

Disadvantages of Metal Roof Truss Structures
1. Skilled labor is required to install metal roof trusses.
2. They are not energy efficient since they allow more temperature
3. Metal roof trusses allow sound to be more easily transmitted.
4. Temperature fluctuations allow them to move more.
5. When the metal is cut, drilled, scratched or welded, rust can become a problem.
6. The workers have a higher risk of electrocution when installing the metal roof trusses.

Different types of Wooden and Steel Roof Trusses:
• King Post Truss
• Queen Post Truss
• Howe Truss
• Pratt Truss
• Fan Truss
• North Light Roof Truss
• Quadrangular Roof Truss
King Post Truss
• King Post Truss is a wooden truss.
• It can also be built of combination of wood and
steel.
• It can be used for spans upto 8m.

Queen Post Truss
ss.• Queen Post Truss is also a wooden tru
• It can be used for spans upto 10m.
Howe Truss
•It is made of combination of wood and steel.
•The vertical members or tension members are
made of steel.
•It can be used for spans from 6-30m.

Pratt Truss
•Pratt Truss is made of steel.
•Vertical members are tension and diagonal
members are compression.
•These are very economical form of roof trusses.
Fan Truss
•It is made of steel.
•In Fan Trusses, top chords are divided into small
lengths in order to provide supports for purlins

ER
NORTHLIGHT ROOF TRUSS
INTRODUCTION:
NORTH LIGHT TRUSSES ARE TRADITIONALLY USED FOR SHORT SPANS IN INDUSTRIAL WORKSHOP-TYPE BUILDINGS. THEY
ALLOW MAXIMUM BENEFIT TO BE GAINED FROM NATURAL LIGHTING BY THE USE OF GLAZING ON THE STEEP PITCH
WHICH GENERALLY FACES NORTH OR NORTH-EAST TO REDUCE THE SOLAR GAIN.
USES –
*IT IS USED IN WAREHOUSE, INDUSTRIES, FACTORIES, ETC.
*NORTH LIGHT TRUSSES ARE TRADITIONALLY USED FOR SHORT SPANS IN INDUSTRIAL WORKSHOP-TYPEBUILDINGS.
*THEY ALLOW MAXIMUM BENEFIT TO BE GAINED FROM NATURAL LIGHTING BY THE USE OF GLAZING ON THE
STEEPER PITCH WHICH GENERALLY FACES NORTH OR NORTH-EAST TO REDUCE THE SOLAR GAIN.

Quadrangular roof Trusses
Quadrangular Roof Truss (for large spans)
•These trusses are used for large spans such as railway sheds and Auditoriums.

Tubular Steel Truss are used for large span constructions such as factories, industry worksheds, shopping
malls, huge exhibition centre, multiplexes etc. They are generally used for spans as large as 25-30m.
TUBULAR STEEL TRUSS:-

Typical Steel Connections
Steel Connections
Many configurations are used for force transfer in connections. The configuration depends
upon the type of connecting elements, nature and magnitude of the forces (and moments),
available equipment, fabrication and erection considerations, cost, etc.
Rivets

Gusset plate connections
• Gusset plates are usually either made from cold rolled or
galvanized steel based upon their use.
• Gusset plates are used for various structures. Gusset plates are
used to connect beams and columns together or to connect
truss members. They can be either the only way of connecting
the beam and columns or they can be used with bolts and
welds.

Galvanized Steel Sheets (Plain andCorrugated)
• Galvanized iron (GI) sheets are steel sheets which are
basically coated with zinc and include a range of hot
dip galvanized and electro-galvanized steel sheets.
• Corrugated galvanised iron or steel is a building
material composed of sheets of hot-dip galvanised
mild steel, cold-rolled to produce a linear corrugated
pattern in them.
• The corrugations increase the bending strength of the
sheet in the direction perpendicular to the
corrugations, but not parallel to them. Normally each
sheet is manufactured longer in its strong direction.
19

Galvanized Corrugated Steel Sheets 20

INSTALLATION OF CORROGATED SHEETS

Building Materials & Construction Module - 3

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