Analysis of Multi-storey Building Frames Subjected to Gravity and Seismic Loads with Varying Inertia

ISSN: 2277-3754
ISO 9001:2008 Certified
International Journal of Engineering and Innovative Technology (IJEIT)
Volume 2, Issue 10, April 2013
132
Abstract— This paper presents an elastic seismic response of
reinforced concrete frames with 3 bay, 5 bay and 7 bay 9 storey
structures which have been analyzed for gravity as well as seismic
forces and their response is studied as the geometric parameters
varying from view point of predicting behavior of similar
structures subjected to similar loads or load combinations. The
structural response of various members when geometry changes
either physically, as in case of linear haunches provided beyond
the face of columns at beam column joints or step variations as in
case of purported T-section due to monolithic action in between
beams and slabs, when the slab is available in compression zone of
the beam was also studied. Every attempt has been made to
describe the things in dimensionless forms. Results, if is expected,
can be readily extended and/or extrapolated for other structures
too. For the sake of clarity various types and kinds of structures
analyzed and results so obtained have been grouped into various
categories. This paper also highlighted on response of reinforced
concrete frames for variation of axial force for spread of haunch
and storey drift.
Index Terms— Bare Frame, Multi-Storey Structure, Storey
Drift, Spread Of Haunch.
I. INTRODUCTION
There is growing responsiveness of multi-storey
reinforced concrete structures, to accommodate growing
population. Generally such structures have prismatic sections
which are common in developing countries, which resist
applied loads without any appreciable deformation of one
part relative to another. It is the need to accomplish some
function, one of them is to receive loads (usually known as
service loads) at certain points & transmit them safely to
other points, that prompts the designer to give life to a
structure furthermore since it is the need for a safe,
serviceable, feasible and aesthetically pleasing fulfillment of
a structure. The ultimate aim of structural analysis is to
design all the structural elements of a structural system in
such a way that they perform their functions satisfactorily and
at the same time assist design to become efficient, elegant and
economical which helps to choose the right type of sections
consistent with economy along with safety of the structure.
II. OBJECTIVE OF STUDY
In order to make multi-storey structures stronger and
stiffer, which are more susceptible to lateral (earthquake
and/or wind) forces, the cross sections of the member
(particularly columns) increases from top to bottom (4)
, makes
the structure uneconomical owing to safety of the structure.
When the given frame with all prismatic sections is subjected
to different types of loads & their combination it exhibits a
typical bending moment distribution pattern i.e. specific to
certain type of load combination. When the bending moments
gets so distributed, it can be easily verified that a certain
portion of every beam shall carry a sagging moment
producing compression at top. Slab being cast monolithically
with beams & since they happen to set in the compression
zone it promotes a T action in sagging moment zone, such a T
beam but imaginary & has only to be conceived. This is not
actually available in the form of T section as & an isolated
section. When properties of such a T section are considered in
analysis, one always find that it has larger inertia than the
corresponding rectangular section, which depends on the
width of flange (2)
, in turn depends upon the length of sagging
moment zone i.e. distance between points of zero moment
consistent with whatever flange width actually materializes.
At the same time beyond the points of contra flexure i.e. in
hogging moment zones the inertia of beam shall be as that of
the same rectangular section referred to above. Naturally,
response of such beam will be totally different from that of
the beam considered in first interaction. It is expected that
such a beam would attract larger bending moment near about
the centre & would attract lesser moments near the ends. It
was decided to find how these changes would occur as such
using the bending moment diagrams of each beam which was
split into three parts, with end segments having same cross
section as before & the central one acting as a T section. The
dimensions of T are appropriately decided (8)
& the structure
was reanalyzed after revising loads on all these beams to cope
up with the requirements. Similarly the haunches are
assumed at support i.e. beyond center line of column (the
flare angle of haunch has been taken as 450
); however for the
purpose of comparison the spread of haunch as observed only
beyond the face of the column (7)
. Various haunch spread
beyond the face of the columns are considered and their
effect studied on variation of axial force and bending moment
at various locations and finally on the sway.
III. DESCRIPTION OF STUDY BUILDING
STRUCTURE
In order to study the behavior of reinforced concrete
frames, three different configurations i.e. 3 bay, 5 bay and 7
bay, 9 stories with beam depths varying from 350 mm to 600
mm are modeled and analyzed numerically. The members are
prismatic and/or non prismatic (viz. stepped and tapered
members); subjected to loads i.e. dead load, live load,
Analysis of Multi-storey Building Frames
Subjected to Gravity and Seismic Loads with
Varying Inertia
Kulkarni J.G., Kore P. N., S. B. Tanawade

ISSN: 2277-3754
133
earthquake load and their combinations for limit state of
collapse and serviceability criteria are considered. Here five
different live load patterns (6)
viz. L.L.1, L.L.2, L.L.3, L.L.4,
and L.L.5 are accounted which produce maximum mid span
moment for beams i.e. L.L.1 & L.L.2 as shown in Fig.1 (a) &
(b), maximum column moment i.e. L.L.3 as shown in Fig.1
(c), maximum joint moment i.e. L.L.4 as shown in Fig. 1 (d),
and maximum axial force in column i.e. L.L.5 as shown in
Fig. 1 (e). These frames are modeled and analyzed in STAAD
pro analysis software package (10)
. All structures are analyzed
based on matrix methods of stiffness analysis (1 & 3)
.
L.L.1 L.L.2 L.L.3
(a) (b) (c)
L.L.4 L.L.5
(d) (e)
Fig. 1 Five different live load patterns considered to produce
maximum mid span moment for beams (L.L.1 & L.L.2),
maximum column moment (L.L.3), maximum joint moment
(L.L.4) and maximum axial force in column (L.L.5).
The sections of columns of bare frames are reduced from
top to bottom, which is kept same for every 3 storey i.e. 1-3,
4-6 and 7-9, in order to achieve an economy in bare frames
itself. In all cases, span length and story elevations are 4 and 3
meters, respectively. A typical frame of this type is shown in
Fig. 2 a (i, iii & v) above.
(i) (ii)
(a) Typical prismatic frame with 3 Bay and with idealised T
beams considered in between points of contra flexures.
(iii) (iv)
(b) Typical prismatic frame with 5 Bay and with idealised T
beams considered in between points of contra flexures.
(v) (vi)
(c) Typical prismatic frame with 7 Bay and with idealised
haunch joints provided beyond column faces at beam column
joints
Fig 2. Different Configurations Of 9 Storey 3 Bay, 5 Bay And
7 Bay Structures
With a view to get a feel of integral action developed
between slab and beam promoting a T action in the structure
an idealized imaginary structure with section behaving as T
beam in the structure have been shown in Fig. 2 a (ii) and b
(iv). Properties of T are determined using the exact distance
between the points of contra flexure located actually on the
beam (8)
using the bending moment diagram of the frame with
beam of depth 350 mm for all the beam segments. The same
is done for 5 bay 9 storey structures as been shown in Fig. 2
(b). For 7 bay 9 storey structures the analysis has been made
first on the frame consisting of only prismatic sections,
afterwards a change in the cross-section in the form of
haunch provided and the effect of same was also considered
as shown in Fig. 2 c (vi). The spreads of haunches beyond
face of column were considered at 0.05B, 0.075B, 0.1B,
0.125B, 0.15B where B is Bay width. While expressing the
considered parameters such as axial force and bending
moment, instead of using absolute values, for sake of
facilitating, a ratio has been taken with the values obtained by
conventional approach i.e. ratio of axial force (Ra) is the ratio
of actual axial force to conventional axial force and for ratio

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134
of bending moment (Rm) is the ratio of actual bending
moment to that of conventional one.
IV. PARAMETRIC STUDY
Analysis has been made to study and compare following
parameters:
1) To study the variation of internal forces i.e. axial force and
bending moment at specified locations as shown in Fig. 2
a, b, c.
2) To study distribution of lateral displacements (sway).
3) To study the effect of varying inertia of beam due to
introduction of T-action for 3 and 5 bay as shown in Fig.
2 a (ii), b (iv) and haunches beyond the face of columns
for 7 bay as shown in Fig. 2 c (vi).
V. RESULTS AND DISCUSSION
For 3 bay and 5 bay structure a beam depth of 350 mm is
considered only to study the effect of varying inertia of beam
due to introduction of T-action in beam as shown in Fig. 2 (a
& b) above and for 7 bay structure for all beam depths
ranging from 350 mm to 600 mm is considered to study the
effects of varying inertia of beam due to introduction of
haunches beyond column faces as shown in Fig. 2 (c) above.
Forces induced viz. axial force and bending moment in
various worst loaded column segments is considered for this
purpose. In order to facilitate the direct comparison between
prismatic and non prismatic frames the latter have been
analyzed for same geometry by locating the exact distance
between points of contra flexure for the same loading
combination for which the prismatic frame yielded the
maximum design force in the members so selected as shown
in Fig.2 a, b and c indicated by member number.
A. 3- Bay 9 storey structures:
To study the variation of axial force in left most column in
various segments typically chosen to have the change of
cross-section in the immediate neighborhood viz. 02, 14, 26,
38 are considered as shown in Fig. 2 (a). Variation of axial
force in the column segments is found to be linear for the
members as we move towards top as seen in Graph No. 01
and the corresponding values are provided in Table I. The
variation in members located at base shows little drop
initially and further shows liner variation. It may be noted
that the conventional method of considering the load
attracted by column using adjoining contributory area
overestimates load in column, average percentage of which is
found as 5.9%, 7.25%, 9.47% and 10.23% for members 38,
26, 14, 02 respectively. This variation suggests that the
conventional method estimate loads in better fashion away
from the base of structure.
Table I:Variation of Axial Force in Member No. 02, 14, 26, 38
with Kb/Kc ratio for 3 Bay 9 storey Structures
Mem-
Ber
02
Mem-
Ber
14
Mem-
Ber
26
Mem
ber
38
0.06 0.905 0.11 0.92 0.21 0.929 0.51 0.932
0.07 0.902 0.13 0.92 0.24 0.93 0.58 0.936
0.08 0.905 0.14 0.922 0.27 0.932 0.66 0.941
0.09 0.907 0.16 0.923 0.30 0.933 0.73 0.947
0.10 0.909 0.17 0.925 0.33 0.935 0.8 0.952
0.11 0.912 0.19 0.925 0.36 0.936 0.87 0.957
Bending moment in the column segments is found to
increase with decrease in the values of Kb/Kc ratio for
considered beam depths as seen in Graph No. 02 and the
corresponding values are provided in Table II. An increase is
found in the lowest segment and subsequently reduces as
segments at higher levels are considered. It is found that
bending moment attracted by column at bottom of segment is
largest for the smallest Kb/Kc at joint, the values are found to
reduce by 52.65%, 34.57%, 10.32%, and 18.34% for
members 02, 14, 26, and 38 respectively as Kb/Kc increases.
Table II: Variation of Bending Moment in Member No. 02, 14,
26, 38 with Kb/Kc ratio for 3 Bay 9 storey Structures
Mem-
Ber
02
Mem
Ber
14
Mem-
Ber
26
Mem
ber
38
0.062 0.336 0.110 0.146 0.210 0.073 0.509 0.029
0.071 0.253 0.125 0.115 0.240 0.071 0.582 0.026
0.079 0.226 0.141 0.107 0.270 0.072 0.655 0.025
0.088 0.199 0.157 0.101 0.300 0.071 0.727 0.024
0.097 0.177 0.172 0.097 0.330 0.071 0.800 0.024
0.106 0.159 0.188 0.095 0.361 0.065 0.873 0.024
Following Load Combinations Sampled At Random And
Worst Loading Combinations As Appropriate For Study Of
Variation Of Lateral Displacement Along Height Of Frame.
1) DL+ EQ
2) DL + 0.8LL4 + 0.8EQ

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Table III: Variation of Lateral Displacement along Height of
Frame for 3 Bay 9 Storey Structures For Beam Depth 350 Mm
Height
(m)
Lateral Sway for
Prismatic Section
(mm)
Lateral Sway for
Non-prismatic
Section (mm)
DL+
EQ
DL+0.8LL4
+0.8EQ
DL+
EQ
DL+0.8LL4
+0.8EQ
30.6 47.296 37.917 43.961 36.932
27.4 44.625 35.751 41.536 34.962
24.2 40.026 32.077 37.334 31.587
21.0 33.585 26.92 31.401 26.811
17.8 26.305 21.093 24.715 21.411
14.6 18.655 14.962 17.636 15.626
11.4 11.881 9.551 11.263 10.231
8.2 6.954 5.595 6.618 6.058
5.0 2.9433 2.386 2.8147 2.611
1.8 0.4653 0.4 0.444 0.429
Provision of T-beam in the portion between points of zero
moments results in the decreased value of sway as seen from
Table III. The sway is found to reduce for loading
combination (D.L. + E.Q.) along height of frame. However
for (D.L. + 0.8L.L.4 + 0.8E.Q.) it is found that the sway
increases up to about 50% height of the structure after which
it reduces as seen in Graph No. 3. However all these
maximum displacement in all loading cases is less than the
maximum permissible relative lateral displacement as
(0.004H) per IS: 1893: 2002(9)
.
B. For 5- bay 9 storey structures
Graph No. 04 shows variation of „Ra‟ in members 02, 35,
68, & 101 for 5 bay 9 storey structures as shown in Fig. 2 (b)
with Kb/Kc as beam depth changes from 350 mm to 600 mm
and the corresponding values are provided in Table IV. It
could be seen very clearly that for members 02, 35, and 68
variation is almost linear and „Ra‟ remains almost constant. It
may be noted that the conventional method of considering the
load attracted by column using adjoining to contributory area
underestimates load in column for lowest beam depth
considered in analysis. It is found that the average percentage
of which is found as -38.779 %, -5.608 %, -0.7739 % and
1.0944 % for members 101, 68, 35, 02 respectively but for
the members located at the base of the structure i.e. member
02 the values are found to be overestimated. This variation
suggests that the conventional method estimates loads in
better fashion at and near the base of structure. This being the
worst loaded portion one may rely on values obtained from
conventional approach in proximity of base.
Table IV: Variation of axial Force in Member No. 02, 35, 68,
101 with Kb/Kc ratio for 5 Bay 9 storey Structures
Mem-
Ber
02
Mem
Ber
35
Mem-
Ber
68
Mem
Ber
101
0.010 0.985 0.017 1.006 0.122 1.058 0.158 1.610
0.015 0.987 0.026 1.007 0.182 1.059 0.236 1.619
0.021 0.988 0.037 1.007 0.259 1.059 0.336 1.628
0.029 0.990 0.050 1.008 0.355 1.059 0.461 1.637
0.038 0.991 0.067 1.009 0.472 1.059 0.613 1.647
0.049 0.993 0.087 1.010 0.613 1.060 0.796 1.658
Variation of axial force in the members is found to be
almost constant as Kb/Kc increase. The conventional load
calculated on the basis of contributory area closely
approximates the true load for almost the 2/3rd
height of
frame from bottom and true load attracted is 60% to 70%
larger at the topmost level than conventional load.
Graph No. 05 shows variation of bending moment of
selected column segments as (Kb/Kc) changes and the
corresponding values are provided in Table V. It is found that
bending moment attracted by column at bottom of segment is
largest for the smallest (Kb/Kc) at joint, the value are found to
reduce by 50.062%, 29.98 %, 12.844% and again increases
by 60.60 % for members 02, 35, 68, & 101 respectively as
(Kb/Kc) increases. Variation of bending moment in the
members is found to decrease with increase in values of
Kb/Kc and it is found to be almost linear for top members.
Table V: Variation of Bending Moment in Member No. 02, 35,
68, 101 with Kb/Kc ratio for 5 Bay 9 storey Structures
Mem-
Ber
02
Mem
Ber
35
Mem-
Ber
68
Mem
Ber
101
0.010 0.355 0.017 0.153 0.122 0.087 0.158 0.035
0.015 0.301 0.026 0.135 0.182 0.084 0.236 0.029
0.021 0.259 0.037 0.123 0.259 0.082 0.336 0.024
0.029 0.226 0.050 0.116 0.355 0.080 0.461 0.020
0.038 0.200 0.067 0.111 0.472 0.078 0.613 0.017
0.049 0.177 0.087 0.107 0.613 0.076 0.796 0.014

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Provision of T-beam in the portion between points of zero
moments results in the decreased value of sway as seen from
Table VI. The sway is found to reduce for loading
combination (D.L. + L.L.4) and (D.L. + E.Q.). However for
(D.L. + 0.8L.L.4 + 0.8E.Q.) it is found that the sway is going
to increase up to the full height of the structure as seen in
Graph No.6. However all these maximum displacement in all
loading cases is less than the maximum permissible relative
lateral displacement as (0.004H) per IS: 1893: 2002(9)
.
Table VI: Variation of lateral displacement along height of
frame for 5 bay 9 storey structures for beam depth 350 mm
Height
(m)
Lateral Sway
for Prismatic Section
(mm)
Lateral Sway
for Non-prismatic
Section
(mm)
DL+
EQ
DL+0.8LL4+
0.8EQ
DL+
EQ
DL+0.8LL4+
0.8EQ
30.6 40.173 50.103 55.762 44.971
27.4 38.211 47.697 53.058 42.764
24.2 34.819 43.454 48.32 38.941
21.0 29.962 37.379 41.535 33.478
17.8 24.201 30.192 33.479 26.994
14.6 17.889 22.304 24.675 19.914
11.4 11.816 14.717 16.261 13.141
8.2 7.052 8.77 9.655 7.808
5.0 3.069 3.798 4.154 3.369
1.8 0.511 0.605 0.651 0.542
0 0 0 0 0
C. For 7- bay 9 storey structures:
Variation of „Ra‟ in member 2, 47, 92, and 137 with Kb/Kc
as beam depth changes from 350 mm to 600 mm for 7 bay 9
storey structures as shown in Fig. 2 (c). It could be seen very
clearly that for member 02, 47, and 92 variation is almost
linear and „Ra‟ remains almost constant as seen in Graph No.
7 and corresponding values are provided in Table VII.
Contrary to this absolute a change in „Ra‟ to show increase in
beginning and temporary small reduction at Kb/Kc of 0.059 is
seen in member No. 137, it may be noted that the value of
„Ra‟ in this case is form to increase by about 4.1%, it may be
noted that the conventional method of considering the load
attracted by column using adjoining to contributing area over
estimates load in column for lowest beam depth considered in
analysis. It is found that 44.3%, 13.3%, 10.1%, and 7.1% for
members 137, 92, 47, 02 respectively. This variation suggests
that the conventional method estimates loads in better fashion
at and near the base of structure. This being the worst loaded
portion one may rely on values obtained from conventional
approach in proximity of base.
Variation of axial force in the column segment is found to
be almost linear for the members as we move towards top.
The variation in the members located at top there is a fraction
drop is observed at end and again it shows linear variation.
The conventional axial force calculated on contributory area
closely approximates the true load in column segment at 1/3rd
height of frame and it reduces for topmost level.
Table VII: Variation of Axial Force in Member No. 02, 47, 92,
137 with Kb/Kc ratio for 5 Bay 9 storey Structures
ME
M
BER
02
ME
M
BER
47
ME
M
BER
92
ME
M
BER
137
0.00
9 0.933
0.01
5 0.908
0.12
2 0.883
0.15
8 0.693
0.01
3 0.935
0.02
3 0.909
0.18
2 0.883
0.23
6 0.699
0.01
8 0.936
0.03
2 0.909
0.25
9 0.883
0.33
6 0.705
0.02
5 0.937
0.04
4 0.909
0.35
5 0.883
0.46
1 0.710
0.03
3 0.938
0.05
9 0.910
0.47
2 0.883
0.61
3 0.708
0.04
3 0.939
0.07
7 0.910
0.61
3 0.884
0.79
6 0.721
Graph No. 08 shows variation of bending moment selected
column in segments has Kb/Kc changes and corresponding
values are provided in Table VIII. It is found that bending
moment attracted by column at bottom of segment is largest
for the smallest Kb/Kc at joint, the value are found to reduce

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137
by 48.61%, 35.89%, 10.30% and 53.21% for members 2, 47,
92, 137 respectively as Kb/Kc increases. Variation of bending
moment in column is found to decrease with increase in
values of Kb/Kc and it is found to be linear for top members.
Table VIII: Variation of Bending Moment in Member No. 02,
47, 92, 137 with Kb/Kc ratio for 5 Bay 9 storey Structures
ME
M
BER
02
ME
M
BER
47
ME
M
BER
92
ME
M
BER
137
0.00
9 0.488
0.01
5 0.205
0.12
2 0.102
0.15
8 0.042
0.01
3 0.419
0.02
3 0.177
0.18
2 0.100
0.23
6 0.036
0.01
8 0.362
0.03
2 0.158
0.25
9 0.097
0.33
6 0.030
0.02
5 0.317
0.04
4 0.145
0.35
5 0.095
0.46
1 0.026
0.03
3 0.281
0.05
9 0.137
0.47
2 0.093
0.61
3 0.023
0.04
3 0.251
0.07
7 0.131
0.61
3 0.092
0.79
6 0.020
Table IX: Variation of lateral displacement along height of
frame for 5 bay 9 storey structures for beam depth 350 mm
Height
(m)
Lateral Sway
for
Prismatic Section
(mm)
Lateral Sway for
Non-prismatic
Section
(mm)
DL+
EQ
DL+0.8LL4+
0.8EQ
DL+
EQ
DL+0.8LL4+
0.8EQ
30.6 53.161 66.339 19.437 24.105
27.4 50.51 63.101 18.601 23.104
24.2 45.79 57.189 16.92 21.003
21.0 39.08 48.809 14.538 18.035
17.8 31.162 38.9 11.875 14.712
14.6 22.591 28.202 8.876 10.987
11.4 14.682 18.307 5.803 7.157
8.2 8.656 10.789 3.638 4.468
5.0 3.701 4.605 1.718 2.084
1.8 0.593 0.714 0.346 0.38
0 0 0 0 0
Due to provision of haunch results in decreased value of
sway. The sway is found to increase for loading combination
(D.L. + 0.8L.L.4 + 0.8E.Q.) as seen from Table IX and Graph
No. 9. However for load cases (D.L. + E.Q.) it is found that
the sway is going to reduce up to the full height of the
structure. The largest load is attracted by the right most
lowest segment of column which is varying from 75.77% for
spread of haunch 0.05B to 79.26% for spread of haunch
0.15B of the conventional axial force considered for the
worst load combination of 1.5 (DL + EQ).
D. Variation of Axial Force at Joint Due to Spread of
Haunch
For the load combination (1.5 D.L. + 1.5 E.Q.) the
variation is observed to be increasing linearly for the
members located at the base level of structure, then for
intermediate levels it remains almost constant but terrace
level it slightly increases again as seen from Graph No. 10
and corresponding values are provided in Table X. For 0.125
B spread of Haunch it shows declined variation and again
slight increment.
Table X: Variation of axial force for spread of haunch for
Beam depth 450 mm and L/C (1.5DL+1.5EQ)
S / W
0.050B 0.075B 0.100B 0.125B 0.150B
0.125 0.3686 0.4389 0.4400 0.3766 0.4435
0.250 0.5986 0.6796 0.6824 0.5857 0.7070
0.375 0.6895 0.6924 0.6838 0.5983 0.7300
0.500 0.6952 0.7010 0.6988 0.5976 0.7317
0.625 0.6954 0.6999 0.7186 0.5838 0.7316
0.750 0.6954 0.7176 0.7222 0.5634 0.7317
0.875 0.6972 0.7199 0.7250 0.5711 0.7348
1.000 0.7577 0.7694 0.7822 0.6828 0.7926

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E. Variation of Bending Moment at Joint Due to
Spread of Haunch
Variation of Bending Moment at joint due to spread of
haunch for Load Case (0.9 DL + 1.5 EQ) as shown in Graph
No. 11 and corresponding values are provided in Table XI.
As spread of haunch increases, the bending moment at end of
left haunch increases continuously at about spread of haunch
0.050 B to 0.100 B and it further decreases as spread of
haunch beyond this value.
Table XI: Variation of bending moment at joint No. 44 in
beam No. 72 with spread of haunch for load (0.9 DL + 1.5 EQ)
Spread of
Haunch
Ratio of Actual Bending
Moment
to Conventional Bending
Moment (Rm)
0.050 B 0.14443
0.075 B 0.14718
0.100 B 0.14969
0.125 B 0.10864
0.150 B 0.15320
VI. CONCLUSION
From the data revealed by the analysis for the structures
with various loading combinations tried following
conclusions are drawn:
1. The conventional axial force calculated on contributory
area closely approximates the true load in column
segment at higher levels for 3 bay 9 storey structures and
the 2/3rd
height of frame from bottom and larger at the
topmost level for 5 bay 9 storey structures and the
column segment at 1/3rd
height of frame and it reduces
for topmost level for 7 bay 9 storey structures.
2. Column segments at lower level attract larger axial
forces as compared to bay variation i.e. as number of
bays going to increase the axial forces in the column at
bottom segments increases. The same is with bending
moment.
3. Variation of bending moment in column segments is
found to increase with decrease in the values of Kb/Kc for
3 bay 9 storey structures and decrease with increase in
values of Kb/Kc and it is found to be linear for top
members for 5 & 7 bay 9 storey structures.
4. For high rise structures, the higher axial forces and
deformations especially in the columns, and
concentration of them over a greater height may cause
bending moment parameter to become predominant.
5. Provision of non prismatic sections in beams prove to
attract more load in turn carry more forces such as axial
force and bending moment and reduces the lateral sway
as compared to prismatic sections which is already in
permissible limit as per IS 1893:2002(09)
.
REFERENCES
[1] V.N. Vazirani & M. M. Ratawani, (1985) Analysis of
structures 10th
edition Khanna Publishers.
[2] Dr. V. L. Shah & Dr. S. R. Karve, (Feb.2005) Illustrated design
of reinforced concrete building 5th
edition Structure
publication.
[3] Weaver Jr. and Gere J.M., (1986) “Matrix analysis of framed
structure”, CBS Publishers and distributor, New Delhi.
[4] Taranath. S. B., (1984): "Structural analysis and design of tall
buildings", McGraw-Hill Book Company.
[5] Smith. B. S. and Coull. A., (1991): "Tall building structures:
Analysis and Design", John Wiley & Sons.
[6] S. S. Bhavikatti (2009) Advanced R.C.C. Design 2nd
edition
New Age International Publishers.
[7] Smith. B. S. and Coull. A., (1991): "Tall building structures:
Analysis and Design", John Wiley & Sons.
[8] I.S. 456-1993, Indian standard code of practice for plain and
reinforced concrete (fourth revision), Bureau of Indian
standards, New Delhi.
[9] I.S. 1893(Part 1)-2002, Criteria for earthquake resistant design
of structure, general provision and building, Bureau of Indian
standards, New Delhi.
[10] STAAD Pro 2006 structural analysis and design commercial
software.
AUTHOR BIOGRAPHY
Kulkarni Jayant G.
B.E. (Civil), M.E. (Civil - Structures)
F.I.E. (I), LM-ISTE, LM-ISRMTT, M-ISSE
Kore Pralhad N.
Tanawade S. B.

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