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Research Paper
International Journal of Informative & Futuristic Research ISSN (Online): 2347-1697
Volume 2 Issue 9 May 2015
Abstract
During an earthquake, buildings are strongly affected by the rigidity of floors and the connections of floors to the walls. Shear walls are normally arranged in such a way that they resist lateral loads most effectively. Therefore, in the present study the structural behavior of the buildings with shear walls at corners has been investigated. A geometrically unsymmetrical building situated in the most prone seismic zone-v as per IS 1893-2002(part-1). it has been outlined that the RC building model consisting of G+5 storey’s is considered and analyzed using both linear static or equivalent static & non-linear static or pushover analysis, for the loads considered as per IS 875 -2000. Also various results such as base shear, storey displacement, storey drift, storey shears, maximum drift, maximum lateral displacement and nonlinear results performance point, performance levels, capacity of the building and hinge status are obtained and these results are Compared for both linear and non-linear analysis, for the gravity load combination as per IS 1893 (part-I) 2002. Modelling and analyzing the considered RC frame building is done using extended three dimensional FEM based analytical software ETABS-9.7.4 version.
Seismic Vulnerability Of Geometrically
Unsymmetrical RC Building By Considering
The Effect Of Shear Walls At Different Position Paper ID IJIFR/ V2/ E9/ 066 Page No. 3420-3428 Research Area
Structural
Engineering
Key Words Shear Wall, Lateral Displacement, Drift, Base Shear, Pushover Analysis
Harsha N C 1 M.Tech. Scholar Department Of Civil Engineering ACS College Of Engineering, Bangalore, Karnataka
Kavitha K 2 Assistant Professor Department Of Civil Engineering ACS College Of Engineering, Bangalore, Karnataka
Syed Ahamed Raza 3 Assistant Professor Department Of Civil Engineering Ghousia College Of Engineering, Ramanagaram, Karnataka
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ISSN (Online): 2347-1697 International Journal of Informative & Futuristic Research (IJIFR)
Volume - 2, Issue - 9, May 2015 21st Edition, Page No: 3420-3428
Harsha N C, Kavitha K , Syed Ahamed Raza:: Seismic Vulnerability Of Geometrically Unsymetric RC Building By Considering The Effect Of Shear Walls At Different Position
1. Introduction RC Multi-Storey Buildings are adequate for resisting both the vertical and horizontal load. When
such building is designed without shear wall, the beam and column sizes are quite heavy, steel
quantity is also required in large amount thus there is lot of congestion at these joint and it is
difficult to place and vibrate concrete at these places and displacement is quite heavy which induces
heavy forces in member. Shear wall may become imperative from the point of view of economy and
control of lateral deflection. In RC multi-storey building R.C.C. lift well or shear wall are usual
requirement. However, on many occasions the design has to be based on the off centre position of
lift and stair case wall with respect to centre of mass which results into an excessive forces in most
of the structural members, unwanted torsion moment and deflection. The use of shear wall structure
has gained popularity in high rise building structure, especially in the construction of service
apartment or office, commercial tower. It is very important to note that shear walls meant to resist
earthquake should be designed for ductility.
2. Methodology
Review of existing literatures by different researchers.
Selection a type of structure.
Modelling of the selected structures.
Analyzing the selected structure by using linear static and non-linear static or push over
methods.
G+5 RC building frame models are considered (SMRF) under seismic zone-V for the hard
soil type-2 and response reduction factor R=5 as per IS 1893-2002(part-1).
For the load combination as per IS 1893 (part-1) 2002.
Plotting pushover curve and obtaining various results as mentioned in abstract.
Finally comparing the results of analyzed models by “analysis to analysis” the conclusion has
given.
3. Methods Of Analysis
3.1 Linear Static Analysis
In linear static procedures the building is modelled as an equivalent single degree of freedom
(SDOF) system with a linear static stiffness and an equivalent viscous damping. The seismic input is
modelled by an equivalent lateral force with the objective to produce the same stresses and strains as
the earthquake it represents. The time period of the building is calculated by the expressions
T=0.075h0.75
for bare frame as given in IS 1893 (Part 1): 2002, where h is the height of the building
in the considered direction of vibration. The lateral load calculation and its distribution along the
height are done as per IS 1893 (Part 1): 2002. The seismic weight is calculated using full dead load
plus 50% of live load. For the equivalent static load analysis the earthquake load is considered in
both X and Y directions.
3.1.1 Modelling
Building Data For Analysis And Modelling:
A multi-storey building is considered with G+5 number of stories with geometrically unsymmetrical
in plan . The dimensions of the building elements are given below
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ISSN (Online): 2347-1697 International Journal of Informative & Futuristic Research (IJIFR)
Volume - 2, Issue - 9, May 2015 21st Edition, Page No: 3420-3428
Harsha N C, Kavitha K , Syed Ahamed Raza:: Seismic Vulnerability Of Geometrically Unsymetric RC Building By Considering The Effect Of Shear Walls At Different Position
Table 1: Structural Data Used:
Modelling has been done and all the dimension of the cross sectional elements of structure,
characteristics compressive strength, yield strength and other required parameters are defined.
The loads on the structure considered as per IS 875-2000. where in as per IS 1893 (part1) 2002,
percentage of imposed load considered as 50%.
The building model is analysed using linear static analysis, the building is situated in sever zone-
V having importance factor I=1 and response reduction factor R=5, the building is situated on
medium soil(type-2).
The defined parameters are assigned to building model and then the building model is analysed
and design for gravity load combination.
Figure 1: Plan (Location Of Shear Wall At Corner)
01 Types of structure Multi Storied RC Rigid Jointed Plane Frame
(Special Moment Resisting Frame)
02 Number of stories G+5
03 Seismic zone V (Table 2, IS 1893 (Part- 1):2002)
04 Importance factor 1
05 Response reduction factor 5
06 Floor height 3m
07 Size of column 650X750 mm
08 Size of beam 400X600 mm
09 Depth of slab 125mm
10 Thickness of shear wall 200mm
11 Imposed load 3.5 KN/m2 on floors
1.75 KN/m2 on roof
12 Floor finish 2 KN/m2
13 Specific weight of infill 18 KN/m3
14 Specific weight of RCC 25 KN/m3
15 Type of soil Medium soil(type-2)
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ISSN (Online): 2347-1697 International Journal of Informative & Futuristic Research (IJIFR)
Volume - 2, Issue - 9, May 2015 21st Edition, Page No: 3420-3428
Harsha N C, Kavitha K , Syed Ahamed Raza:: Seismic Vulnerability Of Geometrically Unsymetric RC Building By Considering The Effect Of Shear Walls At Different Position
Figure 2: Three Dimensional View (Location Of Shear Wall At Corner)
3.2 Non-Linear Static Analysis
Pushover analysis is one of the methods available to understand the behaviour of structures
subjected to earthquake forces. As the name implies, it is the process of pushing horizontally with a
prescribed loading pattern incrementally until the structure reaches a limit state (ATC-40 1996). The
static approximation consist of applying a vertical distribution of lateral loads to a model which
captures the material nonlinearity of an existing or previously designed structure, monotonically
increasing those loads until the peak response of the structure is obtained on a base shear v/s roof
displacement plot.
4. Results Of Analysis
4.1 Storey Shear
The following Table-2 and chart-1shows storey shear for both linear and non-linear static analysis in
longitudinal x direction.
Table 2: Storey Shear
Storey Shear In Kn
Storey Shear Wall At Corner
EQX PUSHX
5 2521.64 49216.58
4 4434.65 86553.91
3 5510.71 107556.2
2 5988.96 116890.5
1 6108.53 119224
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ISSN (Online): 2347-1697 International Journal of Informative & Futuristic Research (IJIFR)
Volume - 2, Issue - 9, May 2015 21st Edition, Page No: 3420-3428
Harsha N C, Kavitha K , Syed Ahamed Raza:: Seismic Vulnerability Of Geometrically Unsymetric RC Building By Considering The Effect Of Shear Walls At Different Position
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
1 2 3 4 5 6
Dis
pla
cem
en
t In
M
STOREYS
EQX
PUSHX
Chart 1: Storey Shear Profile
4.2 point Displacement
The following Table-3 and chart-2shows point displacement for both linear and non-linear static
analysis in longitudinal x direction.
Table 3: Point Displacement
Chart 2: Point Displacement Profile
49216.58
86553.91
107556.16
116890.49
119224
STOREY SHEAR IN kN
STO
REY
S
PUSH X
EQX
point displacement in Meter
Storey shear wall at corner
EQX PUSHX
5 0.002203 0.079418
4 0.0018 0.06141
3 0.0013 0.042347
2 0.0007 0.023967
1 0.0003 0.0086
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ISSN (Online): 2347-1697 International Journal of Informative & Futuristic Research (IJIFR)
Volume - 2, Issue - 9, May 2015 21st Edition, Page No: 3420-3428
Harsha N C, Kavitha K , Syed Ahamed Raza:: Seismic Vulnerability Of Geometrically Unsymetric RC Building By Considering The Effect Of Shear Walls At Different Position
4.3 Storey Drift
The following Table-4 and chart-3 shows storey drift for both linear and non-linear static analysis in
longitudinal x direction.
Table 4: Storey Drift
Storey Drift In Meter
Storey
Shear Wall At Corner
EQX PUSHX
5 0.000154 0.006215
4 0.000176 0.006556
3 0.000176 0.006296
2 0.000153 0.005224
1 0.000094 0.002923
Chart 3: Storey Drift Profile
4.4 Non-Linear Static(pushover) Analysis Results
4.4.1 Pushover Curve
Figure 3: Pushover Curve In X Direction
0
0.002
0.004
0.006
0.008
1 1.5 2 2.5 3 3.5 4 4.5 5
EQX PUSH X
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ISSN (Online): 2347-1697 International Journal of Informative & Futuristic Research (IJIFR)
Volume - 2, Issue - 9, May 2015 21st Edition, Page No: 3420-3428
Harsha N C, Kavitha K , Syed Ahamed Raza:: Seismic Vulnerability Of Geometrically Unsymetric RC Building By Considering The Effect Of Shear Walls At Different Position
Figure 3: Pushover Curve In Y Direction
Chart 4: Pushover Curve Profile
0 12429.3027
103972.6712
121791.4844 119224.0703
0
20000
40000
60000
80000
100000
120000
140000
-0.02 0 0.02 0.04 0.06 0.08 0.1
PO CURVE Linear (PO CURVE)
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ISSN (Online): 2347-1697 International Journal of Informative & Futuristic Research (IJIFR)
Volume - 2, Issue - 9, May 2015 21st Edition, Page No: 3420-3428
Harsha N C, Kavitha K , Syed Ahamed Raza:: Seismic Vulnerability Of Geometrically Unsymetric RC Building By Considering The Effect Of Shear Walls At Different Position
4.4.2 Performance Level
The following Table-5 shows the performance level of the building
Table 5: performance level
Step Displacement Base Force
A-B
B-I
O
IO-L
S
LS
-CP
C-D
D-E
>E
Total
0 0 0 3446 4 0 0 0 0 0 3450
1 0.0045 12429.3027 2651 666 131 2 0 0 0 3450
2 0.0646 103972.6712 2594 540 292 20 3 0 0 3450
3 0.0798 121791.4844 2594 540 292 20 3 1 0 3450
4 0.0788 119224.0703 3450 0 0 0 0 0 0 3450
5. Conclusions
The present work focuses on study of seismic performance evaluation of G+5 RC buildings, which
are located in seismic zone-V for the medium soil condition. These conditions are considered as per
IS 1893-2002 (part-1). The analysis has been carried out using standard package ETABs software.
The analysis results were taken in terms of point Displacements, Storey Drifts, and Storey Shear and
the Performance level of the buildings were tabulated on the basis of linear and non-linear static
analysis. The following are the conclusions are drawn from the present investigation, which are as
follows
Various results such as storey shear, storey displacement and point displacement are
obtained and comparison is done for both linear and non-linear static analysis in longitudinal
X direction.
From the obtained values for various results as shown in the Table 2 to Table 4 and values
are plotted as shown from the chart number 1 to 3 shows that storey shear, point
displacement and storey drift is maximum in non-linear static analysis compared to linear
static analysis, which gives the interference that as storey height increases the values of
storey shear, point displacement and storey drift.
The performance of building is studied and pushover curve is plotted for displacement in X
axis and base forces in Y axis in both X&Y direction.
The building performance is obtained from the non-linear static analysis which shows that
the building performance level lies in the range B-IO (linear range to immediate occupancy).
From this we can interference that the performance level within the immediate occupancy.
References
[1] S.A. Halkude, C.G. Konapure and S.M.Birajdar(2015), “Effect of Location of Shear Walls on Seismic
Performance of Buildings” ijcet, E-issn 2277-4106, P-issn 2347-5161. Volume 5, april 2015
[2] Raman Kumar, Shagunveer Singh Sidhu, Shweta Sidhu, Harjot Singh Gill (2014), “Seismic Behavior
Of Shear Wall Framed Buildings” ijetmas, pp no: 28-38 volume 2 issue 1.
[3] M. S. Aainawala, Dr. P. S. Pajgade (2014), “Design of Multistoried R.C.C. Buildings with and
without Shear Walls”, ijesrt, pp no: 498-510 july 2014.
3428
ISSN (Online): 2347-1697 International Journal of Informative & Futuristic Research (IJIFR)
Volume - 2, Issue - 9, May 2015 21st Edition, Page No: 3420-3428
Harsha N C, Kavitha K , Syed Ahamed Raza:: Seismic Vulnerability Of Geometrically Unsymetric RC Building By Considering The Effect Of Shear Walls At Different Position
[4] Manohar K, Dr. Jagadish Kori(2014), “Analysis On Seismic Performance Of High Rise Building By
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2249-6149, june-july 2014
[5] Mr. Syed Owaise Showkath Peer, Khalid Nayaz Khan(2014), “Seismic Vulnerability of RC Buildings
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[7] Shahzad Jamil Sardar and Umesh. N. Karadi(2013), “Effect Of Change In Shear Wall Location On
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[8] Kasliwal Sagar K , Prof. M.R.Wakchaure , Anantwad Shirish (2012), “effects of numbers and
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