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pushover curve and damage index
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1
SEISMIC THREAT TO HIGH RISE BUILDINGS IN HYDERABAD DUE TO
NEARBY ZONE-3 AREAS
KOLLIPARA.RAJESH
(20111631)
MASTER OF TECNOLOGY
IN
COMPUTER AIDED STRUCTURAL ENGINERRING
International Institute of Information Technology Gachibowli, Hyderabad Andhra
Pradesh, INDIA 500032
2
CERTIFICATE
It is certified that work contained in the project titled “SEISMIC THREAT TO HIGH RISE
BUILDINGS IN HYDERABAD DUE TO NEARBY ZONE-3 AREAS” by RAJESH
KOLLIPARA, has been carried out under my/our supervision and it is not published elsewhere
for a degree.
Advisor: Dr.Ramancharla Pradeep kumar
3
ABSTRACT
This project deals how to find seismic threat to high rise buildings in Hyderabad due to
nearby ZONE 3 areas. Procedure and analysis are explained by taking 3,7,10 and 15
storey building as example problem, which are existing in Hyderabad. Design of building
is done by using IS 456,IS 875 part 3(wind load),IS 1893 (earthquake loads) . Pushover
analysis is used to find final results using software like SAP, excel sheet, Auto Cad,
Matlab.
4
INDEX
1) About Project 7
2) Calculating damage index 8 3) Performance point 8
4) Fragility curve. 10
5) Code for ADRS and Fragility curve 12
6) Building Design 15 7) Design of structure for 3 storied buildings 16
8) Slab Design 18
9) Wind load calculations 21
10) Stair case Design 21
11) Design of structure for 7 storied building 31
12) Design of structure for 10 storied building 37
13) Design of structure for 15 storied building 42
14) Comparing all results 47
15) Seismic threat to building in Hyderabad 49
16) Conclusion. 49
5
LIST OF TABLES
Page
Table 1 Details of G+5 storied Building 16
Table 2 Wind load calculations 21
Table 3 Details of 7 storied Building 32
Table 4 Details of 10 storied Building 37
Table 5 Details of 15 storied Building 43
Table 6 Comparing all base shear and capacity 47
Table 7 No. of buildings in ZONE 49
LIST OF FIGURES
Page
Fig1. A.P zone map 7
Fig2. Building subjected to displacements 8
Fig3. Pushover curve 8
Fig4. Design spectrum 9
Fig5. ADRS format 10
Fig6. Total area under pushover curve (T) 10
Fig7. Fragility curve 11
Fig8. Stair case details 25
Fig9. Stair case section 25
Fig10. Pushover curve for 3 storied building 28
Fig11. ADRS format for 3 storied building 29
Fig12. Fragility curve for 3 storied building 29
6
Fig13. Sap model for 7 storied building 33
Fig14. Pushover curve for 7 storied building 34
Fig15. ADRS for 7 storied building 35
Fig16. Fragility curve for 7 storied building 36
Fig17. Pushover curve for 10 storied building 40
Fig18. ADRS for 10 storied building 41
Fig19. Fragility curve for 10 storied building 41
Fig20. Pushover curve for 15 storied building 45
Fig21. Fragility curve for 15 storied building 46
Fig22. Comparing all pushover analysis 47
Fig23. Comparing all fragility curves 48
LIST OF PLAN
Page
Plan1. 3 storied building 17
Plan2. Reinforcement distribution details for3 storied building 20
Plan3. Beam details for3 storied building 20.1
Plan4. Beam reinforcement details for3 storied building 20.2
Plan5. 7 storied building 31
Plan6. 10 storied building 38
Plan7. 15 storied building 42
7
.
INTRODUCTION
Hyderabad is in ZONE 2 area and surrounded by ZONE 3 areas. Generally, waves with
high frequency affect nearby buildings and waves with low frequency travel long
distance which damages tall buildings in other regions.
. Fig.1 (A.P zone map)
Aeronautical distance from Hyderabad to ZONE 3areas are as follows
1)Bhadrachalam, A.P (260Km)
2)Vijayawada, A.P(247 Km)
3)Latur, Maharashtra(230Km)
4)Khammam, A.P(179Km)
5)Warngal, A.P(140Km)
These areas are ZONE 3 areas which are very near to Hyderabad. We require ground
motions to generate damage index, but ground motions in selected areas are not
available, so by considering few selected ground motion data from other areas are
collected. Ground motions which are considered are as follows.
1)Bhuj
2)Chamba
3)Chamoli
4)Dharmashala
8
Above ground motions are of different “g” values. So they are normalized to 0.1g and
0.16g. Assuming these ground motion occurred in selected ZONE 3 areas. So, by using
available data and matlab program me we can generate damage index. For pushover
analysis 4 buildings are planned and designed according to Hyderabad conditions.
CALCULATING DAMAGE INDEX
To methods are used to generate damage index.
1) Performance point and
2) Fragility curve.
PERFORMANCE POINT
It is a plot between base Sa (vs) Sd. To get performance point we require capacity
curve and demand curve (design spectrum) are converted to ADRS format and plotted
in a single graph. Performance point is points were two curves meet at a point.
Capacity curve (Base shear vs Displacement)
To generate this curve pushover analysis is done. When structure is subjected to lateral
load, we get strength of structure and when it is subjected to lateral displacement, we
get capacity of the structure.
fig.2 (building subject to lateral force or displacement)
fig.3 (Pushover curve )
9
Design demand spectrum (Sa vs T)
The design demand spectrum has to be developed for given site considering range of
earthquakes or IS 1893-2002 code gives design response spectrum for different zones.
IS 1893-2002codes gives design response spectrum for three sites i.e., rocky or hard
soil, medium soil, soft soil sites is represented in figure 2.5. The classification of site into
above mentioned categories is based on IS 1893-2002. The design response spectrum
is for 5% damped structure. IS1893 gives modification factors for other damping values.
For special structure site design spectrum has to be developed. The reduction factors
given in IS1893 for other damping can be used as reduction factors to get reduced
design demand response spectrum.
Fig.4(design spectrum)
To convert demand curve and pushover curve to ADRS format to show performance
point, following steps are followed.
1. Pushover is a plot between base shear (vs) displacements. This plot is converted
to Sa (vs) Sd.
Sa=Base shear (v)/(A*W)
Where A=Z/2*I/R and
W=seismic weight.
Sd=∆/(Pf*φ)
Where ∆=displacement
Pf=participation factor and φ= Mode shape at roof
2. Demand curve is plot between Sa (vs) Time. This plot is converted to Sa (vs) Sd.
Sd=T*T*Sa/(4π*π).
From above steps we get ADRS curve as show below (fig 5)
10
fig 5( ADRS curve)
FRAGILITY CURVES
It is a plot between displacement (vs) damage index (or) acceleration (vs) damage
index. Seismic fragility curves are essential tools for assessing the vulnerability of a
particular building, or a class of buildings, and offer a means of communicating the
probability of damage over a range of potential earthquake ground motion intensities.
Fragility curves for buildings in their retrofitted condition provide a number of
advantages and opportunities for building owners. This includes offering tools to
evaluate alternative retrofit measures for buildings, assess the regional risk to an
inventory comprised of as-built and retrofitted structures, or perform probabilistic return
on investment examinations. Regardless of the ultimate application of such tools,
fragility curves for retrofitted buildings are critical pieces of the risk and reliability
assessment of buildings exposed to the seismic hazard. As such, an appropriate
methodology for their development is necessary.
To generate fragility curve, following steps are required.
1) Find angle of line w.r.to x-axis.
2) Find total area under curve Ee.
3) Deduct elastic area E form Ee
Total area T=Ee-E
4) Similarly find area for different displacement values (ti).
5) Damage Di=ti/T
6) Plot between Di (vs) displacement values.
Fig below explains to calculate total area T
11
Fig 6 (area for T)
Fig 7 below explains for calculating ti values for different displacements.
fig7 (area for t (i))
For area t4=t4+t3+t2+t1.
Triangular area =1/2xf(i)*(x(i)-x’(i))
Where x’(i)=f(i)/tan(φ)
D(i)=t(i)/T
Plot D(i) vs displacement m(i) we get curve as shown (fig 8)
12
Fig.8 (fragility curve)
General code for getting ADRS format and FRAGILITY curve using matlab is as
below.
% Program to find performance point and damage of a 3-storey structure clear all; clc; % Loading values of capacity curve obtained from SAP push=load('Book2.txt'); % Base shear Vs Roof disp roof_disp=push(:,1); Vb=push(:,2); % Constants g=9.81; pi=22/7; % Input from user storey=input('\n'); E=5000*sqrt(fck); disp('enter Mass at each floor'); for i=1:1:storey; m(i)=input('\n'); end disp('enter stiffness'); for i=1:1:storey; k(i)=input('\n'); end W=m*g; % Determination of Dynamic properties M=zeros(storey,storey); for i=1:1:storey
13
M(i,i)=m(i); end k(storey+1)=0; K=zeros(storey,storey); for i=1:1:storey for j=i:1:storey K(i,j)=k(j)+k(j+1); k(i,j+1)=-k(j+1); k(i+1,j)=-k(j+1); end end [m_shape,lamda]=eig(K,M); womega=sqrt(lamda(storey,storey)); for i=1:storey for j=1:storey phi(j,i)=m_shape(j,i)/m_shape(storey,i); end end totalm=0; % Determination of modal contribution for i=1:storey sum1=0; sum2=0; for k=1:storey sum1=sum1+W(k)*phi(k,i); sum2=sum2+W(k)*(phi(k,i)^2); end pf(i)=sum1/sum2; modalm(i)=(sum1^2)/(g*sum2); totalm=totalm+modalm(i); end PF=pf(1); alpha=modalm(1)/totalm; % capacity curve for i=1:length(push(:,1)) Sa(i)=Vb(i)/(alpha*wt)*9.81; Sd(i)=roof_disp(i)/(PF*abs(phi(storey,1))); end %T(1)=0; T=0:0.1:4; % Demand curve for i=1:length(T) if T(i)<=0.1 Sa1(i)=(1+15*T(i));
14
end if T(i)>0.1 && T(i)<=0.4 Sa1(i)=2.5; end if T(i)>0.4 && T(i)<=4 Sa1(i)=(1/T(i)); end Sd1(i)=(T(i)^2/(4*pi^2))*Sa1(i); end % Plotting capacity spectrum plot(Sd,Sa,Sd1,Sa1); xlabel('Spectral displacement Sd'); ylabel('Spectral acceleration Sa'); title('Capacity & Demand curves using MATLAB'); legend('Capacity','Demand'); %Damage curve Emax=trapz(roof_disp,Vb); slope=((Vb(2,1)-Vb(1,1))/(roof_disp(2,1)-roof_disp(1,1))) angle=atan(slope) for i=2:length(Vb) for j=1:i X(j)=push(j,1); Y(j)=push(j,2); end E=trapz(X,Y); X1(i)=Y(i)/tan(angle) area(i)=X1(i)*Y(i)*0.5 E1(i)=E; end for i=2:length(Vb) damage(i)=((E1(i)-area(i))/(Emax-area(length(Vb)))); end figure(1); plot(roof_disp,damage); title('fragility curve') xlabel('Displacement in m'); ylabel('Damage Index'); disp(‘enter displacement value from response spectrum’); rsdisp=input(‘\n’); damagefactor=interp1(roof_disp,damage,rsdisp)
15
Building Design
Most of the building in Hyderabad is open to parking at ground floor, this causes soft
story effect. in this project soft story affect is considered. Project is done for complete
Hyderabad location, so total number of building in Hyderabad are collected from GHMC
and based on height of buildings classification is done. Classification of building is as
follows.
1) up to 3 storied buildings as class 1
2) up to 7 storied buildings as class 2
3) up to 10 storied buildings as class 3
4) more than 10 storied buildings as class 4
Design procedure is as follows.
1) Procuring typical building plan (as per client requirement )
2) Rough orientation columns and beam.
3) Modeling in SAP tool.
4) Calculate live load and dead load for design of slab. We get slab thickness.
5) Calculate load coming from slab to beam using yield line theory and also
calculate wall load to beam. Then apply loads to beams.
6) Calculate wind loads as per IS 875.
7) Calculate earthquake force as per IS 1893.
8) By using 53 load combinations building is designed. During design orientation of
column and beam will be finalized.
After passing of all sections in structure, building is analyzed for pushover analysis.
From this we get capacity curve. By plotting demand curve and capacity curve in a
single plot gives as performance point.
16
For class 1, Design of structure for 3 storied buildings
Building is used as hostel in Hyderabad location.
Table 2(Details of G+3 storied Building)
TYPE OF BUILDING HOSTEL
AREA OF PLOT 725sq.m
GRADE OF CONRETE M25
GRADE OF STEEL Fy415
NO.OF FLOORS G+3
NO.OF COLUMS 56
MAX SIZE OF COLUME 800x230mm
MAX SIZE OF BEAM 500x230mm
TOTAL SEISMIC WEIGTH 31466.683 kN
PEAK DISPLACEMENT ( FROME RESPOUNSE
SPECTRUM ANALYSIS DUE TO 0.1g AND 0.16g) 0.049979m
17
AUTO CAD plan
Plan.1 (3 storied building)
18
Slab design in excel sheet
Design of Two waySlab
Master bed room PANEL (P1)
Fy = 500 N/mm² Ly = 1.550 m
Fck = 20 N/mm² Lx = 1.550 m
Clearcover 20 mm
Slab thickness = 150 mm Beam width 230 mm
D.L.of slab = 3.750 Ley = 1.446 m
Floor finishes = 1.500 Lex = 1.446 m
Partition 0.000
Live load = 10.000 dx= 126
Total 15.250 dy= 118
kN/m²
Ly/Lx = 1.000 Ast Required Ast Provided
1 Edge Condition= Interior panel Ast 8 mm 8
Mx- = αx*1.5*w*lx² = 0.031 1.51 kN-m 180 279 c/c 175
Mx+ = αx*1.5*w*lx² = 0.024 1.13 kN-m 180 279 c/c 175
8 mm 8
My- = αy*1.5*w*lx² = 0.032 1.53 kN-m 180 279 c/c 175
My+ = αy*1.5*w*lx² = 0.024 1.15 kN-m 180 279 c/c 175
Check for deflection
fs = 182
Pt = 0.23 Modification factor = 2.00
d required = 27.8
d provided = 126.0 O.K
19
Design of One way Slab
CORRIDOR Slab P9
Fy = 500 N/mm²
Fck = 20 N/mm² Lx = 1.570 m
Clearcover 25 mm
Slab thickness = 125 mm Beam width 230 mm
D.L.of slab = 3.13
Floor finishes = 4.00
Live load = 3.00 dx= 95
Total 10.125 kN/m² dy= 85
Ast Required
Ast Provided
Ast 10
mm 10
M=1.5*(W*Lx²/10)= 3.744 kN-m 150 523 c/c 150
8
mm 8
Distribution steel=0.12*1000*d/100= 150 335 c/c 175
Check for deflection
fs = 83
Pt = 0.55 Modification factor = 2.00
d required = 39.3
d provided = 95.0 O.K
20
Reinforcement distribution for slab (plan2)
Plan.2 (3 storied building reinforcement details
21
Wind load calculations
Design Of Critical Closed Staircase
Length of span = 5.60 m
Length of Flight = 2.77 m
Width of Flight = 1.20 m
Depth of Slab = 175 mm
Height of riser = 0.15 m
Width of tread = 0.30 m
Clear cover = 20 mm
Grade of concrete = 20 N/mm2 (fck)
Grade of Steel = 500 N/mm2 (fy)
Density of R.C.C = 25 KN/m3
Density of P.C.C = 24 KN/m3
Max dia of bar used = 16 mm
Loads on stair slab:
self weight = 0.175 x 25 = 4.375 KN/m2
Weight on plan = 4.375 x sqrt(0.3^2+0.15^2)
0.30
= 4.89 KN/m2
l w h l w h
1 10 44 1.00 0.88 1.00 38.72 0.90 42.00 27.00 30.00 1.11 1.56 0.5 0.7 1.2 42.00 27.00 30.00 1.11 1.56 0.5 0.7 1.21.08 1.08
2 15 44 1.00 0.94 1.00 41.36 1.03 42.00 27.00 30.00 1.11 1.56 0.5 0.7 1.2 42.00 27.00 30.00 1.11 1.56 0.5 0.7 1.21.23 1.23
3 20 44 1.00 0.98 1.00 43.12 1.12 42.00 27.00 30.00 1.11 1.56 0.5 0.7 1.2 42.00 27.00 30.00 1.11 1.56 0.5 0.7 1.21.34 1.34
4 30 44 1.00 1.03 1.00 45.32 1.23 42.00 27.00 30.00 1.11 1.56 0.5 0.7 1.2 42.00 27.00 30.00 1.11 1.56 0.5 0.7 1.21.48 1.48
5 50 44 1.00 1.09 1.00 47.96 1.38 42.00 27.00 30.00 1.11 1.56 0.5 0.7 1.2 42.00 27.00 30.00 1.11 1.56 0.5 0.7 1.21.66 1.66
Topography
Factor
K3
Building Dimensions
Cpe for
Surface
for wind in
X
direction
Height
up to
Building
Plan
Rario
l/w
Basic
Wind
Speed
Vb in
m/s
Cpi CpS.No.
Design
Wind
Velocity
Vz in
m/s
Building
Height
Ratio
h/w
Risk
Factor
K1
Terrain,
Height and
structure
size factor
K2
CALCULATION OF DESIGN WIND PRESSURE FOR INDIVIDUAL MEMBERS
Building Dimensions
Design
Wind
Pressure
Pz in
KN/sqm
Cp
Design
Wind
Pressure
in X
direction
Design
Wind
Pressure
in Z
direction
Building
Height
Ratio
h/w
Building
Plan
Rario
l/w
Cpe for
Surface
for wind in
Z direction
Cpi
Weight of steps
Floor finish
Live load
Total
Loads on Landing:
self weight
Floor finish
Live load
Total
8.88
A
Ra
1.40
Support Reactions: Ra, Rb Taking Moments about A
Max. B.M
Distance of Zero Shear Force
x
Mx
= 1
x 0.15*0.3
0.30 2
= 1.8 KN/m2
= 1.5 KN/m2
= 3.0 KN/m2
= 11.19 KN/m2
= 0.175 x 25 =
= 1.5 KN/m2
= 3.0 KN/m2
= 8.88 KN/m2
KN/m2
2.32
m 2.77 m 1.40
5.60 m
:
: Rb= 28.04103 KN
Ra= 28.0754 KN
Distance of Zero Shear Force
: 28.05 - ( (8.88+2.32)*x )=0
= 2.51 m
= (28.05 * 2.51) - ((2.32 +8.88)* (2.51^2/2))
= 35.13 KN.m
22
0.15*0.3 x 24
4.375 KN/m2
KN/m2
B
Rb 28.04
m
23
FACTORED Mu = Mx * 1.50
= 52.69 KN.m
Design of slab:
Effective depth of slab = 175-20-8
= 147 mm
Mulim = 0.133 fck bd2
= 57.48 KN-m
Mu < Mulim OK
Ast Required = (1-SQRT(1-4.6*Mu*1000000/Fck/b/1000/d/d/1000/1000))
*0.5*Fck/Fy*b*d*1000*1000
= 824.566965 Sq.mm
Area of Bar = 201.0619298 Sq.mm
No of Bars Required = 5 Nos
Spacing Required = 290 mm
Spacing Provided = 125 mm
No of Bars Provided = 8 Nos
Ast Provided = 1608.50 Sq.mm > Ast Required
OK
Provide # 16 @ 125 mm c/c
Distribution steel:
Min steel required = 0.12 %bd
= 176.40 mm
2
Provide # 8 @ 150 mm c/c
Area of each bar = 50.24 mm2
Ast provided = 334.93 mm2
Deflection check:
24
l/d Provided = 5600/147 38.10
Ast provided 1608.50 mm
2
Pt = 100*Ast/bd
= 0.91 %
Fs = 0.58*fy* Ast required/Ast provided
= 148.66 N/mm2
Modification Factor (F) = MIN(1/(0.225+0.00322* fs+0.625*LOG(F48)), 2)
= 1.47
l/d = 26
l/d Allowable = F*26 29.49
l/d Provided < l/d Allowable ok
Summary: Provide 175 mm Depth of Slab with 16 @ 125 mmC/C as Main Steel
8 @ 150 mm c/c as Distribution Steel
25
Stair case plan Fig.8
fig 9 (stair case section x-x )
26
Sap model
27
SAP BUILDING MODEL
28
PUSHOVER ANALYSIS
Pushover analysis is done on SAP TOOL.
(Fig.10 (pushover curve for 3 storied building))
Seismic weight (W) = 31466.683KN
Alfa=Z/2*I/R*Sa/g
Vd=Alfa*W
Z=0.1, I=1.5 (HOSTEL BUILDING), R=3, T=.0075*H^ (.75) =.0499
Sa/g=2.5
Vb=1966.625KN (DEMAND)
Capacity = 6.78x10^3KN. (Capacity is more than demand)
29
(Fig.11(ADRS format for 3 storied building))
(Fig 12 (fragility curve for 3 storied building))
30
To find damage of the building we need to consider a particular displacement value, for
that value we conduct response spectrum analysis. As mentioned earlier we consider 4
ground motions i.e.
1)Bhuj
2)Chamba
3)Chamoli
4)Dharmashala
Which are normalized to 0.1g and 0.16g. By conducting response spectrum analysis we
get max displacement that can happen to the building due to above ground motions.
From sap we can compute analysis, max displacement occurred is 0.049979 meters
and corresponding damage value is 0.1121.
31
For class 2, Design of structure of 7 storied buildings.
This building is used for residential located in Hyderabad.
Plan.5 (7 storied building plans)
Elevation
32
Table 3 (Details of 7 storied Building)
TYPE OF BUILDING RESIDENTIAL
AREA OF PLOT 1846.46sq.m
GRADE OF CONRETE M25
GRADE OF STEEL Fy415
NO.OF FLOORS G+7
NO.OF COLUMS 120
MAX SIZE OF COLUME 100X300mm
MAX SIZE OF BEAM 500x300mm
TOTAL SEISMIC WEIGTH 132786.482KN
PEAK DISPLACEMENT ( FROME RESPOUNSE
SPECTRUM ANALYSIS DUE TO 0.1g AND
0.16g)
0.016977m
33
SAP model (fig 13)
34
Pushover curve. (fig14)
Seismic weight (W)= 132786.482KN
Alfa=Z/2*I/R*Sa/g
Vd=Alfa*W
Z=0.1, I=1.0(RESIDENTIAL BUILDING), R=3, T=.0075*H^ (.75) =.073
Sa/g=1.5
Vb=3319.66KN (DEMAND)
Capacity = 10.9x10^3KN.
Capacity is more than demand, but has no performance point. In this case Fragility
curve is used to find damage index.
35
ADRS (fig18)
36
Fragility curve (fig16)
Max displacement value from response spectrum is 0.016977 and corresponding
damage factor is 0.2396.
37
For class 3, Design of structure of 10 storied buildings.
This building is used for residential located in Hyderabad.
Table 4 (Details of 10 storied Building)
TYPE OF BUILDING
RESIDENTIAL
AREA OF PLOT
1069.12
GRADE OF CONRETE
M25
GRADE OF STEEL
Fy415
NO.OF FLOORS G+10
NO.OF COLUMS 51
MAX SIZE OF COLUME 1500x450mm
MAX SIZE OF BEAM 530x300
TOTAL SEISMIC WEIGTH 140152.584KN
PEAK DISPLACEMENT ( FROME RESPOUNSE
SPECTRUM ANALYSIS DUE TO 0.1g AND
0.16g)
0. 021172m
38
Building plan (plan 6)
39
SAP model
40
Pushover curve (fig17)
Seismic weight (W)= 140152.584KN
Alfa=Z/2*I/R*Sa/g
Vd=Alfa*W
Z=0.1, I=1.0(RESIDENTIAL BUILDING), R=3, T=.0075*H^ (.75) =1.032
Sa/g=1
Vb=2335.87KN (DEMAND)
Capacity = 6.28x10^3KN. Capacity is more than demand, but has no performance point.
41
ADRS (fig18)
Fragility curve (fig 19)
Max displacement value from response spectrum is 0. 021172m and corresponding
damage factor is 0.0203.
42
For class 4, Design of structure of 15 storied buildings.
This building is used for residential located in Hyderabad.
plan 7 (15 storied building plan)
43
Table 5 (Details of 15 storied Building)
TYPE OF BUILDING RESIDENTIAL
AREA OF PLOT 1566.71sq.m
GRADE OF CONRETE M25
GRADE OF STEEL Fy415
NO.OF FLOORS G+15
NO.OF COLUMS 138
MAX SIZE OF COLUME 1850x300mm
MAX SIZE OF BEAM 530x300mm
TOTAL SEISMIC WEIGTH 398921.376KN
PEAK DISPLACEMENT ( FROME RESPOUNSE
SPECTRUM ANALYSIS DUE TO 0.1g AND 0.16g) 0.010977m
44
SAP model
45
Pushover curve (fig20)
Seismic weight (W)= 398921.376KN Alfa=Z/2*I/R*Sa/g
Vd=Alfa*W
Z=0.1, I=1.0(RESIDENTIAL BUILDING), R=3, T=.0075*H^ (.75) =1.3
Sa/g=.75
Vb=4986.51KN (DEMAND)
46
Fragility curve (fig21)
Max displacement value from response spectrum is 0.010977m and corresponding
damage factor is 0.0068.
47
Pushover curve all together (fig22)
Table.6 (comparing all base shears and capacity)
Z I R Sa/g Ah=z/2*I/R*Sa/g
W KN (seismic wt)
Base shear (Demand) KN
Capacity KN factor
3 floors 0.1 1.5 3 2.5 0.0625 31466.683 1966.66 6780 3.4474 7 floors 0.1 1 3 1.5 0.025 132786.48 3319.6 10900 3.2834 10 floors 0.1 1 3 1 0.0166 140152.58 2335.84 6280 2.6885 15 floors 0.1 1 3 0.75 0.0125 398921.36 4986.51 10531.52 2.112
48
Fragility curve all together (fig23)
Damage factors:-
D 1(3 storied) = 0.1121
D2 (7 storied) = 0. 2396
D3 (10 storied) =0.0203
D4 (15 storied) =0.0068
It means that gradual increase of damage index from 3 to 7 storied building, then
gradual decrease of index from 7 to 10 storied. So in Hyderabad, 7 storied building has
more damage index than compared to others buildings.
49
Seismic Threat to Buildings in Hyderabad
GHMC Hyderabad is divided into 5 zones.
1) East zone
2) South zone
3) West zone
4) East zone
5) Central zone
On average every year 9500 new building are constructed in Hyderabad. Data from
GHMC is taken from 2010-2012 to know which zone has more risk of damage.
Table 7 (no. of buildings as per zones)
Ht of building/Zone
up to G+3
up to G+6
up to G+10
MORE THEN G+10
EAST 4128 257 15 2
CENTRAL 1837 231 30 27
SOUTH 1422 1363 12 2
WEST 3057 610 36 25
NORTH 4111 210 12 8
From above data SOUTH zones is more vulnerable.
Conclusion:-
Even though Hyderabad is in ZONE 2, building can be affected by nearby ZONE 3
areas. To find damage index two methods are used 1) performance point and 2)
Fragility curve. From pushover curve we can tell that all building have more capacity
than demand ( when it is design according to IS 456, IS 1893 and IS 875) but for few
building performance point cannot be achieved, in that case Fragility curve is used to
find damage index. Due to nearby ZONE 3 areas second category building are affected.
From GHMC date, more no. of second category buildings is in SOUTH zone. So, south
zone is more vulnerable for seismic.