Hi.
I'm new at Staad pro. I have tried to describe Eartquake force by using Response Spectrum depend on IBC2012/ASCE 7-10. Also I described Earthquake force by using Equivalent Lateral Force depend on IBC2012/ASCE 7-10.
Eartquake mass is the same in both condition. But when I compare two loads, I realize that Response Spectrum Analysis's base shear is bigger than Equivalent Lateral force's base shear.
I think its not possible..
DEFINE REFERENCE LOADS
LOAD R1 LOADTYPE Dead TITLE DL+DLO
JOINT LOAD
10484 10485 10539 10540 10939 10940 10991 10992 11045 11046 11099 11100 11151 -
11152 11203 11204 11233 11234 11273 11274 11303 11304 11331 11332 11361 -
11362 11389 11390 11439 11440 11466 FY -9.4
10442 10443 FY -4.7
...
LOAD R2 LOADTYPE Live REDUCIBLE TITLE LLR+LLG-E
JOINT LOAD
10484 10485 10539 10540 10939 10940 10991 10992 11045 11046 11099 11100 11151 -
11152 11203 11204 11233 11234 11273 11274 11303 11304 11331 11332 11361 -
11362 11389 11390 11439 11440 11466 FY -41
10442 10443 FY -20.5
...
LOAD R3 LOADTYPE Live REDUCIBLE TITLE LLG-E1
JOINT LOAD
11968 11969 FX -30 FY -140 FZ -40
...
DEFINE IBC 2012 ACCIDENTAL
SS 2.04 S1 0.63 I 1.25 RX 2.5 RZ 2.5 SCLASS 3 PX 0.917 PZ 1.715 TL 8 FA 1 -
FV 1.3 K 0.8
SELFWEIGHT 1
REFERENCE LOAD Y
R1 1.0 R2 0.3 R3 1.0
LOAD 1 LOADTYPE Seismic TITLE EX-EQUIVALENT LOAD
IBC LOAD X 1
LOAD 2 LOADTYPE Seismic TITLE EZ-EQUIVALENT LOAD
IBC LOAD Z 1
...
LOAD 7 LOADTYPE Seismic TITLE EX
SPECTRUM SRSS IBC 2012 TOR ECC 0.05 X 1 ACC DAMP 0.05 LIN
SS 2.040 S1 0.630 SITE CLASS C FA 1.000 FV 1.300 TL 8.000
LOAD 8 LOADTYPE Seismic TITLE EZ
SPECTRUM SRSS IBC 2012 TOR ECC 0.05 Z 1 ACC DAMP 0.05 LIN
SS 2.040 S1 0.630 SITE CLASS C FA 1.000 FV 1.300 TL 8.000