Hello everyone,
I'm trying to understand the Seismic Loads using SRA in STAAD.
The Code Goes:
STAAD SPACE
START JOB INFORMATION
ENGINEER DATE 28-Jul-16
END JOB INFORMATION
INPUT WIDTH 79
UNIT METER KN
JOINT COORDINATES
1 0 0 0
2 0 5 0
3 5 0 0
4 5 5 0
MEMBER INCIDENCES
1 1 2
2 3 4
3 2 4
DEFINE MATERIAL START
ISOTROPIC STEEL
E 2.05e+008
POISSON 0.3
DENSITY 76.8195
ALPHA 1.2e-005
DAMP 0.03
TYPE STEEL
STRENGTH FY 253200 FU 407800 RY 1.5 RT 1.2
END DEFINE MATERIAL
MEMBER PROPERTY AMERICAN
1 TO 3 TABLE ST W10X30
*1 TABLE ST W8X15
CONSTANTS
MATERIAL STEEL ALL
SUPPORTS
1 3 FIXED
DEFINE UBC LOAD
ZONE 0.075 I 1 RWX 3 RWZ 3 STYP 1 NA 1 NV 1
SELFWEIGHT -1
LOAD 1 LOADTYPE Seismic TITLE LOAD CASE 1
UBC LOAD X -1
LOAD 2 LOADTYPE Seismic TITLE LOAD CASE 2
UBC LOAD X 1
LOAD 3 LOADTYPE Dead TITLE LOAD CASE 3
SELFWEIGHT Y -1
LOAD 4 LOADTYPE Seismic TITLE EZ AUTO RESPONSE SPECTRUM
SELFWEIGHT Y 1
SELFWEIGHT X 1
SELFWEIGHT Z 1
SPECTRUM SRSS X -1 ACC SCALE 9.8 DAMP 0.035
0 0.1188; 0.1 0.2931; 0.45 0.2931; 1.2 0.1178; 2 0.0733; 2.8 0.0623;
3.6 0.0575; 4.4 0.0527; 5.2 0.0478; 6 0.043;
LOAD COMBINATION 11
4 -1.0
PERFORM ANALYSIS
FINISH
The thing is on Load Combination 11, i wanted to get a value of the EQ Load opposite the direction of Load 4,
but it just simply negated the resultant values
I also tried Changing the X Factor from 1 to -1 in the spectrum but to no avail. How can I make Seismic Load opposite the direction of Load 4.
I'm using SS4.
Thank you,
Regards.