ibc 2000 ` 2003, base shear
 

ibc 2000 ~ 2003, base shear
i have to update a calc of base shear from ibc 2000 to ibc 2003. i see only one eq (16-56) relevant. is it so simple now? no consideration to sd1. thx in advance for your comments
not so simple...cs is computed from sd, etc
eqn 16-56 is for using the simplified procedure. looking at section 9.5.5.2.1 in asce 7-02 you will see that there are 4 equations to be calculated. the first is for cs and the rest are for the upper and lower bounds of cs. the variables used are sds, sd1 and s1.
regards,
-mike
the ibc 2003, through asce 7-02, equivalent lateral force calculations are almost identical to 2000. the approximate period calcs are a little different and i think they clarified the insane requirement to iterate to determine ax. i can't remember if anything else changed, but the results end up being very similar.
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