STAAD.PRO V8 - AISC LRFD Code Check Cm values used in calculating Beta 1 factors

[trac]

Have asked STAAD as to how or what Cm values are used when calculating BETA1 factors used in code checking to AISC LRFD (For API LRFD code check, cm values can be input manually as for the 9th edition code check), - As yet no response from STAAD (3 weeks now). I assunme that cm values are automatically calculated when the DAM method is used to calculate member forces but not sure if cm values are claculated when only a first order anlaysis is used in calculating member forces. Any comments much appreciated.

 

[Sye123]

As you know the calculation of B1 factor, in which Cm is used, is only essential when one is trying to account for second order effects by amplifying the results of a first order analysis. STAAD does not do that. It supports the more accurate DAM as per Appendix 7 in which both small delta as well as large delta are automatically accounted for as part of the analysis.

I am not sure how you tried to contact Bentley technical support. If you have a service ticket number or can tell me who you communicated with, I can find out why you did not get a response.