Buckling analysis in SAP

[naggary]

Kindly,
I wonder if the SAP Buckling analysis gives value of Pcr as determine from E3 in AISC 2010. I tried to make an example for simple beam and applied axial load 1 Kip and i found the Scale Factor obtained from SAP file is bigger than the value of Pcr dermined from AISC 2010 SEC.E3

 

[ishvaaag]

Since I have only mad e3 or 4 building models in ETABS/SAP 2000 environments and last a pair of years ago I am not much proficient in generating quickly a significative model, yet I may try in some days, except if someone does before.

 

[271828]

The eigenvalue buckling analysis should give the elastic buckling load, Pe=Fe*Ag, not Pn=Fcr*Ag. The latter quantity includes effects such as residual stress and initil out-of-straightness. Check to see if that helps and report back.

 

[JoshPlumSE]

271828 -

That's a good point..... Stated another way:
The Bucklng analysis in a program like SAP is usually just an eigenvalue solution of the ELASTIC buckling of the structure.

For typical structures, the critical buckling loads will probably be in the inelastic range.

 

[naggary]

Dear all,
Thank you very much for your cooperation.

 

[ishvaaag]

Refer to thread

http://www.eng-tips.com/viewthread.cfm?qid=299602&page=1