P-delta experts?

[clemsonC]

I'm working on an interesting steel frame problem that doesn't completely follow standard guidance, but I'm basically following AISC, using 2nd order analysis by amplified 1st order analysis.

Rather than using AISC's guidance to determine and use B2 to estimate total Mlt, can I sub (B2*Mlt) with (P*bigdelta + M due to H), where bigdelta is the max delta my frame can translate? (This would cut out Pe2 and associated variables.)

It seems like the equations for B2 were developed because bigdelta is unknown and/or difficult to determine. (not the case for my problem) However, I realize that I may be missing something. Also, this method may not really save time, but understanding the theory is important.

Any comments?

 

[Galambos]

clemsonSC,
Either check Salmon & Johnson or the Silver LRFD Book (commentary or beam chapter (not spec)). I remember in undergrad learning that you could substitute the maximum story drift and reading about it in one of these two sources.