I found something wrong in STAAD Pro. V8i SS6 about beam unbraced length and the respective analyzed results.

I found something wrong in STAAD Pro. V8i SS6 about beam unbraced length and the respective analyzed results with Canadian code.

Three identical beams with exception for the unbraced length parameters (LT,LY,LZ, UB and UT). Please see the comparison of STAAD results and values in CISC steel hand book 10^th edition “beam selection table” below:

W200x27 section (fy=50 ksi)

Unbraced length              1.5ft(about 500mm)     11.5ft (about 3500mm)   13ft(about 4000mm)  25ft(about 7500mm)

STAAD Mz resistance      86.6kN-m                         83.9kN-m                             80.9kN-m                         55.8kN-m

Steel handbook table     86.6kN-m                         64.1kN-m                             56.0kN-m                          about 25kN-m

So, STAAD unbraced length parameters in this SS6 version don’t seem working right!?

Thanks

Alex