Dear all,
I am modelling a simple roof steel frame and the steel beam design is not passing the design check for AIS-360 LRFD LBT
I have defined UNT and LY for the steel beam and it should meet the condition of Lp < Lb < Lr, however the design results shows the nominal flexural strength Mn is calculated for the case of Lb > Lr (F2-3)
I thought STAAD would consider UNT or LY as Lb, but it didn't?
Could someone please help me to understand what I did wrong here~? Thanks.
Below please find the STD file:
steel roof.STD