Hi all,
I have an entrance steel structure which is modelled in Staad pro. The member design has been done using Staad pro itself for basic load combinations as per BS code. With TRACK 2 option, the output file shows the service load combination 201-1.0DL+1.0LL has governed all the member design. When the service load combination was deactivated, the last ultimate load combo was governing i.e.105- 1.2DL+1.2LL+1.2WL(F). In order to countercheck the results, I have deactivated both 201 & 105 and found load combination 104-1.2DL+1.2LL+1.2WL(L) was governing all member design.
The issue here is the utilization ratio for members is found higher in following order 104>105>201 which means the governing combination should be 104 when none of the load combinations were deactivated but the service load combination “201” was governing while all combinations are used which may lead to under design of members.
can anybody help me to understand the bug. Your help is much appreciated.