Steel Design

Question

Hi 
 I have designed a steel building using IS 800-2007 . A few beams have failed . I am not able to identify the reason for this failure pattern. Please help. ( I have attached the staad file )

Sudip Narayan Choudhury · Answer

You need to get you input file correct in the first place. You have used the UNL parameter which is not a valid parameter for IS 800 LSD. For Lateral Torsional Buckling, please use parameters KX (effective length factor for lateral torsional buckling), LX (effective length for lateral torsional buckling)and LAT (Lateral Restraint parameter for compression flange). 
 Moreover, IS 800 2007 LSD implementation in STAAD does not as yet consider the double profile sections. You have assigned these sections to a lot of members. This is the reason why this has not been designed.

Sudip Narayan Choudhury · Answer

Please find the attached screen shot. Which version of STAAD are you using?

Sudip Narayan Choudhury · Answer

You are using a very old version and it would not be possible at tis point of time to relate to the problems that had existed in that version. I guess KX, LX and LAT were introduced later. Please upgrade to the current version.