IBC 06 vs ACSE 7/05 Special Seismic Load Combos 1

[mrpid]

I have reviewed other threads in the site and I have not come across this specific question. Any insight would be appreciated. IBC 06 section 1605.4 includes the same combination for both ASD and LRFD(Strength design; however, the ASCE 7/05 includes two sets of load combos: one for ASD and one for LRFD. My question arises as I look at a sample problem from NCEES in which there is an analysis of a collector element in which case the sample problem uses the IBC combo 16-22 to calculate the actual bending stress, but uses combo 5 under ASD to calculate the actual axial stress. (As I have noticed in another thread, I do realize that IBC combo 16-22 equals ASCE 7/05 combo 5 under strength design, but this is not the case under ASD). Should one adhere to the equations set forth in IBC even when using ASD design processes which would be the conservative approach or use the equations within ASCE 07 for ASD? I may be misinterpreting the code or have overlooked something.
Again, I appreciate any feedback.
Stu

 

[OldPaperMaker]

mrpid,
I suggest that you browse to

http://www.gostructural.com,

the February 2008 issue, and review the article titled "2006 IBC Section 1605.4: Special Seismic Load Combinations"

This explains some of the inconsistencies that the code police have created.

I hope that this helps.