Orthogonal Load Combinations for Seismic Drift Calculation

[mike20793]

I know this has been brought up on here before, but I couldn't really find a consensus. If the orthogonal load combinations are required for seismic design, are they also used for seismic drift computation as well? Thanks in advance.

 

[mike20793]

I'm referring to the 100/30 combinations when I say orthogonal load combinations. Sorry if I was unclear.

 

[Hokie93]

I believe that is the intent of ASCE 7-05 (and ASCE 7-10) but it is not specifically addressed in the Standard to the best of my knowledge. It doesn't make sense to me to use the orthogonal loading pattern for strength and use something different for drift.

 

[wannabeSE]

Mike - I assume you are referring to ASCE 7-10 section 12.5.3a where it says:
"The requirement of Section 12.5.1 is deemed satisfied if members and their foundations are designed for 100 percent of the forces for one direction plus 30 percent of the forces for the perpendicular direction."