R-value for podium builds in seismic design

[justincaseph1]

If i have a steel moment frame system on the first level with a couple levels of wood shear walls above do i analyze the wood shear wall levels with a 6.5 R-Value, or do i need to increase my seismic base shear based on the R value of the steel moment frame R value due to a vertical irregularity?

 

[phamENG]

You need to read ASCE 7-16 chapter 12. Specifically the section on R, C[sub]d[/sub], and Omega[sub]0[/sub] Values for Vertical Combinations.

 

[LockeBT]

What type of moment frame system on the first level? It matters because if it's OMF with an R of 3.5 you are allowed to use the 2-stage analysis procedure per ASCE 12.2.3.2. Which means, if you meet the criteria, you are allowed to use the R for wood for the upper portion and use the R for your OMF for the lower portion.

Albeit you do need to prove the lower portion (your first level) is 10x stiffer than your upper portion.