Are there any CA structural engineers on this forum?

[16d @ 4"]

Need help with interpreting the UBC!

 

[Bystander]

What part?

 

[16d @ 4"]

What part?

The part of the special seismic load combo with 1.2DL+0.5LL+Em.
When I use this equation, do I apply a 1.33 increase if I choose to stay in
ASD, or do I have to multiply Em by 1.4 (to bring to strength level) and then apply a 1.7 increase.

My boss told me that Em is in strength level already and that a 1.7 increase is applicable.

Any suggestions?

Thanks,

 

[Bystander]

Figured it was going to be seismic. At which point I can't help you. You might try the local building dept. --- if they're competent. Local building codes probably include very specific local amendments, and rules for application --- wouldn't surprise me, nor would it surprise me if CA has a blanket amendment incorporating "design factors to be determined from whatever counts as the latest study of damages from previous quakes."

 

[16d @ 4"]

Thanks for the attempt.

Figured it was going to be seismic. At which point I can't help you. You might try the local building dept. --- if they're competent. Local building codes probably include very specific local amendments, and rules for application --- wouldn't surprise me, nor would it surprise me if CA has a blanket amendment incorporating "design factors to be determined from whatever counts as the latest study of damages from previous quakes."

 

[haynewp]

I am sure you have it figured out by now, but that whole equation (including Em) is strength level equation. So for ASD, you would divide the Em part by 1.4 and then get to use a 1/3 stress increase if you choose (latest Codes have taken out the 1/3 increase). It is easiest to just start with the service level equations if you are using ASD: D+L+Em/1.4... etc.

Be sure not to mix and match factors between service and strength design.