overstrength factor for nonbuilding structure similar to buildings 1

[TTTKAO]

Hello Friends,

I am a newer to use ASCE 07-10 design code, i have a question about where to use overstrength factor when following building system defined in table 15.4-1.

as per section 15.4.1 item 9 quoted " 9. where specially required by chapter 15, the design seismic force on nonbuilding structures shall be as defined in section 12.4.3" my understanding is the overstrength factor request by section 12 need not to follow once using the system defined in table 15.4-1?

looking forward to you experience and advice.

Thank you!

 

[driftLimiter]

I believe that this is simply saying that some Ch 15. systems have specific requirements that may reference overstrength load combinations. And when they do, you go to Ch 12.4.3 to properly include the effect of overstrength.

So I think I would adjust your understanding a bit:
- determine appropriate seismic system from Ch 15.
- review all references to detailing requirements, and Ch. 15 requirements.
- Apply overstrength according to Ch 12.4.3 where required by Ch 15 or other Detailing Requirements

 

[TTTKAO]

Hi driftLimiter,

Thank you for the reply. I have the same understanding. so it's not necessary to follow chapter 12 overstrength requirement unless it's specified on chapter 15 or other detailing requirement.

Regards!

 

[driftLimiter]

Yes, in general the Overstrength factor is applied to specific elements to ensure ductility is achieved as expected based on the R factor of the system selected. Just be aware that concrete anchorage is often designed using overstrength, based on requirements set forth in the ACI 318. So like I said just review all the references in Ch 15 and specific detailing requirements to ensure you have identified where overstrength is or isn't required.