# Siesmic Bracing for trapeze



## Easy (Oct 18, 2017)

When is Siesmic Bracing required for non-structural equipment such as electrical conduits installed in trapeze? I know that this probably something an engineer would address but I was just wondering if there were any basic rules or guidelines I could go by. I bring up this discussion because it’s part of title 24 and California Building standards where I live in earthquake country. 

Below is the only reference I have to this subject. 
Section 13.6 of ASCE 7-10 provides the requirements of seismic bracing for mechanical and electrical components. 
1.	12 Inch Rule: When a distributed system such as conduit ducts or pipes are suspended from the structure with hangers less than 12 inches in length, seismic bracing is not required.
2.	If the support carrying multiple pipes or conduits weighs less than 10 pound/feet of lineal weight of the component, the seismic bracing of the support does not have to be considered.


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## joebanana (Dec 21, 2010)

Isn't title 24 just wonderful? (not) It's different in different "zones", some areas require all 4 corners of troffers wired AND screwed. Check the spec sheet. As far as I remember, basically anything that "free" hangs more than a foot off the lid has to have lateral bracing.
Start here:
https://up.codes/viewer/california/ca-building-code-2016-v2/chapter/16A/structural-design#16A


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## TheLivingBubba (Jul 23, 2015)

Been here many of times. Install the traps and pipe and if needed retrofit after was always the motto. Our Project engineers were all from back east and had no clue on seismic. It was always drawn without and if an inspector wanted it he would tell us what he wanted. 



Not the best method or theory, but I think that the 4000 psi concrete full of glue so it dries quicker is going to be more a hazard then if some 4" emt comes crashing down.


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## Easy (Oct 18, 2017)

TheLivingBubba said:


> Been here many of times. Install the traps and pipe and if needed retrofit after was always the motto. Our Project engineers were all from back east and had no clue on seismic. It was always drawn without and if an inspector wanted it he would tell us what he wanted.
> 
> 
> 
> Not the best method or theory, but I think that the 4000 psi concrete full of glue so it dries quicker is going to be more a hazard then if some 4" emt comes crashing down.


This is basically what the boss told me. "wait and see if the inspector requires it" The good thing is that it can be installed after the fact without any major changes to the trapeze's that are already in place. My gripe is that the inspector probably wont require it and the drop rods I installed are 4 to 5 feet in length. The engineer on this project is clueless as well. The kits are not that cheap so even if I suggest it my boss will get upset and if I don't install them I won't sleep well at night.


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## Easy (Oct 18, 2017)

joebanana said:


> Isn't title 24 just wonderful? (not) It's different in different "zones", some areas require all 4 corners of troffers wired AND screwed. Check the spec sheet. As far as I remember, basically anything that "free" hangs more than a foot off the lid has to have lateral bracing.
> Start here:
> https://up.codes/viewer/california/ca-building-code-2016-v2/chapter/16A/structural-design#16A


Yes that's how I read it as well over 12" must be braced. I looked at the link you provided and it's a lot to digest but it has some accurate information as it applies to my wonderful state. :sad:


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## Easy (Oct 18, 2017)

Section 13.6 of ASCE 7-10
American Society of Civil Engineers
Requirements of seismic bracing for mechanical and
electrical components.
1) More than 12 inches of suspension from structure.
2) More than 10 pounds per foot of lineal weight.


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## Easy (Oct 18, 2017)

Something else of interest... 
According to Unistrut you also need a certification to install Seismic Bracing that they sell.


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