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Suspending lit signage from a slanted I beam.

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Malachi Dodge:
Greetings,

Putting together a new set for our church and we're planning to hang what is essentially lit signage. Where we are needing to hang these items the only structural component available to hang from is an I beam that is slanted at about 20 degrees.

I've never attempted to hang anything from a slanted structural component before. What is best practice?

For a little more info: I need to suspend 1/16 aircraft cable. It's just one cable, full load will be ~90lbs. We're just using some of Griplocks cable grippers to hang the actual fixture.

Cailen Waddell:
You’ll be looking for a mounting component that has a rating that applies in more than a vertical.  For example, many eye bolts (that are rated forged shouldered, made in the USA, and designed for overhead lifting) will specify a rating at vertical and a reduced rating at some number of degrees off of vertical.  You would partner that eye bolt with a clamping device with similar designations. 

That said - you should be consulting a structural engineer to designate any components used in overhead lifting.  They should be able to specify Methods and materials to safely achieve what you want to do. 

I would also question the 1/16th AC...  most of it has a WLL under 100# and a breaking strength under 500#.  I prefer an 8:1 or 10:1 ratio when suspending over peoples heads.... 


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Erik Jerde:
You could drill the beam and install a rated shoulder eye bolt.  Consult an engineer for verification that the hole won’t cause a structural problem.  Install the eye on the proper axis for your loading scenario.

Get a beam clamp rated for use on angled steel.  Consult a qualified rigging shop to source the clamp.  You’ll need a clamp where you can attach off axis.

Either way make sure you do your off axis de-rating calculations and adjust WLL for your safety factor as Cailen already wisel advised you.

If you’re unsure on any of this then hire a pro.

Jeff Lelko:

--- Quote from: Erik Jerde on March 13, 2019, 01:22:03 AM ---If you’re unsure on any of this then hire a pro.

--- End quote ---

+1.  Given the other citations you're dealing with from your AHJ I'd proceed with extreme caution and discretion.  If you're not 100% confident in what you're doing (and by asking an online forum for help seems to imply you're not), either hire a professional or find another way to achieve your vision.  Rigging and electrical are two things you never want to mess up. 

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