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4 bars on a truss

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Frank D. Campbell:
I apologize if this is a stupid question but has anyone attached 4-bars to a 2 point flat truss. I hope everyone knows by my description what I am talking about. I am looking to add some more lighting without creating a ton more work since most of this will be done from the stage. I own 3 4-bars and I thought I could connect them altogether on a truss that gets hung up in a trailer. But that is getting a little wide. So I have been looking around and found a 10 foot truss I could hang 2 of the 4-bars on the bottom. They also have T-bars on each side and I thought I could hang an additional 4-bar on each side too. For a total of 4 4-bars.

Mac Kerr:

--- Quote from: 1960lespaul on July 03, 2018, 04:35:50 AM ---I apologize if this is a stupid question

--- End quote ---

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Jeff Lelko:
Hi Frank.  I’m not sure I fully grasp what you’re trying to explain, but The Light Source sells all sorts of clamps and junction components to build just about anything you’d like.  If the truss kit you bought is one of the light-duty Musician’s Friend type I’d suggest the wrap-around style of clamps.  Just make sure you get the right size!  Sharing links of exactly which lights and truss you bought can help get you better advice too.  Hope this helps!

Mark Cadwallader:
Frank, the load carrying capacity of truss should be listed by the maker for a maximum center point load, a load at the third and/or quarter points, and total uniformly distributed load for various lengths of truss assembly.  The rating should also list the deflection from horizontal at those loads, which will increase as the truss gets longer and/or the weight increases.

As with suspending anything over people's head, allow for a comfortable margin of safety by not loading truss to its max allowable load.  Nobody should get hurt or die due to falling gear or failed truss or lifts.

When you look at how much load you have on a truss, don't forget to take into account the added weight of cables and cords, as well as clamps or other stuff loaded on the truss. It adds up in a hurry.

An I-beam like truss can be very strong with static hanging loads, if it is well designed and constructed. An extension ladder, while in the same basic shape, is not designed or constructed for overhead rigging.

So check the load specs on the specific truss you have, and see if it will handle the weight of your lights and cabling.  Also, if you are using stands or lifts to hold up the truss, be sure to take those load ratings into account too. The higher you lift, the sturdier and stiffer they need to be.  If you think it looks sketchy or marginal,  it probably is.

Finally, I assume you are doing this indoors. If you are out where there might be wind loads you will need to calcuate those loads too, with an even higher safety factor.

Frank D. Campbell:
Thank you both. I should have explained better. All I have now are the stands that go with my 4bars. I thought I would see if anyone  had ever done this. I don't have the truss yet. Wanted to make sure it was doable first. I did find a guy who did it and it looked good. I was hoping to get the 4bars on a truss because I hate the light stands. And I thought I could leave them hooked up and hang them in my trailer. Thank you both for the advise! What I would like to do is get a 10 foot I-Beam truss and hang two 4bars on the bottom. Center each 4bar on each 5 piece section. then hand another 4bar on the top but kind of upside down right in the middle  where the two 5 piece sections meet. Then one small special on each end. The 4bars only weigh 29lb a piece so I'm not looking to have something too heavy. I want to make it as easy a possible.

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