Hanging Platform

jsm99

Member
I’m the set designer for an upcoming production in my theater company’s black box. and can seat around 80 people maximum. I would like to hang a platform from a taller, much longer platform. The platform doesn’t need to swing , but just hang on all corners. All of the research I’ve done explains rigging to the lighting grid, but not rigging wood to more wood, so I’m looking for advice!

We use 4’x8’ platforms (made of 2x4 and composite) all connected to each other, with legs made of 4x4 lumber that is 8’ tall. The height up to the lighting grid is about 13’, so nobody will need to stand on these tall platforms. Hanging from the center platform would be another 4’x8’ platform, and this platform would be hanging 2’ above the ground. I’m somewhat familiar with rigging using wire rope, thimbles, eye bolts, and wire rope clips, but not enough to be confident doing this without additional research.

I imagine I could simply hang it with wire rope and eye bolts on both the upper platform and on the hanging platform, but I’m not sure if this is the safest, sturdiest way to go. Would we be able to hang it simply with thick rope? Are there better ways to hang heavy loads for wood? Should I reinforce the lid of the taller platforms with additional plywood? Thank you for the help!
 
You don't say whether anybody will be on or under these platforms. If the answer is no, for a similar problem I once had a local machine ship fabricate some giant bottom hanger irons and if I remember correctly it wasn't terribly expensive. The hook part was 2x4 sized instead of 1x3 sized, and I think I made them 2" or 3" wide so there was plenty of room for a few screw holes for attaching to the face of the 2x4. You want to load the platforms in compression, not tension. If you're attaching through the lid of the upper platform, I'd fabricate big square "washers" to spread the load.

You say you're somewhat familiar with rigging. If anyone will be on or under these platforms or if the damage from failure could be significant, I'd suggest that you have someone who is very familiar with rigging advise you on this.
 
So you are hanging a single 4x8 yes? Given that you typically use 2x4 construction a reminder that the strength of the platform is the FRAME not the plywood cladding.

Personally for something like this I would make a custom platform out of steel (more strength for less weight). I have no idea how much rigging experience and training you have, but have to remind that when anyone is around (or on/under) this thing you really do need at least 10:1 rating.

I am not comfortable giving any "real" advice on this not in person, and it is against Control Booth policy to give rigging consultation in a lot of ways. And this is for really good reasons. However, we are more than happy to help you through your planning process.

THE PROBLEM is I'm sure pretty much any method you choose to use WILL hold up the load, even if for a time. Failures do not happen immediately. Something like this really needs care to be sure it's done safely. The last thing you want is actors going to the hospital on closing night.
 
I have SO many questions...

How big is the 'top' platform? How is it framed/supported? if it's a 4x8 and the piece you want to suspend is 4x8 there's really no sense in suspending it just secure it to the same legs; unless I'm missing something here. Without know how your upper platform is framed and supported there is no way to determine the correct manner or material to use to suspend the lower platform. Have you got a thumbnail or even napkin sketch of your intent?
 
This is where your theater company needs a structural engineer on its board of directors. "Hey Sam, how do we do this safely?"

Too much of theater has been "how do we make this look like...." instead of "how do we not kill or injure people, and HOW DO WE KNOW FOR SURE?"
 
Hi all,

Thank you for your help!! I hope I can provide some more clarifications. Here is a sketch of what the director has in mind (you can ignore the other little platforms and the decorations):

IMG_5444.jpg


Nobody will be on top of the tallest platform. Nobody will be underneath the hanging platform. But, we would like people to be standing on top of the hanging platform, which is underneath the tallest platform. The top platform would be 27' long, framed with 2x4, and supported on tall 4x4 legs. It's made of premade 4x8 platforms and 2 1.5'x4' platforms to give it the extra length. The hanging 4x8 platform would hang from the center.

For some additional context, we're a student theater group at a university, so there's no "Board of Directors," just students on our own Executive Board, hence why I'm looking for advice here. I do, however, have relationships with professional technical directors with the university, and I can reach out to them in person as well. Thank you again for all the advice!
 
Does it absolutely need to be hanging? Or is there another solution to get the look you want - like putting legs on it, masking them with some stage magic, and using non-load bearing rope to make it look like it's hanging from the center.

There are just SO many ways this could go wrong.
 
I do, however, have relationships with professional technical directors with the university, and I can reach out to them in person as well.

Please do that.

You need a purpose-engineered solution. Why cobble together standard 4x8 platforms up there? I fear the answer is "that's what we have".
 
Definitely get proper engineering help on this. I do not count for proper engineering help.

If I'm interpreting the drawing properly, you have about a sixteen foot span in between the supports for the upper deck thingy. That's a long unsupported span for a 2x4-based platform; in typical house construction, that span of floor framing would likely use something along the lines of 2x10 joists on 12" centers. You may well not need quite the same strength in this application, but that's still a very big jump from a couple of 2x4's!

(Lighting underneath the upper platform looks like it would be...interesting, as well.)
 
@jsm99 sadly, this question falls into a very dangerous zone where I'm afraid the answers are:
1) Anyone who is actually a qualified expert who can answer the question will not do it. They know the risks involved and don't want the liability of trusting a complete stranger to execute their plans safely.
2) Anyone who is crazy enough to give out answers to this on the internet should not be trusted to give you safe answers because of point #1.

Thus this is one of those posts where we say with all respect, the fact that you have to ask the question shows you are not qualified to do it. But find a local expert and get help. There's very likely someone at a local college or university with the skills to pull it off. Or, find a way to do it yourself out of wood using hidden ground supports.

Many thanks to the CB community for giving you solid safe advice. Too many other corners of the internet would jump right away into dangerous speculation.
 
Does it absolutely need to be hanging? Or is there another solution to get the look you want - like putting legs on it, masking them with some stage magic, and using non-load bearing rope to make it look like it's hanging from the center.
I think this is the solution. It is only 2ft off the ground Supporting legs taking the majority if not all of the weight. Set the leg back from the front of the platform by a little bit counter weight the back and light it correctly and those legs will disappear without a trace. Use nice rope to "suspend" the platform and create the illusion. The last thing you want is to have the platform swing transferring dynamic loads to the structure.
Regards
Geoff
 
I’m the set designer for an upcoming production in my theater company’s black box. and can seat around 80 people maximum. I would like to hang a platform from a taller, much longer platform. The platform doesn’t need to swing , but just hang on all corners. All of the research I’ve done explains rigging to the lighting grid, but not rigging wood to more wood, so I’m looking for advice!

We use 4’x8’ platforms (made of 2x4 and composite) all connected to each other, with legs made of 4x4 lumber that is 8’ tall. The height up to the lighting grid is about 13’, so nobody will need to stand on these tall platforms. Hanging from the center platform would be another 4’x8’ platform, and this platform would be hanging 2’ above the ground. I’m somewhat familiar with rigging using wire rope, thimbles, eye bolts, and wire rope clips, but not enough to be confident doing this without additional research.

I imagine I could simply hang it with wire rope and eye bolts on both the upper platform and on the hanging platform, but I’m not sure if this is the safest, sturdiest way to go. Would we be able to hang it simply with thick rope? Are there better ways to hang heavy loads for wood? Should I reinforce the lid of the taller platforms with additional plywood? Thank you for the help!
@jsm99 What is the director's vision, what is this supposed to look like, achieve, convey to the patrons; those sorts of queries?
Toodleoo!
Ron Hebbard
 
I think this is the solution. It is only 2ft off the ground Supporting legs taking the majority if not all of the weight. Set the leg back from the front of the platform by a little bit counter weight the back and light it correctly and those legs will disappear without a trace. Use nice rope to "suspend" the platform and create the illusion. The last thing you want is to have the platform swing transferring dynamic loads to the structure.
Regards
Geoff
Yes, cantilever the front of the platform out a bit by counter weighting the back. At 2' off the ground legs will be fairly hard to see anyway. You could even use the old magic trick of hiding the legs under with mirrors.
 

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