# Large Stressed Skin Platform



## kvnwlkr (Sep 13, 2011)

Hi Folks,

I am faced with creating a large (16'x16') platform which can start flown level(horizontal), descend to be used as an acting surface and then flown to a vertical position on one or two pick points. The designer has suggested a stressed skin platform to save weight and add strength. I have not done stressed skin at this scale before and so an looking for advice. Wood frame? steel frame? deck thickness? Deck seam problems to expect or look for . . . and just "is it possible?", will the seams between the 4x8 sheets weaken the platform too much? 

Need some advice!


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## kicknargel (Sep 13, 2011)

Sorry, I don't know if you're going to get anyone to touch this. It can be done, and safely, but would require some serious engineering analysis and math.


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## avkid (Sep 14, 2011)

With pre-made steel decks this would be easy, however DIY adds quite a few concerns.


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## Van (Sep 14, 2011)

Ok, I'll touch it.... IMHO your best bet would be to utilized an aluminum frame then fill in between each aluminum framing member with EPS foam. At a bare minimum I would suggest laying 1/2" Okumi or high grade Luan on top of the framing after appyling a liberal amount of Construction adhesive f to the foam and the framing members. Secure the 1/2" to the frame via 1 1/4" modified truss head "tek" screws. at 12" centers. After the 1/2" is installed I would lay down a coat of PVA glue and then lay down a layer of 1/4" Luan at a right angle to the 1/2" layer, making sure to overlap seam. < Start by splitting a seam with the luan overlay then finish the outsdie edges wit half sheets. You would nee to do this for both sides. In the construction process you would need to use construction adhesive in between each sheet of 1/2". The adhesive will do two things it wil help stop squeaks and it will help tie things together, though more of the former and less of the latter. Yes you would need this construction on both sides, Yeah you probably could do it with steel but it's going to weigh a ton more. No. I wont spec the framing members I would suggest running some engineering numbers on them prior to starting this project. 
Hope maybe that helps get you on the right path. and please remember this a suggestion not an endorsement


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## kvnwlkr (Sep 14, 2011)

Hi Guys, Thanks for the feedback! In reading what you wrote I realized that I had not included some very important information. This platform will not be supporting people while moving (I told them no) and when used as an acting platform will be supported by a studwall support system. I was concerned with the unit supporting itself and not folding in mid air. Any changes in reconendation considering this?


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## Footer (Sep 14, 2011)

kvnwlkr said:


> Hi Guys, Thanks for the feedback! In reading what you wrote I realized that I had not included some very important information. This platform will not be supporting people while moving (I told them no) and when used as an acting platform will be supported by a studwall support system. I was concerned with the unit supporting itself and not folding in mid air. Any changes in reconendation considering this?


 
So, your building a flying lid? Totally different them. I would still do it out of aluminum if you can, but steel in reality. Is there a limit to what the studwall system looks like or is it just an US/DS wall? If possible, can the studwall support system have a lid and be an actual deck? If so, this project becomes much easier. You can them build a system that does nothing more then transfer the weight through. Then all you need to be concerned about is bending when fits flying. So, I would do steel frame, probably 1x2 .049 MT1010 (once again, aluminum would be better!) on 4' centers. Covered and filled like Van said. Depending on how it moves, hoist rings would be the way to go for pick points. 

Now the 300# question.... whats your rigging situation and have you ever worked with carpet arbors?


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## Van (Sep 14, 2011)

Heck yeah, I think you could easily replace the aluminum with Steel, and you could forget the Foam and simple ahere to the steel surfaces. I'd keep the same screw pattern. You might want to go back and fill the dead spaces with Expanding Poly foam or some such just as a sound deadener. 
I'd have to run numbers but I bet, and this is just spit balling, you could run an I-beam of some sort at the seams and capture a 2x or 1x material on 16" centers in the feild. Let me know if that doesn't make sense. And be sure to run the numbers first... Even if nobodies riding it it would be a very sad things if it folded on itself after all that work....


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