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Discussion Starter · #1 ·
Hello all....

Maybe someone on this forum can help with this concrete forming dilemma. We (my company) has to pour a 10 - 30' long x 10' wide x 13" thick reinforced concrete slabs on top of a stone barrier in order to cap it. The slab has epoxy coated rebar and we are using standard wood forms. The problem comes in supporting the form work as we can't brace the form from the outside because it is a granite stone bottom and nothing but air on each side.

We were thinking of using fiberglass coil bar for bracing from the inside (hook to rebar on inside and poke through the outside of form and secure with nut) and then just cutting it off - thus no rust issues. Anyone have any other less costly ideas? Maybe bridge over top with some kind of bracket?

Thanks!
 

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How tall is the wall and how far is the slab to cantilever in clear air. Also, is there no structural engineer on this project?
 

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Discussion Starter · #3 ·
no cantilever just no way of typically supporting the form from the outside as there is no gravel base....just pouring over granite. The slab is 14" thick on one side of the 10' width and 12" on the other - to shed water.
 

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Use a 12' 2 x 4 nailed or screwed across the top to each side about 3'- 4' OC. It would be a beech pouring it, but once its set a little, you could pull those cross braces and finish it out. Depends a lot on how good of a finish you have to do on the top. Good luck.
 

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Discussion Starter · #8 ·
Needles you nailed the final solution. That's what we decided to do. This leaves the full top exposed to work on.

Thanks for the help
 

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It seems like I've welded a million snap-ties to rebar to make custom-length ties for odd width or hard to brace pours. I've used cat heads and pencil rod or 9 wire plenty of times, too, but never liked those as much as welding ties.

Also, remember that an edge form generally don't really get more more than a certain amount of pressure on it. After about 2 or 3 feet back from the form, it don't matter if the pour is 5' wide or a hundred miles.
 

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You could get a pre-cast concrete co. to make them for you.
That way you all you would have to do is set them in place.
They will weigh about 49,000 lbs. ea.
 

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Definitely minimal pressure on the form. Under the circumstances with no way to shore it form the outside and less screwing around. Coil rods is a good solution.

If there was no coils I might have twist braided some tie wire from rebar or a ral pin through the forms held by a 16 dup. But even that is fcking around way.
 
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