cutting welded rebar

Feb 25, 2005 7 Replies

I need to remove 100 feet of 1/4" flat plate that is attached to my shop floor. Every foot the plate is attached to the floor with 1/2" rebar that is welded in the center of the plate. When the shop floor was poured, the pieces of rebar were concreted in and stuck 1/2" above the slab. Then the 1/4" plate was drilled every foot for the rebar, laid down flat on the slab, and welded. To remove it I've considered using a 7" grinder(very slow), trying to use a torch at an angle(difficult since the plate is solid against the concrete) and using a gouging electrode and a prybar. Any and all might work, but I'm sure open to some better ideas.



I would try hitting the top of the weld with your angle grinder to get a flat spot. Center punch what you think is the middle, and drill with

1/2 inch or 5/8 inch drill to eliminate weld. If you get the concrete hot with the torch it will pop off bits of cement at you.

Dan

tomd wrote:

Several things come to mind. My first idea is to use a carbide tipped hole saw in a mag drill and cut through the plate around the rebar and weld area. I suggest the mag drill as you can control the depth so you are not trying to punch through the concrete. You might be able to hold just a little shy of all the way.

Another thing to think about is why the steel plate is there in the first place. From your description this sounds like the 1/4" plate might very well be a structural component of your building and removing this may cause a world of grief. If a smooth floor is your goal, you might wish to consider a self leveling compound to top everything off and leave the plate in place. I strongly urge you to consult with a structural engineer before you remove the plate.

If you torch it you'll spall the concrete.

Rent or own a magnetic base Drill - core drill around the rebar - e.g. 1" holes. Then lift off the plate and cut circles off as wanted - torch or real metal work

- a good sledge and cold chisel.

Martin

I would pull up one or two plates by whatever laborious means are available--even grinding, so you can get a look at the concrete. Since the floor was poured with the expectation that it would be covered with steel, it may not be well finished. If it's going to require a topcoat to make it usable, there may not be much downside to using a torch on the steel anchor points. It would be a big waste to take up the steel very carefully, only to find that you don't have a good surface under there anyway.

Remember, also, that you are going to have to deal with all those re-bar stubs. It may turn out that the easiest way is to cover them with an inch or so of new concrete.

Man, that's going to be a LOT of work, no matter how you do it. WHY do you want it removed? It could be an advantage having it there. For instance, you could use it as a giant welding table. You could tack weld pieces in place to hold them. You could weld machinery anchors to it. You could weld jigs to it for large frame-ups or bending patterns. A lot easier to do and change than drilled anchors in concrete. Think about it. Bob

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