Slab wall connection (rebar join) options

[AtomicRob]

A reinforced concrete wall is poured, allowed to cure, then a reinforced concrete floor slab is poured. The rebar in the slab must be joined to the rebar in the wall. If protruding bars need to be avoided, what methods may be used to join the bars? I have already considered
1) Couplers recessed or embedded in the wall
2) Covered pre-bent bars
Can anyone suggest other options?

 

[dlew]

AtomicRob,

If the wall vertical rebars are small (#4 or #5) they could be extended, projecting straight up above the joint. Normally, vertical rebars do not interfer with the forms.
After the concrete is set and has reached some strength, the rebars could be bent in place without damage to the concrete.

When using threaded couplings the bent bar has to be turned, interfering with the adjacent bars.

 

[JimParks]

Rob,

From my reading of your post the new floor is not necessarily being poured so as to rest on top of the wall as is the case where DLew has provided an option. So if this new floor has to be poured adjacent to an existing wall another option in addition to the embedded couplers is to use epoxy or polyester based adhesives. While this is more expensive than the embedded couplers, it does allow for accurate placement of the bars once the forms are removed.

If you have any doubts about the quality of the contractor to be used (and his field surveyor) you might be safer planning on epoxy from the start. The other side of the argument is that the contractor will have to pay for the epoxy embedment if he screws up the coupler placement, but you still might end up seeing the couplers above or below a slab. And then you have a choice of visible rusty (eventually) couplers or an ugly patch.

If this is a large job with an established contractor and good superintendent and surveyor, the couplers will probably be placed ok.

Good luck,

Jim

 

[AtomicRob]

Thanks Jim and Dlew for your responses. (FYI: Yes, the floor slab is to be poured adjacent to an existing wall, as opposed to on top of it - sorry, I should have specified).

I have also recieved the suggestion that the rebar could be welded directly to an embedded steel plate in the wall - any thoughts on that (pros, cons, potential problems, etc.)?

Rob

 

[ishvaaag]

I don´t think properly welding rebar to a plate should be much cheaper than using mechanical or adhesive insets. In any case if you go for it a relatively thick plate (over half the diameter thick) should be used, AND complete warrant of the weldability of the used rebar steel is required, since some rebar used for steel change for the worst their mechanical properties upon welding (be it upon then acquired fragility or loss of strength) that you can't count it as normal and reliable reinforcement.

 

[LPPE]

Rule of thumb is to never weld rebar.

 

[LPPE]

And heres the rest -
Instead, weld A36 threaded rods or the like instead of rebar.