6" 2-way concrete slab to wall connection

[pelotoner]

A current project has a 6" 2-way concrete slab supported by interior steel posts and 8" masonry walls at all exterior edges.

The contractor is pushing to lay the masonry block up to the bottom of the slab with no bond beam or tie beam.

I would like any input on this as I have not seen it done and would like to see more continuity with the wall (btw, the design works without relying on stiffness from the wall). Also, I find no limitation in ACI.

Thanks.

 

[ron9876]

I don't see a problem with it.

 

[ishvaaag]

Normally minimum steel rebar will be enough to ensure continuity enough; it was when wood members, or precast members were used that some perimetral members were truly required to keep geometry as projected along the life of the building. Better ensure that two bars run all along the limits, yet at 6 inch thick it is not uncommon to forfeit embedded members since so small depth makes difficult their proper construction.

The main concern, then (except the dimensions bewteen structural joints are excessive) is proper behaviour of the joint; the slab will rotate at the support and some notional eccentricity is to be accounted when checking the wall.

 

[BAretired]

The slab has a tendency to curl upward at corners. Some refer to these as "corner-levers". To prevent that, you should tie all corners down through the block to the foundation.

The bond beam is not strictly required, but it prevents the slab concrete from flowing down the open cells. The slab should be tied to the block with nominal vertical bars hooked into the slab at about four foot centers.

BA

 

[pelotoner]

I concur with all. This is obviously for form-saving costs and I intended to at least do what BAretired suggested and require a KO block which will be poured continuous with the slab. So, in lieu of a tie beam, this will be the method.

Thanks to all for your input! Cheers.