Load bearing wall on existing concrete slab-on-grade

[braves25]

I have an existing slab-on-grade (a pre-engineered metal building), I'm not sure of the slab thickness at the moment. We will be adding a new wall which will be a load bearing wall. Total load about 700 PLF. With this being a PEMB and near an existing frame line, I'd rather not sawcut the slab to place a typical "thickened slab". If this were a 4" slab, would it be acceptable to place the new load bearing wall directly on the slab? Looking at ACI 13.2.4 gives some guidance, but no real "slab thickness" direction. Seems with this section (13.2.4) it is different than the "footing" section 13.3.1.2 where the depth must be at least 6". Thoughts??? Thank you and have a great day.

 

[JAE]

This document is for a thickened slab so may not be exactly what you need here, but at least gets you some guidance on wall loads vs. thickness.



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[spats]

There is an excel spreadsheet program called GRDSLAB, written by Alex Tomanovich that is all over the web. It covers slab design for line/wall loads, as well as uniform loads, wheel loads, post loads, etc. The latest version, I believe, is version 2.

 

[JoshPlumSE]

Why not take a core of the slab reasonably close to where the wall is going to go. Use a GPR to test location of rebar first. Then core around it. Everything else is guess work. Once you've done that you should know thickness, strength and reinforcement spacing. And, a single core should be easy to repair.