Edge Loading of Concrete Wall

[thehoser]

Hello, I have an 8" stem wall which is notched out at the top 2-1/2" for joist framing. The PROBLEM is that I have a steel beam that is sitting on that 2-1/2" edge and I am not sure how to calculate the capacity of that bearing connection before you have some kind of shear slip failure toward the free face of the wall 2-1/2" in from the end of the beam.

I thought there would be some kind of shear equation analogous to "punching shear" or "shear slip" that would tell me how much I could load the 2-1/2" edge with my steel beam before a crack formed at some angle inward toward the inner face of the wall. This doesn't seem to match up though with the typical punching shear model with an outward shear path from the point load.

Is it really concrete in bearing that dictates my capacity??? What's the best way to go about this design???

 

[COEngineeer]

So you have about 5 1/2" of concrete at the top of the wall correct? Is this steel beam supporting a steel beam along exterior wall OR perpendicular? I would put the bearing plate half on concrete and the other half on the wood and put blocking underneath. how much load are we talking about here?

 

[scottiesei]

Per AISC, you must have a steel bearing plate below that steel beam. See page 2-141 in 9th edition ASD. I am not sure that you going to be able to get that to work as is.

 

[scottiesei]

Edit above, this is not a requirement BUT a recomendation. But I still question the design.

 

[vincentpa]

The PCA Notes On ACI 318 have an example using a shear friction model. Support the beam on a plate. Assume a diagonal crack occurs. Tie the plate to rebar or headed studs that develop on the other side of the crack. See shear friction in ACI 318 and that example.

 

[thehoser]

Thanks Vincentpa, for the direction on that. It seems like the angle or plate with a welded bar developed into the wall is the best solution. Section 11.7.4 definitely helps.