Partially Encased Steel Beams
Partially Encased Steel Beams
(OP)
Hello Everyone. I am working on an increasing the live load capacity of an existing structure. I would like to remove the existing 4" concrete floor slab and replace it with a 6" concrete floor slab at the original elevation, thereby encasing the beam flanges in 2" of concrete. Does anyone know if it is possible to look at this beam as a partially composite beam in some way? I just want to rely on the friction between the two materials and not add any shear connectors. Thanks for your help.






RE: Partially Encased Steel Beams
RE: Partially Encased Steel Beams
The rebar in the prior post could even take the shape of closed "clip" loops, to further engage the concrete head.
RE: Partially Encased Steel Beams
RE: Partially Encased Steel Beams
RE: Partially Encased Steel Beams
RE: Partially Encased Steel Beams
RE: Partially Encased Steel Beams
I agree with the above - composite action without shear connectors is not acceptable. AISC doesn't acknowledge composite action without the studs or other shear connector.
RE: Partially Encased Steel Beams
Well...sorta...if you fully encase the beam in concrete you can use elastic superposition of the composite section up to first yield of the steel beam without shear connectors per I3.3a of 13th ed. though I have not seen this done in practice. You can also ignore LTB if fully encased. Note that the detailing provisions associated with a fully encased beam were left out of the 13th ed, but you can go back to the 3rd and see the minimum cover requirements.
RE: Partially Encased Steel Beams
One chunk - about the size of an American football, fell through the windshield of a brand new Lexus in a parking garage and was held in place halfway through the glass, about an inch from the dashboard.