Concrete Metal Deck attached to Side of WF Beam

[8thStreet]

Hi All,

I am working on a large custom residence where the floor system is concrete metal deck system with all steel framing. The architect wants to reduce the depth of the floor system, so instead of the deck running continuous over the top of the beams, they want the the concrete metal deck to be inset into the depth of the wide flange beam, so that top of concrete is flush with top of the wide flange.

Please see attached sketch.

Do you forsee any issues with this type of system?

I know that all of the deck spans will be single span, so that reduces the effectiveness of the floor system. Also, with all of the decks designed as simple spans, so they will likely be some sort of cracking in the finish located above the steel beam.

Thanks.

 

[KootK]

I did a little digging into the delta beam option because I'm no expert when it comes to that product. Some concerns that I have:

1) The shallowest delta beams seem to be about 8" deep. Here, would we let some of the delta beam project from the top of the slab? I was under the impression that the whole thing needs to be filled with concrete such that the delta beam is torsionally integrated with the slab.

2) The fire ratings, at least in some instances, seem to rely on the presence of rebar within the delta beam. I would have to think that the delta beam would need to be solid filled with rebar in order to do it's job under fire condiitions.

 

[jayrod12]

REgarding having the delta beam project below, this is no issue, they've done it on some of my project previously. They just weld a bearing plate at a higher elevation instead of it being at the bottom of beam. However, I feel that this instance may in fact be such shallow a floor, that this ends up being significantly non-economical.

For their fire rating, it's based fully on testing and does completely disregard any contribution from the bottom plate and uses the reinforcing welded to the inside of the side wall plates. You can still fireproof them with intumescent paint or spray on if required.