Composite Slab on Metal Deck with Rebar
Composite Slab on Metal Deck with Rebar
(OP)
My client specifically requested REBAR over WWF and fibers. 5.5" thick slab (3.5" over a 2" VLI composite deck). I was leaning towards #3@12" o/c for longitudinal direction and #4 @ 24" o/c for transverse...but now I'm thinking just a #3@12" o/c mat that is set directly on top of the flutes, but I don't love that. It spans 8 to 9 feet.
Any of you all done one with Rebar?
Obviously it's more reinf. than the WWF provides, but I don't want to space it too far apart either...I'd actually prefer fibers myself, but client wants rebar.
Any of you all done one with Rebar?
Obviously it's more reinf. than the WWF provides, but I don't want to space it too far apart either...I'd actually prefer fibers myself, but client wants rebar.






RE: Composite Slab on Metal Deck with Rebar
RE: Composite Slab on Metal Deck with Rebar
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Composite Slab on Metal Deck with Rebar
The biggest problem I've had with WWF is the contractor can never get the size and spacing I specify. The ACI lists a bunch of sizes and spacings, but if they're not stocked, you're out of luck. Maybe if you're ordering an acre of the stuff, they'll run an order, but my projects are pretty small.
And why fight your client? It's not your money, and like I said, reinforcing is cheap.
RE: Composite Slab on Metal Deck with Rebar
RE: Composite Slab on Metal Deck with Rebar
Reinforcement laid on the deck 3.5" below the top of the slab will work for crack control in the minor direction (controlling cracks parallel to the ribs) just as well as if placed higher. But it won't do much good for flexural reinforcement. The theory of "just let it crack" sounds like me for slabs on grade, but I don't like cracks in suspended slabs. Cracks will occur, but I do what I can to control them.
RE: Composite Slab on Metal Deck with Rebar
Good About "A": Better chance of controlling shrinkage cracking (albeit Hokie argues depth doesn't matter that much) at top surface.
Good About "B": Will help with flexure and controlling cracking. Also much more constructible.
Either way i'll have bars over the girders for negative moment too. I don't want to overkill this slab design. It's just a mercantile building. Any other thoughts? I'm leaning "B".
RE: Composite Slab on Metal Deck with Rebar
RE: Composite Slab on Metal Deck with Rebar
If the owner can live with cracks over the beams, there is no need to provide negative slab reinforcement. The Vulcraft catalog states that by not providing negative slab reinforcement, it will simply act as a series of simple spans.