Composite Deck - Reverse Bending
Composite Deck - Reverse Bending
(OP)
I am analysising a composite floor deck (2" type B steel deck 4" conc.) which has some fairly high reverse bending due to point loads.
Am I allowed to take any bending strength from the inherent strength of the steel deck by itself?
ie if my analysis resultes in a moment capicity of X for the full section, and the mfgr listed strength of the steel deck is Y, is my total Moment capicity X+Y, or does Y get ignored?
Thanks
Am I allowed to take any bending strength from the inherent strength of the steel deck by itself?
ie if my analysis resultes in a moment capicity of X for the full section, and the mfgr listed strength of the steel deck is Y, is my total Moment capicity X+Y, or does Y get ignored?
Thanks






RE: Composite Deck - Reverse Bending
RE: Composite Deck - Reverse Bending
Yes, if you can somehow arrive at the flexural strength of the deck only. You probably can, using the manufacturer's literature and the appropriate effective elastic section modulus.
"ie if my analysis resultes in a moment capicity of X for the full section, and the mfgr listed strength of the steel deck is Y, is my total Moment capicity X+Y, or does Y get ignored?"
No. For positive moments, the section acts like a concrete beam with the deck acting like bottom rebar. Therefore, you can't add this strength to the strength of the deck acting alone. FOr negative moments, your deck does act alone because the concrete is cracked, or assumed cracked.
RE: Composite Deck - Reverse Bending
In many cases, WWF is included in the concrete and if you can get them to chair it up at the beams, you effectively have negative moment reinforcing and can count on that.
RE: Composite Deck - Reverse Bending
Would I be ok to take the allowable moment from my conc. and reinf. and add it to the allowable bending from the steel deck?
And yes, my negative moment is occurring over a support and my deck is installed in a 3-span condition.
RE: Composite Deck - Reverse Bending
RE: Composite Deck - Reverse Bending
I wouldn't do that. The compression/tension couple you are using with the concrete and the rebar (assuming its chaired as hokie66 states) is what you want to use. The deck would have some bending capacity, but how they interact would be tough to calculate - not worth my time I know that.
RE: Composite Deck - Reverse Bending