Elevated Exterior Concrete Deck
Elevated Exterior Concrete Deck
(OP)
Working on an elevated exterior concrete deck for a restaurant. It will be open below. The deck spans approximately 6 ft. between supports and is 20' x 25' in rectangular dimension.
The framing is I-beams. The slab is proposed to be 6" total thickness and tapering to 4 1/2" at the internal floor drain. I am considering using 18ga inverted composite deck, G90 (unshored) and adding sufficient flexural reinforcement to carry the concrete if the deck rusts out. Also, adding a significant amount of temp. and shrinkage reinf. to minimize cracking. A collegue of mine suggested using shored 22ga. 0.6C G90 conform and constructing it as only a reinforced slab. His contention is there will be less cracking potential due to the smaller rib height. Any thoughts? Also, the client does not want to add any topping,tile or other substrates to the slab. I was thinking about spec'ing a hardnener/densifier in lieu of any other topping. He is aware that the deck may no last as long it would otherwise. Thanks for your help in advance. FWIW, I have witnessed many exterior suspended slabs in our area that are 60 years old and show no signs of issues.
The framing is I-beams. The slab is proposed to be 6" total thickness and tapering to 4 1/2" at the internal floor drain. I am considering using 18ga inverted composite deck, G90 (unshored) and adding sufficient flexural reinforcement to carry the concrete if the deck rusts out. Also, adding a significant amount of temp. and shrinkage reinf. to minimize cracking. A collegue of mine suggested using shored 22ga. 0.6C G90 conform and constructing it as only a reinforced slab. His contention is there will be less cracking potential due to the smaller rib height. Any thoughts? Also, the client does not want to add any topping,tile or other substrates to the slab. I was thinking about spec'ing a hardnener/densifier in lieu of any other topping. He is aware that the deck may no last as long it would otherwise. Thanks for your help in advance. FWIW, I have witnessed many exterior suspended slabs in our area that are 60 years old and show no signs of issues.






RE: Elevated Exterior Concrete Deck
If you are designing the slab reinforcing as if the metal deck did not exist, why incur the cost of composite metal deck?
Ralph
Structures Consulting
Northeast USA
RE: Elevated Exterior Concrete Deck
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RE: Elevated Exterior Concrete Deck
@JAE - I will pass this along to the client - Thanks
FWIW, I called W.R. Meadows and they recommended a penetrating sealer applied annually instead of the densifier. I like the idea of the Neogard better - hopefully the client will as well.
My concrete consultant also recommended using only 3000 psi concrete with a mid-range water reducer and 6" max. slump to further help prevent cracking.
RE: Elevated Exterior Concrete Deck
RE: Elevated Exterior Concrete Deck
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: Elevated Exterior Concrete Deck
I was def. going to specify wet curing for 7 days. How do you finish the concrete w/o a trowel - broom?
RE: Elevated Exterior Concrete Deck
RE: Elevated Exterior Concrete Deck
RE: Elevated Exterior Concrete Deck
See attached excerpt from CANAM catalogue. You definitely don't want moisture trapped in the system. Galvanizing will also help.
RE: Elevated Exterior Concrete Deck
RE: Elevated Exterior Concrete Deck