Non Concrete Slab over Metal Deck
Non Concrete Slab over Metal Deck
(OP)
I'm designing a concrete slab over metal deck in which neither the steel beams nor the steel deck are composite with the slab (deck is used as a form). The total thickness of the slab is 6", (2" flute + 4" slab). The span is 8'-6" and the equipment load is 1.00 Ton/m^2. I am thinking of providing reinforcement in the flutes 3/4" clear from bottom parallel to the deck and temperature and shrinkage steel perpendicular to the deck at mid-depth. Thoughts are more than welcome.






RE: Non Concrete Slab over Metal Deck
RE: Non Concrete Slab over Metal Deck
i am currently doing a similar elevated deck slab with equipment loads and i already have 0.9 unity ratio for 20 gage vulcraft non-composite deck spanning only 4'-0" for 7" thick slab for 1 span analysis. 2span and 3span analysis is ok.
RE: Non Concrete Slab over Metal Deck
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Non Concrete Slab over Metal Deck
RE: Non Concrete Slab over Metal Deck
BA
RE: Non Concrete Slab over Metal Deck
RE: Non Concrete Slab over Metal Deck
I could consider the possibility of using composite deck. This means that the deck provides reinforcement in the longitudinal direction which lowers my positive reinforcement? How do you determine the b width for positive and negative reinforcement calculation? If the beams are non composite with the slab, can it still be assumed that the steel beams are restrained against LTB, for when the deck is running parallel and for when it is running perpendicular to them?
RE: Non Concrete Slab over Metal Deck
i used 7" coz i'll have 2 layers of rebars for positive and negative moments of the slab.
but i am still considering using composite deck so i will only need top bars. vulcraft has VL series composite deck.
can someone explain to me the advantage of using non-composite vulcraft C series metal deck?
RE: Non Concrete Slab over Metal Deck
You may be able to find some information in this thread:
http://www.eng-tips.com/viewthread.cfm?qid=223271
delagina
I have used C deck over composite deck in instances when I thought there would be a chance of the deck rotting out over time.... or when the chance of the deck rotting out was dire.
In those instances, I used a top and bottom mat of reinforcing to support the loading on the slab, and the deck was there to act as a form only.
RE: Non Concrete Slab over Metal Deck
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Non Concrete Slab over Metal Deck
Noncomposite beams are still braced...the deck has to be connected, usually by puddle welds, to the beams. In addition to corrosion, fire rating is another consideration in using composite deck.
RE: Non Concrete Slab over Metal Deck
We usually design a composite deck by picking something out of a deck manufacture's span tables. Pick your favorite manufacture, and look at there technical literature. If you want to calculate the capacity by hand, it may be worth looking at the Steel Deck Institute's standards http://www.sdi.org/sdiansi2010.htm
Another reason for a non-composite deck design is when vibrating or moving loads (forklift etc) are expected. These loads can break the bond between the concrete and metal deck.
RE: Non Concrete Slab over Metal Deck
i have a 2-hr fire rating requirement.
RE: Non Concrete Slab over Metal Deck
If the deck is just used as permanent formwork, the fire rating requirements would be different. But again, you would need to know whether your fire rating agency has any special requirements for clearance to the reinforcement because of the ribs, and whether the total or an equivalent depth is to be considered for the fire rated element.