Structural opinion about solution

2 inches is light. You usually spec that as the deck depth plus the overlay as, say 1.5 + 2 for a 3.5" total depth of concrete. I would expect a 4" (1.5 + 2.5) minimum slab depth here

To answer your question though, with composite action, no. You might want to check your response frequency though for vibration response.


Mike McCann, PE, SE (WA)

Have you checked vibration and the floor fire rating needed? That slab is thin.

Beat me to it.

Yes is a steel deck of 4 inch, the concrete over is 2 inch

I suspect that 2" concrete over metal deck is inadequate for fire rating of slab. Is concrete lightweight or normal weight?

I recommend doing a vibration analysis for transient loads. Many times for open, long span floors, we would have to add concrete to dampen down the vibratory response.

will be normal weight concrete.

I don't think a composite W24x68 spanning 46'-0" is small at all. In fact, by my calculations, the beam should have adequate strength as non-composite unless your dead loads are very high. As others have already commented, the slab thickness looks thin. Besides vibration and fire rating concerns and assuming you are following the 2010 AISC Specification, the minimum cover over a headed stud is 1/2" and the studs are required to have a minimum projection of 1 1/2" above the steel deck. Thus, with 2" of concrete topping, you are providing no tolerance for the installation of the studs and the placement of the concrete. With a 46'-0" span, you will want to keep a close eye on the pre-composite deflection and provide camber as necessary.

I would say your deck is 4 inch with some 2 inch areas maying for a an average depth of 3 inch.

How about you respond to the questions and also tell everyone what w deck your using and tech data.

"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning."

Are these metal decks used for construction ease? Are they used mainly in buildings?

RamSteel used to have a provision to check for vibration; I'm sure it still does. If you have access to that run a check on it and I suspect you'll find that what others have told you is true: that vibration will be a concern. If you don't have access to RamSteel check whatever software package you're running to see if that have a provision to check it; I think you'll find it illuminating.

That's a big vibration concern from me.

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