Suspended Slab Design

[CScottFlanagan]

I have to design a retrofit suspended floor slab on the second floor of a 5-story warehouse. The floor is to support a live load of 150 psf, along with a forklift load of 4.0 kip per wheel on a 40" wheel center (8.0 kip per axle). The existing columns bays are spaced 10'-8" x 25'.

Anyone know of some good resource material (books, manuals, etc.) for the design of the slab and reinforcement? I'm particularly concerned about designing for the negative moments at the support beams generated from the moving loads.

(Composite beams are not desired for this application due to the construction sequence.)

 

[shemp]

I don't really understand your question. Seems to me you would just need ACI 318 to design the negative moment reinforcement in the slab.

Is this slab suspended from the roof (or another floor)? Why would composite floor beams interfere with the construction sequence? Is this slab supported on steel beams?

 

[jrmack]

As far a moment, this is a ACI 318 thing. Dont forget shear. The forklift could give you some problems with shear, especially with tipping, maximum wheel loads, depending on how thin your slab is.

 

[CScottFlanagan]

I have a book "Designing Floor Slabs On Grade" that does a good job of explaining things. I was hoping to find a similar publication regarding suspended slabs. I'm especially interested in trying to use some composite decking to eliminate shoring. I'm not sure that ACI 318 addresses this. Plus ACI 318 doesn't help much with determining the loads and coming up with an economical design.

I agree that the forklift adds a "degree of difficulty" to the design. Determining the critical loads is a bit more tricky, but manageable.

The construction sequence I mentioned is that the owner may only want to install the beams now, and the concrete floor later (when there is mor money in textile manufacturing). I will have to design anough lateral bracing in the floor to adequately brace the existing columns.

Thanks for the help!