Composite Steel Floor Deck Design

[LeeEng]

I've found myself in a bit of a connundrum. I had offered to assist a friend of mine with a residential home design, but I may have gotten in over my head. He is looking for a concrete house to be built in tornado alley (Oklahoma). The architectural design is very simple - 2 stacked rectangles with a flat roof. The walls will be designed for ICF construction. Is there a good reference or contact to assist me in designing the roofing system? The roof will be a double span @ 15' with a 2' cantilever on each side. (The house is 30'x50' with an intermediate steel beam.) I thought about using a composite steel floor deck. Is there a good resource that I could follow for this design -or- can someone point me in the right direction to get this designed? Thank you.

 

[scottiesei]

Lee, if you got in over your head, myabe you should hire a consulting engineer to help with the roof.

 

[LeeEng]

Thanks, I think I may be headed in that direction. Do you happen to know anyone? It's really a simple design, but I'm not sure I'm ready to take the risk on this design.

 

[scottiesei]

I would suggest finding someone local to you. If you do not know anyone, try talking to local builders in the area who have constructed similar systems and ask who they used. Good luck!

 

[dik]

Further to using a local consulatant, can you contact a good local contractor and ask for some advice? Can you use factory fabricated roof trusses? and whatever local construction practice for roof construction?

As far as composite design, information can be obtained from

http://www.cssbi.ca

They also have span tables for joists.

VicWest has a part of their site that allows you to design composite floors. In these environs, I'd be looking at using cold formed steel joists @ 2' with v-rib form and 2-1/2" topping for the conc deck.

Is there a need for concrete/non-combustible framng? or for that matter compoite design?

It's good advice to seek a local consultant, also.

Dik

 

[LeeEng]

Thanks Dik for the input. I would agree that I should contact a local contractor.

As for roof trusses, I am sure that they would be entertained if the overall cost was advantageous. However, he is not looking to give up any floor-to-floor height.

The requirement for a composite roof is not generated by any need other than a request for a concrete roof. The 15' span appeared to be well within the limits of the composite design. Joists would provide another alternative.

Thanks Again

 

[dik]

I haven't done the sums, but for two span 15', you might be looking at 3" composite deck and maybe 4 or 5" concrete (can use semi-light weight, perhaps) Don't know what magnitude of loading you are looking at. Composite deck can be shored and used as a form (for 15' likely have to support the deck prior to casting conrete. Can use roof deck (smooth) and run bot bars in trough with top bars over the supporting beam. Good luck...

Dik