Steel Deck Factors 2

[Veer007]

Hey Guys,

I have a few clarifications, What is the maximum span of the steel deck? Is this okay to provide deck at single-span instead of three-span? Can the deck be non-galvanized? Are there any other factors to be considered except this? like weld detail, side lap, and end lap?

Thanks in advance!!

 

[CANPRO]

Veer007, as a fabricator, this info should be supplied to you by the EOR. Typically steel deck is sized for multiple spans, without a closer look at specific locations I would assume single span is unacceptable.

All of your questions are project specific. Span of steel deck is governed by the in service loading or possibly limited by the maximum un-shored span if there is concrete on top. The fastening pattern is governed by uplift conditions and diaphragm requirements. Canam has good literature on this. See links below - design examples included.

Steel Deck Catalogue
Diaphragm

Once you review the above references I'm sure you'll have some follow up questions.

 

[phamENG]

I disagree a little with CANPRO - steel deck can be used in single span. But it's like asking if a 2x4 can be used single span or if it has to be multiple spans. It can be single span if you consider deflection, etc. as you would with any other structural member. Be aware, however, that most all of the load tables provided by the manufacturers assume multiple spans. To go less than that, you have you manually calculate the capacity of the deck.

Otherwise, I agree with CANPRO. Many of your questions are specific to the application.

The non galvanized question is really only applicable to form deck with a concrete topping. If you do not galvanize it or paint it per the manufacturer's requirements, you have to assume that it doesn't exist in the final construction. In other words, the concrete has to be capable of supporting its own wait and the wait of all loads on top of it. If it is galvanized, then it can be assumed to carry the dead load of the slab in service while the slab carries all dead and live load applied after the slab has cured.

To your last questions, yes. All of those are important considerations.

In addition to the catalogs CANPRO referenced, check out the SDI generalized specs and design guides.

 

[CANPRO]

phamENG, no disagreement here - for sure you can use single span deck. But in my experience the deck is almost always selected based on multiple spans. So without any more information my initial assumption would be single span deck would be a no-go.

 

[phamENG]

Fair enough. I misunderstood - thanks for clearing it up.

 

[Veer007]

So max. Deck length could be?

Thanks in advance!!

 

[KootK]

Steel deck comes is many thicknesses, depths, and profiles. Establishing the maximum span will require consideration of all of that in concert with the project loads and the degree of continuity provided by multi-span setup. Grab a supplier's catalog or three and see what their load tables have to say. I've used spans ranging from 3' to 8' with a whole lot of 1.5" x 22/20 gauge in the 5' to 6' range for roofs.

 

[JedClampett]

And there's cellular decks (these seem to be out of style) that can span 14 or 15 ft. See this 2010 Vulcraft Catalogue (I think they've merged with Verco), among many others.

 

[Veer007]

I found that max deck length can be 30 feet, is this correct?

Thanks in advance!!

 

[r13]

Veer007,

Can you show us how, and from where, you got that number (provide deck type, number of span, composite/non-composite, slab depth, floor design load, deflection criteria).

 

[KootK]

The 30' number sounds more like a maximum sheet length based on standard production runs and shipping & handling limitations. Is that your concern rather than the actually spanning capability of the deck?