3 inch metal roof deck over process area

[Boiler106]

Does anyone have experience in the US spacing roof wide flange beams out to 8'/10' oc using 3 inch metal roof deck (vs bar joists at 6' oc with 1.5in metal roof deck)?

Has this affected utility negatively supports in a heavy utility area of, say, 30-40 psf collateral? I'm conerned about the wide spacing of the beams.

Any other words of wisdom for a roof type like this?

Seismic Design Cat C and V=140mph asce 7-10

 

[r13]

I guess you are talking about 3" form metal deck, for which, you shall follow manufacture's catalog, or check Steel Deck Institute (SDI) for design considerations. You may need to add concrete overlay and/or reinforcing steel.

 

[Boiler106]

No, im talking about 3N metal roof deck. I dont have a structural issue with the deck itself. No concrete will be used.

Im looking to see if anyone has had success on industrial/process projects using similar deck spans. Mostly, im looking for nonstructural issues with this system selection.

 

[r13]

Mostly, im looking for nonstructural issues with this system selection.

You need to be more specific on these issues of concern. To me, there are a few structural issues - deflection and ponding, water proofing, vibration (if there is dynamic source), thermal expansion, heating and cooling, connections.

 

[strucbells]

Are you concerned about pipe support spacing between roof framing? What type of building is it (use)?

It probably depends on what diameter piping and how much of it you will have. For small/plastic piping, you may need additional intermediate strut supports between roof beams, but unless it's super dense and extensive I don't think this would be a huge deal.

 

[JLNJ]

Large bays, joist/joist girder framing with 3" deck is the cheapest way to frame a building.

If you are looking at 40 psf collateral load, you might be pushing it for regular LH joists in big spans. At 10' on center you might be looking at 800 to 1000 plf per joist.

 

[CANPRO]

I agree with JLNJ on the overall economy of the system.

I can think of a couple of downsides: Framing openings in the deck is going to require larger members due to the span between beams. If you require a lot of fall arrest anchors you'll need a lot of supplementary framing for the anchors in between roof beams. The deck comes in sheets only 2ft wide (instead of 3ft) and is heavier per sheet, so cost and time to install the deck will increase slightly.