Walkable ceiling with light gauge. 2

[WARose]

I got a client that wants to do a walkable/suspended ceiling with light gauge. I'm not real cozy with this idea because the bay size is about 30' x 20'.

Has anyone done this themselves? What kind of layout are we talking? Stability/bracing really worries me here.

 

[dik]

I've been using CUFSM for a decade or more... it's a little tempermental occasionally, but well worth the cost (free).

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[dhengr]

WARose:
As seems usual these days, Structural Engineers don’t actually do a complete, integrated bldg. design any more; they spend much of their time and effort justifying a client’s weird-assed concepts/ideas, details and material combinations, and then having to fight like hell if they can’t make the stupidity work out well, or cost almost nothing. But, they are still there as the insurer of last resort when the crazy ideas don’t work so well.

Like GC_Hopi, I’d frame the 20’x30’ panels with struct. stl. and infill with the 20’ CFS jsts. There may be some advantage to a gridwork of stl. beams and 10’ CFS jsts. You don’t say why the walkability is needed, what the uniform and concentrated live loads are, how high this ceiling is, how it is really intended to be supported, etc. Is this a new design, so roof jsts. can be designed for the hanging loads, are roof framing stl., columns and ftgs. designed for these new loads vs. a lt. wt. hanging ceiling? I would be temped to look at assembling these 20’x30’ panels on the fl. slab. btwn. their four corner columns, stl. framing, CFS, and the 3/4” plywd. sheathing. Then lift them 7’-8’ and install the ceiling, and then lift them to their final elev. and fix them to some sort of collars on the bldg. columns, maybe with some discrete hanging point on the interior of the panels to improve their structural performance for full LL. The panels could be jacked up or pulled up around the four corner columns.

 

[dik]

and just be greatful that they don't want the floor elevation to be adjustable.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[WARose]

While we are on the topic.....can anyone recommend a good product for screwing down 3/4" plywood to light gauge steel? (I'm looking for testimonials as much as anything.)

 

[XR250]

These work nicely but I think you need 16ga joists min. for the wings to shear off properly. Regular TEK screws don't work well unless the plywood it pre-drilled.

http://fastening-solutions.itwbuild...teks-3-wtm-wood-to-metal-self-drilling-screws

 

[dik]

See (from my wood guy):

https://www.strongtie.com/screwsand...eApplicationMenuFacet:Fastening+Wood-to-Steel

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[SandwichEngine]

I recommend you get ahold of some PEMB manufacturers in your area. They use heavier cold formed steel for purlins and girts all the time and they can be spaced for the size of floor you're talking about. Would still do I shapes or something stronger at the edges.

 

[dik]

I've used Bailey Metal Products for decades... they make almost anything and the material has always been available. Still, any issues with combustibility.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik