AISI & CFS - Cold-Formed Steel Stud Shearwalls

[BSVBD]

Cold-Formed Steel Stud Shearwalls

RE: AISI S213-07/S1-09 (2012) Tables C2.1-1 & C2.1-3

I see an allowance to specify 33, 43, 54 & 68 mil or 20, 18, 16 & 14 Gage respectively, as well as an allowance to specify #8 & #10 (TEK) Screws.

On other CD's I've seen specifications for 97 mil 12 Gage as well as #12 & #14 TEKs.

Why do I not find these in AISI or IBC docs?

Where can I find resources / tables for 97 mil 12 Gage and #12 & #14 TEKs?

Thank you!

 

[phamENG]

I don't think you will. Those values were developed empirically. Shear wall assemblies are, arguably, too complex for any sort of direct analysis. The number of fasteners, spread of connections, slip in the connections, various stiffnesses, etc. makes it really impractical. So...they built a bunch of them and broke them to measure performance. That performance was verified several times, and the results published in the code as minimum strength and stiffness based on a worst case aspect ratio.

Maybe some of those engineers attempted to "reverse engineer" the tables and extrapolate. Or maybe they were really close (D/C ratio at 1.1, say), so they just bumped up to bigger screws and thicker studs to feel better. I wouldn't advise either of those approaches.