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Re: Thickened footings under interior braced walls (Was: RE Hardy Frames)

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Two points to make:

First, in response to Antonio,  the Code People (in particular, John Henry
of the ICBO/ICC) make a distinction between BRACED walls and SHEAR walls.
Braced walls occur in Conventional Light-frame construction, and include
let-in braces and gypsum sheathing (shudder).   The conventional framing
section of the code does not mention Shear Walls.  So while any engineer
knows that OF COURSE you need a foundation under a Shear Wall, the code does
not require them under Braced Walls.

Which brings up point #2:  Section 2320.11.3 requires that "sills shall be
bolted to the foundation or slab in accordance with Section 1806.6".  It
does not say what thicknes the slab should be.  Section 1806.6 requires
7-inch bolt embedment into concrete (not a combination of concrete and
dirt...)   If you have an "alternate braced wall panel" that requires
tie-downs with the 1800 or 3000 pound capacities, you are not going to get
the manufacturer's rated uplift capacities by embedding an anchor rod for
the tie-down into a 3-1/2 inch slab.

I don't see any way that a reasonably responsible building official could
allow installing a braced wall panel on a slab (or thickened part of the
slab) less than 10 inches thick.   Note the qualifier used before "building

As for the Conventional Framing section of the code and the IRC, I think
they have their place--but we are seeing huge abuses of them where designers
are pushing the envelope in every direction possible, all at the same time.

Thor Matteson, SE

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