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Re: Shear Walls and 3x Framing (UBC)

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I believe capacity is the same as allowable.  I personally don't agree with this and say that if the design strength is less than 350plf then the 3x plate is not required.  If you are using Hem-fir framing there is a way around this.  Footnote 1 states that you take 0.82 x Struct I value.  This provides a capacity of 0.82 x 430 psf = 352.6.  We round this to 350.

I truthfully don't think the building official will ding us for this.

The other thing that I've heard is that when designing shear walls you are supposed to design all connections for the capacity of the sheathing.  Including hold-downs.  This seems a little over kill to me.  Not sure if this was code related or something academics were suggesting.

Seth

At 08:07 AM 12/11/2003, you wrote:
According to footnote 3 under UBC Table 23-II-I-1, any shear wall with a capacity greater than 350 PLF in seismic zones 3 & 4 need 3x members at abutting panel edges and foundation sill plates (unless the anchor bolts are designed for half?).
 
According to the table, a shear wall 15/32? CDX w/8d @ 4? has a tabulated capacity of 380 PLF.
 
Question:
 
If I design a structure such that wherever I have a shear wall meeting the above specification the design load is no more than 349 PLF, do I still need 3x members at abutting panel edges and foundation sill plates when my anchor bolts are not designed for half capacity? The concern I have is that, even though I limit the design force in this shear wall to no more than 349 PLF, it still has a capacity of 380 PLF.
 
TIA,
 
T. William (Bill) Allen, S.E. (CA #2607)
V/F (949) 248-8588
San Juan Capistrano, CA
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