For double sided shear walls I specify 3x sill plates and usually a 3x plus
a 2x top plate, as well as 3x or 4x's at the panel edges. Plate fasteners
are usually with lag or wood screws. Of course I get nothing but grief from
the builders. Their biggest complaint is that they can not end nail the
studs in a conventional fashion with anything less than a 30d nail.
For some conditions, usually a retrofit, with a double sided 4" nailing I
have specified double 2x6 plates and alternated the edge nails from the
upper plate on one side and the lower top plate on the other side and
additional plate nails, but technically this is not allowable.
Does the UBC voodoo deflection formula apply for double sided shear walls? I
would say no, unless it has been tested, and tested for a full range of
aspect ratios. But since that is all we have, would you simply double the
I do not recall seeing any official detailing guidelines for double sided
shearwalls, yet I have been detailing them since I started out. William
Vaughn from the SEAOC Code Committee was editor for a real nice guideline in
1997. However, it did not address double sided walls. Does the new Breyer
book have any design examples? I hope the ICBO code examples will address
some of these issues.
Anyone have any comments?