For wind shear, I used a wall with 2X8's @ 16" and 2-2X8's edge to edge
between them as a "web". I suppose for super heavy duty shear resistance,
you could use two or more "wythes" of 2X's in the web and stagger the edges.
From: Jeff Smith <smthengr(--nospam--at)sirius.com>
To: seaint(--nospam--at)seaint.org <seaint(--nospam--at)seaint.org>
Date: Wednesday, June 02, 1999 12:16 PM
Subject: double sided shear walls
>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?
>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
>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?