Wednesday, September 16, 2009

Re: Steel straps on wood shear walls

Thor is correct (as usual) except that Simpson's catalog does cover this
on pg 150, noting the requirement for 2.5" nails.

Thor Matteson wrote:
> As for "definitive references" there are none that I know of. But
> conceptually it should not matter which side of the shear panels you
> place a structural element. The forces are transferring directly from
> the shear panels into the strap--it's not as if you have the panels
> acting as a "shim" between the framing and the strap if you put the
> strap on the outside face of the panels, in that you are not trying to
> transfer forces from the far side of the shear panel into the strap.
>
> You must have tight-fitting blocks to act in compression and the strap
> must be taught.
>
> You may wish to consider the possibility that panel nailing into the
> blocks IN ADDITION to the strap nailing could easily split the blocks,
> and consider that nails through the strap can serve double-duty as
> also connecting the panels to the blocking.
>
> Another "mistake" is to require nails in EVERY hole in the strap,
> which can amount to 2-inch nail spacing (in the case of a Simpson
> CS-16, for example)--if your panel edge-nail spacing is two inches,
> then you need this, but otherwise it's likely to cause splitting in
> the wood and make your design look like it's over-kill (which it would
> be in that case).
>
> Thor Matteson, SE
> www.shearwalls.com <http://www.shearwalls.com>
>
>
>
>
> From: Chuck Utzman <chuckutzman@gmail.com>
> To: seaint@seaint.org
> Subject: Re: Steel straps on wood shear walls
>
>
> Around here, over the shear ply is SOP. Underneath, structural
> observation is more complicated.
>
> Jim Wilson wrote:
> > Is there a definitive reference stating that steel straps are okay to
> > be placed over wall sheathing and not directly to the studs before the
> > sheathing is installed? I've googled it, I've called Simpson and I've
> > tried to look to the APA but I can only find indirect statements
> about it.
> >
> > Simpson does mention that different nail sizes can be used for the
> > different installation methods. That isn't generic enough for the
> > condition.
> >
> > Thanks,
> > Jim Wilson, PE
> > Stroudsburg, PA
>
>


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