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Fwd: Re: plywood shear transfer detail

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This response may apply to two threads. Based on the "Conventional Framing
Provisions" of the UBC, the top plates are nailed with 16d @ 16". Of
course, this is only good for about 140 PLF. I believe that the nailing of
the top plates together should be part of the shear wall schedule as would
be the sole plate nailing, etc.

Now for the "Convention Framing Provisions" issue. While this seciton of
the Code is handy for a junior engineer to get a feel for what the
"minimums" might be, this section of the Code is perceived by many
(Contractors and Architects) as "Standard" framing. As soon as we specify
anything greater than this, we are subject to the criticism of
over-engineering. There are several sections to this Code where it is not
appropriate even for the simplest of structures. For example, the face
nailing of the roof rafter to the ceiling joist will not transfer the
tension forces induced by truss action of roof framing. Top plate splices
are another example.

I believe either this section should be removed from the Code or the
disclaimers should me made more obvious so that it doesn't mislead
Contractors or Architects. I compare this section of the Code to the
standard details provided by many building departments for the "famous"
6'-0" block fences which don't calc. either.

Bill Allen

> From: Alexander Itsekson <engineers(--nospam--at)>
> To: seaoc(--nospam--at)
> Subject: Re: plywood shear transfer detail
> Date: Friday, April 04, 1997 1:53 AM
> At 10:38 PM 4/3/97 -0500, you wrote:
> >      I am refering to residential wood frame construction, with plywood
> >shear panels.
> >      Typically, on the plans, i see a top plate shear transfer detail
> >shows a plywood panel edge nailed to the upper plate ( wood 2 x 4 ) of
> >double top plate then a simpson a35 to a block above.
> >     While performing structural observation today i see a problem that
> >be common:    The plywood panel is 8'tall-1/8". The wood wall is 8'-1" (
> >92-1/4" studs ). With a minimum  !/2" ( even 3/8 " ) the top edge nails
> >either in the crack between the two top plates or in the bottom top
> >that may ( probably ) not have appropriate shear transfer to the upper
> >plate and the a-35 above.  
> >     If the nails are angled, they must be over/under penetrating the
> >by the nailhead.
> >
> >     Since this is such a common condition , i would appreciate any
> >on this detail.
> >     This may be hard to understand in this text but next time you
> >the top plate edge nailing of an 8' shear panel you may see what i mean.
> >
> >     Tom Harris, SE
> >     Thousand Oaks, CA
> Tom,
> I have seen this condition too.  The way one can deal with it is by
> the plywood to the bottom plate and nailing both plates together with 16d
> at edge nailing spacing staggered.  It may not be the cheapest solutution
> but may be the easiest.
> Regards,
> Sasha Itsekson
> Huntington Design Associates, Inc.
> Oakland, CA

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Subject: Re: plywood shear transfer detail
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