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Re: Shear tranfer from roof diaphragm to shearwalls with eaves?

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Dan,

Yes blocking is required, even if it has to be cut to fit.  Not only do you
have to have positive load transfer from the roof to the top plates for
horizontal diaphragm forces, most trusses or joists require stability
blocking at the end supports anyway.

If the transfer from roof to blocking is calculated and provided at the same
level as the diaphragm shear, you must also evaluate the top plate and top
plate splice capacity to function as a drag between wall segments.
Additionally you must provide a continuous chord for forces acting in the
other direction.

Trust what you were taught, the advice you are receiving is meaningless
drivel.  If this is an engineering company, get a new job.

Paul Feather PE, SE
pfeather(--nospam--at)SE-Solutions.net
www.SE-Solutions.net
----- Original Message ----- 
From: "Dan Boltz" <dboltz(--nospam--at)mckinleyassoc.com>
To: "SEAINT" <seaint(--nospam--at)seaint.org>
Sent: Wednesday, November 12, 2003 2:28 PM
Subject: Shear tranfer from roof diaphragm to shearwalls with eaves?


> When pre-engineered wood roof trusses are shown with a 1'6" eave, is
> blocking required above the shearwall to transfer the horizontal load out
of
> the roof panels/diaphragm?  The eave currently shown has a non-standard
> height above the shearwall location so the blocking would have to be cut
to
> the required size.
>
> The standard detail I'm referring to is on page 744 of "Design of Wood
> Structures" by Breyer, 3rd Edition.
>
> Also, two of the buildings I'm designing are approximately 40' x 80'
> rectangular single story buildings.  I'm being told that I shouldn't worry
> about the horizontal shear and that shearwalls aren't required or the
> blocking I'm referring to above!  Am I missing something here?  I know
there
> is a lot of redundancy in the wall panels, but I was taught to ensure a
> proper load path from the horizontal diaphragms to the vertical shear
> elements into the foundation.
>
> Thanks.
>
>
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