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

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Yes, blocking IS required, unless you have an alternate load path.  However,
it doesn't have to be in every truss space - just enough to transfer the
shear from the roof diaphragm to the shear wall (every other space or 2 out
of 3 for example).  Also, it doesn't have to be solid blocking - if the roof
is steep enough, you can build a box out of 2x4's (nail the top to the roof,
bottom to your top plate, and the sides to the trusses) between the trusses.
Nail structural sheathing to the 2x4 box like a miniature shear wall.

Actually, you probably can't block every truss space because of attic
ventilation requirements.

----
Jason Kilgore
Leigh & O'Kane, L.L.C.
jkilgore(--nospam--at)leok.com
816-444-3144
816-444-9655 (FAX)
----- Original Message ----- 
From: "Dan Boltz" <dboltz(--nospam--at)mckinleyassoc.com>
To: "SEAINT" <seaint(--nospam--at)seaint.org>
Sent: Wednesday, November 12, 2003 4:28 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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