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RE: Wood Shear Walls

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Sum(Li) is just the total usable length not the total length.  The way I
read it was the full height segments need to have a bottom plate connection
that is good for a design tension with same magnitude as the design unit
shear.  

The only overturning restraint that is required are tiedown anchors at the
outside ends of the perforated wall.

Scott M Haan  P.E.
Plan Review Engineer
Building Safety Division http://www.muni.org/building, 
Development Services Department,
Municipality of Anchorage
phone: 907-343-8183   fax: 907-249-7399
mailto:haansm(--nospam--at)ci.anchorage.ak.us

> -----Original Message-----
> From:	David B Merrick [SMTP:mrkgp(--nospam--at)pacbell.net]
> Sent:	Friday, March 30, 2001 7:42 AM
> To:	seaint(--nospam--at)seaint.org
> Subject:	Re: Wood Shear Walls
> 
> For tdesign=V/[Co*sum(Li)] it would be rational to not use Li but to use
> the
> height of the edge of opening adjacent to the interior HD.
> If Li were to be larger than H, the interior HDs could then become larger
> than
> the end HD's.
> If I am understanding it correctly, what a silly criteria! HD demands
> usually
> reduce by increasing the wall length (Li).
> Is the equation correct?
> 
> "Haan, Scott M." wrote:
> 
> > The IBC requires each end of each full height piece to be restrained
> even
> > when using a perforated methodology.  The last draft of the 2000 NEHRP I
> saw
> > has the following provisions:
> >
> > for full height segment bottom plate - top plate shear connection:
> >
> > vdesign=V/[Co*sum(Li)]
> >
> > for full height segment bottom plate uplift connection:
> >
> > tdesign=V/[Co*sum(Li)]
> >
> > for shearwall chord tension at the extreme ends of the wall
> >
> > Tdesign=vdesign*H
> >
> > for wall nailing:
> >
> > vtable*Co < V/sum(Li)
> >
> > The NEHRP also limits the wall shear strength to 640 plf, says to design
> > collectors, limits wall height, requires anchors to have direct load
> path to
> > foundation and does not mention using gravity loads to resist
> > overturning-uplift.
> >
> > Scott M Haan  P.E.
> > Plan Review Engineer
> > Building Safety Division http://www.muni.org/building,
> > Development Services Department,
> > Municipality of Anchorage
> > phone: 907-343-8183   fax: 907-249-7399
> > mailto:haansm(--nospam--at)ci.anchorage.ak.us
> >
> > > -----Original Message-----
> > > From: David B Merrick [SMTP:mrkgp(--nospam--at)pacbell.net]
> > > Sent: Friday, March 30, 2001 2:19 AM
> > > To:   seaint(--nospam--at)seaint.org
> > > Subject:      Re: Wood Shear Walls
> > >
> > > recall my quest of last week and I concluded with the equation that
> > > represents
> > > the chart in the IBC2000
> > >
> > > Co = 100/(B(1-3A)+3A)
> > >
> > > Reference table 2305.3.7.2
> > >
> > > Let A= the ratio of maximum opening height to the wall height.
> > > That's the value across the top of the chart.
> > >
> > > Let B= percent of full height sheathing to full length of wall.
> > > That's the left column on chart.
> > >
> > >
> > >
> > > Jason Kilgore wrote:
> > >
> > > > Ok, the subject is back.
> > > >
> > > > I recently received a 3-story wood project.  It's a teen shelter
> shaped
> > > like
> > > > a house, 50'x60'.
> > > >
> > > > The problem is that the architect is apparently into the
> "swiss-cheese"
> > > > look.  I can't find a single patch of wall more than 3ft wide
> extending
> > > from
> > > > the foundation to the roof.
> > > > None of the windows and doors line up.  Walls move in and out of
> plane.
> > > >
> > > > Anyone know of a good reference for designing such a beast?
> > > >
> > > > The walls will have to be designed as big shear walls with holes.
> Is
> > > there
> > > > a reference for nailing patterns around the openings?  Does the UBC
> > > contain
> > > > this information.
> > > >
> > > > Speaking of the UBC, the city where this is located is still using
> the
> > > 1991
> > > > UBC.
> > > >
> > > > ----
> > > > Jason W. Kilgore, P.E.
> > > > Leigh & O'Kane, L.L.C.
> > > > jkilgore(--nospam--at)leok.com
> > > > (816) 444-3144
> > > >
> > >
> > >
> > >
> >
> 
>