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RE: schoo l- roof snow 125 psf - top hung joist hangers over two layers existing gypsum wall board

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Assuming the gypboard to be 2 layers of 5/8" (1.25" ) with the edge
terminating at the face of the header member would allow for 1.25" of
deformation due to crushing of the gypsum board (assuming that crushing
could take place).  This would correspond to a flange rotation of about 27
degrees, thereby reducing the hanger capacity.  It has been my experience
that regions with snow loads of 125 psf really do experience those loads,
and I would never allow this type of connection.  It is the designers
requirement to verify the header capacity according Simpson, and commonly
accepted engineering practice.

Bill S. Marczewski

-----Original Message-----
From: Paul Feather [mailto:pfeather(--nospam--at)san.rr.com]
Sent: Friday, March 09, 2001 1:31 PM
To: seaint(--nospam--at)seaint.org
Subject: Re: schoo l- roof snow 125 psf - top hung joist hangers over
two layers existing gypsum wall board


Simpson performed tests of their hangers for application over plywood
sheathing, and have a data sheet to indicate the allowable reduced values.

Hangers over drywall would be out of the question.  IMO the drywall will
deform under the hanger flange and create unacceptable bending stresses and
potential fracture of the hanger.

A detail such as you describe would never be allowed out of our office.

Paul Feather
----- Original Message -----
From: "Haan, Scott M." <HaanSM(--nospam--at)ci.anchorage.ak.us>
To: "Se-Practice List (E-mail)" <se-practice(--nospam--at)polhemus.cc>; "Seaint list
(E-mail)" <seaint(--nospam--at)seaint.org>; "IBC list (E-mail)" <IBC_IRC(--nospam--at)listbot.com>;
"Aec-Residential List (E-mail)" <aec-residential(--nospam--at)polhemus.cc>; "Jim Mattison
(E-mail)" <jmattison(--nospam--at)strongtie.com>
Sent: Friday, March 09, 2001 8:54 AM
Subject: schoo l- roof snow 125 psf - top hung joist hangers over two layers
existing gypsum wall board


> I am a plan checker looking at plans for a school alteration.  The roof
snow
> load is 125 psf at the particular location. The plans have a detail where
> new roof wood joists are being hung off an existing wall with Simpson top
> hung joist hangers butted against 2 layers of existing gypsum wall board.
>
> The engineer says there is an existing similar condition at the school
that
> is doing fine.  I told the architect just because it was done wrong before
> does not mean I am going to issue a permit for an incorrect new
application.
> The reason they are getting the permit is the roof collapsed in a
different
> portion of the building.
>
>
> Does Simpson have any guidelines on this type of application?   Has anyone
> had problems with this type of application?
>
>
> Scott M Haan  P.E.
> Plan Review Engineer
> Building Safety Division http://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
>
>
>