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Re: wood frame bldg deformation and windows

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I need to jump in here.  Residential windows do not fall under the
requirements of 1633.2.4.2.  1633.2.4.2 is intended for rigid panel elements
such as precast cladding or prefabricated cladding panels and the
connections of these elements at different floor lines having the capacity
to accommodate seismic drift without failure of the panel support
connections or the panels themselves.  The references that invoke the
requirements for 1633.2.4.2 are contained in section 1632.2 "For applicable
forces and Component Response Modification Factors in connectors for
exterior panels and diaphragms, refer to Sections 1633.2.4, 1633.2.8, and
1633.2.9"  Residential windows can hardly be considered an exterior panel or
diaphragm.  In fact having a window means there is a hole in the exterior
panel or diaphragm.

The intent of these provisions was to ensure that large cladding elements do
not fall off the structure and endanger the public during a seismic event.
Additionally these provisions are intended to prevent rigid exterior panels
from binding and acting as unintended shear resisting elements or failing
from unintended load transfer when supported by more flexible frame systems.
Read the other five requirements under 1633.2.4.2 and you will realize that
applying these requirements to a residential window in a wood framed
structure is completely incorrect and taking pieces of the code out of
context.

Paul Feather


----- Original Message -----
From: "Regis King" <steelfishes(--nospam--at)hotmail.com>
To: <seaint(--nospam--at)seaint.org>
Sent: Tuesday, January 08, 2002 4:42 PM
Subject: Re: wood frame bldg deformation and windows


> You think non-conformance with the building code is a "non-issue"?  Seems
a
> little cavalier to me.  I'm sure the difference between 2x and 3x plates
is
> also a bit of a "non-issue", but you won't soon forget the experience of
> inadvertantly specifying 2x plates in a high-seismic area, believe me.
>
> Regis
>
>
> >From: "Conrad Guymon" <conrad(--nospam--at)karren.com>
> >Reply-To: <seaint(--nospam--at)seaint.org>
> >To: <seaint(--nospam--at)seaint.org>
> >Subject: Re: wood frame bldg deformation and windows
> >Date: Tue, 8 Jan 2002 15:35:49 -0700
> >
> >Are the windows the full story height?   If they are not, would it be
> >appropriate to use (window height/story height)*Delta M to obtain the
drift
> >differential between the bottom and top of the window?  Would this reduce
> >the value to something you could handle?  Do you have drift calculations
on
> >the wood shear walls?
> >
> >It sure seems like this is a non-issue.
> >
> >That's my two cents worth.
> >
> >Conrad
> >----- Original Message -----
> >From: "regis king" <steelfishez(--nospam--at)hotmail.com>
> >To: <seaint(--nospam--at)seaint.org>
> >Sent: Tuesday, January 08, 2002 4:42 PM
> >Subject: wood frame bldg deformation and windows
> >
> >
> > > Have any of the list members had to address the effect of seismic
drift
> >on
> > > the windows of a wood frame apartment building? I am not referring to
a
> > > large retail window wall system, but rather typical residential
windows.
> >UBC
> > > 1633.2.4.2 includes "elements that are attached to or enclose the
> >exterior".
> > > Most vinyl windows are attached with vinyl flanges on the outside. I
> >believe
> > > that the vinyl itself has some inherent flexibility, but this is
> >obviously
> > > difficult to quantify. I know that slotted holes can be used. However,
> >the
> > > slotted holes are not likely long enough to meet the code requirements
> >if
> >a
> > > residential window is included in UBC 1633.2.4.2. Note that this same
> > > section requires the greater of Delta M or 0.5 inches. The slot would
> >have
> > > to be 1" + the width of the screw to qualify. I have never addressed
> >this
> > > issue and it has been brought up on one of my jobs.
> > >
> > > Thanks in advance for any help.
> > >
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