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Re: Discontinuous shear wall load path

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Sharad

The section you refer to is under 1630.8 Overturning
This section was developed from the SEAOC Blue Book section 105.8.  The
commentary for section 105.8 states "elements used to redistribute or
transfer the effects of overturning moments should be designed ..."

This is a stiffness and strength requirement to prevent local failure or
collapse of the redistribution elements.

All that being said,  I would apply the amplified requirements as follows:

"Hold down device and post," No

" beam supporting hold down device, beam connection to adjacent wall, post
and footing supporting this beam,"
Yes with the exception that the requirements do not apply to the foundation
soil interface (per SEAOC Blue Book).

" floor diaphragm (magnify shear load to check strength level of
diaphragm?), and finally...the adjacent shear walls (since,
technically, they are the "supports" for the lateral load from the above,
offset, shear wall?"
No, the shear resistance is not the effect of overturning moments, it is the
cause.  Adequate resistance / transfer for the calculated shear loads must
be provided, but do not require amplification.

Paul Feather
----- Original Message -----
From: "Sharad T. Patel" <stpatel(--nospam--at)vcaengineers.net>
To: <seaint(--nospam--at)seaint.org>
Sent: Thursday, May 24, 2001 2:01 PM
Subject: Discontinuous shear wall load path


> In accordance with UBC 1630.8.2, "elements" supporting discontinuous
systems
> shall have the design strength to resist the combination loads resulting
> from the special seismic load combinations of Section 1612.4, with the
> exception that Em need not exceed the maximum force that can be
transferred
> to the element by the lateral force resisting system.
>
> Now, assuming that the "maximum force that can be transferred to the
system"
> is adequately determined, my question is:  What constitutes "elements"?
> Specifically:
>
> Assume that in a wood framed structure, there is an interior second floor
> shear wall which occurs over floor joists that are perpendicular to the
> wall.  There is no stacking wall below and the nearest shear wall is
several
> feet away (load is transferred via the diaphragm to adjacent walls).  Also
> assume that there are overturning loads and resisting devices at each end
of
> the wall.  So...which element(s) need to be designed for the special load
> combinations?
>
> Here is a list of the elements:  >
>
> Sharad T. Patel, S.E.
> VCA Engineers
> 295 N. Rampart Street, Suite A
> Orange, CA 92868
> Phone:  (714) 978 - 9780 ext. 120
> Fax:  (714) 978 - 9926
>
>
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