George is correct - the 1997 UBC values represent changes to the previous
prescriptive methods based on the values of APA's work. The testing and work
done by Professor Reynaud Serrette identified differences in performance of
sheathed walls. They identified a potential failure of the wall in shearing
of the screws caused by the stiffness of the studs. To provide better
performance, Professor Serrette reduced the stiffness of the studs - from 16
or 18-gauge to 20-gauge and tested the walls to reach their realistic
failure due to stud buckling.
To the best of my knowledge, APA does not agree with the reduction in values
that was adopted and published in the 97 UBC. I do not know what further
testing has been done by APA that may increase the values in future code
cycles and possibly John Rose may enlighten us.
Serrette has also perform cyclic testing of metal stud walls using the test
provisions established by SEAOSC and, I believe, these are represented in
the 97 UBC.
There is also an example of a multi-story residential design in the ICBO
Seismic Design Manual Volume II that you may reference.
The evolution of the work done by Professor Serrette is available in the
LGSEA newsletters which are available to the professional community for free
download. You may review the newsletters in PDF format at
You can also find more links to Cold-Form Steel on the Reference pages of
the Structuralist.Net Professional page - which includes available reference
documents from National Steel Alliance, HUD, AISI and other sources. This is
Dennis S. Wish, PE
The Structuralist Administrator for:
(208) 361-5447 E-Fax
ICQ # 95561393
From: George Richards, P.E. [mailto:george(--nospam--at)BORM.com]
Sent: Monday, January 29, 2001 9:36 AM
Subject: RE: Plywood & Mtl. Studs
Check out the 1997 UBC. The values are now in the code.
George Richards, P.E.
From: ASLCSE(--nospam--at)aol.com [mailto:ASLCSE(--nospam--at)aol.com]
Sent: Monday, January 29, 2001 8:51 AM
Subject: Plywood & Mtl. Studs
I am sure there are "approved" values for plywood shear panels screwed onto
metal studs. Can anyone refer me to those values (incl. L.A. City).
Anotnio S. "Tony" Luisoni
phone/fax (818) 363-6531