Subject: RE: Wood Fire Rated Wall Assembly F'c reduction
From: "Mark E. Deardorff" <MarkD(--nospam--at)DandDEng.com>
Date: Tue, 4 Jan 2000 13:17:46 -0800
temperature is for serivce conditions, however, and would not apply to a fire
situation. The service condition of a fire wall is a non-fire condition.
Certainly, in the event of a fire, normal live load conditions would not apply.
In addition, the temperature levels wouldn't be very high until well after the
transient exit loading had ceased.
-----Original Message----- From: Sam Chang
[mailto:szchang(--nospam--at)mail.arc.nasa.gov] Sent: Tuesday, January 04, 2000
11:19 AM To: seaint(--nospam--at)seaint.org Cc: Jeff Albert
<jeffa(--nospam--at)kpff.com>; Bart Needham Subject: Re: Wood Fire Rated
Wall Assembly F'c reduction
Very interesting point about
the 78% reduction for 1-hour rated wall.
However, I can't
find the exact reduction in NDS. The closest thing I get
NDS Table 2.3.4 -Temperature Factor, Ct for bending can be
adjusted to 1.0, 0.8, 0.7 when T <100, <125, <150 degrees
Is the requirement hidden in NDS somewhere
At 05:30 PM 1/3/00 -0800, you wrote:
Jeff Albert wrote:
The Uniform Building Code
requires that the design stress for studs be reduced to 78 percent of
allowable F'c for all 1-hour rated walls. This appears in a footnote
#18 for Table 7-B
This requirement is also in the
NDS, although the 78 percent may be different. .
First, my question is whether other engineers in California,
and other UBC states are applying this provision to their wood
Yes, following the requirments found in the
how have building officials responded / reacted to designs not using the
reduction. I will note that it is my belief that a reduction is
unnecessary, and that designs done without using the reduced values are
It has always been my understanding that, depending
on moisture content, wood is stronger at colder temperatures, and weaker
at higher temperatures. I am not sure on what your belief is based.