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Re: Wood Fire Rated Wall Assembly F'c reduction

[Subject Prev][Subject Next][Thread Prev][Thread Next] 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 is:

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 respectively.

Is the requirement hidden in NDS somewhere else?



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 design.

Yes, following the requirments found in the NDS.

Also, 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 safe.

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.

Bart Needham