] [Thread] [Date] [Author]

[utej(--nospam--at)attbi.com]

The 2000 IBC section 2306 references the NDS for ASD 
design and I do not see any deletions or substitutions 
similar to the '97 UBC section 2316.2.  The '97 UBC 
section 2316.2 states that "When using Section 
1612.3.2....the 1/3 increase shall not be used 
concurrently with the Load Duration Factor, CD."  It 
also revises the NDS table 2.3.2 to use CD=1.33 for 
earthquake and 1.6 for wind for members and nailed and 
bolted connections exhibiting Mode III or IV behavior.

I could not find these deletions and substitutions in 
the 2000 IBC and in IBC section 1605.3.1.1 it states 
that "Increases in allowable stresses specified in the 
appropriate materials section of this code....shall not 
be used with the load combinations of 1605.3.1 except 
that a duration of load increase shall be permitted in 
accordance with Chapter 23."  There is no statements 
that I could find in the 2000 IBC that stated that one 
shall not take the 1.33 or 1.6 load duration factor 
increase in conjunction with the 1.33 stress increase 
such as the '97 UBC section 2316.2 states.

Are these purposeful omissions and modification of 
design requirements in the 2000 IBC compared to the 1997 
UBC or perhaps an oversight? 

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