This is turning into an interesting thread because the issues are loaded
with a great deal of confusion and uncertainty over the intent of the code.
I don't mean this to be a plug for the new reference library (Cybrary) I am
trying to create, but I would like to take the information we come up with
and creating some kind of flow chart that could be used as reference in the
future for those who raise similar questions and need fast answers.
You don't need to do any more than resolve the issue in the thread providing
as much exact code reference to the supporting information as possible. Once
we have narrowed down an answer, I will create a flow chart that tracks each
section of code for wind and seismic to see where they finally meet up.
Dennis S. Wish, PE
> -----Original Message-----
> From: Sherman, William [mailto:ShermanWC(--nospam--at)cdm.com]
> Sent: Wednesday, May 16, 2001 1:08 PM
> To: 'seaint(--nospam--at)seaint.org'
> Subject: RE: Wood diaphragm allowables per IBC
> Bill Polhemus wrote: "IIRC UBC 1997 and SBC 1999 do not allow the increase
> for wind design."
> Actually SBC 1999 Section 2313.2.4 does allow the 40% increase - this is
> where I first encountered it. The SBC 1999 Commentary refers to the change
> in load factors for wood, but it is not clear what load factors they are
> referring to.
> Eric Ober wrote: "The factor of safety for wind and seismic loading are
> different. I believe that the FS for wind is 2.0 while that for seismic is
> The SBC Commentary does note that this 1.4 factor is based on a "change in
> load factors for wood structural panels from 2.8 to 2.0 (2.8/2.0 = 1.4)".
> But what load factors / factors of safety are these referring to,
> i.e. where
> are they defined and how are they applied to allowable stresses?
> Are they in
> addition to the 1/3 allowable stress increase?
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