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Re: Question for wood panel at SEAOC Convention

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Shafat did not ask your question.  There were many questions handed in,
and many that Shafat had got by e-mail.  There was only time for a few

However, from the discussion that was heard, I can tell you that the
panel would be split on their response to your question.  

John Coil and Doug Thompson were the main ones trying to tell us that
rigid diaphragm analysis for wood structures was a good thing.  The DSA
representative (I can't remember his name right now) came right out and
said that as of this minute, the DSA office he represents (San Diego I
think) is not requiring the rigid diaphragm analysis.  And you have to
read around the edges to interpret this response to mean that the San
Diego section of DSA does not at this time believe that the rigid
diaphragm analysis is warranted.  

Dennis seemed to focus mostly on the gap between the prescriptive
conventional framing provisions of the Code and the Engineered building
section of the Code.  Andrew Alderman of the City of Los Angeles
Department of Building and Safety was in the audience and indicated that
in the future, the City of LA would not necessarily require a rigid
diaphragm analysis of light wood framed buildings.

The discussion was much the same as has been had here on the list.  No
new ground really.  There was an indication that there was a problem
with the way the code is currently written by ALL members of the panel,
and that there was some urgency to resolving the problems.  

I hope a special committee will be formed, and direction from that
committee will the forthcoming in the not to distant future.

Again, ALL panel members agreed that changes need to be made.  There was
not agreement on the extent of the problems and not much discussion at
all about what specifically should be changed.

We shall see how it will all come out.  I am not sure who is in charge
of this whole thing.  I hope it just doesn't die after this first


Mark T. Swingle" wrote:
> Dear Shafat,
> Following are two questions for this morning's
> wood panel at the
> SEAOC Convention.  Please present them on my
> behalf if there is
> sufficient time.
> Thanks,
> Mark Swingle, SE    Oakland, CA
> -----------------------------------
> Consider the following proposed change to the 1997
> UBC:
> Add a new 4th paragraph to Section 1630.6
> "Horizontal Distribution
> of Shear" as follows:
> "Buildings whose primary lateral-force-resisting
> system consists
> of wood structural panel diaphragms and shear
> walls may have the
> prescribed story shears distributed to the shear
> walls based upon
> tributary mass principles.  In addition,
> redundancy, story drift,
> and horizontal torsion need not be considered."
> Question 1:  Would you be in favor of such a
> change, if there were
> a mechanism for its adoption?
> Question 2:  If your answer is "no" to question 1,
> can you imagine
> a building which would pose a life-safety threat
> to its occupants
> (when designed according to the above code
> change), due to
> redistribution of forces by the diaphragm?  Please
> describe in
> sufficient detail to support your answer.