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Re: Effects of the New Code on Wood structures - good orbad?????-Part 1

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I believe the diaphragm rigidity analysis requirement in the code was never 
intended for the type of residential construction that Dennis and others, 
including myself, are involved with. I, personally, will not perform such an 
analysis and will continue to design my single family residences the old 
fashion way. I will use the simplified static method, if I have too, which 
does not require drift calculations as I understand (I still have not had the 
chance to read the '97 UBC completely.)

My reasons are:
1. The City of LA does not allow more than 15% cantilever nor the principle 
of rotation in a wood diaphragm. This was implemented after the Northridge 
Earthquake based on the findings of the Joint Task Force of SEAOSC and the 
City of LA I guess they found out that the rotation principle in a wood 
diaphragm that had been so widely used in the design of older apartment 
buildings with an open parking side was a DISASTER (Northridge Meadowes 
Apartments and others) and did not work!

2. The fact that we still have not heard any "OFFICIAL" response to the 
numerous questions raised on this list regarding this issue, other than 
personal, defensive ones, tells me that the authors or co-authors of the code 
do not know the answers because it was never intended for the type of 
residential construction we are dealing with.

3. The presence of the conventional "wood" framing section in the code tells 
me that sophisticated analysis is not intended for wood framed construction. 
Even a rectangular, box-shaped building framed using the prescriptive 
(conventional) method will fail miserably when calculated using chapter 16 of 
UBC.

4. A good engineering judgment and a well connected structure is far more 
better than a sophisticated design that can never be implemented in the field 
with the type of construction and constructors we are dealing with.

Oshin Tosounian, S.E.<====  See The S.E. I am proud of it ( in reply to 
Engineers-Low Profile:)