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Re: Rigid vs Flexible residential diaphragm discussion

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In a message dated 8/10/99 8:52:07 AM Pacific Daylight Time, 
chrisw(--nospam--at)skypoint.com writes:

<< Why the problems 
 defining diaphragm action in residential construction? It just seems like 
 someone isn't minding the store. >>
Chris,
There are many people involved with various different agenda's. By agenda's I 
am refering to the importance of Vision 2000 to the engineers in SEA, the 
work being done by CUREe-Caltech, that work being done by committees of ASCE 
and much more. To add to this, there is the politics of the lobby for 
contractors and architects that really muddy the playing field.
I think that structurals have taken the bull by the horns realizing that the 
only thing they can do without getting gored is to address methodology issues 
and hope that the education and training of the field inspectors and 
contractors building structural systems gains support in time from the 
various lobby's.
The issue of testing is a bit more complicated in my opinion because of the 
shear number of configurations and variables. I think that this is the reason 
that the code became so restrictive - the seismology committee expected every 
material to fit within the guidlines of a neat, but generic deisgn 
methodology. This has proven to be inadequate and the complexity of the task 
at hand is just now being realized.

As I stated in past posts, residential wood structures have historically been 
considered outside of the scope of the seismology committee concerns as the 
risk was always considered low. I personally believe that the escalating 
value of homes and the rise in construction materials and labor has forced 
the engineering community to take a different look at residential structures 
to reduce the liabitlity to the public and to the insurance / government from 
damage. Therefore, wood structures, if possible, should be able to be 
designed to some level of predictable performance. This, however, has proven 
to be a very difficult if unrealistic task without consideration for 
construction quality.

"Another fine mess we've gotten into, Oli"

Dennis