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Questions about Residential design and 1997 UBC

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Dennis, here are some brief responses from my point of view...

Rw and residential Construction:  I use Rw of 8, unless the
configuration is without much redundancy.

Rigid Diaphragm and shearwall stiffness analysis in residential:  Your
prospects of higher fees for a more complex analysis may be too
optimistic.  Until the building departments enforce uniformity among
engineers in the extent of the analysis done, there will always be
someone skirting by with limited effort for a cheap fee.  Often times, a
plan checker is primarily looking for a engineer's stamp indicating
someone is taking responsibility than worrying about whether the
diaphragm is accurately modeled.  Sad but true.

Prescriptive Residential Construction vs. new design standards:  
Your statement, "Are we putting the cart before the horse by creating
more regulations to prevent construction quality control problems rather
than attempting to educate the construction industry...."
It is unfortunate for us (engineers) that when poor workmanship is to
blame, we pay the price of more arbitrary regulations and a penalty of
higher construction costs applied to those who are quality
constructors.  But the regulatory agencies have tried to enforce wide
spread field problems before with little success.  I think it is the
opinion of many code writers that it is easier to expect us engineers to
follow a building code than the field workers to follow the plans.

Perforated Shearwall:
I must wait and see the final report and test data, however I am
interested in the approach.  In this day in age, the code seems to
become more and more complex and placing quite a burden on engineers to
analyze a simple house.  If the "empirical" approach can be shown to be
conservative based on experience and testing, then it falls into a
similar category as conventional construction.  Similarly, diaphragm
values were based on tests, and then an equation was developed to match
the results.  If done properly, there's nothing wrong with this approach
to developing new products.

John Lawson SE
Kramer & Associates Structural Engineers, Inc.
jlawson(--nospam--at)kramerinc.com