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RSDG: Residential Structural Design Guide: 2000 Edition

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I received a copy of the RSDG published by the U.S. Department of Housing
and Urban Development Office of Policy Development and Research. The RSDG
was prepared for HUD and NAHB "Housing Affordability Through Design
Efficiency Program" by National Association of Home Builders.
Although the publication was sent to me as a member of the Research
Coordination Group, I had very little to do with this other than persistent
e-mails and concerns to NAHB. The credit for this publication is deserved by
Jay H. Crandell, P.E. who is the Director, Structural & Materials Division.
Contributors to this document include APA (nice work John Rose), Wood Truss
Council of America (nice work Kirk Grundahl)and the American Wood Council
(thanks Brad Douglas) as well as others. I might add that I know of only a
couple individuals who are associated with SEA and on the Advisory list but
not mentioned in the manual. If my memory is correct, these include Kelly
Cobeen, Frank McClure and myself - sorry if I missed anyone else.
NOTE: As far as I know, these individuals were not representing SEA in the
creation of this publication which demonstrates the tremendous chasm that
exists between those in the housing industry and code makers. I think
Seismology Committee would have had much to learn from this publication that
may have helped shape the design methods for wood structures.

I recommend this publication for anyone involved in residential structural
design including single and multi-family buildings of wood, masonry or
concrete. It does not attempt to solve the problems that exist in the code,
but alerts the engineer and architect of the intent to improve the quality
of home construction through a government program called Partnership for
Advancing Technology in Housing or PATH. You can learn more of the PATH
program on their website at www.pathnet.org.

The document covers (from the table of content) the following Chapters:
Basics of Residential Construction
Structural Design Concepts
Design Loads for Residential Buildings
Design of Foundations
Design of Wood Framing
Lateral Resistance to Wind and Earthquakes (including flexible / rigid
analysis AND ASD/LRFD with some nice examples)
Connections

The document clearly identifies many of the complexities of viewing a wood
framed building as a structural system with regards to redundancies. It also
questions the need for more complicated codes and suggests a strong need for
simplified methodologies.

The two shortcomings that I see in the manual is that it assumes a posture
of life safety and does not place enough emphasis on performance and cost of
repair. Second, the document fails to point out the potential negative
effect of a static conventional construction standards and an expanding
complex code method. In this regard it shows how prescriptive methods can be
used but fails to compare the performance benefit or even acknowledge the
below minimum engineered standard of conventional construction.

Admittedly, the book admits to a great deal of ignorance by the
architectural and engineering community as to the performance of residential
structures while trying to design code methods.

While we were discussing and arguing the problems with the current UBC, NAHB
was doing something about it. I commend them for their work on this
excellent document. I would recommend that the document be used as a
foundation for the work that the Wood Committee needs to do so as to place
code and policy making issues into proper perspective as seen by the rest of
the building Partners. There is a point where we forget the needs of the
public in search for a perfect scientific solution which may never exist.
SEA needs to put their feet back on the ground and start looking at single
and multi-family dwellings in a practical light - balancing life safety,
good performance and economics.

Finally, as I mentioned before, there is a major discontinuity between SEA
and other organizations working for the design and construction of
affordable housing in this country. It's SEA's responsibility to bridge this
gap and join these organizations in the work they are doing. Without total
cooperation between professional organizations we remain a series of
disconnected elements unproductively working in different directions. This
is a very important document, in my opinion, as it is the first attempt to
bring the building industry together with the professionals (architects and
engineers). There is still a long way to go, but this is a hell of a good
start.

Copies may be ordered through:
HUD User @ 1-800-245-2691 (www.huduser.org) or from the NAHB Research Center
at 1-800-638-8556 (www.nahbrc.org).

Document: Residential Structural Design Guide, 2000 Edition


Regards,
Dennis S. Wish, PE
Structural Engineering Consultant
structures(--nospam--at)engineer.com <mailto:structures(--nospam--at)engineer.com>
(208) 361-5447 E-Fax