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RE: History of conventional wood framing- update -Reply

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** High Priority **

The purpose of the building code provisions is to provide life safety
during catastrophic events such as fire, earthquakes, etc.  It is not
intended to prevent damage to the structure, but to provide a reasonably
safe structure which when in a condition of near failure provides
advanced warning in the form of cracks, extreme deflections, and sound
(creaks, and groans), to warn the occupants.

In my experience at observing many residences which sustained damage
during the Northridge earthquake I found only one two story residence
which suffered severe damage and was in jeopardy of collapse.  The
reason for the problem appeared to be that the structure was sitting on
20' to 25' of compacted fill which compacted  another 1 to 2% effectively
settling the property a few inches.

The residences which I observed were anywhere from Thousand Oaks
down to Hollywood and ranged in age from 1 to 75  years.  The damage
sustained appeared to be in direct relationship to ground motion which the
structure was subjected.  I viewed construction which appeared to be
per code and also non complying conditions.  Quite frankly there did not
appear to be any major inadequacies as far a protecting the occupants
from loss of life.  There are many factors to consider in the final analysis
of damage to these structures with the most prevalent factor being that
of the soils. There did appear to be more damage associated with the non
complying structures, however not the same degree as the effect the
soils had on the structure.

My opinion is that the municipalities implementing the building codes that
the residences were built under, the architects and/or engineers who
designed them, and the contractors who built them, should all feel proud
of a job well done in protecting the residences of these structures.

Dave Puskas
BSW International