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RE: History of conventional wood framing- update -Reply

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David,
I agree with you when speaking historically. However, with the rise of
real-estate values in the last twenty years, it becomes more important to
provide some revision to the code that would help to minimize or mitigate
damage better than it has in the past.
I repaired a two story wood frame structure in Sylmar which was heavily
damaged. It is true that the structure maintained it's structural integrity
long enough to safely remove the occupants, but the cost to repair was more
than the home was worth.
The cause of damage was the fact that the stucco lath (the only shear
element on the home) was not properly connected to the studs. From all
indication, the stucco appeared undamaged, but when I grabbed hold of the
drip scree at the bottom of the wall, I could pull it away from the studs
for almost the full two stories. The racking damage that was caused by lack
of appropriate shear resistance caused many of the interior partitions to
absorb the force - tearing them from their shotpinned connection to the slab
and causing the walls to walk as much as six inches out of plumb.
This was one of six homes that I repaired in this area which exhibited
similar damage. All of the homes were located between Simi Valley and
Sylmar.

A search of the SEAint archives will reveal my staunch stand on conventional
wood framing as I am convinced that there is a great deal of abuse by
developers who are willing to take whatever shortcut is necessary to
increase their profit margin on the project.

I think it is important that we as professionals understand our limits of
liability to life safety protection, but that we also provide services that
are cognizant of the extent of damage that occurs when designing to minimum
code standards. The final cost is shared by us all in our insurance premiums
(if insurance is available after - as we saw when companies closed their
doors after the hit they took from Northridge).

Designing to minimum standards is not enough to protect the financial lose
that many homeowners incurred.  I personally feel that we have to extend our
professional responsibility to consider the effects of damage and offer our
clients a performance based contract - leaving the final decision to those
who must pay for it in the end.
To protect those who purchase homes direct from a developer, we need to
educate the public and inform them of the standard under which the home was
designed and constructed - i.e., minimum or greater than minimum
construction/design standards. Then we need to educate the buyers so that
they understand both what this means AND what they may need to invest to
improve the structures performance. This provides the purchaser the freedom
of choice by providing them the knowledge that they normally take for
granted.
Finally, we as a professional community, need to help educate the
construction industry and help establish higher standards which require
those who construct structural elements to be licensed or certified as
having the knowledge and ability to perform this type of work (i.e.,
licensing framers).

Dennis S. Wish PE

-----Original Message-----
From: David Puskas [mailto:david_puskas(--nospam--at)bswintl.com]
Sent: Tuesday, February 23, 1999 8:42 AM
To: seaint(--nospam--at)seaint.org
Subject: RE: History of conventional wood framing- update -Reply


** 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