From: "Dennis S. Wish" <dennis.wish(--nospam--at)gte.net>
Date: Mon, 22 May 2000 16:32:20 -0700
Please excuse my last posting - I failed to read it through enough times and
correct my spelling word choice. Here is, I hope, an improved version.
While I tend to agree wholeheartedly with your comments, I believe that the
non-life-threatening damage caused to residential structures after recent
hurricanes, tornadoes and earthquakes may have been greatly reduced if
conventional framing standards were raised and designers and framers had a
better understanding of Lateral Force Resisting Systems (LFRS).
Historically, NAHB preferred that engineers NOT be involved in residential
construction. Considering the current code issues, I might agree with them.
However, NAHB, I think, demonstrates that the issues related to damage were
quality of construction and lack of appropriate code enforcement rather than
failure of the code methods to protect lives. Still, NAHB believes that the
minimum standard is life safety and nothing beyond. This would also explain
why there is no pressing need in the document to improve the conventional
construction section of codes. Statistically, conventional construction has
protected life safety.
The economic climate in this country has changed significantly since the
early seventies. The financial burden suffered by even moderately damaged
homes has had a dramatic affect reaching beyond the home owner and into the
pockets of the tax payer. The damaged incurred from hurricanes, tornadoes
and earthquakes in the last twelve years has shown the burden on community
property values where homes exist that are not repaired, insurance companies
bailing out or premiums skyrocketing. We all pay the price and the dollar
does not represent the same proportions of labor and materials as it did in
the Forties or Fifties.
My point is that there is room for engineers to be involved. Raising the
minimum standard of conventional construction to the baseline of an
engineered structure will have a significant financial affect on the
building industry. The incentive for builders to make performance choices
motivated solely on profit margins would reduce and performance our improve.
California home owners learned from developing mitigation methods that a
$2500.00 "investment" to strengthen cripple walls and anchor sole plates to
foundations of homes built prior to 1969 could save as much as 10 times this
cost to bring a failed home back on to its foundation and repair
consequential damages. This assumes the "deductible" portion of the
insurance coverage and still does not consider the savings to the community
in damage mitigation, financial loss to the insurance industry and federal
government emergency plans.
The homes which are most affected by these code differentials are owned by
those who are least likely to afford to repair them. A survey of homeowners
in Riverside County California a few years ago (published in the Desert Sun
Newspaper) demonstrated that the majority of homeowners lived in an area of
greatest risk in the state (proximity to the San Andreas Fault) and had
little or no earthquake coverage. The demographics were primarily families
of lower to middle income, who could not afford the coverage let alone the
15% deductible. When homes sit unrepaired, the financial burden weighs upon
the entire community. Property values reduce and the pride of community
begins to deteriorate.
None of these points are life-safety issues. This is the problem with the
document - it only attempts to be a "companion" to the code rather than to
suggest much needed compromises. Yet there exists a wide gap between NAHB
who believes conventional construction is a sufficient minimum standard and
SEA who believes that only more complicated codes (pure science?) is the
answer. Neither side is willing to meet a compromise.
As an engineer, I am biased. I think that I am open minded enough to
recognize the dichotomy that exists between the two sides and passionate
enough to stand by the homeowner and consider his burden.
I don't think it is time for SEA to step out of residential design UNLESS
engineers are able to step into NAHB and raise the minimum level of
compliance for conventional construction. Not only does this include the
obvious code change, but it includes mandatory measures to insure
appropriate demonstration of skills by those who are building (and
designing) structural systems. This is another long issue, but it is fair to
say that the majority of designers and builders of conventionally
constructed homes have never the read prescriptive design methodology.
Once this is accomplished, then I would agree with your assessment. The
problem now, from our end, is that our Seismology Committee members do not
understand, are not willing to compromise, or they simply not interested in
single and multi-family structures. They have no responsibility for the
concerns of the public or the effect their actions may have on the decline
of construction quality. Maybe this is their acceptable level of risk.
NAHB is not ready to run free, but they have taken the Bull by the horns and
have opened a door of opportunity for engineers to become a part of the real
Dennis S. Wish, PE