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Re: History of conventional wood framing- update

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I agree with the first part and disagree with the very last part.

The fact is that unless there are some very unusual circumstances or
some very specific well known deficiencies present, the low rise wood
frame structure will not pose a life-safety risk in an earthquake.  We
only have to look at Northridge to see this.

I am at a loss to explain all these supposed "lessons learned" from the
Northridge earthquake.  As far as our Code being deficient from a
life-safety prospective, there were only a few "lessons learned".  The
behavior of the tucked under garage supported on small diameter steel
columns, steel moment connection problems, and perhaps some problems
with tilt-up wall to roof connections.  

I observed HUNDREDS of damaged 1960's and earlier, low rise, wood
framed, plaster and drywall type buildings.  From a Life-safety
perspective, they ALL did fine.  I know one house slid down a hill, and
a few others had some problems, but when you consider the MILLIONS of
older wood framed structures that performed adequately from a life
safety perspective, I was SHOCKED when the City of LA and now the
upcoming UBC (to a lessor degree though) made major changes is the
seismic design requirements for these buildings.  If you pull out the
1997 UBC and use it to determine the adequacy of a three story wood and
plaster structure, it wood fail miserably.  Plaster and gypboard are now
considered worthless when resisting seismic forces.  Yet, it seems to me
that these materials seemed to provide basic life safety for their


I know this is an unpopular point of view, and I have wanted to post
something about this for a long time.  These structures do not do very
badly at limiting damage either, although I do acknowledge that most of
these building required a lot or repair.  However, very few actually
needed to be torn down and replaced.

So I for one do not buy into the popular notion that drywall and plaster
cannot be used effectively to provide a basic life-safety level of
protection to the occupants of low rise wood framed buildings.

There, I said it.  :)


SDGSE(--nospam--at) wrote:

> I totally agree.
> Research engineers and code writers in their enclosed environment rarely see
> the real world of wood framed houses. They must think that the framer on the
> field is going to spend the time to reproduce their perfectly done model in
> the lab.
> This is how I see it:
> Research is done in the lab.
> Research results are interpreted into a complicated mathematical model.
> Complicated mathematical equations are written to arrive at the same results.
> Simplified equations are written to sell to code writers.
> Code is written.
> Engineers learn it and struggle to implement it in their "architecturally
> dreamed structural nightmares."
> Plan checkers insist on the nitty-gritty in their comfortable chairs.
> The framer doesn't look at it or ignores it and frame it the "he's been doing
> it for ? years and nobody said anything" way.
> The building inspector may or may not see it.
> The engineer may or may not catch it.
> When caught, it's to late to redo it. Then the engineer tries to fix it with a
> workaround.
> And then, god knows how the structure will behave in a "previously unknown
> earthquake event."
> Just my thoughts!
> Oshin Tosounian, S.E.