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Re: Structural failure of NY's WTC



Larry Smith asked if the hijackers anticipated the total collapse of the
building.

I don't know specifically what goes through the minds of terrorists, but I
would suspect they knew exactly what they were doing. I believe the
collapse of skyscrapers because of prolonged intense fire is predicted.
Even though it is not common knowledge, it is not secret.

Others on this list have suggested there have to be alternatives. I think
the only alternative is not to build tall buildings at all. Remember the
engineering feat involved here. The building cannot be rigid... it must
sway with winds and during earthquakes. The building cannot be incredibly
over-designed... it has to be affordable. Until last week, the fact that an
intense prolonged fire would be practically guaranteed to collapse a
skyscraper was considered an acceptable risk. Have we changed our minds on
this? If so, how many other "acceptable risks" are we now going to declare
as unacceptable?

For example, having been a graduate student at Michigan State University, I
attended quite a few Big-10 football games along with anywhere from 60,000
to 100,000 people at each game. That's a pretty attractive target for a
terrorist. How could we possibly construct a football stadium to be immune
to a jetliner being crashed into it? I think we can't. So what's the
alternative? Do we now say this is an unacceptable risk and quit playing
Big-10 football? (Perhaps that wouldn't be a bad idea for some reasons, but
probably not for this reason.)

I think if we want high population density in a small footprint,
skyscrapers, football stadiums, shopping malls, etc. are what we are stuck
with. But I don't know how to design these to withstand what we saw last
week. That terrorist problem needs solved in another arena... not in the
engineering arena. Our engineering expertise would be better spent at the
airport, not the skyscraper.


Michael D. Edmiston, Ph.D. Phone/voice-mail: 419-358-3270
Professor of Chemistry & Physics FAX: 419-358-3323
Chairman, Science Department E-Mail edmiston@bluffton.edu
Bluffton College
280 West College Avenue
Bluffton, OH 45817