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Re: FURTHER ON WTC

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The point is, the blame is on the terrorists.

People can second guess the truss connections all they want, but the fact is they are gravity connections and performed fine up until they were asked to do something unintended.

Can a sprinkler system be expected to put out a fire like that and save the building? No. Was the facade supposed to shred up the airplane and withstand blast pressures? No.

Simple as that.

The collapse mechanism theories I have no quarrels with (except for the ones spewing controlled demolition), I only take issue with people claiming the structural design was flawed and this event proved it. It wasn't and this event was not in the design criteria.

-g


On 9/21/07, ASC <ggg(--nospam--at)bigpond.net.au> wrote:
GM WROTE:
 
***But I am aware of at least one 'flimsiness' aspect, that was the most
likely contributing
cause to WTC collapse.***

That would be the airplane crashing into it at a high velocity fully loaded
with jet fuel with the fire that ensued.

"flimsiness" is not something I'd classify the WTC as. I haven't studied it
in detail like Dr. Astaneh, but I believe his flimsiness comment was in
relation to the Sears Tower.

Why was the Sears Tower not flimsy or as flimsy? Because it was designed for
a purposeful airplane attack? No, not likely. It was probably "more sturdy"
for a number of reasons including it being taller, it being in a high wind
zone, and the decisions made by Fazlur Khan to overcome those design
challenges. I doubt seriously that it was because he was trying to comply
with some provision in the local building code. His decisions were obviously
different than Robertson's, but that is likely highly dependent on the
forces from wind testing, story heights, the architectural requirements of
the exterior look of the building, and the nature of the building not being
as slender since it's footprint grows at the lower stories. The buildings
are different and of course economics played a role.

Tall buildings can make people sea sick if they are too flimsy. Tuned Mass
Dampers lessen that effect. Would Le Messier's (SP) building withstand a jet
impact? Is his building Too Flimsy? He corrected a construction flaw to his
credit, but if those planes hit his high profile high rise, would he be
considered "morally corrupt?"

If the WTC was built to the NY building code, would it have withstood the
collision and fire without collapse? I don't know and I'm pretty sure no one
knows that answer. What exact code deviation is the most significant factor
in this "flimsy" categorization? Live Loads, Wind Loads, Drift???

 
 
REPLY:
 
Your guess as to flimsiness was not what I had in mind.
I did study the building.
 
You meant the over-all flexibility, which would be expressed in story drift.
I did not mean that, and there is no grounds for such an allegation.
 
It is generally agreed that the bldg survive the airplane impact and that
it collapsed due to secondary causes of that event.
 
 
 
Sincerely, Gregory from Oz
 
 

 




--
-gm