Dr. Usmani's WTC theory

[JackieO]

http://technology.nzoom.com/technology_detail/0,1608,196263-113-380,00.html

Has this been discussed here? What do you think, anything new?

(No, I'm not trying to promote this, just want feedback)

[Kevin Fenton]

1. It's hard to say

Because it's just an article in the press and there's not many numbers. For example we need the amount of combustibles, the duration of the fire he modeled, how hot it was, how much they would have needed to expand, whether his theory actually matched the facts or is completely at variance with them, how much of the fireproofing would need to be stripped to make this work, etc., etc. to make an informed judgement.

Dr. Usmani neglected to mention the viscoelastic dampers (aka little rubber thingies that stopped the towers swaying, diagram on page 66 of the NIST report) that connected the floor framing to the outer walls and may have enabled the beams to expand without having the effects he described. Only the bottom of a beam was connected by a damper and I doubt they could have made much difference, but it is odd he doesn't mention them.

Does anybody have a link to the full article by him?

[rman]

2. The towers were designed specifically to not be vulnerable to fire.

And it worked quite well on 9-11, given that the fire remained confined mostly to the floors that were hit by the planes. Except for a few oddly out of place local fires some distance away from the impact location - but clearly the fire did not spread very much.

This particular theory would explain only how the floors where there was fire had failed - it does not explain how failure of a few floors would lead to complete collapse of the towers.

It is simply assumed that once a few floors fail, the whole building collapses:

"That lateral support vanished as soon they buckled and that is why the building fell in on itself."

As though it is self-evident that when part of a building fails, the whole thing goes down - completely contrary to what the historic record shows. There's not even the slightest attempt to explain this anomaly.

It's interesting though how various official explanations contradict one another:

FEMA says the connections of the floors to the core and walls were weak and failed when the floors started 'sagging' due to the fire.
NIST says those same connections were so strong that the 'sagging' floors pulled the outer walls inward, causing them to buckle.
Now this new theory says the floors themselves were the weak point, and did not 'sag' but rather did buckle.

[spooked911]

3. sounds exactly like the old pancake theory, which has been discussed

here before. Thanks for the article.

[Peter Frank]

4. Exactly...

This is the official theory put forth initially; but it doesn't answer a number of questions, which have also been discussed.

[Old and In the Way]

5. Is any group working on dynamic models of WTC 1/2/7 ?

Seems to me that it would make a great engineering project and provide tremendous insight to have an open source, 3D model of each building that could be tested with variables to validate the NIST findings, both in time to collapse and collapse rate. Of course, we'd need access to the original building blueprints to do it correctly....

[MrSammo1]

6. Faulty logic by Dr U........

at the time of the collapses the temperatures of the fires were their lowest.

Expansion of the steel would of had to take place at the height of the fires.

That time already had came and went in the first fifteen minutes.