Wednesday, June 20, 2007

Would the towers collapse the way they did without . . .

If one were to agree with the 9/11 Commission, and/or the National Institute of Standards and Technology (NIST), that the collapse of 1 and 2 World Trade Center was caused solely by aircraft impact and resulting fire, would the towers collapse the way they did?

To obtain an answer we posed this question to Jeff King—a graduate of the Massachusetts Institute of Technology who worked as an electro-mechanical engineer. His response:

"You would have to make worst-case assumptions about the extent of the initial damage, especially to the core, and make the most generous assumptions about the effects of heating to somehow get the initiation of a collapse. And even if you could push the envelope enough to get it to fail, it would still have to start with gradual bending and crumpling type failures. This would be at much less than free-fall speed and would have to involve a lot of bending and twisting, and the initial acceleration would have been much more gradual than was actually observed.

"Even if you can push the assumptions enough to get collapse initiation (which NIST does by relentless tweaking of the parameters in their computer model), it is very difficult to get the collapse to continue to propagate down the tower. This is especially true without that initial acceleration since the first floor to give way won't be hitting the next floor fast enough to plausibly break it loose."

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