Collapse of building #7 on 9/11

  • #1
The official NIST report on the collapse of building 7 on 9/11 states that the thermal expansion of a floor beam due to the fires disrupted a support column on the thirteenth floor, and that is what ultimately caused the building to collapse. Is this the sole cause or could there have been other contributing factors?
 

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  • #2
Bystander
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russ_watters
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The official NIST report on the collapse of building 7 on 9/11 states that the thermal expansion of a floor beam due to the fires disrupted a support column on the thirteenth floor, and that is what ultimately caused the building to collapse. Is this the sole cause or could there have been other contributing factors?
Have you read the report? There are three additional explicitly listed contributing factors and more than a dozen recommendations for mitigating them and other potential contributing and tangential factors. Your one sentence summary is a good start, but the reality is far more complicated.
 
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No, I just read the Wikipedia version. What are the contributing factors that you know of? Do you have a link to the report? The reason I'm asking is that when I was listening to the radio when it was happening, they mentioned that building 7, unlike the others in the area, shared a common basement with the twin towers, although I haven't heard mention of this since. This got me to wondering about, when the North Tower collapsed, might it have pressed air into building 7's basement, weakening it's foundation?
 
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they mentioned that building 7, unlike the others in the area, shared a common basement with the twin towers
Looking (quickly) at the report, I see no mention of this common basement when they discuss the connection between building 7 and the rest of the WTC.

This got me to wondering about, when the North Tower collapsed, might it have pressed air into building 7's basement, weakening it's foundation?
It appears that the report found that the fire was sufficient to explain what happened to building 7. They say that even the structural damage from the debris of the North Tower played no significant role.
 
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