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      10-05-2011, 05:19 AM   #57
BrokenVert
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Quote:
Originally Posted by Rochdale Pioneers View Post
Question for the engineers. OK, so lets say I buy the rational explanation of Tower 7. There have been very similar towers with much larger fires burning for longer that have not collapsed, or have seen a smaller cascade collapse on part of the structure.

If it only takes an office fire to cause a 47 storey building to collapse why has it vere happened before?

And none of you have explained the molten for days pools of steel yet. I know it doesn't fit your rational explanations but it was there. What (a) heated the steel up to melting temperature and (b) kept it so hot for so long?


WTC 7 didnt have a functioning sprinkler system, also firefighters essentially ignored 7 because of the immediate search for survivors in the wake of towers 1 and 2 falling. Not that they could do much, because there was no water pressure due to broken lines.


Most of the time firefighters are doing their best to beat back a blaze. This reduces the heat involved in a fire and it also reduces the severity of a fire, so the building doesnt undergo the same set of events that led to the collapse of 7.


I can believe that some steel melted during the collapse. Friction can heat steel just as much as fire. So some steel wouldve melted due to very high point frictions due to the forces of a 110 story building coming down. Especially on the members directly exposed to the fire, as they were already heated to about 2/3 of their melting point.


Concrete is also a good insulator. I dont see it as happening but in theory you could have a few puddles melted by friction and then kept warm inside a shell of concrete. (but like I said I dont really see that happening)
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