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Originally Posted by willravel
Yes, but the steel they used in the towers was intended to withstand a fire, even from diesel fuel or a bomb. Bear in mind that the 1993 bombing, which was a bomb made from urea pellets, nitroglycerin, sulfuric acid, aluminum azide, magnesium azide, and bottled hydrogen, created much more heat initially than the burining fuel did 8 years later. My point is not that the original attack was more likely to bring down the building, in fact it was almost impossibl for a urea-nitrate bomb of that size to bring down the building. My point is that the building is a known national landmark. It has always been a target for terrorism. As a matter of fact, the engineers who designed them specifically said that they could withstand a collission from a plane not much smaller than the ones that hit them. Included in this were the ability to not topple due to the initial force of a strike, the destruction of supports by a strike, the subsequent fire due to a strike (planes don't fly without fuel), and the ability to evacuate the building in the event of a strike.
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The towers were designed to withstand the impact of a 707 that had gotten lost during landing maneuvres. Even if we assume that the aircraft was near maximum operating weight (technically impossible but, as you noted, quite close to that of a 757) a 707 flying at approach speeds will do much less damage toa structure than a 757 or even an identical plane with the throttle jammed wide open. This becomes important if we assume, as the FEMA report seems to indicate, that the damage to the insulation around the steel supports was a factor in the collapse. The speed of the aircraft would greatly affect the extent of the damage.
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Originally Posted by willravel
One very important thing we have to remember is that almost ALL of the fuel was burned up on impact. The initial strike breeched the tanks and ignighted the fuel (thus the big explosions), what was left no one can say, but the fires could not habve burned at airplane fuel temperatures for long. In other words, the estimate heat of the fire based on the fuel is not a temperature that was consistant from strike to fall. There was a sharp drop immediatally after the collission, and then it probably went down to the 400-500 degree range or lower (office furniture, paper, carpert, etc. burning temps). This would have done nothing to the steel.
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This site seems to suggest otherwise. According to this as well as other sources I've read, steel will lose a lot of it's strength at relatively low temperatures - 650C is sufficient to rob a steel support of half of it's support strength and it begins to weaken much lower than that, close to 400C. I haven't checked his sources, but that site does explain both the heat ranges and temperature ranges far more succinctly than I'm capable of.
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 I'm glad you're doing research, this will enrich the discussion even further.
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I do hope you understand my skepticism, then. It's telling that I haven't even finished high school, yet I'm able to refute a great many of the claims made with no additional research or effort made.
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Okay, bear with me. This is going to be mathimtical...
We know from seismic records that one of the WTC towers too approx 8.4 seconds to collapse. s=˝at˛ is the formula for distance and time. s is distance in feet, a is gravatational constant (32 ft/sec˛), and t is time.
s = ˝ * 32 * 8.5˛ = 1156'
WTC Tower 1 had a roof height of 1368'. Tower 2 was 1362'. As far as I'm concerned, it's proven that the towers' structures were destroyed at very close to free fall speed, perhaps faster since there is air resistance to consider. Impossible without explosives. (some help from reopen911.org for the math).
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This math at a glance appears to be accurate; however, it seems to be in direct contradiction to what I've read. Earlier sources of mine seemed to indicate a collapse duration of approximately 10 seconds, which obviously changes the numbers completely. I'm unable to find those sources right now, but if I dig them up I'll post them. Either way, it's not surprising even if the towers did fall at near free-fall speed. The resistance offered by the lower floors would be nearly insignifigant in the face of the energy being released in the fall of severl hundreds of thousands of tons of building. The lower floors gave instantaneously, lending an appearance reminiscant of a controlled demolition.
This is a picture from the southeast side of the building. There is almost no damage from Towers 1 or 2.[/QUOTE]
Do you have another source for this image? i can't see it.