Interesting Read (Warning)

[Meph]

www.physics.byu.edu/research/energy/htm7.html

At least somebody is putting some science to this all and actually asking questions. Conspiracy aside, just accepting without investigating is even worse than the act itself.

[Decker]

Personly I dont have a stance as to what actully happend. I beilve one of the 2 way to find out is to A) make a time machene go back and watch it form EVERY angle and such, or B) make a an exact replica of the building about a thousand times and try each and every single theroy to find out if its possible.

One thing I did wach on the discovery channel is how when the plane hit metal shards from the explodeing plane hit the fire retardent and damaged it enoughf to allow the burning jet fuel to set fire to it, Than once the metal started to burn it kept going.

Now I dont have a stance here Im just playing devils advocate.

[Vashthestampede]

I can see the argument for the WTC 7 building, but WTC 1 and 2 were built in a different manner then most buildings. They were built of lightweight trusses supported by an external support structure. The building fire proofing was only designed to survive a 707 simply lost in the process of landing not a 757 going 400knots. The impact blasted the fireproofing off the internal trusses causing them to weaken (not melt) and as trusses failed at there connections more and more weight was placed on the already damaged external structure until the inner trusses overloaded the remaining structural integrity of the build and the build fell in upon itself due to its unique design which many conspiracy theorists seem to overlook.

EDIT: See that they touched on the buildings structure, but I see they have made quite a few valid points, but as both sides are based on alot of assumptions of what happened I am going to remain neutral. You can't just say that the jet fuel burned out immediately because how can you know that?

Also here is a good counter article: www.tms.org/pubs/journals/JOM/0112/Eagar/Eagar-0112.html

Good counterpoint about the lack of heat for the fire

It is known that structural steel begins to soften around 425°C and loses about half of its strength at 650°C.4 This is why steel is stress relieved in this temperature range. But even a 50% loss of strength is still insufficient, by itself, to explain the WTC collapse. It was noted above that the wind load controlled the design allowables. The WTC, on this low-wind day, was likely not stressed more than a third of the design allowable, which is roughly one-fifth of the yield strength of the steel. Even with its strength halved, the steel could still support two to three times the stresses imposed by a 650°C fire.

The additional problem was distortion of the steel in the fire. The temperature of the fire was not uniform everywhere, and the temperature on the outside of the box columns was clearly lower than on the side facing the fire. The temperature along the 18 m long joists was certainly not uniform. Given the thermal expansion of steel, a 150°C temperature difference from one location to another will produce yield-level residual stresses. This produced distortions in the slender structural steel, which resulted in buckling failures. Thus, the failure of the steel was due to two factors: loss of strength due to the temperature of the fire, and loss of structural integrity due to distortion of the steel from the non-uniform temperatures in the fire.

[Turtle-Prophet of Doom]

We should also remember that while fire did not effect all the floors above and below the impact site, the weight of the above floors colapsing on the lower floors is waht caused the fall of the building. It wasn't just on floor falling onto anopther but all the floors above it was well.

[Kreeper X]

SO you've read the kooks, now read the truth.

www.popularmechanics.com/science/defense/1227842.html

Turtle is right. Wind had ZERO effect on the collapse of the WTC EXCEPT that the high level winds helped to fuel the fires in the effected floors of the trade center.

What brought the towers down was very simple. The Bolts that held the Trusses in place snapped due to the trusses themselves not melting but rather bowing as the steal weakened in the fires.

Each floor acts as an anchor for the outer steel frame. Once the fire had weakened the steel in the impact zone enough, it was the weight of the floors above that buckled the outer frame and the inner core. Once ONE FLOOR fell, it was enough to cause a chain reaction which caused a rapicly escallading force of downward pressure as gravity pulled on the floors above the impact zone, and a rapidly decending level of support holding the building together.

The result was that one or two floors fell, leaving the weight above to be held ONLY by the outer steal frame and the inner core frame.

Looking at the colapse of the towers frame by frame, you can actually see the areas where the floors fell buckle. The result was the floors above suddenly find themselves with very little support and the tower falls.

Seriously, read the whole link I posted. It goes into detail about some of the kooks out there coming up with the conspiracy theories...

[Decker]

Ahh yes kreep I read that whole article in my copy of PM I love that so much I got a subscription to it. Really its a great read.