Twin Towers collapse

[funkyrich]

Why did the twin towers collapse the way they did on that dreadful day? They both collapsed straight down into their own footprint rather like a controlled demolition. The "Pancake" theory doesn't hold up because this is not possible at freefall speed(they took approx 12 seconds to fall). Surely this is against the laws of physics?

[lord molly]

i'm not sure about the pankake theory, but apperently the reson they collapsed straight down is due to the jet fuel from the aircraft being thrown down the lift shafts tnd igniting on the way down, eventually reaching the base of the lifts and the head slowly distroying the founfadion core and wall of the buildings

[Llamatron]

Wo, now there's a can of worms.

The metal structure of the two towers, as with all buildings I think, had to pass certain standards. One of these standards was that it's melting point be above 6000 degrees (If I remember rightly). Jet fuel doesn't burn at anything even approaching that temperature so could not have melted the superstructure.

There's also the reports of many explosions, one after the other, that the fireman heard. And the small puffs of smoke running down the towers ahead of the collapse visible on the videos.

I'm sure someone out there has more details.

[LazyGun]

The results of the 3 year investigation rule out the pancaking theory, thats true. However, there is absolutely no evidence whatsoever to indicate "controlled demolition". Rather, the unique combination of circumstances ( Hi level collision, fires fuelled by 23,000 gallons of aviation fuel, weakening of the steel structure etc) precipitated the collapse.

The report can be found here, and IMO is a far more reasonable and likely explanation of the events than the repeated assertions that this was an "inside job".

http://wtc.nist.gov/pubs/factsheets/faqs_8_200 6.htm

[stevie21]

Llamatron - wasn't it discovered very early on that the steel reinforcements in the building weren't properly insulated? Maybe that means that these standards weren't met.

[Llamatron]

I think there are far too many unanswered questions about that day.

[fo3nix]

Plus, the lift shafts were hermetically sealed.

I'd recommend anyone interested watching Short Change. Some of the informtion there has been been found to not be totally true, but a good deal of it is very much unexplained and makes you think.

[bernardo]

There was a documentary about it on Channel 4 a few years ago which explained it well. The initial impact / explosion blew away some of the insulating foam on the steel frames. The heat of the fire did not melt the metal, but weakened it. Therefore a point wa reached at which they stopped being strong enough to hold up the weight above. BTW I don't know what the pancake theory is.

[Loosehead]

Despite what the conspiracy crackpots will tell you this has been very thoroughly explained many times buy reputable sources. The channel 4 program referred to by Bernardo is a good example.

[scuzzball]

The whole thing was filmed on a hollywood filmset. The same one that they filmed the so called 'moon landing' on.

[scuzzball]

By the way, did I just split an infinitive? I am mortified if I did.

[jenky]

scuzzball - I don't think that is a split infinitive, so you can relax. You did however, end a sentence with a preposition which deserves a mild spank

[Peter Pedant]

The terminal velocity I think was 200 km/hr -which I thought was almost free fall. Sorry I know US is still FPS.

The pile was only ten storeys tall because the towers were only 10% metal and the rest was sort of air. So you expect the 100 floors to collapse to ten

and finally it collapsed down vertically because there was no big turning force to trun it over

There's a site somewhere by the fella who wrote the original report - prof of phys or engineering.

[Peter Pedant]

yeah its:

http://www.tms.org/pubs/journals/JOM/0112/Eaga r/Eagar-0112.html

wh is the standard explanation

[Nay37]

Yes it was against the laws of physics. Must've been some sort of controlled demolition. Plus WTC 7 building fell the same way and wasn't hit by anything!