9/11 conspiracy theory debunked by Cambridge Engineer

Che Guava

The Juicy Revolutionary
Apr 19, 2005
Score one for reason and science!

9/11 demolition theory challenged

An analysis of the World Trade Center collapse has challenged a conspiracy theory surrounding the 9/11 attacks.

The study by a Cambridge University engineer demonstrates that once the collapse of the twin towers began, it was destined to be rapid and total.

One of many conspiracy theories proposes that the buildings came down in a manner consistent with a "controlled demolition".

The new data shows this is not needed to explain the way the towers fell.

Over 2,800 people were killed in the devastating attacks on New York.

After reviewing television footage of the Trade Center's destruction, engineers had proposed the idea of "progressive collapse" to explain the way the twin towers disintegrated on 11 September 2001.

This mode of structural failure describes the way the building fell straight down rather than toppling, with each successive floor crushing the one beneath (an effect called "pancaking").

Resistance to collapse

Dr Keith Seffen set out to test mathematically whether this chain reaction really could explain what happened in Lower Manhattan six years ago. The findings are to be published in the Journal of Engineering Mechanics.

Previous studies have tended to focus on the initial stages of collapse, showing that there was an initial, localised failure around the aircraft impact zones, and that this probably led to the progressive collapse of both structures.

Once the collapse began, it was destined to be "rapid and total"

In other words, the damaged parts of the tower were bound to fall down, but it was not clear why the undamaged building should have offered little resistance to these falling parts.

"The initiation part has been quantified by many people; but no one had put numbers on the progressive collapse," Dr Seffen told the BBC News website.

Dr Seffen was able to calculate the "residual capacity" of the undamaged building: that is, simply speaking, the ability of the undamaged structure to resist or comply with collapse.

His calculations suggest the residual capacity of the north and south towers was limited, and that once the collapse was set in motion, it would take only nine seconds for the building to go down.

This is just a little longer than a free-falling coin, dropped from the top of either tower, would take to reach the ground.

'Fair assumption'

The University of Cambridge engineer said his results therefore suggested progressive collapse was "a fair assumption in terms of how the building fell".

"One thing that confounded engineers was how falling parts of the structure ploughed through undamaged building beneath and brought the towers down so quickly," said Dr Seffen.

Conspiracy theorists see evidence of a "controlled detonation"

He added that his calculations showed this was a "very ordinary thing to happen" and that no other intervention, such as explosive charges laid inside the building, was needed to explain the behaviour of the buildings.

The controlled detonation idea, espoused on several internet websites, asserts that the manner of collapse is consistent with synchronised rows of explosives going off inside the World Trade Center.

This would have generated a demolition wave that explained the speed, uniformity and similarity between the collapses of both towers.

Conspiracy theorists assert that these explosive "squibs" can actually be seen going off in photos and video footage of the collapse. These appear as ejections of gas and debris from the sides of the building, well below the descending rubble.

Other observers say this could be explained by debris falling down lift shafts and impacting on lower floors during the collapse.

Dr Seffen's research could help inform future building design.

Not that it'll ever quiet the conspiracy theorists. We'll be hearing from them for the rest of our lives.

Edit: Crosspost agreement with Eran.
Finnally this will shut all of them up and make me sure.
Of course. This is what should be the final nail in the coffin. But of course it won't be.
I don't like conspiracy theories. I'd prefer institutional research, which is already concerning enough. I don't believe in the demolition thing, unless some valid evidence is given. How could the Bush people get those bombs and the required wire-work into that structure in time, if they cant get electricity into Baghdad.

But I also doubt that Osama was the one who planned the strike.
South Park Bush said:
Quite simple to pull of really. All I had to do was have explosives planted in the base of the Towers. Then on 9/11 we pretended like four planes were being hijacked when really we just rerouted them to Pennsylvania, then flew two military jets into the World Trade Center filled with more explosives and shot down all the witnesses on Flight 93 with an F-15 after blowing up the Pentagon with a cruise missile. It was only the world's most intricate and flawlessly executed plot ever ever.

like most of you are saying this will never shut them up like most far left crazies they'll just try to discredit the crap out of this scientist by calling him a corporate toadie and so on
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