Demolition contractors say the darndest things--demolition, tipping over

[HamdenRice]

This is a comment just days after 9/11 from a demolition contractor who did not believe the collapse of the towers were caused by controlled demolition. But his observation about what the collapse looked like and what could have happened under other circumstances (ie tipping over of the towers) is very interesting, given his experience. And this was published in a scientific newsletter.

http://www.newscientist.com/article.ns?id=dn1281

Design choice for towers saved lives
13:14 12 September 2001
From New Scientist Print Edition. Subscribe and get 4 free issues.
Eugenie Samuel and Damian Carrington

A lucky choice of design for the World Trade Center towers reduced the death toll caused by their destruction, say engineers

<snip>

Classic demolition

The collapse of the WTC towers looked like a classic controlled demolition, said Mike Taylor of the National Association of Demolition Contractors in Doylestown, Pennsylvania.

"If there's any good thing about this it's that the towers tended not to weaken to one side," said Taylor. "They could have tipped onto other buildings or into the river across the West Side highway."

The collapse of the WTC towers mirrored the strategy used by demolition experts. In controlled demolitions, explosives are placed not just on the lowest three floors but also on several consecutive floors about a third of the way up the building.

The explosions at the higher floors enable the collapse to gain downward momentum as gravity pulls the full weight of unsupported higher floors down into lower floors in a snowballing effect.

On Tuesday, the impacts of aeroplanes on the higher floors replaced the explosives. The collapse of the higher floors caused the floors below to be crushed. "It cascaded down like an implosion," says Taylor.

The lack of collapse in higher stories was one reason why the 454 kilogram bomb detonated in the underground garage of the World Trade Center in 1993 failed to destroy the building.

<end quote>

Now that's interesting. The head of the trade group representing demolition contractors says that its a good thing the buildings were constructed the way they were and damaged the way they were, because otherwise, they might have fallen over destroying much more of lower Manhattan.

But wait a minute! Haven't the OCTAs (official conspiracy theory apologists, for those who don't remember the acronym) told us over and over and over ad adnauseum that because of the mass of the buildings, they could never have tipped over under any circumstances whatsoever?!?

Hmmmmm. Who are you going to believe about "tipping over" -- our resident OCTAs or the head of the demolition contractors trade association of the US?

[dailykoff]

1. The demolition guy has it right

but the engineer is already selling snake oil:

"Skyscrapers like the World Trade Center are not built to withstand direct hits by large aeroplanes, he says."

That's baloney. And this Hooper works for the firm that did the WTC engineering?

I'm beginning to suspect that people like Robertston and others who worked on the Trade Center figured out what went down immediately, but were either contacted by government agents or by principles in their firms and clammed up fast. Ditto the trade publications.

Evidently the demo guys (like Romero and this Taylor fellow) didn't get the message until later.

Good catch HamdenRice.

[mirandapriestly]

2. well, I read there was a lawsuit in 1985 to release info

about the construction of the towers. So something could have been in the works all along.

[hack89]

3. You did notice, did you not...

that your link validates the physics of the NIST report concerning the collapse?

The explosions at the higher floors enable the collapse to gain downward momentum as gravity pulls the full weight of unsupported higher floors down into lower floors in a snowballing effect.

On Tuesday, the impacts of aeroplanes on the higher floors replaced the explosives. The collapse of the higher floors caused the floors below to be crushed. "It cascaded down like an implosion," says Taylor.

I thought that the pancake theory was impossible.

In essence, what he is saying is that a collapse due to a plane crash would look the same as controlled demolition. Considering that physics is physics, I have no problem with that.

[dailykoff]

4. Yes, but this isn't physics.

It's journalism, and not terribly accurate journalism. Notice that the story doesn't make a lot of sense: if conventional demolition places explosives only "about a third of the way up the building," how would the WTC plane crashes, which were both well above that, "replace" them?

So it looks like the reporter somehow mangled the demo guy's analysis, but that's nothing unusual.

[hack89]

5. You crack me up..

if this reporter wrote a pro CT piece, it would be trumpeted as another "smoking gun". Do you seriously believe that the standard of journalism demonstrated in this pieces is worse than the multitude of 9/11 research web sites that purport to tell us the "truth" about 9/11?

The point of the "one third up" is to create a "hammer" with the weight of the building as it falls - pancaking the floors below (something CTrs insist is impossible). I don't think the "one third" mark is set in stone when you consider that the portions of the WTC above the impact zones weighed more than most buildings that are imploded. Its all about the weight - if there is enough weight falling then the building below will collapse.

[dailykoff]

6. You have to judge each source on its merits.

The best evidence is going to be the least interpretive: photographs, construction documents, and so on. Then I suppose eyewitness accounts, and then for reports and analyses, you have to ask, What's factual and what's baloney?

In this case, the reporter is doing what you just did: twisting the interview to fit a preconceived storyline. The demo guy says it looked like controlled demolition, and the reporter tries to turn that into a defense of the OCT, and mangles it.

In the case of "CT" sites, the only one I've looked at carefully is wtc7.net, and the information checks out.

[hack89]

7. OK - if you say so. n/t

[stickdog]

8. Nice catch. I'll believe the physics professor.

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

The main challenge in bringing a building down is controlling which way it falls. Ideally, a blasting crew will be able to tumble the building over on one side, into a parking lot or other open area. This sort of blast is the easiest to execute (favored by the Law of Increasing Entropy). Tipping a building over is something like felling a tree. To topple the building to the north, the blasters detonate explosives on the north side of the building first.

Sometimes, though, a building is surrounded by structures that must be preserved. In this case, the blasters proceed with a true implosion, demolishing the building so that it collapses straight down into its own footprint (the total area at the base of the building). This feat requires such skill that only a handful of demolition companies in the world will attempt it. (Again, consistent with the Second Law of Thermodynamics.)