• Security incident: ISF was recently accessed by intruders. Please change your password, and change it anywhere else you used it. Read more

New paper on WTC 7 by Charles M. Beck

metamars

Graduate Poster
M
Joined
Apr 4, 2007
Messages
1,207
Charles M. Beck has a new paper on arxiv.org re WTC 7

(Submitted on 29 Jun 2008)

Abstract: We use finite differences and the mathematical model of ``crush-up'' mode of progressive collapse proposed by Ba\v{z}ant and Verdure (2006) to examine anonymously published WTC 7 descent curve. We find that the collapse of the building consisted of two phases: a free-fall phase for the first 16-26 m of descent, followed by a deceleration phase that lasted till the end. The free fall phase directly contradicts the Federal Emergency Management Agency (FEMA) hypothesis (2002) regarding the initiation of collapse in WTC 7, by which the load-bearing structure slowly lost its strength due to environmental factors. We estimate the magnitude of the resistive force (the force with which the moving part of the building resisted its destruction) and find that it supports two possibilities: one put forth by Ba\v{z}ant and Verdure (2006), by which the moving part was intact, and the other put by Beck (2007), by which the strength of the moving part was reduced by $\sim50$%. The FEMA analysis suggests that the moving part was severely damaged prior to collapse.
Click to expand...
 
metamars said:
Charles M. Beck has a new paper on arxiv.org re WTC 7
Click to expand...

Interesting. Beck is trying very hard to imply that the fall of WTC7 was suspicious without actually saying so.

The load-bearing vertical columns begin to fail one by one, each at location near the source of damage. When the remaining columns cannot carry their load any more, the building is set in motion. However, as the building starts to move the remaining columns continue to offer resistance before their eventual failure. It is important to observe that as a result the acceleration of the building is initially fairly small, but then starts to increases as more and more columns fail. With the failure of last of the remaining columns the top section achieves a near-free fall acceleration. The free fall lasts until the top section reaches the ground when it starts to decelerate.
Click to expand...

No citation or line of reasoning advanced to support this assertion. More tellingly, there is no estimate given of the duration of the increase in acceleration to near freefall; in particular, whether it would be detectable over the timescale of the available measurements. Since columns would be expected to have negligible resistance after a total shortening of a few per cent, I would suspect that this initial period of low acceleration would be so brief as to be undetectable. Beck states that the near-freefall acceleration is achieved after 0.7m of drop; that hardly seems surprising, as this is about 17% of the height of a single storey. Beck is trying to dance around his own analysis by refusing to quantify it. It's that good old unevaluated inequality fallacy again, a great favourite of the truth movement.
​
​
​
Well defined failure point and initial free-fall acceleration of the top section both indicate that the collapse of WTC 7 was not spontaneous.
Click to expand...

Again, an assertion unsupported by any citation or line of reasoning. The flaw in Beck's analysis is that he's assuming that the collapse of WTC7 commenced with the movement of the roof line, and neglecting the prior fall of the mechanical penthouse. He's then deducing that something must have destroyed or severely damaged the core columns. Could that, perhaps, have been caused by having a large structure collapse through them? This isn't a possibility that Beck seems to consider.

And even after all this careful misdirection, Beck can't come up with anything. He's forced to admit that Bazant and Verdure's crush-up model is an equally good description of the collapse as his own vague generalisations about damage to 50% of the columns. Even that is based on his own unpublished work on the Twin Towers collapses, which uses a gross overestimate of the column dimensions - Beck assumed that the ground level column dimensions were continued all the way to the roof - followed by an assumption that WTC7 was built to the same strength.

Overall, a nice try to slip some truthiness into a serious paper, but this is poor reasoning that falls far short of supporting the conclusion it's designed to support; as a result Beck has backed off from actually stating the conclusion he'd like to. He's working very cleverly, though, as a stealth truther, and if he goes on like this he may slip something past a group of peer reviewers who are having an off day.

Dave
 
Ah yes, the PENTHOUSE argument, ..... how predictable!

In that case, didn't the collapse take about 6 hours, not 6 seconds?
 
Could moderators please move this thread to the PENTHOUSE FORUM
 
Last edited:
Apollo20 said:
Ah yes, the PENTHOUSE argument, ..... how predictable!
Click to expand...

If it's so predictable, perhaps Beck could have predicted it and addressed it in his model.

And as for predictability, that's hardly a criticism. If a truther comes into this forum and says "The Twin Towers collapsed faster than freefall, which is impossible without explosives," it's entirely predictable that about a dozen of us will direct him, more or less politely depending on personal preference, to your series of papers on the subject. Does that somehow invalidate your work?

Dave
 
the penthouse lol, JREFers still in denial....
a shame
 
How is the collapse of the penthouse not relevant?
 
Travis said:
How is the collapse of the penthouse not relevant?
Click to expand...

Because it's been mentioned before. Apparently we only get to use facts once for debunking a truther theory; if they state it again we have to come up with a new debunk, even if they haven't answered the old one. And then, of course, they can accuse us of inconsistency.

"Your honour, in this appeal the prosecution has stated that seven witnesses saw my client shoot the victim, he had gunshot residues on his hands, and the markings on the bullet that killed the victim matched the gun that's registered to my client and was in his posession when he was arrested. But that's just so predictable; that's exactly what they said in the original trial. Move to strike."

Truthers, unless you can come up with a reason why the collapse of the penthouses was irrelevant to the collapse of the building as a whole, you have to consider it when you model the collapse. So far, the only truther argument that could support that position is Heiwa's bizarrre belief that one structure can fall through another without damaging it. Has anybody got any sane reasons for assuming that the collapse of the penthouses doesn't indicate prior collapse of the core?

And incidentally, did anybody actually read post 2, which consists of rather more than the word "penthouse"? There's a lot more wrong with Beck's analysis than just neglecting the penthouse collapse, and he still can't come up with anything that disagrees with Bazant and Verdure.

Dave
 
I think one of the major problems with this paper is that the author assumes that there is even a "crush-up" phase. There's not. The nature of the collapse of WTC7 removed all structural stability on all floors above the column failure.

WTC 1&2 were similar, but had an interesting mechanism which left intact the structural stability in the floors above, but pulled-in the wall columns on one (maybe a few) floors. In WTC7, the failed column pulled in the exterior columns on all floors above.
 
Yes I hear a lot of truthers and "Agnostics" (Frank) dismissing the penthouse part of the collapse, yet I have not seen anyone prove that it is irrelevant.

That would be a good start.

TAM:)
 
You must log in or register to reply here.

Share this page

ISF - Join now!

Every member here is approved by hand. No bots, no spam, just people who care about evidence and honest debate.

Membership is free!

Create your free account

Back
Top Bottom