Why a one-way Crush down is not possible

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Seymour Butz said:
So what about 2 then?

Do you agree that the analysis fails?
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WTC1 and WTC2 were very diffent collpses, Or should have been. Actually they were remarkably similar in most ways even thogh they had much different collapse dynamics.
 
Heiwa said:
That's a good question. Remove the upper, three horizontal elements (your top floor), so that the vertical elements have no lateral support there. The first lateral support is at next horizontal element level!

Those arrows (vectors) are the forces 4 F acting on the tops of the vertical elements.

Instead of tilting them, it is easier just to add forces 4 Fh that act laterally on the top of each vertical element. They are balanced by forces -4 Fh at ground level. The combination F and Fh is a tilted arrow, so to say. What happens?
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What happens is that the columns up top are subject to forces they weren't designed to handle, and the joint between them and the columns below easily snaps. Then your 'C' falls another 3.7M or so and hits the next floor with even more mass and velocity.
 
3bodyproblem said:
lol, OK. Please show me a calculation of said probabilities. You do know what probabilities are right? There not things you make up in your head to suit your fantasies. There's two outcomes, the buildigns fall or they don't. They did. The probability they didn't is 0. You're working with a very small sampling population (do you know what that means?) with only one observed outcome.

You don't know what you are talking about. All you have done is assigned a fake probability to you incredulity. Why would you come to a skeptical forum and make up statistics that can't be supported by any evidence and not expect to be called on it? Do you really think you will find people here that are going to suddenly bend their understanding of mathematics to suit your fancy? You may think this works in other forums, but seriously, it's not going to fly here. You are being called out as a liar, show how you arrived at your "probabilities" or admit you made them up.
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Have you ever read Candide, ou l'Optimisme by Voltaire? It's very much like the official 9/11 story - everything that could possibly go wrong does go wrong. The series of catastrophies that unfolds in Candide is obviously improbable in real life, although possible in theory. Some of the events of 9/11, on the other hand, appear to be impossible. Even if they were possible, the story would still be as absurdly improbable as Voltaire's masterpiece. The fact that you'd ask somebody to put a number on this kind of probablility just shows how desperate you are to put people off asking valid questions.


Dave Rogers said:
That's known as the a priori - a posteriori fallacy, isn't it? We know, in any scenario, that some outcome must have occurred. Claiming that the actual outcome was low-probability is simply a pointless observation, as in a highly complex scenario with a very large range of possible outcomes, every outcome is low-probability. It would only be cause for suspicion if you could demonstrate that that specific outcome had been predicted or intended, and on that you have nothing more than speculation.
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Let's imagine a team of demolition experts had been given the job of razing the WTC complex to the ground, using only two Boeing 767's which could be flown by remote control to target any two of the seven buildings. Public health is not an issue, but they are asked to minimize damage to the surrounding area as far as possible.

Could the demolition team have done a better job with the benefit of careful planning than the terrorists did by sheer chance? Could the demolition team even guarantee they'd do an equally good job as the terrorists? My common-sense understanding of probablity tells me they probably couldn't. It tells me that the official story of what happened at the WTC is so far fetched that it's absolutely unbelievable for anybody with an everyday knowledge of how things work.


Dave Rogers said:
There's no evidence that - for example - al-Qaeda specifically set out to destroy WTC7, but leave the entire WFC still standing. How do you account for the failure to destroy any of the World Financial Centre, when the clear aim of the attack was the financial centre of the USA? Clearly, the attack could have been more successful than it was.
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These questions are pointless, since 'al Qaeda' probably didn't play any part in the attacks .
 
Heiwa said:
Seriously, please do not compare an acceleration of anything and not ... an upper block (???) to the strength of a floor below.

You are just making a fool of yourself!
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To be more precise, it is the kinetic energy from acceleration. A simple clarification that even you can understand.

Now if you care to address the actual topic, be my guest.
 
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Seymour Butz said:
Try every one of your posts where you fail to explain how you can hold BOTH the "bounce" scenario and "entanglement" scenario to be true, for starters.

Picking one or the other would be a first step in building some credibility.

But you won't, will you?
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I like the "bounce scenario" the mental image of the top bouncing up and then bouncing down the street is right out of the cartoons.
 
Heiwa said:
Seriously? In detail? :)
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Yup, calculations in detail. 'Mechanics of Progressive Collapse: Learning from World Trade Center and Building Demolitions' pp 3 to 10.
Published in Journal of Engineering Mechanics, Vol. 133, No. 3, March 2007.

How many engineering journals have you published your 'bounce' theory in Heiwa? Throw us a link to them.
 
I'm reposting this with a slight correction for wording. It apparently threw Heiwa off the deep end, so in an effort not to confuse him further, the repost;

Note to Tony S. regarding the missing jolt paper.

Tony, I have a very hard time following your logic. On p. 10 you state 'Bazant claims that a minimum force amplification of 31g, or 31 times the static weight of the
upper stories, would have occurred in a collision between the upper and lower blocks of the Twin Towers after a fall of one story. [17]' (17. Bazant and Zhou, 2002, p. 3.)

You use this 31g figure as the basis to calculate your estimate for the kinetic energy losses, hence the 'jolt'. However, when you actually read p 3 of 'Why did the World Trade Center Collapse?' it is clearly stated that 'The solution P = Pdyn yields the following elastically calculated overload ratio due to impact of the upper part:

where Po=mg=design load capacity.

So all it does is give a calculation for the overload ratio vs the design load capacity. It demonstrates with calculations that the kinetic energy of the upper block far exceeds the strength of the impacted floor below.

There is no valid reason that there should be massive deceleration. As stated in the 2006 paper 'Mechanics of Progressive Collapse:
Learning from World Trade Center and Building Demolitions ' Bazant and Verdure; 'the kinetic energy of
the falling upper part far exceeded the energy that could be absorbed by limited plastic deformations and fracturing in the lower part of tower. ' The kinetic energy of the top part of tower impacting the floor below was found to be about 8.4 × larger than the plastic energy absorption capability of the underlying story, and considerably higher than that if fracturing would be taken into account (p3)

They then provide very comprehensive Crush-down/Crush-up calculations to show in detail how much energy was involved. The summary of these findings is published in the Journal of Engineering Mechanics, 'What Did and Did not Cause Collapse of WTC Twin Towers in New York'.

It is very clear from their calculations that the buildings were not in freefall, as your analysis also finds. This of course immediately argues against explosive demolition, and we don't need to bother with it further at this point. But also it is clear that the loss of kinetic energy amounts to a fairly small percent, and certainly there is no agreement with your assertion that there would be an enormous deceleration.

Tony, your jolt theory paper is of course nowhere near as comprehensive an analysis as either of the Bazant papers, nor was your paper published in an engineering journal. But even so, you have completely ignored the loss of perimeter column capacity due to bowing, where Bazant et al have not. So the context for your analysis lacks the appropriate parameters to be meaninful in the first place; the bowing of columns cannot be handwaved out of existence, it is central to the mechanism for the collapse of the towers.

Further, the bowing, without a doubt caused by the high-speed plane impacts and subsequent fires, cannot plausibly be the result of some mythical pyrotechnic devices planted there by unspecified Men In Black (not Jewish, of course). That is a ludicrous and pathetic hypothesis, not based in science at all. In my view it is a cop out, an abandonment of serious inquiry.

So comparing the 3 Bazant papers with your paper's claims, not only does your main claim NOT fit with the statements in the Bazant papers, making for a rather poor refutation to begin with, but you haven't even BEGUN to formulate good math counter to the Bazant Crush-Down/Crush-up equations. You don't even bother, instead focusing on what appears to be a misrepresentation of Bazant's work, and an attempt at misdirection to justify your argument to incredulity.

If you're going to continue making wild claims about explosives, you ought to at least consult with leading experts in demolitions to look at the feasibility. I think if you were really serious about this inquiry, you'd have done so long ago, and probably would've modified your approach to EXCLUDE controlled demolition, as it just doesn't fit.

I also noticed you mentioned the '2.25s close to freefall' in the WTC7 collapse, the Holy Grail of truther 'CD in the gaps' conspiracy theories. I will address that another time, this is enough for today. I'm going canoeing now.

This obsession you guys have with CD is making fools out of you. Seriously.
 
bill smith said:
The floors of C and A. There is no question of the upright columns failing at this point so C must become impaled on A like a cocktail sausage on a stick.
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Heiwa refuses to answer my question. You are his disciple, so give it a try.

Several floors of the building have collapsed and gather weight and momentum as they fall. They hit the ceiling of the next floor. What is supposed to stop them?
 
Heiwa said:
Yes, jackals just feed on the corpses. No brains, whatsoever. Look out for snakes, though.
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All the floors that have collapsed fall on top of the ceiling of the next floor. You claim that something stops them. What is supposed to stop them? It is obvious to almost everyone else that the collapsing floors crash through.
 
It really is amazing how something that happened three times in one day can't be scaled. Not even a computer model can look like anything close that was witnessed that day.

Keep apologizing. Maybe if you do it will eventually work and you won't need to check into this crutch mental facility of a sub-forum any longer.

But I doubt it.
 
alienentity said:
I'm reposting this with a slight correction for wording. It apparently threw Heiwa off the deep end, so in an effort not to confuse him further, the repost;

Note to Tony S. regarding the missing jolt paper.

Tony, I have a very hard time following your logic. On p. 10 you state 'Bazant claims that a minimum force amplification of 31g, or 31 times the static weight of the
upper stories, would have occurred in a collision between the upper and lower blocks of the Twin Towers after a fall of one story. [17]' (17. Bazant and Zhou, 2002, p. 3.)

You use this 31g figure as the basis to calculate your estimate for the kinetic energy losses, hence the 'jolt'. However, when you actually read p 3 of 'Why did the World Trade Center Collapse?' it is clearly stated that 'The solution P = Pdyn yields the following elastically calculated overload ratio due to impact of the upper part:

where Po=mg=design load capacity.

So all it does is give a calculation for the overload ratio vs the design load capacity. It demonstrates with calculations that the kinetic energy of the upper block far exceeds the strength of the impacted floor below.
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We don't use the 31g as a basis to calculate the energy losses. The energy losses are a function of the strength of the columns at the top of the lower block and at the bottom of the upper block or on the 97th and 99th floors which are assumed to elastically and plastically deform and then buckle.

Dr. Bazant actually has an error in terms here as Po is the actual design load not the load capacity which would have been at least three times greater due to the factors of safety used in the column design.

There is no valid reason that there should be massive deceleration. As stated in the 2006 paper 'Mechanics of Progressive Collapse:
Learning from World Trade Center and Building Demolitions ' Bazant and Verdure; 'the kinetic energy of
the falling upper part far exceeded the energy that could be absorbed by limited plastic deformations and fracturing in the lower part of tower. ' The kinetic energy of the top part of tower impacting the floor below was found to be about 8.4 × larger than the plastic energy absorption capability of the underlying story, and considerably higher than that if fracturing would be taken into account (p3)
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There is plenty of valid reason for a massive jolt. How do you think the kinetic energy gets transferred? Why do you think Bazant said there had to be a powerful jolt?

They then provide very comprehensive Crush-down/Crush-up calculations to show in detail how much energy was involved. The summary of these findings is published in the Journal of Engineering Mechanics, 'What Did and Did not Cause Collapse of WTC Twin Towers in New York'.

It is very clear from their calculations that the buildings were not in freefall, as your analysis also finds. This of course immediately argues against explosive demolition, and we don't need to bother with it further at this point. But also it is clear that the loss of kinetic energy amounts to a fairly small percent, and certainly there is no agreement with your assertion that there would be an enormous deceleration.
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The lack of freefall does not argue against controlled demolition. All it says is that there was some residual resistance remaining. I used an example here the other day where you have a 100 lb. weight supported by 30 columns which can each support 10 lbs. and you then remove 27 of the columns. What happens? The 100 lb. weight fall at 0.7g, not freefall. All that needs to be done is to remove enough columns so that the load above cannot be supported to create the fall.

Tony, your jolt theory paper is of course nowhere near as comprehensive an analysis as either of the Bazant papers, nor was your paper published in an engineering journal. But even so, you have completely ignored the loss of perimeter column capacity due to bowing, where Bazant et al have not. So the context for your analysis lacks the appropriate parameters to be meaninful in the first place; the bowing of columns cannot be handwaved out of existence, it is central to the mechanism for the collapse of the towers.

Further, the bowing, without a doubt caused by the high-speed plane impacts and subsequent fires, cannot plausibly be the result of some mythical pyrotechnic devices planted there by unspecified Men In Black (not Jewish, of course). That is a ludicrous and pathetic hypothesis, not based in science at all. In my view it is a cop out, an abandonment of serious inquiry.
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Please show how the bowing has any import to the continuation of the collapse once it was initiated. It is the continuation of the collapse that the jolt is necessary for, and what the paper addresses.

So comparing the 3 Bazant papers with your paper's claims, not only does your main claim NOT fit with the statements in the Bazant papers, making for a rather poor refutation to begin with, but you haven't even BEGUN to formulate good math counter to the Bazant Crush-Down/Crush-up equations. You don't even bother, instead focusing on what appears to be a misrepresentation of Bazant's work, and an attempt at misdirection to justify your argument to incredulity.
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If you have actually read "The Missing Jolt" paper you would have noticed that we found a significant error in Bazant and Zhou's calculation of the axial stiffness of the columns. They calculate 71 GN/m when it is actually 7.1 GN/m. So they were off by a factor of ten, probably the result of a misplaced decimal point. Using the correct stiffness (C) of 7.1 GN/m in Bazant's equation for overload ratio, gives an 11g Pdyn/Po ratio. In addition to that, I showed you the design load vs. design capacity term error above made by them also, which is somewhat misleading. The columns actually had a capacity of at least 3 times their actual load so now the overload is down to about 367%, not the 3100% Bazant and Zhou show. So much for your credits of mathematical superiority to the Bazant papers over the one I was involved in.

Admittedly, a 367% overload ratio is more than sufficient but how do you transmit it to the lower structure? The answer is that there must be an impulse with it's requisite deceleration to transfer the kinetic energy. If there is no deceleration there is no 367% overload. Bazant knew this and that is why he felt there must have been a very powerful jolt. He just never measured for it. When someone finally measured for it it turned out that there was no deceleration of the upper block and thus no transfer of this kinetic energy could have been accomplished. The problem for Bazant's papers is that his core requirement of a jolt isn't there, so his hypothesis is rendered meaningless as far as it's being able to explain the collapse of the North Tower.

If you're going to continue making wild claims about explosives, you ought to at least consult with leading experts in demolitions to look at the feasibility. I think if you were really serious about this inquiry, you'd have done so long ago, and probably would've modified your approach to EXCLUDE controlled demolition, as it just doesn't fit.

This obsession you guys have with CD is making fools out of you. Seriously.
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I don't know what you do for a living but from what you say above it appears you are not qualified to comment on these matters, and it is thus incredibly indulgent of you to suggest I seek out leading experts as though I have no expertise of my own and haven't already sought comment from other professionals qualified in this area.

I see no need to continue this discussion as with this reply I think I have laid out everything you would need to come to an informed decision.
 
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bardamu said:
Have you ever read Candide, ou l'Optimisme by Voltaire? It's very much like the official 9/11 story - everything that could possibly go wrong does go wrong. The series of catastrophies that unfolds in Candide is obviously improbable in real life, although possible in theory. Some of the events of 9/11, on the other hand, appear to be impossible. Even if they were possible, the story would still be as absurdly improbable as Voltaire's masterpiece. The fact that you'd ask somebody to put a number on this kind of probablility just shows how desperate you are to put people off asking valid questions.
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Blah Blah Blah, wine wine, blah Voltaire,blah blah...

I'm not putting off people asking valid questions, I'm pointing out idiotic statements made by ignorant people.

You're arguing from incredulity. Just admit it and move on. The fact is all the 110 story buildings that have been hit by planes have collpased. Given the number of events and known outcomes there is no probability, just a known certainty.
 
Tony Szamboti said:
There is plenty of valid reason for a massive jolt. How do you think the kinetic energy gets transferred? Why do you think Bazant said there had to be a powerful jolt?
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Floors which function to provide the lateral bracing to the building and not the vertical loads from the weight of the building itself generally won't succeed in offering any appreciably visible "jolt." I find that given their survival of the main collapse, the core structures of both towers weren't as much a mechanism in the collapse progression as the failure of the floor connections and the perimeter columns. You'll have top forgive me if for lack of better wording I describe your contention that there should have been one massive visible jolt a bit bizarre


Tony Szamboti said:
The lack of freefall does not argue against controlled demolition. All it says is that there was some residual resistance remaining.
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Never cared for the freefall argument... the only thing controlled demolitions and progressive collapse have in common is that they both involve some form of structural failure.

Tony Szamboti said:
All that needs to be done is to remove enough columns so that the load above cannot be supported to create the fall.
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I do hate to nit pick at this but the moment a demolition is made into some haphazard application, it's not really controlled anymore. The core columns in both towers didn't collapse until after everything else had already failed, so unless you're arguing that the charges must have been applied in the impact zone (which based on my reading doesn't appear to be the case)... I'm baffled as to how this was even necessary for the continuation of the collapse when clearly their failure wasn't necessary to facilitate the progressive nature of the collapse.

As for your paper... I haven't had a shot at reading it in it's entirety... since I'm bored I suppose I'll put my tin foil hat on and take the time to read it... I'll get back to you once I finish....
 
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Re Tony S. last reply, he admits that EVEN accounting for the quibbles with Bazant's math, you still have plenty of kinetic energy to destroy the floors below.

In fact in Tony's words 'Admittedly, the 367% overload ratio is more than sufficient' OK, basically it's game over for the necessity of explosives, as if we didn't already know this. Tony then asks' but how do you transmit it to the lower structure?' Tony doesn't know, or doesn't care to elaborate, past insisting on a visible jolt or explosives.

It's a false dichotomy. Tony doesn't know, so he simply defaults to the truther axiom 'must be controlled demolition'. Even though it obviously CAN'T be CD based on the ACTUAL events and collapses.

As I said Tony, go ahead and publish this paper in a respected mechanical engineering journal, as opposed to the bogus Journal of 9/11 studies, and get back to us. I very much doubt your idea will last very long outside of the twoofersphere.

You've conveniently handwaved the bowed columns into nothing, merely and irrelevant detail for you to ignore. But unfortunately it poisons your entire premise, because it provides the necessary motion to initiate collapse, just not the way you want to see it.

That's just too bad. No explosive squibs, no visible detonations, no controlled demolition. If you don't understand it by now, you never will.

You're making fools out of yourselves. Be my guest. I won't stop you.
 
Grizzly Bear said:
Floors which function to provide the lateral bracing to the building and not the vertical loads from the weight of the building itself generally won't succeed in offering any appreciably visible "jolt." I find that given their survival of the main collapse, the core structures of both towers weren't as much a mechanism in the collapse progression as the failure of the floor connections and the perimeter columns. You'll have top forgive me if for lack of better wording I describe your contention that there should have been one massive visible jolt a bit bizarre



Never cared for the freefall argument... the only thing controlled demolitions and progressive collapse have in common is that they both involve some form of structural failure.


I do hate to nit pick at this but the moment a demolition is made into some haphazard application, it's not really controlled anymore. The core columns in both towers didn't collapse until after everything else had already failed, so unless you're arguing that the charges must have been applied in the impact zone (which based on my reading doesn't appear to be the case)... I'm baffled as to how this was even necessary for the continuation of the collapse when clearly their failure wasn't necessary to facilitate the progressive nature of the collapse.
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The 50 to 60 stories of core columns remaining after the collapse front passed by were only interior core columns. All of the outer core columns, which were the largest columns in the buildings, went down with the collapse front. I don't know how many people realize this.

If the outer core columns were taken out every three stories it explains the floors collapsing and the perimeter columns coming down and also the lower interior columns remaining. The interior columns could survive temporarily once the columns were strong enough to withstand their connections being broken from the outer core columns pulling on them. Hence the lower interior columns remained standing for a time. Once the collapse front was completely on the ground the remaining interior columns were too tall and slender to support their own weight and buckled as a group and fell to the ground.
 
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alienentity said:
Re Tony S. last reply, he admits that EVEN accounting for the quibbles with Bazant's math, you still have plenty of kinetic energy to destroy the floors below.

In fact in Tony's words 'Admittedly, the 367% overload ratio is more than sufficient' OK, basically it's game over for the necessity of explosives, as if we didn't already know this. Tony then asks' but how do you transmit it to the lower structure?' Tony doesn't know, or doesn't care to elaborate, past insisting on a visible jolt or explosives.

It's a false dichotomy. Tony doesn't know, so he simply defaults to the truther axiom 'must be controlled demolition'. Even though it obviously CAN'T be CD based on the ACTUAL events and collapses.

As I said Tony, go ahead and publish this paper in a respected mechanical engineering journal, as opposed to the bogus Journal of 9/11 studies, and get back to us. I very much doubt your idea will last very long outside of the twoofersphere.

You've conveniently handwaved the bowed columns into nothing, merely and irrelevant detail for you to ignore. But unfortunately it poisons your entire premise, because it provides the necessary motion to initiate collapse, just not the way you want to see it.

That's just too bad. No explosive squibs, no visible detonations, no controlled demolition. If you don't understand it by now, you never will.

You're making fools out of yourselves. Be my guest. I won't stop you.
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Alright, you made me respond. You sir are twisting words here in an indescribable way and causing me to be suspicious of your motives.

I completely explained that while the energy was there to cause the next lower stories to collapse that the energy needs to be delivered by an impulse. An impulse requires deceleration and we find none in the collapse of the upper block of the North Tower. If there is no deceleration there is NO natural mechanism for natural collapse. This is what the Missing Jolt paper discusses. Unfortunately, it has either gone over your head or you are intentionally trying to manipulate for an ulterior motive you have.
 
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