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OOS Collapse Propagation Model

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Once again:

"A simplified one-dimensional analytical
solution of the collapse front propagation will be presented. It
will be shown how this solution can be used to determine the
energy absorption capability of individual stories if the motion
history is precisely recorded. Because of the shroud of dust and
smoke, these histories can be identified from the videos of the
collapsing WTC towers only for the first few seconds of collapse,
and so little can be learned in this regard from that collapse."

you see, he would like to apply it to the WTC1 if the motion history was precisely recorded. That was his intention as he states, but he cannot because of all the dust and smoke.

The intention of these equations is to map the actual propagation front, just as he states.

Myriad, please show where Dr Bazant intends the equations to be used only as a best case scenario, rather than to map the actual collapse front of the actual building.

>>>>>>>>>>>>>>>>>>

I watched Dr Benson apply it to the first few seconds of data over many, many posts. He tries to match real data of the real building to the equations, not some "best case scenario".

>>>>>>>>>>>>>>>>>

I asked: Myriad, in BL, can you explain why Dr Bazant insists that crush down must be complete before crush up occurs.

Myriad answers: Dr. Bazant provided a rigorous explanation of that, in the analysis just before he stated the conclusion resulting from that analysis. The conclusion was: "So it must be concluded that the simplifying hypothesis of one-way crushing (i.e., of absence of simultaneous crush-up), made in the original paper, was perfectly justified and caused only an imperceptible difference in the results." If you read the part before that conclusion, you'll see the reasoning leading to that conclusion.

That is good advice. Did you do it? That is the part I wanted you to answer. Explain the reasoning behind why he believes significant crush up doesn't occur. (Hint; It has something to do with the columns in the upper block)
 
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He is applying it to his model of a WTC tower, which incorporates best-case assumptions for the possibility of collapse arrest. That he is analyzing a model is indicated by the methodology used -- which is performing mathematics on the model, as opposed to, say, running up and down the tower with a tape measure as it was collapsing.

In other words, complete crush-down preceding significant crush-up is not an arbitrary assumption imposed on the best-case model to simplify the calculations, it is also a result derivable from analysis of the best-case model.

If it could be shown with actual evidence that crush-down did not in fact precede crush-up in the real event, all that would mean is that the real case was far worse, in terms of the likelihood of collapse arrest, than the assumed best case. (Which we already knew, because for most of the collapse, the load sheared floors from the columns instead of buckling the columns, reducing the actual amount of energy absorbed in inelastic strain to only a small fraction of the maximum theoretically possible).

Again: if your goal is to show that there should have been a better than best-case outcome, showing that there was a worse than best-case event won't get you there, or even move you in the right direction. You're basically pushing on a rope here.

Respectfully,
Myriad

What do you mean with "best case"?

See video evidence of WTC-1 collapse, crush up precedes crush down in the first seconds. Why continued crush up would not had lead to collapse arrest?
 
Hey, Major_Tom learned what Bazant was talking about when he said "paradigm", amazing!
 
Myriad, please show where Dr Bazant intends the equations to be used only as a best case scenario, rather than to map the actual collapse front of the actual building.


Here y'go:

Abstract: This paper presents a simplified approximate analysis of the overall collapse of the towers of World Trade Center in New York on September 11, 2001. The analysis shows that if prolonged heating caused the majority of columns of a single floor to lose their load carrying capacity, the whole tower was doomed. The structural resistance is found to be an order of magnitude less than necessary for survival, even though the most optimistic simplifying assumptions are introduced. [emphasis added]

Clever of Bazant, wasn't it, to hide his intentions in the abstract. I mean, who reads those, right? :rolleyes:

Respectfully,
Myriad
 
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I am really not an expert, but my common sense says that:

When the upper block is smashed by the intact block underneath, then the upper block had lost its destructive energy.

What do you figure happened to the mass of the upper block? That is after all the "destructive" part (whether it's intact or not)
 
Myriad, you are aware of the difference between BZ and BV?

Here is the abstract from the BZ paper:

Abstract: This paper presents a simplified approximate analysis of the overall collapse of the towers of World Trade Center in New York
on September 11, 2001. The analysis shows that if prolonged heating caused the majority of columns of a single floor to lose their load
carrying capacity, the whole tower was doomed.

It is identical to your quote so I assume you are quoting from BZ?

Is this true?

Like I said, if you keep mixing BV and BZ you will argue yourself into a corner.

Please read the introduction in BV instead.
 
What do you figure happened to the mass of the upper block? That is after all the "destructive" part (whether it's intact or not)

see the video evidence of wtc-1, the upper block was destroyed to a big part the first seconds, before the block underneath was affected at all.
 
See video evidence of WTC-1 collapse, crush up precedes crush down in the first seconds. Why continued crush up would not had lead to collapse arrest?

Why would it? If it crushes up it adds rubble on the top of the remaining building until such time as the floor supports would fail and then the building would crush down.

I happen to think that it crushed up and down after the first half second or so but it really doesn't matter. Its the initiation event that counts.
 
see the video evidence of wtc-1, the upper block was destroyed to a big part the first seconds, before the block underneath was affected at all.
Are you claiming this mass disappeared? If not, what makes you think the "rubble" from the top block would be less destructive then the intact structure?

I believe it would be more because it would be denser (more compact mass).
 
see the video evidence of wtc-1, the upper block was destroyed to a big part the first seconds, before the block underneath was affected at all.

The fact that you're wrong doesn't make you right, y'know. It just makes you wrong. Your opinions do not change reality.

 
Bazant's model is a limiting case representing the most favorable assumptions for collapse arrest. Among those assumptions is that all the weight of the falling mass -- even the already crushed and broken rubble -- somehow lands squarely on columns.

In that model, meaning under those assumptions, crush-down precedes crush-up. Bazant shows how and why.

The extent to which crush-down did not precede crush-up in the actual collapse indicates only that those favorable assumptions for collapse arrest were not true, so collapse arrest was even more impossible.

Try this analogy, Major Tom: suppose you're skydiving and your chute fails to open. Bazant, who happens to be looking on, quickly assesses the situation and says, "His best chance to survive is if he lands on that giant pile of mattresses over there. But even then, my calculations say the landing will kill him." You respond (since you have nothing better to do whilst plummeting earthward), "Ha! I'm landing nowhere near those mattresses! In fact, I'm heading right for that Upright Steel Spikes Inc. storage yard 1000 feet west instead. You believe I'm going to land on the mattresses but the facts contradict you. So your prediction that I'm going to die has no validity!

At that point Bazant rightly figures that there's no point in saying anything further. Why bother to argue with someone who thinks that proving a situation is worse than the best-case scenario somehow means that one should expect better than the best-case outcome?

Respectfully,
Myriad

Worst case scenario? More made up official lies.:rolleyes:

Yes you proved the column will buckle when loaded to 100 lbs but what happens if I load it to 500 lbs, can't answer that can you dubunker?:boggled:
 
Why would it? If it crushes up it adds rubble on the top of the remaining building until such time as the floor supports would fail and then the building would crush down.

I happen to think that it crushed up and down after the first half second or so but it really doesn't matter. Its the initiation event that counts.

There is a difference whether the mass falls down on or just lies on something: As the upper block fell down on the block underneath and was smashed for a big part, then this is evidence for me, that it lost its destructive energy. Especially when we take into account, that the block underneath stayed intact the first seconds.
 
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I am really not an expert, but my common sense says that:

When the upper block is smashed by the intact block underneath, then the upper block had lost its destructive energy.
Did you help Major Tom with his conclusions? You support your claim with solid evidence. Major Tom needs support like this.

There is a difference whether the mass falls down on or just lies on something: As the upper block fell down on the block underneath and was smashed for a big part, then this is evidence for me, that it lost its destructive energy. Especially when we take into account, that the block underneath stayed intact the first seconds.
It did not stop, it made the next section fail, and then with more mass the next section, all the way to the ground. A floor in the WTC can not hold the mass that fell from above it on 911. A floor only holds so much weight and fails, even if you just place it softly on the floor. How many pounds can your imaginary never fail WTC floor hold?

Real structural engineers understand the collapse of the WTC. Like the chief structural engineer of the WTC who calls the 911 truth movement nonsense. I suggest you find some engineers who are not in 911 truth and get their advice. Oops, you are getting that but ignoring it, right here.

8 years; you could have had a PhD in engineering structures, and you would see Major Tom's work as nonsense and not be supporting his work with your common sense nonsense.
 
Myriad, in your last post, when asked a question about BL, you quoted an abstract from the wrong paper.

Once again: Myriad, please show where Dr Bazant intends the equations to be used only as a best case scenario, rather than to map the actual collapse front of the actual building.

Remember he gives the equations in BV. The intention of BV is different than that of BZ, as anyone can see by reading the introduction of the correct paper.

Can you answer this without citing the wrong paper?
 
Did you help Major Tom with his conclusions? You support your claim with solid evidence. Major Tom needs support like this.


It did not stop, it made the next section fail, and then with more mass the next section, all the way to the ground. A floor in the WTC can not hold the mass that fell from above it on 911. A floor only holds so much weight and fails, even if you just place it softly on the floor. How many pounds can your imaginary never fail WTC floor hold?

(...)

no - I cannot see such a "pancaking" of floors, the mass of the towers were exploding to the outside. There was no "mass of rubble", where the towers stood, everything was distributed at Ground Zero. We can see that on the remaining core and perimeter columns. Furthermore we can see that, by the survivors, who survived in the fourth floor of WTC 1.

Jay Jonas is actually inside the North Tower, on its fourth floor. Seconds before the collapse he feels “a tremendous vibration and shaking; the floor began waving.”
Providence Journal, 9/11/2002

I just try to find out, what the official collapse explanation is. I do not understand, what Major_Tom is writing about, but his inputs help me a lot.
 
no - I cannot see such a "pancaking" of floors, the mass of the towers were exploding to the outside. There was no "mass of rubble", where the towers stood, everything was distributed at Ground Zero. We can see that on the remaining core and perimeter columns. Furthermore we can see that, by the survivors, who survived in the fourth floor of WTC 1.

Jay Jonas is actually inside the North Tower, on its fourth floor. Seconds before the collapse he feels “a tremendous vibration and shaking; the floor began waving.”
Providence Journal, 9/11/2002

I just try to find out, what the official collapse explanation is. I do not understand, what Major_Tom is writing about, but his inputs help me a lot.

When the floors fail the shell sections are not supported and they fall off. It has been 8 years and you don't understand the construction of the WTC? What have you been studying, lies, hearsay, and fantasy?

The WTC is a system of core, floors and shell, they formed a very strong structure. The WTC was not designed for 470 and 590 mph aircraft impact, it was designed for a 180 mph impact which would survive.

Major Tom is only trying to make a paper so he can say, " see, it could be CD". He cares less about who died on 911 but more about his fantasy conspiracy theory about CD, thermite or some other crazy idea of how the WTC fell and some inside job by the US government.

My parents sent me to engineering school and the USAF to engineering grad school, it helps me see quickly the BS Major Tom's paper is. Anyone with a grade school education can figure it out also, my training is not needed to call BS on Major Tom's work; why can't you figure it out?

What would Leslie Robertson say?
 
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Myriad, in your last post, when asked a question about BL, you quoted an abstract from the wrong paper. [...]
Can you answer this without citing the wrong paper?

Seeing as how there is no paper by Bazant and Le that is relevant here, and you've ignored requests to clarify what you mean, I think you should cool it a bit.

Do you mean Bazant, Le, Greening, and Benson (2008), sometimes known as BLGB? Or are you even more confused than we thought?
 
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Myriad, in your last post, when asked a question about BL, you quoted an abstract from the wrong paper.

Once again: Myriad, please show where Dr Bazant intends the equations to be used only as a best case scenario, rather than to map the actual collapse front of the actual building.

Remember he gives the equations in BV. The intention of BV is different than that of BZ, as anyone can see by reading the introduction of the correct paper.

Can you answer this without citing the wrong paper?


I cited the paper that contains the answer to the question you asked regarding whether Bazant intended the assumptions made in his collapse model of the WTC towers to represent a limiting best (most favorable to collapse arrest) case. In the paper in which he introduced that model and first applied it to the WTC collapses, he clearly stated that it was (using the phrase "most optimistic.") That paper is cited in "BV" so presumably Bazant still stands by its claims; nor does he need to repeat that information in "BV," having cited it.

What is this bizarre game you're playing with "answer my question using only the paper I tell you to?" Can I play too? What's the capital of Michigan, and please back up your answer using only passages from Shakespeare's prime numbered sonnets. Thanks!

Respectfully,
Myriad

ETA: Actually there's a misstatement in the above that I'll gladly own up to. I did not actually cite the paper containing the answer, I merely quoted the answer itself from the paper. However, since you had no difficulty discerning which paper I was quoting from, no harm done I trust.
 
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