The NIST report, start to finish

Here's another example of how "optimistic" Bazant was in his model: he didn't even take into account the buildings' full structural integrity. He only took into account design loads.

The second error made by Dr. Bazant is his failure to take account of the factor of safety
designed into the towers' construction. He makes no mention whatsoever of this crucial
design parameter. This failure leads to a major underestimation of the ability of the
columns to resist the downward acting forces.

The effect of this error by Dr. Bazant is an error in his ratio of energies. If this is adjusted
to take account of a factor of safety of 4 the ratio is reduced from his value of 8.4 to 2.1.
It must also be noted that the ratio mentioned by Dr. Bazant is relevant only to the first
collision after a freefall of one storey. He is specifically dealing with a situation where
the energy of the fall through two storeys is resisted by the columns of one storey. The
continuation of the collapse would not have these conditions but rather have the fall of
one storey resisted by the columns of one storey. Without the period of uncontested
freefall the ratio of energies would be reduced for the remaining duration of the collapse
from Dr. Bazant's figure of 8.4 to 1.05.

Since Dr. Bazant has stated that his figure of 8.4 corresponds with the observed collapse
times of the towers, we can easily reverse this logic to say that if 8.4 corresponds to
the collapse times which were present, then 2.1 certainly does not. Indeed examination of
a simple series of calculations such as Dr. Bazant mentions shows a theoretical, total
collapse time of about 11 seconds, but adjustment of the ratio to give due consideration to
the safety factor increases the theoretical collapse time to about three times this figure,
about 35 seconds. Thus even using his flawed analysis and assumptions, and making only
one change to take account of the safety factor, it can be simply shown that the collapse
times obtained by this analysis do not correspond to the collapse times which were
observed in reality.

www.journalof911studies.com...


Already we are seeing that "7x the amount of energy necessary" claim vanishing into thin air.

First of all it was based on all the energy being isolated to the first floor to be impacted when obviously it would have dissipated across numerous floors simultaneously as described earlier.

On top of that he isn't even taking into account the full strength of the buildings.

And of course he is assuming a total free-fall to start all this off, which also didn't happen.


You don't need to make up bizarre metaphors for what Bazant is doing. It's this easy to plainly state. He was not making assumptions in favor of a collapse arresting. He was doing everything possible in order for his model to fully collapse, which is the exact opposite.

This also shows in the energy calculations where he also assumes 50-95% of the mass must remain available for the entire collapse. That takes his model completely out of the realm of possibility, even by itself.

reply to post by bsbray11


When you are trying to defend an indefensible position you end up being pushed into pretty ridiculous corners.

It will always be amazing what lengths they people will go to in denying reality and logic for something they feel they should believe.

reply to post by Darkwing01


It is an overestimation. The reason this is done is because the actual events are unknown. So you start to figure out what would happen in the most optimitic case. If in the most optimitsic case the collapse would not arrest, it would also not arrest in a less optimitic case. This is sound logic, just like my example with the rope. Unless of course you can point out relevant assumtions that were ignored or wrong. But it is not wrong by default.

Originally posted by bsbray11
PLB claimed earlier in the thread that Bazant's model was enough to prove that a collapse could not be arrested after the first undamaged floor failed. But immediately he refused to discuss the actual assumptions of that model.

Not going to answer to all your rubbish, but I never made such a claim. You are very confused.

It is an overestimation. The reason this is done is because the actual events are unknown. So you start to figure out what would happen in the most optimitic case. If in the most optimitsic case the collapse would not arrest, it would also not arrest in a less optimitic case. This is sound logic, just like my example with the rope. Unless of course you can point out relevant assumtions that were ignored or wrong. But it is not wrong by default.

reply to post by -PLB-


No, it isn't wrong by default, but that wasn't the only assumption Bazant made. The paper is loaded with unsubstantiated assumptions made simply on the basis of denying any possibility of CD.

Again: Even if you make the assumption of large values for one and small values for three 1 + 1 is still not 3.

When you get to the density of assumption that Bazant was making you had better be sure the empirical support for your positions is ironclad. Newton's laws, for example, make some pretty extensive simplifying assumptions too.

But Newton's law is exquisitely falsifiable and amenable to forming the basis of repeatable experiments. Bazant's is...

...well...

..build a model that behaves as Bazant predicts then maybe we can talk. As of now however all empirical data point to the fact that Bazant is, in the immortal words of Wolfgang Pauli, "...nicht nur nicht richtig, es ist nicht einmal falsch!" (not even wrong).

en.wikipedia.org...

Originally posted by Darkwing01
The paper is loaded with unsubstantiated assumptions made simply on the basis of denying any possibility of CD.

Such as? You may start with listing a single one, and explain how the assumption was made on the basis of denying any possibility of CD.

Originally posted by -PLB-
Such as? You may start with listing a single one, and explain how the assumption was made on the basis of denying any possibility of CD.

You seriously want to see just a single flaw with that paper, in favor of forcing a collapse to progress?

Why don't you read the top of this page, or the paper it comes from?

reply to post by bsbray11


Like I said I rather discuss the subject with someone who understands it. The text you quoted is fundamentally wrong. They confuse forces with energy. The forces exceeded 31 times the design load capacity according to Bazant. Even if Bazant did not include the 4 times safety margin, the load would still exceed the load capacity by a large margin.

Anyway, I don't think you will be open to any argument or reason, and I don't think you will really understand my argument why it is fundamentally wrong. If you did you would have figured it out yourself, as its not really that hard. This is the reason I don't want to debate the subject with you.

Originally posted by -PLB-
Like I said I rather discuss the subject with someone who understands it.

I would too, but I'm willing to work with what little you have to offer. You don't have the same stomach that I do?

The text you quoted is fundamentally wrong. They confuse forces with energy. The forces exceeded 31 times the design load capacity according to Bazant.

Energy and force are integrally related. Energy represents the ability to do work and work is defined as a force applied through a distance. I assume you did the calculations to prove that Ross's conversion of the forces into energies was off, or are you just confused by basic physics again?

Even if Bazant did not include the 4 times safety margin, the load would still exceed the load capacity by a large margin.

Even if Bazant did not include the "4 times safety margin".... That's strike #1 against Bazant's paper, and a very embarrassing elementary mistake in his model that causes it to be off by a factor of 4 right off the bat. That's without considering the other problems mentioned in the same paper.

reply to post by bsbray11


As expected you don't understand why the quoted text is fundamentally wrong, yet you do realize that forces and energy is not the same. On top of that it is based on absolutely nothing that Bazant left out a savety factor in his calculations. In fact, he says he made an approximation himself because detailed information was missing. This garbage isn't worth discussing.

Originally posted by -PLB-
As expected you don't understand why the quoted text is fundamentally wrong, yet you do realize that forces and energy is not the same.

I just explained to you that force and energy are related through the physics concept of work. Force applied across a distance is work, and the amount of work is dependent upon energy. Therefore energy is directly related to how much force can be applied across a distance. If you never learned physics 101 and this is all new and complicated to you then do some Google searches and figure it out yourself.

On top of that it is based on absolutely nothing that Bazant left out a savety factor in his calculations. In fact, he says he made an approximation himself because detailed information was missing. This garbage isn't worth discussing.

No kidding this garbage isn't even worth discussing. That's why you didn't want to discuss it in the first place. If it actually proved something you would be cramming it in our faces. Instead you want to hide it under the rug, when it's your own source. Yes, Bazant made lots of "approximations" in the face of missing data it seems. He also incorrectly applied all of the energy of the upper block onto the first floor directly below only. As Ross explained himself, if the upper block is transferring force through floors to the bottom of the block, then you can't pretend the same force wouldn't also be absorbed by the lower block, and try to force it all to act on the uppermost part of it only. Yet this is also exactly what Bazant did in order to lie about there being more than enough energy to complete a collapse.

Originally posted by bsbray11
I just explained to you that force and energy are related through the physics concept of work. Force applied across a distance is work, and the amount of work is dependent upon energy. Therefore energy is directly related to how much force can be applied across a distance. If you never learned physics 101 and this is all new and complicated to you then do some Google searches and figure it out yourself.

Yet the person you quote doesn't understand any of this, and applies the safety factor of the load (which is a force) directly to the energy consumed in bending the columns. Even you can figure out that this is totally wrong.

No kidding this garbage isn't even worth discussing. That's why you didn't want to discuss it in the first place. If it actually proved something you would be cramming it in our faces. Instead you want to hide it under the rug, when it's your own source. Yes, Bazant made lots of "approximations" in the face of missing data it seems. He also incorrectly applied all of the energy of the upper block onto the first floor directly below only. As Ross explained himself, if the upper block is transferring force through floors to the bottom of the block, then you can't pretend the same force wouldn't also be absorbed by the lower block, and try to force it all to act on the uppermost part of it only. Yet this is also exactly what Bazant did in order to lie about there being more than enough energy to complete a collapse.

The forces would very likely either make a column in the upper part fail or a column in the lower part, but both failing at exactly the same time seems extremely unlikely. But for all I care it may indeed be added to the already extremely unlikely assumptions Bazant makes. And guess what. The collapse still doesn't arrest.

Originally posted by -PLB-

Originally posted by bsbray11
I just explained to you that force and energy are related through the physics concept of work. Force applied across a distance is work, and the amount of work is dependent upon energy. Therefore energy is directly related to how much force can be applied across a distance. If you never learned physics 101 and this is all new and complicated to you then do some Google searches and figure it out yourself.

Yet the person you quote doesn't understand any of this, and applies the safety factor of the load (which is a force) directly to the energy consumed in bending the columns. Even you can figure out that this is totally wrong.

The person I quoted is a professional engineer. And no, I only see that you are still confused about how these terms inter-relate with each other. Neglecting a safety factor translates into several different things in physics. It means the same as imagining much of the physical steel is not even there for one thing, because that is what the numbers suggest when he ignores the FoS. When factored back in, yes, it represents less energy available to progress the collapse, and less force to do the same. You still do not understand that these concepts are related in physics.

The forces would very likely either make a column in the upper part fail or a column in the lower part, but both failing at exactly the same time seems extremely unlikely.

That is not what I was talking about and you are only continuing to demonstrate that you are the one that doesn't understand any of this. When two solid objects impact, force travels through those objects from the point of impact in a compression wave. This is what Ross is talking about when he explains how Bazant is assuming no energy was absorbed by the lower building, and it all went purely to destroying the uppermost floor only, which is impossible. Why does Bazant assume the lowermost floor of the upper block to pack the full potential energy of the entire upper block? Because that energy and those forces travel through the block, in compressive waves of force that I just described.

The same thing had to happen with the lower block, but Bazant ignores this fact because it also saps the amount of energy he has to work with to make a collapse progress.

reply to post by -PLB-

Such as? You may start with listing a single one, and explain how the assumption was made on the basis of denying any possibility of CD.

Aside from anything else he assumes that fire alone was responsible for the collapse and explicitly states at the outset that his intention is to show how that can be the case.

This is not proper form if you are trying to prove that it wasn't CD, so Bazant's paper is automatically disqualified from making that assessment before any further assumptions are made unless it were independently established that fire alone was the cause.

The problem is that instead you people who insist that fire alone was the cause rely implicitly or explicitly on Bazant to support that view...

As I say: It is not even wrong, not even the basic initial assumption is supported by empirical data. It is as real as Pokemon.

reply to post by Darkwing01


Bazants work does not rely on fire being the cause of collapse initiation. His work is also valid when explosives are the cause of collapse initiation. His work isn't about collapse initiation. It doesn't matter how the supports fail. He shows that, given the supports on one floor failed, the collapse would not arrest.

reply to post by -PLB-


I suppose I could have phrased that better.

Yes you are correct that he only assumed explicitly that the initiation was caused by fire, but the assumption that fire induced failure would result in a one story drop is unsupported. The idea that the upper part behaved as a solid block that interacts perfectly inelastically with only the very topmost story of the lower portion is also not a realistic scenario.

In the end though it doesn't matter which assumptions you make if your conclusions can be consistently empirically validated. Bazant's can't. Even if he made no unrealistic assumptions and only used all his equations correctly, if his model still failed to predict reality it would be the engineering equations that would be up for review, not reality.

As it is (fortunately) the engineering equations are perfectly safe.

It is better to be approximately right than precisely wrong.

Originally posted by Darkwing01
In the end though it doesn't matter which assumptions you make if your conclusions can be consistently empirically validated. Bazant's can't. Even if he made no unrealistic assumptions and only used all his equations correctly, if his model still failed to predict reality it would be the engineering equations that would be up for review, not reality.

As it is (fortunately) the engineering equations are perfectly safe.

It is better to be approximately right than precisely wrong.

edit on 25-5-2011 by Darkwing01 because: ly

I disagree. His primary goal was not to model the real collapse, but to create a very simple model to prove there was too little resistance to arrest the collapse. I think you can safely say that without computer simulations you can not come up with an accurate model that describes the actual collapse. It is even likely that a computer model isn't up to the task. For comparison, the truth movement hasn't been able to produce any model that relates the the WTC as far as I know. You can find it questionable that he tries demonstrates his model matches the actual collapse, but to me that isn't really interesting. The knowledge that the collapse would not arrest without any explosives is enough for me. The details are only interesting for structural engineers who design high rise buildings.

reply to post by -PLB-


The paper was drafted less than a week after the attack and, in his words,

This paper presents a simplified approximate analysis of the overall collapse of the towers ofWorld 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.

A simplified and approximate analysis. If you read the paper from an outside point of view it is actually very informative.

I suspect many of you read the simplified version such as this one...

911research.wtc7.net...

But not the actual report.

www.civil.northwestern.edu...

It is not as bad as many say and is better than a pole with some washers on it claiming to solve 9/11. It was also published to ascelibrary.org... which is also known as the ASCE. These guys...www.asce.org... who I think are more than qualified and I am sure includes members of the 9/11 truth movement if they are engineers and are ASCE certified. We would hope...

Originally posted by esdad71
Look It was drafted less than a week after the attack and, in his words, ...
A simplified and approximate analysis. If you read the paper from an outside point of view it is actually very informative.

So you're making excuses for all the bad physics in it but still find it "very informative." Which part is more informative to you?: The part where he incorrectly assumes the full energy of the upper block would be absorbed only by the first floor below and by no other part of the structure beneath? The part where he assumes a full 1-story free-fall drop before the upper block touches anything? The part where he makes up numbers based on nothing for the redundancy of the steel in the building, and makes up ridiculous numbers for up to 95% of the total building mass staying within the footprints instead of going out over the sides?

I suspect many of you read the simplified version such as this one...

911research.wtc7.net...

But not the actual report.

www.civil.northwestern.edu...

Actually Bazant has written a series of papers like this because he is constantly shown gross errors in his own work. The last of them was still assuming up to 95% of the building mass falling straight down, in which case you would have expected to see almost all of the debris in two big piles where the towers used to stand, but which was obviously not the case. He constantly weasels in erroneous assumptions like this and then justifies it by essentially saying "my model wouldn't work if I didn't assume this." No kidding?

Is not that bad.

How would you know? I've never seen you comment on any errors in his work even though there are plenty to be found. Of course it's "not that bad" when you aren't even looking for problems and just trying to praise it solely because it agrees with your point of view. That's as unscientific as the paper itself.

reply to post by bsbray11


No, i was trying to state this paper is not something that should be used as absolute proof but at the same time is not a poorly written paper. I have read it. It does not seem so far fetched except in a few areas but it is better then people saying space lasers took out the WTC.

If anything, I am not opposed to another investigation but it should not be publicly funded. Why not? FEMA was a why, NIST created a how to not happen again but no one actually ever definitively stated how it all happened from a scientific POV.