Bazant was right!! Imagine that

[Mobertermy]

I agreed with you. Bazants model was right thats what Im going to use to argue against truthers. Thanks. What should I tell them when they point out that the top of the building isnt falling straight down but is toppling over?

 

[NoZed Avenger]

Edited by Gaspode: 

Edited for civility.

Despite my conviction that I am simply another hopeless social retard, I will make a stab at this.

I am not a mathy person or a science guy, so maybe I can help bridge the gap between you and the people spending time on this.

First, let's see if everyone is communicating. This is my lay understanding. Let me break this out into discrete steps and please tell me what you believe is incorrect or needs adjustment (open to anyone else who feels I am going wrong):

(1) Bazant was not creating a model for the Towers' collapse.
(2) Bazant was creating a model to test if a collapse would occur if an upper area were dropped straight onto the intact floors beneath.
(3) Bazant concluded a collapse would occur, even in those circumstances.
(4) The *actual* circumstances were even more favorable for collapse than his model.
(5) Whether "intact" or not, a large volume of stuff was dropped onto lower floors.
(6) Whether "symmetrical" or not, a large volume of stuff was dropped onto lower floors
(7) The fact that the load was not dropped straight down onto the supporting members below it actually made the collapse more likely by stressing weaker elements.

As for the video and the non-explosive demolition,

(8) it provides some support for Bazant's theoretical work, in that it does successfully show explosives and thermite were not necessary to cause a collapse under similar (though not identical) circumstances.



Are we together so far? If so, the contention from the JREF-centric crowd is that the differences you point to -- the lack of symmetry, for example -- are, *at best*, irrelevant to the cause-and-effect analysis. They actually make the case for a collapse without explosives stronger.

Whether you agree or disagree with the end conclusion, is the argument at least laid out in a clear manner?

 

[Newtons Bit]

It would also help Mobertermy to actually read Bazant's paper for true understanding.

The details of the failure process after the decisive initial trigger that sets the upper part in motion are of course very complicated and their clarification would require large computer simulations. For example, the upper part of one tower is tilting as it begins to fall ~Appendix II!; the distribution of impact forces among the underlying columns of the framed tube and the core, and between the columns and the floor-supporting trusses, is highly nonuniform; etc. However, a computer is not necessary to conclude that the collapse of the majority of columns of one floor must have caused the whole tower to collapse. This may be demonstrated by the following elementary calculations, in which simplifying assumptions most optimistic in regard to survival are made.

I've hi-lighted the last sentence, which is the most important to the point Mobertermy does not understand. Bazant's paper is not suppose to exactly reflect reality. It's extremely difficult to compute exactly and he explains why. Bazant instead chooses to model a scenario that is most favorable to collapse prevention. This is what is known in engineering as enveloping.

 

[carlitos]

Well, I think that we have seen this act before, but I'll try again.

Are you able to answer this question?

Do you understand that Bazant's idealized case is the best posible scenario for the towers and the actual events were more likely to result in a global collapse than Bazant's model?

Or this one?

Bazant's model is a limiting case. It is used to envelope the problem. Do you know what that means?

Or this one?

are you suggesting that an upper block that is not intact impacting an intact lower block is a best case scenario for collapse arrest?

"I agree with you" is not an answer to the above questions. "Yes" or "No" would be acceptable.

ETA - sorry for piling on. I'm on a boring conference call....

 

[Hokulele]

Edited by Gaspode: 

Edited for civility.

I will take one more try at this, but you have to help in return by answering the questions I put to you. As a start, do you understand what is meant by calculating the limiting conditions?

To do this with another analogy, let's say that someone comes up who claims that they were hit on the head by an icicle. There are several possibilities for how this could happen, but the two main categories of possibilities are it was a natural accident and it was a criminal act by another person. So the first thing we can do is to figure out if a natural accident is even possible in this case. We can do this by calculating the limiting conditions for icicle formation (0 degree weather would be one requirement).

If it can be shown that natural icicle formation is impossible, say that the incident took place outdoors in July in Honolulu, we know that by the limiting conditions it is far more likely that the icicle incident was an "inside job". If it can be shown that natural icicle formation is not only possible, but inevitable, then we do not need to leap to the "inside job" conclusion, especially when there is no evidence such a conclusion is warranted.

Please note, the icicle formation model doesn't have to mimic the real conditions exactly, if it is shown that icicles will happen at -5 degrees on a roof with a 4 in 12 pitch, you do not have to develop an entirely new model that shows they will form at -20 degrees with a roof pitch of 5 in 12.

Bazant's model is the -5 degree model and you are requesting the -20 degree model.

If you cant get that the OP's argument is inadvertently helping truthers you're hopeless.

It only helps those who do not want to listen to explanations. It is the sound-bite mentality that is helping CTists, not us.

 

[johnny karate]

Maybe because he explicitly says it looks alot like the WTC.

.. which he immediately follows with a qualifying statement that you seem hellbent on ignoring. I actually bolded it for you in my previous post.

Which is true of WTC7 but not true of 1 and 2. And no one has ever used Bazant to explain WTC 7 so I really dont see how the OP has made anything but a bad argument and the fact that you all have jumped on board to protect him mkaes me wonder exactly what type of group think is going on here.

Maybe what you view as "group think" is really other people's ability to comprehend something that seems to elude you.

 

[alienentity]

I agreed with you. Bazants model was right thats what Im going to use to argue against truthers. Thanks. What should I tell them when they point out that the top of the building isnt falling straight down but is toppling over?

That they fell asymmetrically outside their own footprints, totally unlike any CD.
Instead of having structure removed instantly across a whole floor or two, for example, they experienced initial collapse on one side, thus tilting in the process.

You also have repeated that the upper blocks were not intact, and that Bazant requires it. Both assumptions/interpretations are wrong - the upper blocks were, contrary to disingenuous truther myths, intact as far as we know when the collapses began, at least for a few seconds. By the time the collapses had progressed 2 or 3 seconds, the collapsing mass had grown in both mass and velocity, thus creating an even more destructive force.

ETA I addressed that point in this video:



*The asymmetry is important because you had eccentric/asymmetrical loading of flanges, bolts and whatever other structure was being impacted - obviously not what the buildings were designed to withstand.
That they would fail is not really worth debating - they could do nothing else under those conditions, as explained by Bazant's limiting case, the NIST report and others.

Bazant doesn't require the buildings to look exactly like the model at all. That is just silly. As Newtons Bit has kindly pointed out about the limiting case.

So once you remove some of the influence of truther myths on the phrasing of your questions, they are not so difficult to answer. You probably don't realize where you're still buying into various truther assumptions, that's all.

I linked you to a different verinage video because it looks more like the WTC towers (tall and skinny) and, while deliberate, demonstrates the basic principles of Bazant's paper. The Balzac-Vitry demo of the OP is actually still an upper-block crush-down, so it doesn't demonstrate a lateral progressive collapse very well (WTC7).

For that, I recommend these ones, which show how failure in one area can lead to a global failure. Hope that helps. Good luck with your truther family members but don't be surprised if they ignore relevant evidence which contradicts their beliefs. It's similar to telling a Christian that their religion is based on a lot of mythology - pretty pointless, even if you're right.



http://www.youtube.com/watch?v=tIsE8CkZI6U

The second video mainly addresses the claims of the now-banned Heiwa that a small section failure couldn't cause a larger section to fail.


http://www.youtube.com/watch?v=prwvj-npt5s

 

[jaydeehess]

And the planes crashing into the towers - that is what triggerred the chain of events leading to the fires in WTC7, and eventually the collapse of the building - were not "human intervention" ?

I am sure the Jihadists would say something along the lines of that this was human intervention inspired by, and with the devine guiding hand of, Allah.

 

[twinstead]

Mobertermy, some of science involved in 911 IS complicated. Hell, I don't understand a lot of it myself. There's no reason to think that it's all smoke and mirrors because of it.

 

[Horatius]

What are models for? (thanks for not calling me a truther.)

They are for trying to understand reality in cases where actual reality is difficult or impossible to calculate directly. They will never correspond completely with reality, but for one with a mind willing to understand, they can still provide useful insights.

It's that "one with a mind willing to understand" part that eludes Truthers, and seems to be eluding you. However, I will also give it one more go, taking a slightly different tack from the others.

Look, all of you that are defending Bazant's model are missing one very simple fact. It requires an intact upper block. His model could basically be called the "intact upper block crushing straight down model." Without that intact upper block everything else meaningless.

The bolded part is right where you have made your error, and you compound that error by insisting that "Without that intact upper block everything else meaningless." I'll explain.

Bazant's model involves an intact upper block, which leads you to assume that it therefore requires an intact upper block. What everyone is trying to explain to you in asking about "limiting cases", is that, by understanding Bazant, we can come to some conclusions about events slightly diffferent from his limiting case of the intact upper block.

Bazant determined that, in the limiting case of the intact upper block, the impact had more than enough energy to collapse the lower structure, even in the case of a straight-down movement, that allowed the lower block to resist the impact with its maximum resistance. That "more than enough energy" is the key point.

Because there is more than enough energy, we know that at least some collapses, with less-than-totally-intact upper block could also cause a total collapse, even if they were to somehow follow the perfect straight-down path.

Also, because there is more than enough energy, we know that many impacts which do not follow the straight-down path will also cause a total collapse, as the lower structure will provide even less resistance in that case.

When we combine these two bits of understanding, we can conclude that there are several plausible scenarios in which a less-than-intact upper block, following a less-that perfectly-straight-down path, will also cause a total collapse. You could potentially argue that there are also potential such scenarios that wouldn't lead to such a collapse, but no truther has every shown proper calculations to show that any of these such cases are plausible or likely.

Having seen two such collapses, with different size upper blocks, and different degrees of tilt, and with no competing model to suggest that the observed collapses are impossible, we can conclude, from Bazant's paper, combined with an understanding of how the world works, that nothing more happened on 9/11 than what was to be expected.

Of course, if you lack a mind willing to understand, none of the above will make a bit of difference to you.

 

[jaydeehess]

I agreed with you. Bazants model was right thats what Im going to use to argue against truthers. Thanks. What should I tell them when they point out that the top of the building isnt falling straight down but is toppling over?

I would ask that Newton's Bit read this over and tell me if I have it basically correct...........

Despite the fact that the upper portion of the building is tilting it never gets a significant amount of its mass beyond the walls of the lower section. Thus the great bulk of the upper portion's mass is still above the lower portion of the structure. Why is this important?
Because that tilting movement, that is to say the amount of rotation per second, before initial collapse is pivoting about a 'hinge point' somewhere at the junction of the two sections. However at the moment that this 'hinge' fails and the upper section starts to drop, the angular momentum would now have it rotating about the upper section's center of mass and the center of mass is falling straight down, it is not moving sideways at all. Thus the great bulk of the mass of the upper section is still going to impact the lower section and the difference in time from the leading part of the upper section hitting the next floor down to the lagging side doing so is going to be less than half a second. That is where the only assymetrry that is significant comes from.

Imagine a big stationary wheel , you drop it and it falls straight down. Now imagine that same wheel rotating in space but with no lateral movement and if you drop it, it still falls straight down. It does not matter if you then take a 2X4 and have it rotate about its center of mass and then let it dro, it will also still drop straight down.

So, it is established that the great bulk of the mass of the upper section did in fact fall straight down, it has no choice absent a lateral force such as a wind. Tilt and drift are not the same thing, ask any sailor.

Now the mass in the verniage technique also falls onto the lower section. The biggest difference between this and the towers is where the mass impacts the lower section. In the case of the towers, specifically because of the initial tilt, the upper section mass is going to largely not be impinged upon the lower section's columns but on the floor space it first encounters. These floorspaces were designed to carry floor loads, NOT the load of a ten storey section of the structure. This ensures that, as Bazant made clear, that the floor collapses immediately having been completely overwhelmed by the dynamic load of the crushing mass. This mass then slows imperceptibly and builds even more velocity before impacting the next floor down.

lower section columns are left then with no lateral bracing over several levels and simply cannot survive without buckling under their own long column stresses let alone combined with buffeting by the falling debris.

After a few floors the entire upper section ahs come apart BUT its mass is moving even faster AND it is still subject to one driving force, gravity, that is still, and continues to this day to, acts in the direction we refer to as straight down.

yes there is some assymettry to all of this but once again the driving force makes the preferential direction of travel of any falling object the same thus one side of a floorspace may fail ahead of the opposite side(that's the assymettry) but the entire floorspace fails in pretty much the same fashion.

In fact it is likely that the so called squibs are evidence of this internal collapse happening in places a faster than the destruction of the perimeter walls(thus illustrating the assymettry in the last paragraph)

This is the basic sequence that Bazant uses except that he assumes a solid upper section. He does have the mass impacting the floorspace.

Truthers do not (and I again state I am not stating you are one) what NB's above referred to as enveloping a problem. It is setting the parameters for an approximation. this is to allow one to view the problem in a more basic form and not get bogged down in introducing other details such as an assymettric failing of the floors. So you pick the syymetric case and see what the math brings, you set the upper mass as a solid.

Truthers have argued, "oh its (the upper section) not solid, it will be coming apart". Bazant's model showed a 30 fold greater force on the floorspace than would be required to fail even a pristine, intact floor.
Truthers counter that they can easily take away some of the energy of the impact by using it to break apart the lower conticting parts of the uppers section but if they wish to introduce more deatil in this aspect then they should also introduce the detail that the next level down would have not been in pristine, intact condition having been involved in the initial impact and the subsequent fires. If the floor was already sagging it would offer much less ability to support a static load and even less ability to absorb a dynamic load.

Bazant showed then that there was much more force available to initiate a self propigating global collapse.

the verniage technique is different in detail but illustrates that even when the mass impacts the load carrying columns of a much stiffer masonry structure there is enough force available to initiate a self propigating global collapse.

 

[Newtons Bit]

I would ask that Newton's Bit read this over and tell me if I have it basically correct...........

Obligatory-almost-non-sequitur-Simpsons-reference: I was elected to lead. Not to read.

Despite the fact that the upper portion of the building is tilting it never gets a significant amount of its mass beyond the walls of the lower section. Thus the great bulk of the upper portion's mass is still above the lower portion of the structure. Why is this important?
Because that tilting movement, that is to say the amount of rotation per second, before initial collapse is pivoting about a 'hinge point' somewhere at the junction of the two sections. However at the moment that this 'hinge' fails and the upper section starts to drop, the angular momentum would now have it rotating about the upper section's center of mass and the center of mass is falling straight down, it is not moving sideways at all. Thus the great bulk of the mass of the upper section is still going to impact the lower section and the difference in time from the leading part of the upper section hitting the next floor down to the lagging side doing so is going to be less than half a second. That is where the only assymetrry that is significant comes from.

Imagine a big stationary wheel , you drop it and it falls straight down. Now imagine that same wheel rotating in space but with no lateral movement and if you drop it, it still falls straight down. It does not matter if you then take a 2X4 and have it rotate about its center of mass and then let it dro, it will also still drop straight down.

So, it is established that the great bulk of the mass of the upper section did in fact fall straight down, it has no choice absent a lateral force such as a wind. Tilt and drift are not the same thing, ask any sailor.

Now the mass in the verniage technique also falls onto the lower section. The biggest difference between this and the towers is where the mass impacts the lower section. In the case of the towers, specifically because of the initial tilt, the upper section mass is going to largely not be impinged upon the lower section's columns but on the floor space it first encounters. These floorspaces were designed to carry floor loads, NOT the load of a ten storey section of the structure. This ensures that, as Bazant made clear, that the floor collapses immediately having been completely overwhelmed by the dynamic load of the crushing mass. This mass then slows imperceptibly and builds even more velocity before impacting the next floor down.

lower section columns are left then with no lateral bracing over several levels and simply cannot survive without buckling under their own long column stresses let alone combined with buffeting by the falling debris.

After a few floors the entire upper section ahs come apart BUT its mass is moving even faster AND it is still subject to one driving force, gravity, that is still, and continues to this day to, acts in the direction we refer to as straight down.

yes there is some assymettry to all of this but once again the driving force makes the preferential direction of travel of any falling object the same thus one side of a floorspace may fail ahead of the opposite side(that's the assymettry) but the entire floorspace fails in pretty much the same fashion.

In fact it is likely that the so called squibs are evidence of this internal collapse happening in places a faster than the destruction of the perimeter walls(thus illustrating the assymettry in the last paragraph)

This is the basic sequence that Bazant uses except that he assumes a solid upper section. He does have the mass impacting the floorspace.

Truthers do not (and I again state I am not stating you are one) what NB's above referred to as enveloping a problem. It is setting the parameters for an approximation. this is to allow one to view the problem in a more basic form and not get bogged down in introducing other details such as an assymettric failing of the floors. So you pick the syymetric case and see what the math brings, you set the upper mass as a solid.

Truthers have argued, "oh its (the upper section) not solid, it will be coming apart". Bazant's model showed a 30 fold greater force on the floorspace than would be required to fail even a pristine, intact floor.
Truthers counter that they can easily take away some of the energy of the impact by using it to break apart the lower conticting parts of the uppers section but if they wish to introduce more deatil in this aspect then they should also introduce the detail that the next level down would have not been in pristine, intact condition having been involved in the initial impact and the subsequent fires. If the floor was already sagging it would offer much less ability to support a static load and even less ability to absorb a dynamic load.

Bazant showed then that there was much more force available to initiate a self propigating global collapse.

the verniage technique is different in detail but illustrates that even when the mass impacts the load carrying columns of a much stiffer masonry structure there is enough force available to initiate a self propigating global collapse.

You're correct for the most part

Here's a simpler way of looking at what Bazant did. There's two limiting cases:

1. The upper block is not intact and each individual floor of the lower block must resist the entire weight of the upper block.

2. The upper block is intact and the columns of the lower block can resist the impact of the upper block.

The first obviously (to anyone reading the Journal of Engineering Mechanics) results in a collapse. The second requires math to prove.

As far as your station wheel analogy goes, here's a picture to help illustrate:

 

[bardamu]

When you show any interest in understanding what you're discussing please let us know. :\
The discussion is becoming rather pointless since you're making an argument based on a malformed understanding of what you're talking about.

When the debunkers run out of bogus arguments, their last resort is to tell their opponent he doesn't understand the issue or he's missing the point. It's a good sign and I'm pleased to say I get it all the time.

I agreed with you. Bazants model was right thats what Im going to use to argue against truthers. Thanks. What should I tell them when they point out that the top of the building isnt falling straight down but is toppling over?

Mobertermy, if you want see how reasonable people deal with these issues, try these sites:

http://www.ae911truth.org/

http://heiwaco.tripod.com/nist.htm

And the planes crashing into the towers - that is what triggerred the chain of events leading to the fires in WTC7, and eventually the collapse of the building - were not "human intervention" ?

I could answer this but it would be way off topic and there's already a thread on the subject.

I am sure the Jihadists would say something along the lines of that this was human intervention inspired by, and with the devine guiding hand of, Allah.

Stanley Praimneth believes his life was saved by God.

 

[BigAl]

When the debunkers run out of bogus arguments, their last resort is to tell their opponent he doesn't understand the issue or he's missing the point. It's a good sign and I'm pleased to say I get it all the time.

You don't show any sign of knowing any relevant engineering or science. That's got to be a handicap when people say sciency things.

 

[twinstead]

Stanley Praimneth believes his life was saved by God.

I wonder what he would think about a small, insignificant cult that thinks he's lying about his experiences on 9/11?

 

[Hokulele]

I must admit, that is the first time I have seen "Heiwa" and "reasonable people" used in the same post.

 

[alienentity]

I must admit, that is the first time I have seen "Heiwa" and "reasonable people" used in the same post.

What an oxymoron.

 

[johnny karate]

Mobertermy, if you want see how reasonable people deal with these issues...

Mobertermy, keep in mind bardamu believes the FDNY was complicit in a 9/11 inside job. I'll leave it to you to decide whether or not he has the capacity to determine who or what is reasonable.

 

[Hokulele]

I will say, if Mobertermy has a problem with Bazant's model of the Twin Towers, I can't wait to read his/her reaction to Heiwa's lemon/pizza box/sushi models of the Twin Towers.

 

[Horatius]

I will say, if Mobertermy has a problem with Bazant's model of the Twin Towers, I can't wait to read his/her reaction to Heiwa's lemon/pizza box/sushi models of the Twin Towers.

I always thought there was something fishy about his sushi model.