WTC: Rate of Fall (rate of crush)

[Tony Szamboti]

Jaz quoted someone:



I'm guessing this person doesn't have a background in physics or mechanical/civil engineering.

It is entirely possible to have momentary decelerations vastly greater than 1G while also having average deceleration of less than 1 G - that is just early high school mathematics/statistics - a load of 1000G for 0.001 second will probably destroy whatever is subjected to it, but not noticeably slow down an overall acceleration of 1G that it is s short "part of".

Start stringing such "instantaneous" high decelerations together one after the other and you will eventually get a noticeable effect on the larger picture - but that will not affect the nature of the events themselves.

The reality is that the deceleration involved in a natural collapse would have caused a velocity loss which would be observable. It wasn't. Have you seen this video?

This is not early high school math or statistics and that is a nonsense statement.

 

[Jazzy]

The upper section of the North Tower was 12 stories and weighed approximately 73 million lbs. There was no horizontal or lateral load involved and it would have fallen in place, that is straight down with columns impacting columns. This would have occurred for the first couple of stories at the very least. The fact that there is no deceleration means something was removing the structural integrity. Those who want to say the columns would have been misaligned somehow can't explain how that would happen.

You only have to observe the motion of the mast, which appears to rock, or rotate, as it begins its downward motion. This suggests it was following a cyclical or helical failure of its support columns. It's only an opinion.

The effect of the remaining flooring would be to concentrate the hottest fire gases pretty evenly over the downwind end underside of every involved floor. This would allow a collapse to initiate at some weakest point in it, and easily propagate, as surrounding columns would be in a similar condition. Once the motion carried to stronger members the momentum did obviously more than compensate.

 

[Jazzy]

The reality is that the deceleration involved in a natural collapse would have caused a velocity loss which would be observable. It wasn't. This is not early high school math or statistics and that is a nonsense statement.

I'm pissed off with your refusal to face reality.

Haven't we already agreed a downward acceleration of around 0.7G? That is a 0.3G deceleration from natural free fall. That will cause a velocity loss, and I will show you what it is, and shut you up about it.

Using V^2 = 2*f*s,

where velocity at ground zero is V, f is the acceleration, and s the distance (417 meters), and the fraction of G is 0.7, then the tower top speed V = root (2*0.7*9.81*417) = 75.7 meters/sec or 169 mph.

The free fall speed would be root (2*9.81*417) = 90.5 meters/sec or 202 mph.

So the velocity loss WAS 33 mph.

 

[Hitstirrer]

I'm pissed off with your refusal to face reality.

Haven't we already agreed a downward acceleration of around 0.7G? That is a 0.3G deceleration from natural free fall. That will cause a velocity loss, and I will show you what it is, and shut you up about it.

Using V^2 = 2*f*s,

where velocity at ground zero is V, f is the acceleration, and s the distance (417 meters), and the fraction of G is 0.7, then the tower top speed V = root (2*0.7*9.81*417) = 75.7 meters/sec or 169 mph.

The free fall speed would be root (2*9.81*417) = 90.5 meters/sec or 202 mph.

So the velocity loss WAS 33 mph.

Quite how you continually get away with being impolite, condescending, and in this case downright rude, I dont know when my replies drawing attention to that are always deleted. I am told to address the comments rather than the writer but when the comments are risible its hard to separate the two.

Thank you for showing us how to apply just about the simplest of the kinematic equations. No doubt some are impressed.

The problem is that you make the massive leap to conclude that a fall at 0.7g represents a 'natural collapse'. Tony S's point is that the collapse was far from natural, and that if it had indeed been natural then a much smaller acceleration would have been observed. It is in fact highly likely that in such a natural collapse, then arrest of fall would have occurred within a few floors drop as velocity decreased, mass decreased, ( You did observe mass being ejected in all directions didn't you?), and strength underneath increased.

Simply applying an equation to show a small difference in final velocity actually makes his point. He said - "The reality is that the deceleration involved in a natural collapse would have caused a velocity loss which would be observable. It wasn't."

He was referring to a 'natural collapse' that would have been accelerating at a far slower rate, and probably only for a few floors. What he is saying is that 0.7g is un-natural, and is only usually seen in a CD operation of such a building.

You keep working from the assumption that what you saw was natural but can't produce any evidence to support that view other than produce results of equations that are within the competence of junior science students.

 

[Jazzy]

Quite how you continually get away with being impolite, condescending, and in this case downright rude

How about downright correct?

I dont know when my replies drawing attention to that are always deleted.

It happens to me too. Mick just will not let me tell you how lacking in -----------, and incredibly ------- the both of you are.

I am told to address the comments rather than the writer but when the comments are risible its hard to separate the two.

There you go. A bit of useless common ground.

Thank you for showing us how to apply just about the simplest of the kinematic equations. No doubt some are impressed.

All but you two see it for the underlying truth.

The problem is that you make the massive leap to conclude that a fall at 0.7g represents a 'natural collapse'. Tony S's point is that the collapse was far from natural, and that if it had indeed been natural then a much smaller acceleration would have been observed.

It's YOUR problem, not mine. It's up to Szamboti to prove that to me, not vice versa, and especially when all the time I can demonstrate business as usual for a natural collapse.

It is in fact highly likely that in such a natural collapse, then arrest of fall would have occurred within a few floors drop

So show how. Neither of you have done so.

as velocity decreased, mass decreased, (You did observe mass being ejected in all directions didn't you?), and strength underneath increased.

You did observe mass being gathered as a large floor sandwich, didn't you? I think that more mass was accruing from beneath than being ejected out the sides, but I don't have to prove to the contrary, YOU DO.

Simply applying an equation to show a small difference in final velocity actually makes his point. He said - "The reality is that the deceleration involved in a natural collapse would have caused a velocity loss which would be observable. It wasn't."

But it WAS observable. So he lied. Do you wish to lie too?

He was referring to a 'natural collapse' that would have been accelerating at a far slower rate, and probably only for a few floors. What he is saying is that 0.7g is un-natural, and is only usually seen in a CD operation of such a building.

It's an opinion he (and you) have which is merely that. He has done nothing to show additional energy added to the mix from that which already existed.

You keep working from the assumption that what you saw was natural but can't produce any evidence to support that view other than produce results of equations that are within the competence of junior science students.

Quite the reverse, old boy. It is he that has to provide evidence to support the opposite view. All I can do is show him things consistent with natural events, which I do.

It's not my fault that I only need schoolboy maths to prove him wrong, and it sort of follows naturally from the behavior of both of you, which I take for gross impoliteness when I find my questions ignored.

Neither of you realize how far from scientific practice you have strayed. Any scientist would lay forward his agenda as a foundation for his work to stand on. Szamboti conceals his.

This is a political act, and politics has no place in science. While you support this, nor do you.

 

[Hitstirrer]

............ when all the time I can demonstrate business as usual for a natural collapse.

You did observe mass being gathered as a large floor sandwich, didn't you? I think that more mass was accruing from beneath than being ejected out the sides, but I don't have to prove to the contrary, YOU DO.


But it WAS observable. So he lied. Do you wish to lie too?

All I can do is show him things consistent with natural events, which I do.

This is a political act, and politics has no place in science.

You cannot demonstrate 'business as usual for a natural collapse' at all. All that you are doing is to observe what happened and make calculations to show that what was observed fitted in with those calculations.

Of course that would work !

If someone tells you that measurements and calculations have shown that it fell at 0.7g, then every subsequent calculation you wish to make using that figure as a given will - err - prove that it fell at 0.7g. Nothing more, nothing less. You are just confirming a known given.

But you fail to address what allowed that building to achieve 0.7g, and instead simply assert that it was 'natural'. It wasn't natural at all. It was very un-natural. In all past instances of such 0.7g collapses it has required carefully planned and expert CD to acheive 0.7g. Why would it suddenly be 'natural' for fire and gravity to do that for the first time ?

Your claim that - " I think that more mass was accruing from beneath than being ejected out the sides" - makes no sense. First of all the word 'think' is very pertinent. 'Think' doesn't exactly give me confidence to accept your assertion.

To address the comment itself - The total mass available is finite. We observe huge ejections of steel sections and powdered material. Mass ejected means that its not there any more. The structure was designed to support that (now) missing mass plus a large factor in excess. As the collapse procedes more and more mass is seen ejected. The remaining lower and lower mass is then supported by stronger and stronger columns. So, claiming that somehow 'more mass was accruing' is simply wrong. You have far less mass available than at the start, so how can more be materialising from somewhere ?

The undamaged supporting structure is now coping with less mass - not more. Of course the dynamics come into play, but using less mass to do those calculations than originally there - not more. We see a massive tonnage of steel being hurled 300 feet sideways in all directions that now cannot add to any kinetic input. Untold tons of pulverised concrete that required energy input to attain that state. And at the same time removing mass from the falling structure.

And despite this clear evidence you still cling to the notion that a lower and lower mass meeting stronger and stronger resistance can continue to accelerate at a constant rate of 0.7g. I don't need to PROVE that a lower mass was available to continue to fall because that is self evident from all the videos. I don't need to PROVE that the undamaged building lower down consisted of stronger and stronger steel because that is a feature of all such buildings.

As to your statement that we LIE, all I can say is that you have still not understood that we don't dispute what was seen, or what your schoolboy calculations show. What we are saying is that such an acceleration was NOT natural. For the reasons given above. (As an aside it will be interesting to see what the admin in here make of your accusation. Seems to me to be a bit impolite.)

Your next statement - " All I can do is show him things consistent with natural events, which I do" - has been addressed already. All that you have done is to confirm a known given by re-working the equation that produced that given in the first place. You have NOT demonstrated that the 0.7g observed was 'natural' at all. Merely provided smoke n mirrors info that prove an already known figure.

Then you come out with this gem. " This is a political act, and politics has no place in science".

I could not agree more. The irony, old boy, is that you fail to see the irony in that statement.

 

[Mick West]

The structure was designed to support that (now) missing mass plus a large factor in excess.

It was designed to support it when it was not falling.

Rest a hammer on a lightbulb. It supports it just fine.
Hit a lightbulb with a hammer. It does not support it.

Rest a bullet on your head. It supports it just fine.
Shoot a bullet at your head. It does not support it.

Rest several floors of WTC on the lower portion. It supports it just fine.
Drop several floors of WTC on the lower portion. It does not support it.

Static vs. dynamic.

 

[Hitstirrer]

Static vs. dynamic.

That is why I wrote as follows - " Of course the dynamics come into play, but using less mass to do those calculations than originally there - not more."

And this - " We see a massive tonnage of steel being hurled 300 feet sideways in all directions that now cannot add to any kinetic input."

That is a given. But at least lets accept that the dynamic load is diminishing. And the resistance is increasing.

 

[Jazzy]

You cannot demonstrate 'business as usual for a natural collapse' at all. All that you are doing is to observe what happened and make calculations to show that what was observed fitted in with those calculations. Of course that would work! If someone tells you that measurements and calculations have shown that it fell at 0.7g, then every subsequent calculation you wish to make using that figure as a given will - err - prove that it fell at 0.7g. Nothing more, nothing less. You are just confirming a known given.

No.

I used it to show that the energy expenditure (into damaging both the tower and top) was equivalent to sixty tons of TNT. That is, the expenditure of that NATURAL energy flowing through that system which had been stored (as gravitational energy) since the towers were built.

But you fail to address what allowed that building to achieve 0.7g, and instead simply assert that it was 'natural'. It wasn't natural at all. It was very un-natural. In all past instances of such 0.7g collapses it has required carefully planned and expert CD to acheive 0.7g. Why would it suddenly be 'natural' for fire and gravity to do that for the first time?

Because that is they way they work. It has been noted since the beginning of time. Steel structures have collapsed before. You are complaining the towers were big.

Your claim that - " I think that more mass was accruing from beneath than being ejected out the sides" - makes no sense. First of all the word 'think' is very pertinent. 'Think' doesn't exactly give me confidence to accept your assertion.

Thinking, in your case, isn't very trustworthy. It's not the same for me. What I see is are tower tops shedding their exterior columns whilst accepting floors. I think that floors beat, or at least match, the exterior in terms of mass. After all, they were all carrying a deadload.

To address the comment itself - The total mass available is finite. We observe huge ejections of steel sections and powdered material. Mass ejected means that its not there any more. The structure was designed to support that (now) missing mass plus a large factor in excess. As the collapse procedes more and more mass is seen ejected. The remaining lower and lower mass is then supported by stronger and stronger columns. So, claiming that somehow 'more mass was accruing' is simply wrong. You have far less mass available than at the start, so how can more be materialising from somewhere?

It's materializing from beneath.

The undamaged supporting structure is now coping with less mass - not more. Of course the dynamics come into play, but using less mass to do those calculations than originally there - not more. We see a massive tonnage of steel being hurled 300 feet sideways in all directions that now cannot add to any kinetic input. Untold tons of pulverised concrete that required energy input to attain that state. And at the same time removing mass from the falling structure.

All within the brief of a third of the tower's potential energy. That sixty tons of TNT.

And despite this clear evidence you still cling to the notion that a lower and lower mass meeting stronger and stronger resistance can continue to accelerate at a constant rate of 0.7g. I don't need to PROVE that a lower mass was available to continue to fall because that is self evident from all the videos.

It was building up on the underside of the tower top. We know this because it was there in the basement: a massive pancake of material. It was there IN THE SOLID.

When the top hit the next floor down, where had that floor to end up? The answer is stuck to the underside of the tower top.

I don't need to PROVE that the undamaged building lower down consisted of stronger and stronger steel because that is a feature of all such buildings.

And rain is wet.

As to your statement that we LIE, all I can say is that you have still not understood that we don't dispute what was seen, or what your schoolboy calculations show. What we are saying is that such an acceleration was NOT natural. For the reasons given above. (As an aside it will be interesting to see what the admin in here make of your accusation. Seems to me to be a bit impolite.)

Well let's say he contradicted the truth. It still seems to make him a liar. He can always apologize.

Your next statement - " All I can do is show him things consistent with natural events, which I do" - has been addressed already. All that you have done is to confirm a known given by re-working the equation that produced that given in the first place. You have NOT demonstrated that the 0.7g observed was 'natural' at all. Merely provided smoke n mirrors info that prove an already known figure.

The smoke and mirrors are all yours, and you are still doing it. I don't have to prove that 0.7G was an unnatural rate of fall: YOU DO.

Then you come out with this gem. "This is a political act, and politics has no place in science". I could not agree more. The irony, old boy, is that you fail to see the irony in that statement.

He's still not coming clean with his agenda. Not that it isn't obvious with both of you. You don't understand what I mean, do you?

 

[Mick West]

That is why I wrote as follows - " Of course the dynamics come into play, but using less mass to do those calculations than originally there - not more."

And this - " We see a massive tonnage of steel being hurled 300 feet sideways in all directions that now cannot add to any kinetic input."

That is a given. But at least lets accept that the dynamic load is diminishing. And the resistance is increasing.

How do you know it's diminishing? Every floor that collapses adds to the falling load. Seems like the load would quite rapidly be increasing.

 

[Hitstirrer]

What I see is are tower tops shedding their exterior columns whilst accepting floors. I think that floors beat, or at least match, the exterior in terms of mass.

It's materializing from beneath. It was building up on the underside of the tower top. We know this because it was there in the basement: a massive pancake of material. It was there IN THE SOLID.

Well let's say he contradicted the truth. It still seems to make him a liar. He can always apologize.

I don't have to prove that 0.7G was an unnatural rate of fall: YOU DO.

You don't understand what I mean, do you?

There you go again - thinking - rather than proving.

But of course you fail to accept that the dust IS the concrete. And the concrete IS the 'floors'. If the floors -made of concrete - turn to dust and fly all over Manhattan, then how can they simultaneously, as you claim - " beat, or at least match, the exterior in terms of mass"?

You are also able to imagine material 'materialising from beneath' , It was already there. It was already stationary, supported by undamaged columns, waiting to be struck by a diminishing mass from above. Each floor of concrete, when struck, then itself turned to dust, and that dust then flew in all directions - as observed. Mass decreased.

What 'pancake' in the basement ? You are now disagreeing with NIST, who discarded the 'pancake' theory very early into the investigation, when the realised that the lack of basement evidence made that untenable. The mass left in the basement was a tiny fraction of what should have been there if a 'pancake' effect had been real. Do a bit of research before you make such simple errors in future.

TS didn't lie. You failed to understand what he said, despite me explaining it to you. You repeat that calumny, and I again note that you have not been sanctioned for it.

As to proof of a theory. You have a theory that global collapse, with an acceleration of 0.7g, is normal when highrise steelframe buildings catch fire. I disagree, and cite 100 years of past experience to support that view. Can you provide any evidence to support your own theory ? If not then I fall back on the basic requirement of science to ask you to demonstrate repeatabilty, under controlled conditions, before your theory can be considered further.

And your last point :- " You don't understand what I mean, do you" ?

Well - no. And I would refer you to Mick West on this subject, who holds the view that the onus is on the person who isn't understood to make the point clearer. You appear to hold opinions at variance with NIST. You appear to think that the mass of the building is increasing as it falls, rather than decreasing, and you seem to think that the basement was full of many dozens of 'floors' when clearly that wasn't so.

To summarise ; No, I don't understand, because you make no sense and prefer to insult people and provide no evidence to support your view. You say that you 'think' something as if that makes it fact. You produce calculations that simply prove themselves.

I think that you need to work on your theory a bit more and provide a modicum of proof, along with a more explicit explanation of what you 'think' was happening. And please try to be more polite, old boy.

 

[Hitstirrer]

Seems like the load would quite rapidly be increasing.

I assume that you meant to write "Dynamic load" there. Mass (load) was quite definitely decreasing. If my assumption is right, and you claim that dynamic load was increasing, then I would be unable to prove otherwise because we have no data to show what fraction of the upper mass was being ejected. It had to be a considerable % though.

Others may be capable of discovering where the break even point would be, factoring in decreasing mass against increasing velocity to maintain a 0.7g acceleration. But on the face of it, maintaining that 0.7g acceleration, through increasing resistance, would need as much help as it could get, and throwing much of the mass aside would not do that.

You disagree with me over increase/decrease of dynamic load. C'est la vie. There is no way forward from that of course as we don't have data to support either opinion. Work has already been done on this with much disagreement between the various factions. So debate in here would be futile on that aspect.

If it would help I would amend my sentence - " That is a given. But at least lets accept that the dynamic load is diminishing. And the resistance is increasing." - and move on.





.

 

[Mick West]

But of course you fail to accept that the dust IS the concrete.

It's some of it. A lot of drywall too.

 

[MikeC]

Jazzy quoted someone who wrote:

But you fail to address what allowed that building to achieve 0.7g, and instead simply assert that it was 'natural'.

that would be "gravity" - the force, not the rather spectacular movie which I enjoyed!

Gravity has this attribute that it tries to accelerate things at a rate conventionally termed "1g" - and when the thing being accelerated meets some resistance then the acceleration will be decreased.

Apparently it turns out that when buildings are collapsing under their own weight the resistance is often enough to reduce the acceleration to 0.7g

One thing about this "debate" that amuses me - as far as I can tell, when you DO demolish a building, it would seem that het "9/11 truther" physics would have that building stop dead once it has fallen as far as the demolished floors allow - eg if you demolish 1 floor of supports the building should fall 1 floor and then stop, since the weight of the upper sections cannot possibly cause the remaining intact floors to collapse.

 

[Hitstirrer]

It's some of it. A lot of drywall too.

Yes. Mass ejected. Not now available to contribute to a dynamic load.

 

[Jazzy]

There you go again - thinking - rather than proving.

Just because thinking (or reading, apparently) is an unreliable activity for you doesn't mean it is for me.

But of course you fail to accept that the dust IS the concrete. And the concrete IS the 'floors'. If the floors -made of concrete - turn to dust and fly all over Manhattan, then how can they simultaneously, as you claim - " beat, or at least match, the exterior in terms of mass"?

Now why would you put words in my mouth? Truthers tell me that there were 425,000 cubic yards of mostly lightweight concrete, so that's around 400,000 tons. Truthers also tell me, by calculation, that 10,000 tons of dust was created. So 2.5% of the concrete turned to dust. According to truthers.

You are also able to imagine material 'materialising from beneath', It was already there. It was already stationary, supported by undamaged columns, waiting to be struck by a diminishing mass from above. Each floor of concrete, when struck, then itself turned to dust, and that dust then flew in all directions - as observed. Mass decreased.

The increment of mass lost 2.5% of itself. (I ruled out the lie.)

One has to remember the 97.5% of the concrete and all those dead loads.

What 'pancake' in the basement?

You are now disagreeing with NIST, who discarded the 'pancake' theory very early into the investigation, when the realised that the lack of basement evidence made that untenable. The mass left in the basement was a tiny fraction of what should have been there if a 'pancake' effect had been real. Do a bit of research before you make such simple errors in future.

It looks like a forty-foot deep pancake to me. What you see here is "ground level". Wash your mouth out with soap. It's the only way to lose the egg. Put out your pants as well. I often disagree with NIST.

TS didn't lie. You failed to understand what he said, despite me explaining it to you. You repeat that calumny, and I again note that you have not been sanctioned for it.

I beg your pardon. Are you a child of Goebbels? My dad fought the Nazis to get rid of such tricks as The BIG LIE Technique. They thought such lies didn't do any harm as well.

As to proof of a theory. You have a theory that global collapse, with an acceleration of 0.7g, is normal when highrise steelframe buildings catch fire. I disagree, and cite 100 years of past experience to support that view. Can you provide any evidence to support your own theory? If not then I fall back on the basic requirement of science to ask you to demonstrate repeatabilty, under controlled conditions, before your theory can be considered further.

Still with the smoke and mirrors? I think the collapses were natural. YOU have to prove otherwise.

And your last point :- " You don't understand what I mean, do you"? Well - no. And I would refer you to Mick West on this subject, who holds the view that the onus is on the person who isn't understood to make the point clearer.

Not in this case.

You appear to hold opinions at variance with NIST. You appear to think that the mass of the building is increasing as it falls, rather than decreasing, and you seem to think that the basement was full of many dozens of 'floors' when clearly that wasn't so.

It's almost as if we were talking about different events...

To summarise ; No, I don't understand, because you make no sense and prefer to insult people and provide no evidence to support your view. You say that you 'think' something as if that makes it fact. You produce calculations that simply prove themselves.

I make no sense to the senseless. I don't need to support my view that much. You still don't acknowledge the true nature of those calculations. You can't can you? You have condemned yourself to mislabel them in perpetuity.

I think that you need to work on your theory a bit more and provide a modicum of proof, along with a more explicit explanation of what you 'think' was happening. And please try to be more polite, old boy.

I tend not to be polite to liars and those that defend them, must admit. I'll stick with what I knew to be true when I first saw the collapses, thanks.

I would be unable to prove otherwise because we have no data to show what fraction of the upper mass was being ejected. It had to be a considerable % though.

You could always go through the pictures. The ejecta tended not to clump much, so it should be possible to take a census of the scattered steel. Meh.

Others may be capable of discovering where the break even point would be, factoring in decreasing mass against increasing velocity to maintain a 0.7g acceleration. But on the face of it, maintaining that 0.7g acceleration, through increasing resistance, would need as much help as it could get, and throwing much of the mass aside would not do that.

It didn't happen that way at all. Your opinion on something that never happened holds no value to anyone.

So debate in here would be futile on that aspect.

On every.

If it would help I would amend my sentence - " That is a given. But at least lets accept that the resistance is increasing."

And water wet.
.

 

[OneWhiteEye]

Can I interject?

Deceleration is acceleration in opposition to the direction of motion. When Szamboti talks about deceleration, he does literally mean acceleration upwards, not simply a downward acceleration reduced in magnitude from g. Both cases result from a resistive force acting in opposition to the motion, with the only difference being the magnitude. He does in fact slog through the mechanics (this time correctly or at least mostly so) of a simple 1D approximation to ascertain the motion over time of an effectively rigid block. What he is saying is that his calculations indicate that there should have been true measurable deceleration.*

The correctness of the analysis depends on two things, and on those two things it is flawed. It presumes the applicability of an extremely simplified 1D model for finer motion detail, and it plugs in bogus numbers. On the first, he neglects tilt entirely and makes false claims about the magnitude of the tilt. On the second matter, he assumes 100% residual capacity in the load displacement relation which is the structural component of resistive force. This requires the capacity of perfect axial alignment, ideal bearing surfaces and no eccentricity, a fantastical notion to say the least.

Acknowledging the obvious regarding questionable model scope and outrageous assumptions of residual capacity, there's nothing left to defend. Oh, but he will defend it. Expect to see claims of how anonymity is synonymous with no credibility, for starters, as if that affects the content of what is said. He's already claiming that no horizontal force of sufficient magnitude exists to displace the upper section enough to cause even the slightest loss of effective capacity, yet I have shown that a fraction of one percent of the peak axial force provided by the columns is sufficient over the descent of single story to cause misalignment which reduces axial capacity to a small fraction.

He has tried to invoke St. Venant's principle to claim the local deformations will magically redistribute the imposed loads such that they can be handled by the intact portions above and below. This fails automatically because St. Venant's principle applies to not only static conditions, but conditions of static equivalence (that is, the distribution of forces imposed on a body between cases must sum to the same net force/torque). When called on it, he attempted to invoke a dynamic form of St. Venant's principle. Never mind that the dynamic form is a proposed methodology rather than a universally adopted one, the same sort of objection applies even were it not a tentative principle: dynamic equivalence is required, which has not been demonstrated and, IMO, could not be demonstrated.

The root fallacy is that there is some magic wand in this principle which assures local failure is arrested, that either a static or dynamic equilibrium can somehow be automatically assumed in a scenario which involves the chaotic displacement of buckling and likely some measure of fracture. Of course the intact and undeformed columns above and below would be subject to stresses diffuse relative to the point of origin (contact) and simply experience a net overall force, but local inability to arrest motion means continued failure and additional motion, adding to the existing kinetic energy that the "intact" region must dissipate in order to slow or arrest the motion. In fact, if local failures continue, distortion will propagate as well, rendering the formerly intact regions deformed and at reduced residual capacity. Keith Seffen made this point in his submission to JEM, something I notice Szamboti never touches.

Thought I'd save you all some time, but please have fun anyway if you want.


*it should be noted that his arguments and methodologies have changed over time; I am directing my comments towards the most recent arguments.

 

[OneWhiteEye]

Additional remark which might clarify a bit: the argument hinges on the effective residual capacity of both the upper and lower sections. Szamboti claims the following:

1) Bazant (grossly) underestimated the magnitude of 100% design capacity
2) Szamboti has corrected those estimates
3) Those 100% capacity estimates apply to at least the initial "impact" and next story of displacement, and possibly up to 5 subsequent stories (!) to give arrest
4) Since the displacement over time of the roofline proxy is considerably greater than what what his calculations show, other actions must have been at play to reduce capacity
5) These actions are only attributable to outside assistance in the form of explosives or artificial thermal weakening

C'mon!

100% capacity? What he's saying is that you could expect the top to drop through a failed story and achieve the exact same global capacity from mangled and displaced column ends, tilted top, etc, as could be achieved by painstaking assembly of the structure to print. Does that even make sense?

Actually, he's claimed that the capacity would increase due to work hardening... which, like St. Venant's principle, is a factual principle but misapplied. He hangs his hat on these two principles to justify employing no capacity reduction whatsoever, despite the fact that some (major) capacity reduction must be factored in by virtue of straightforward observation of the actual kinematics in video footage.

 

[MichaelStox]

The reality is that the deceleration involved in a natural collapse would have caused a velocity loss which would be observable. It wasn't. Have you seen this video?

This is not early high school math or statistics and that is a nonsense statement.

Debunkers use this video (of the gravity driven collapse) in an attempt to debunk CD theories without realizing that it actually debunks the official explanation of the collapse

 

[Jazzy]

Thought I'd save you all some time, but please have fun anyway if you want.

You did. Shall do.

 

[Jazzy]

Debunkers use this video (of the gravity driven collapse) in an attempt to debunk CD theories without realizing that it actually debunks the official explanation of the collapse

The use of the word "consumed" in this short video is fallacious. (Just like contrails "dissipate")

The structure is broken, but still there, threaded around the core, tied together with its floor reinforcing steel, sliding towards ground zero.

It hasn't been 'consumed', and is just as capable of doing damage as it was when intact.

By the time it reached ground zero it weighed around 300,000 tons, and reached a speed of 120 mph by most accounts, although it calculates out at 169 mph.

Pretty difficult to stop, but the Earth managed it…
.

 

[Tony Szamboti]

It was designed to support it when it was not falling.

Rest a hammer on a lightbulb. It supports it just fine.
Hit a lightbulb with a hammer. It does not support it.

Rest a bullet on your head. It supports it just fine.
Shoot a bullet at your head. It does not support it.

Rest several floors of WTC on the lower portion. It supports it just fine.
Drop several floors of WTC on the lower portion. It does not support it.

Static vs. dynamic.

In the hammer and bullet examples the force amplification beyond the static load is achieved through deceleration of the hammer and the bullet. It is due to an impulse in which the impacting object transfers its kinetic energy and thus loses velocity. Did you forget that part or do you still not understand it?

 

[Tony Szamboti]

Debunkers use this video (of the gravity driven collapse) in an attempt to debunk CD theories without realizing that it actually debunks the official explanation of the collapse

What actually happened is those claiming the WTC collapses were natural at first tried to use the Balzac-Vitry building demolition video to show a natural collapse was possible. However, when it was shown that it decelerates, as we said it would have to in a natural situation, and that the North Tower never decelerated, they stopped using it.

 

[Mick West]

What actually happened is those claiming the WTC collapses were natural at first tried to use the Balzac-Vitry building demolition video to show a natural collapse was possible. However, when it was shown that it decelerates, as we said it would have to in a natural situation, and that the North Tower never decelerated, they stopped using it.

I still use it. It decelerates because it pretty much starts at the bottom (i.e only a handful of floors from the bottom), and it's made of concrete. It's a very different type of building.

I prefer this one though:


Check out those "squibs"

Here it is to scale:

 

[Mick West]

In the hammer and bullet examples the force amplification beyond the static load is achieved through deceleration of the hammer and the bullet. It is due to an impulse in which the impacting object transfers its kinetic energy and thus loses velocity. Did you forget that part or do you still not understand it?

I understand it perfectly Tony. I've always understood the actual mechanics, it's just your insistence on describing it as "force amplification" that I thought was confusing and misleading.

The disagreement is if the events more closely resemble the nail, or the lightbulb.

It's an easy appeal to ignorance to say it's the nail. After all, the WTC towers were built with girders, not glass. They were tough, not fragile.

But then you've got to account for scale, and construction, and the impact angles and offsets, and you see it's actually more towards the light bulb than you might think.

 

[Tony Szamboti]

I still use it. It decelerates because it pretty much starts at the bottom (i.e only a handful of floors from the bottom), and it's made of concrete. It's a very different type of building.

I prefer this one though:


Check out those "squibs"

Here it is to scale:

Mick, you will have to explain to me why you think the construction materials matter as to whether or not a deceleration needs to occur in a natural building collapse. It actually is easier to collapse a masonary structure than it is a steel structure, because it fractures more easily. This goes against your argument.

The materials have little to do with whether a deceleration is required. It always is for a structure built to withstand several times the load above it being collapsed by that load naturally.

By the way, I seriously doubt you ever measured the fall of the Verinage demolition of the building you prefer, because it has been measured and it decelerates. The North Tower never does.

It is clear that the naysayers on this forum have no argument against the lack of deceleration showing the North Tower collapse was not natural.

 

[Mick West]

Mick, you will have to explain to me why you think the construction materials matter as to whether or not a deceleration needs to occur in a natural building collapse. It actually is easier to collapse a masonary structure than it is a steel structure, because it fractures more easily. This goes against your argument.

The columns are very close together, so it needs to "crush" a lot more stuff per floor to continue the descent. In the WTC the floors were stipped away, and thenmuch less force was needed to remove the columns.

By the way, I seriously doubt you ever measured the fall of the Verinage demolition of the building you prefer, because it has been measured and it decelerates. The North Tower never does.

Huh, I just said it decelerates. "It decelerates because it pretty much starts at the bottom"

It is clear that the naysayers on this forum have no argument against the lack of deceleration showing the North Tower collapse was not natural.

Not one you'd agree with, no. But we still have one. It's quite clearly laid out above. There was deceleration, just not as big as you think it was, so it only showed up in the aggregate.

 

[Tony Szamboti]

The columns are very close together, so it needs to "crush" a lot more stuff per floor to continue the descent. In the WTC the floors were stipped away, and thenmuch less force was needed to remove the columns.


Huh, I just said it decelerates. "It decelerates because it pretty much starts at the bottom"


Not one you'd agree with, no. But we still have one. It's quite clearly laid out above. There was deceleration, just not as big as you think it was, so it only showed up in the aggregate.

The columns were much closer together in the twin towers than in any of the Verinage demolitions and the floors were not stripped away immediately. What was going on in those first few stories?

Can I see a plot of the deceleration you claim is in the descent of the North Tower?

 

[Mick West]

The columns were much closer together in the twin towers than in any of the Verinage demolitions and the floors were not stripped away immediately. What was going on in those first few stories?

Can I see a plot of the deceleration you claim is in the descent of the North Tower?

The top of WTC1 tilted as it fell. 1 degree in the first 20 feet. Also the initial collapse was clearly on multiple floors, and not symmetrical.

And the distance between columns I'm referring to is between the core and the walls. There's nothing like that in the Verinage buildings.

I claim it's within the margin of error of the video measurement. There's not enough data to claim anything else. It was extremely chaotic, and nothing like your simplistic model, or Bazants.

 

[Tony Szamboti]

The top of WTC1 tilted as it fell. 1 degree in the first 20 feet. Also the initial collapse was clearly on multiple floors, and not symmetrical.

And the distance between columns I'm referring to is between the core and the walls. There's nothing like that in the Verinage buildings.

I claim it's within the margin of error of the video measurement. There's not enough data to claim anything else. It was extremely chaotic, and nothing like your simplistic model, or Bazants.

The small tilt in the North Tower would have had nothing to do with its lack of deceleration.

The collapse in the North Tower clearly initiated evenly at the 98th floor. NIST admits to this.

The distance between the core to perimeter columns would also have had nothing to do with its lack of deceleration.

There is plenty of data to do calculations with and discern what had to happen to cause the observations.

Your argument is now nothing more than one big hand wave where you claim that it was too chaotic and impossible to discern anything. So it is like I say........you have no argument, just an unsupported belief.

 

[Mick West]

The small tilt in the North Tower would have had nothing to do with its lack of deceleration.

No? Wouldn't it had misaligned the columns? I mean the TOP of the tower moved several feet, where was the center of rotation?

 

[Tony Szamboti]

No? Wouldn't it had misaligned the columns? I mean the TOP of the tower moved several feet, where was the center of rotation?

No, the trigonometry says 1 degree of rotation over 207 feet amounts to 0.378 inches of offset horizontally. In the North Tower the fulcrum was the north face.

 

[OneWhiteEye]

What does the trigonometry say about the differential vertical displacement between north and south? What does this do to your simultaneous impact scenario? What, in turn, does this do to the peak structural component of the resistive force?

 

[Tony Szamboti]

What does the trigonometry say about the differential vertical displacement between north and south? What does this do to your simultaneous impact scenario? What, in turn, does this do to the peak structural component of the resistive force?

The full upper section fell at a one degree or less angle for the first couple of stories.

 

[OneWhiteEye]

The full upper section fell at a one degree or less angle for the first couple of stories.

Putting aside this disputed claim, what is the consequence of 1 degree of tilt with respect to the difference in elevations of the north and south sides? You're very keen on emphasizing the miniscule horizontal displacement resulting from that tilt, but what about vertical?

 

[Tony Szamboti]

Putting aside this disputed claim, what is the consequence of 1 degree of tilt with respect to the difference in elevations of the north and south sides? You're very keen on emphasizing the miniscule horizontal displacement resulting from that tilt, but what about vertical?

It is the horizontal offset that counts and it shows the columns would not be misaligned by the small tilt.

 

[Josh Heuer]

What does the trigonometry say about the differential vertical displacement between north and south? What does this do to your simultaneous impact scenario? What, in turn, does this do to the peak structural component of the resistive force?

Do you know the answers to these questions?
Or are you just asking questions?

 

[OneWhiteEye]

Do you know the answers to these questions?
Or are you just asking questions?

I know an answer to each question asked. These questions, and others of similar ilk, have been asked of Tony quite a bit in the last year. He knows the answers, too.

A one degree tilt with a hinge on the north wall means (at a minimum, assuming tilt exclusively in the north-south dimension) the south wall of the upper section has displaced downwards 1.1m further than the north wall. The column impacts claimed are therefore staggered by this distance. In a grossly simplified model such as the one Tony uses, this amounts to an expectation that resistive force offered by the columns will be spatially homogenized to a significant degree. Using an aggregate load displacement response with the same profile as a single column in order to solve for motion, as he has done, is not appropriate for anyone talking about the "mysterious" lack of deceleration.

Explained from here to bottom of page.

 

[OneWhiteEye]

It is the horizontal offset that counts and it shows the columns would not be misaligned by the small tilt.

Counts for what? The calculations dependent on the assumptions of 100% capacity and a load-displacement peak of sufficient magnitude to cause measurable deceleration of the roofline? Yes, I'd agree with that. It's not the only thing that counts, in fact it's literally overwhelmed into irrelevance by all the other things that count.

 

[OneWhiteEye]

Explained from here to bottom of page.

Read on to the next page if you want more answers. Start from the beginning of the thread if you want to see how the very first revision of the (then) newly released Missing Jolt came about.