WTC: Rate of Fall (rate of crush)

Mick West

Administrator
Staff member
You can't have it both ways. If it's so spindly, then how did it crush the rest of the building you're now bigging up? Or maybe it's the dreaded spindly sledgehammer - they're the worst kind. Look at those titchy little cranes sitting on top - they look a bit spindly to me.

I think you missed that I put the word "relatively" in front of the word "spindly".
 

lee h oswald

Banned
Banned
Perhaps you could give an example of what you mean by this?

NLM (Newton's laws of motion) are described in idealized terms as point masses or springs - but that doesn't mean NLM are not applicable to the very deformable body of a human being - or anything else for that matter. You keep repeating that Newton's laws are irrelevant, but you are very badly wrong and it's not right you should be presenting like this.
The reason you are sitting in your seat is described by Newton's third law - action =-reaction, your arse is dragged to ground by gravity and that chair pushes back on your arse with an equal and opposite force. Pushing on a keypad; holding a knife; chewing on food; standing up; head butting a lamp post...

Action =-reaction is something we experience every day.

You need a refresher - and this one might be quite handy for anyone flirting round the edges of this,

MIT Physics lecture - About first 21 mins (I think, from memory) gives you a good description of all 3 NLMs

http://ocw.mit.edu/courses/physics/8...res/lecture-6/
 

Oxymoron

Banned
Banned
That's a very strong looking structure. After all, it has to carry the weight of the entire World Trade Center. Of course the exterior beams you show there are the underground levels and the lobby floor (which actually was "mostly glass" in terms of area, not that that changes anything). Here's a better image you can use showing it more clearly.
Ok, this may not be particularly scientific in terms of formulae and workings out but I still think it relevant.

I am struck by the ratio of floorspace to inner steel core. It appears to me the inner steel core takes up around 30% of the floorspace, more at the lobby level... agreed?

I am going out on a limb here but could I liken the core somewhat to say The Eiffel Tower? (accepting the Eiffel Tower has a much broader base and narrower upper structure) the principle is similar?



So basically we have an internal steel structure, (like Eiffel Tower) and an exterior steel and glass structure, (60% steel), tied together with the long span steel reinforced lightweight concrete flooring and load bearing steel girders.



Now I know it is all a bit of a flight of fancy but... why did the flooring surrounding the extremely strong steel core not fall away from the core leaving it partially intact whilst at the same time pushing the exterior steel and glass away from the centre core? Something akin to peeling a banana?


Sorry if it's a dumb question but it just seems more logical to me as I cannot imagine the Eiffel Tower being crushed.
 
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lee h oswald

Banned
Banned
Originally Posted by lee h oswald

You can't have it both ways. If it's so spindly, then how did it crush the rest of the building you're now bigging up? Or maybe it's the dreaded spindly sledgehammer - they're the worst kind.


I think you missed that I put the word "relatively" in front of the word "spindly".


I most certainly did not miss it - it's the basis of the point; I think you've made another error of judgement. You said that the top of the tower was relatively spindly looking. Relative to what? What could you have been relating this idea of spindliness to, I wonder....Ice cream and jelly? Er, no, relative to the rest of the building below it, obviously. I think your argument is getting thinner and thinner with that latest self-defeating effort.

You can't have it both ways. Can you?
 
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George B

Extinct but not forgotten Staff Member
Seems the whole thing comes down to the accuracy of the estimates in the strength of the building under the dreaded spindly sledgehammer and was the sledgehammer a sledgehammer or was it a hand-full of loose rubble when it hit the first few floors under the damage . . . even Greening says the following . . .
 

lee h oswald

Banned
Banned
"the dreaded spindly sledgehammer " . . . that is a great catch phrase Lee . . . !!!

I quite like it - sounds a bit like a Conan-Doyle - The Mysterious Case of The Dreaded Spindly Sledgehammer.

How many buildings will fall before the case is solved....?
 

Mick West

Administrator
Staff member
Now I know it is all a bit of a flight of fancy but... why did the flooring surrounding the extremely strong steel core not fall away from the core leaving it partially intact whilst at the same time pushing the exterior steel and glass away from the centre core? Something akin to peeling a banana?

Well, that is somewhat like what happened. Large section of the exterior wall did peel away, and large sections of the (stronger, lower) core did remain standing for a while. However the exterior broke up as it peeled off (it was impossible for it not to), and the remaining core was not stable, and eventually collapsed when it had lost all lateral support. See:

 

Mick West

Administrator
Staff member
NLM (Newton's laws of motion) are described in idealized terms as point masses or springs - but that doesn't means NLM are not applicable to the very deformable body of a human being - or anything else for that matter. You keep repeating that Newton's laws are irrelevant, but you are very badly wrong and it's not right you should be presenting like this.
The reason you are sitting in your seat is described by Newton's third law - action =-reaction, your arse is dragged to ground by gravity and that chair pushes back on your arse with an equal and opposite force. Pushing on a keypad; holding a knife; chewing on food; standing up; head butting a lamp post...

Action =-reaction is something we experience every day.

You need a refresher - and this one might be quite handy for anyone flirting round the edges of this,

MIT Physics lecture - About first 21 mins (I think, from memory) gives you a good description of all 3 NLMs

[video]http://ocw.mit.edu/courses/physics/8-01-physics-i-classical-mechanics-fall-1999/video-lectures/lecture-6/[/video]

.

Yes, but the problem is when you try to use the laws to describe the motion of the top of the tower and the reaction of the bottom of the tower. The descriptions of how the bottom should "push back" against the motion of the top are in fact describing what would happen to a point mass (the top) and a spring (the bottom). It does not describe what is actually an aggregate of billions of actions between separate yet connected deformable bodies.

NLM also does not describe what is going on when you crush a soda can or when a large weight buckles a steel girder. Part of the force goes into deforming the metal, not as an "equal and opposite reaction".
 

Oxymoron

Banned
Banned
Like George, I find many things intuitively wrong with 9/11 collapses. To me the core should have stood longer than the rest, at the top maybe bending over, (due to lack of surrounding support) before fracturing and falling.

Near the bottom it should have stood independently. But it just seemed to 'disintegrate' as the building fell and at the bottom it stood for a few seconds and kind of 'evaporated'. Steel girders should, in my world view, fall over... not fall straight down or evaporate.


Adding fuel to the fire...it is interesting that Greening has produced a 'withering critique' of NIST's WTC 7 report

http://the911forum.freeforums.org/withering-critique-of-the-new-wtc7-report-t44.html

 

Mick West

Administrator
Staff member
Like George, I find many things intuitively wrong with 9/11 collapses. To me the core should have stood longer than the rest, at the top maybe bending over, (due to lack of surrounding support) before fracturing and falling.

Near the bottom it should have stood independently. But it just seemed to 'disintegrate' as the building fell and at the bottom it stood for a few seconds and kind of 'evaporated'. Steel girders should, in my world view, fall over... not fall straight down or evaporate.

The un-intuitiveness of what happened is mostly a problem with scale. We are simply totally unprepared to imagine what might happen to such structures, so we impose instead what we are familiar with with smaller structures.

Try to imaging a 400 foot high girder, made up of multiple girders bolted together, balance on its end. It's very unstable (which is why antennas have guy-wires). But when something like that fails, it fails by buckling, and the joints failing, because it is so heavy.

In the case of the spire, what seems to be happening with the disintegration is:

1) The building collapsed around the spire, coating it with dust and debris.
2) The tallest part of the spire leans and buckles near the base
3) Most of the spire falls the height of a few stories
4) It impacts the ground, sending a huge violent jolt through the spire, dislodging debris and rust flakes from the spire.
5) The spire continues to buckle and fall, but the precise nature is lost in the clouds of dust.

Now this is not the same thing, but notice how this antenna seems to be sinking into the ground, instead of simply toppling over.


And notice how this tower just collapses after a guy wire is cut:


and these towers don't just fall over, they crumple:


And here's a tower taller than the WTC towers


Of course it's not the same thing, as the radio masts have a significantly lighter structure. But it's still somewhat illustrative of buckling. Remember while the wtc girders are stronger, they also had to support a lot of weight. As soon as they get off vertical, then they can't do it any more.
 

George B

Extinct but not forgotten Staff Member
The un-intuitiveness of what happened is mostly a problem with scale. We are simply totally unprepared to imagine what might happen ot such structures, so we impose instead what we are familiar with with smaller structures.

Try to imaging a 400 foot high girder, made up of multiple girders bolted together, balance on its end. It's very unstable (which is why antennas have guy-wires). But when something like that fails, it fails by buckling, and the joints failing, because it is so heavy.

In the case of the spire, what seems to be happening with the disintegration is:

1) The building collapsed around the spire, coating it with dust and debris.
2) The tallest part of the spire leans and buckles near the base
3) Most of the spire falls the height of a few stories
4) It impacts the ground, sending a huge violent jolt through the spire, dislodging debris and rust flakes from the spire.
5) The spire continues to buckle and fall, but the precise nature is lost in the clouds of dust.

Now this is not the same thing, but notice how this antenna seems to be sinking into the ground, instead of simply toppling over.


And notice how this tower just collapses after a guy wire is cut:


and these towers don't just fall over, they crumple:


And here's a tower taller than the WTC towers


Of course it's not the same thing, as the radio masts have a significantly lighter structure. But it's still somewhat illustrative of buckling. Remember while the wtc girders are stronger, they also had to support a lot of weight. As soon as they get off vertical, then they can't do it any more.

Mick, with all that bending, deformation of metal and collisions with the ground and all . . . the heat energy must have been incredible . . . I didn't see the aluminum burst into flames or melt . . . or just disintegrate like the images above . . .
 

Mick West

Administrator
Staff member
Mick, with all that bending, deformation of metal and collisions with the ground and all . . . the heat energy must have been incredible . . . I didn't see the aluminum burst into flames or melt . . . or just disintegrate like the images above . . .

It didn't disintegrate.


Why would it burst into flames?
 
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lee h oswald

Banned
Banned
Yes, but the problem is when you try to use the laws to describe the motion of the top of the tower and the reaction of the bottom of the tower. The descriptions of how the bottom should "push back" against the motion of the top are in fact describing what would happen to a point mass (the top) and a spring (the bottom). It does not describe what is actually an aggregate of billions of actions between separate yet connected deformable bodies.

NLM also does not describe what is going on when you crush a soda can or when a large weight buckles a steel girder. Part of the force goes into deforming the metal, not as an "equal and opposite reaction".

No! NLM isn't the only tool in the box, but it's a critical and reliable one. All Newton's laws are just approximations - albeit approximations that work very well at our level of interpretation, our reference frame - and it'll only be the law until someone changes it. Get up to speeds approaching the speed of light and NLM doesn't work any more (which begs a tricky question). Special Relativity takes up the challenge at that point...even Einstein couldn't quite grasp it....and he might even agree that the greatest shortcoming of physics is that it neglects to fully account for human beings being a part of its study of the physical universe, which is what physics is.
 

Mick West

Administrator
Staff member
So you are saying it fell out of view and left the dust in mid air? Plausible . . .

Yes, as you can see here (sorry I uploaded a clipped version earlier, you might need to refresh the page to see it in full) the tallest beam can just be seen falling behind the trail of dust it leaves. Those photos are highly misleading.

 
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Mick West

Administrator
Staff member
No! NLM isn't the only tool in the box, but it's a critical and reliable one. All Newton's laws are just approximations - albeit approximations that work very well at our level of interpretation, our reference frame - and it'll only be the law until someone changes it. Get up to speeds approaching the speed of light and NLM doesn't work any more (which begs a tricky question). Special Relativity takes up the challenge at that point...even Einstein couldn't quite grasp it....and he might even agree that the greatest shortcoming of physics is that it neglects to fully account for human beings being a part of its study of the physical universe, which is what physics is.

But neither NLM nor special relativity are anything to do with buckling girders.
 

Mick West

Administrator
Staff member
Here's an image showing where the spire is in relation to the building. It actually goes over half way up it.
 
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Oxymoron

Banned
Banned
Here's an image showing where the spire is in relation to the building. It actually goes over half way up it.

Lol, you been raiding the CIA files again Mick :) Good perspective.

But seriously, there must be a formula like Newton's Third Law that covers this.

It's like in martial arts... if you punch an object very hard but it does not give, (say a car window), you will likely damage your hand... but if you punch with enough force to breakthrough the window, you will hardly feel it. It is almost as if there was nothing much there.

Using this fact, there must be studies whereby objects of differing mass have been dropped from varying heights onto objects with varying but known, strength and a formula derived.

i.e. say a bowling ball 'm', dropped from 150' onto 10 glass sheets 'g' with 15' in between each.

Finding how much weight 'm' is slowed from normal gravity acceleration, or it may even get to glass sheet 5 and not pass through because of lack of force, much like a bullet coming to rest in ballistics gel.

The other point I would make, is as the top broke up, 'dustified', what impacted the lower part of the towers was technically a dense 'fluid' containing larger solids.

Also, there should be some info on the maximum weight possible of the aggregated 'dustified' top section which was impacting the lower section, taking into account ejecta and 'overflowing'.

Just wondered if your CIA banks ran to that sort of info :)
 
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Cairenn

Senior Member.
Dust still has weight. Only a small amount of the weight of it was in the air. A ton of feathers is still a ton
 

George B

Extinct but not forgotten Staff Member
Dust still has weight. Only a small amount of the weight of it was in the air. A ton of feathers is still a ton
True but its fall rate is much slower because it has so much surface area and is so small it floats in air turbulence and forms clouds that may escape the crush zones . . . the question is how much escaped?
 

Oxymoron

Banned
Banned
True but its fall rate is much slower because it has so much surface area and is so small it floats in air turbulence and forms clouds that may escape the crush zones . . . the question is how much escaped?

Well this is right, how much escaped, overflowed, dusted into the air etc... but ultimately, what was the maximum weight/force of the 'fluidic' bearing down on the upstanding towers.

Undoubtedly a ton of feathers is as heavy as a ton of steel but will it cause the same damage, (if not contained in a solid form)?
 

Mick West

Administrator
Staff member
Lol, you been raiding the CIA files again Mick :) Good perspective.

But seriously, there must be a formula like Newton's Third Law that covers this.

It's like in martial arts... if you punch an object very hard but it does not give, (say a car window), you will likely damage your hand... but if you punch with enough force to breakthrough the window, you will hardly feel it. It is almost as if there was nothing much there.

Using this fact, there must be studies whereby objects of differing mass have been dropped from varying heights onto objects with varying but known, strength and a formula derived.

i.e. say a bowling ball 'm', dropped from 150' onto 10 glass sheets 'g' with 15' in between each.

Finding how much weight 'm' is slowed from normal gravity acceleration, or it may even get to glass sheet 5 and not pass through because of lack of force, much like a bullet coming to rest in ballistics gel.

The other point I would make, is as the top broke up, 'dustified', what impacted the lower part of the towers was technically a dense 'fluid' containing larger solids.

Also, there should be some info on the maximum weight possible of the aggregated 'dustified' top section which was impacting the lower section, taking into account ejecta and 'overflowing'.

Just wondered if your CIA banks ran to that sort of info :)

I just made that image from a youtube video. It's a "cinemagraph", they are very easy to make.

There are certainly formula that cover this, but not one simple one. The problem is that "damage" is not a simple quantity. Consider impact analysis in car crashes. One might say that it's a simple problem - a car travelling at 30 mph hits a tree. And yet the end result will vary radically based on which type of car you are in. It's actually a very complex problem, one that is not solvable by simple equations like "F1 = -F2". It requires a simulation to see what really happens, and the technique most often used is finite element modeling.


Newton's third laws says that "for every action there is an equal and opposite reaction". If you push something it will push back. If you stand on ice and push someone of equal weight, you will move away from each other.

But if you take a thin steel rod and rapidly bend it in two over your knee, then what exactly is the applicability of Newton's law? Did the rod push back, sure it pushed back against your hands, and against your knee. But a portion of the force went into breaking the molecular bonds in the middle of the rod, hence softening it, bending it, and heating it up. That's why Newton's laws cant really describe what is going on, because they say nothing about molecules, and deformation, and heat.

To your example with the bowling ball. That is something that you could probably make a good estimate of, if you have a good understanding of the materials involved. It's not simply mass we are talking about, it's also hardness and shape. Five pounds is not just five pounds of force. It's how it impacts, and over what period. A five pound iron ball will be very different to a five pound water ballon, and very different to a five pound rubber ball. and a five pound cube will have a different effect if you drop it on its point or on its side. It will also made a difference if you drop it in the middle, or at the edge by a support.

So it's quite complicated to do using equations of motion - which is why attempts to do so usually make overly simplistic assumptions, and don't account for what is actually happening. The most common mistake is failure to distinguish between static forces (simple weight, the force of thirty pounds held by your hand) and dynamic forces (the much more complex force exerted in a collision, such as the force of a thirty pound weight falling on your hand from thirty feet up).

So we usually discuss such things in terms of energy. Energy is measured in joules, there are different forms of energy: potential, kinetic, heat, sound, chemical, electric, etc. Here were are mostly concerned with the first four. We know how much energy is in the top part of the building (and in each floor below it). We know how much energy gets converted from potential to kinetic when it drops so many floor. We can estimate how much energy it takes to destroy a floor (to buckle all the columns to the point of failure). We can then simply add up the energy as we go, and see if it matches the observations.

Of course this is still a simplification. There are many unknowns, and sever assumptions. The columns might, for example, buckle over longer lengths than a single floor. The floors might be stripped away before or after the buckling. Some columns might not buckle at all, but spear through for a few floors.

But we can at least get some baseline worst case estimates.

The dispute then falls into three camps. On the one had we have people who say that Newton's Third Law is broken, and this energy talk is bunk. With them we can only try to explain why Newton does not really apply. Secondly we have people who just dispute the energy requirements, and there we need to drill down to try to find why the estimates differ. Finally you have people who have a whole other theory entirely, usually based on some rather dodgy physics.
 

Oxymoron

Banned
Banned
The dispute then falls into three camps. On the one had we have people who say that Newton's Third Law is broken, and this energy talk is bunk. With them we can only try to explain why Newton does not really apply. Secondly we have people who just dispute the energy requirements, and there we need to drill down to try to find why the estimates differ. Finally you have people who have a whole other theory entirely, usually based on some rather dodgy physics.

I was with you Mick, right up to 'The dispute then falls into three camps...'

It seems to me there are simply too many variables for anyone to make an adequate assessment or analysis.

I mean, just for eg, how did NIST identify the joint which allegedly failed and brought 7 tumbling down when they do not even know when, where or how the fires started?
 

Mick West

Administrator
Staff member
I was with you Mick, right up to 'The dispute then falls into three camps...'

It seems to me there are simply too many variables for anyone to make an adequate assessment or analysis.

I mean, just for eg, how did NIST identify the joint which allegedly failed and brought 7 tumbling down when they do not even know when, where or how the fires started?

Well, maybe "three or more" camps then :) But I was mostly talking about the debate over the fall speed.

NIST has used the best information available. NIST NCSTAR 1-5A is 392 pages of analysis of what exactly was the damage from the impact and the fires to WTC 1 and WTC2. You should at least look it over.

https://www.metabunk.org/files/NIST...age Estimate - Timeline Analysis_unlocked.pdf (115MB)


For WTC7, read NIST NCSTAR 1-9, which is an incredible amount of analysis, 797 pages, where everything possible is done to find out the sequence of events. You should really look that over.

https://www.metabunk.org/files/NCSTAR_1-9_WTC7_unlocked.pdf (53MB)

The identification of the column is made essential by observation of the way the penthouse fell, and the observed buckling and collapse. See chapter 8. It's consistent with what fires were observed (and a huge section of the document - section 5.6 - goes into identifying where and when the fires were burning). There's only a few columns under the penthouse so one or more of them must have given out for it to collapse. C79 was directly in the middle of it, and so the loss of C79 was consistent with how the penthouse fell.



Since the above files are large I would recommend downloading them (right click, save as), and reading offline, rather than in the browser.
 
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George B

Extinct but not forgotten Staff Member
I think it is time to propose a solution:

Next time a high-rise steel reinforced building is to be demolished . . .

1) Do a systematic elastic strength and mass analysis . . . account for the proper parameters, formulae, and data needed to get E1 predicted as close as possible and

2) accomplish a Verinage demolition without weakening the lower floors and foundations prior to detonation or hydraulic removal of the chosen floor or floors . . .

3) Record the speed(s) of fall of multiple target landmarks while recording seismic data from start to finish . . .

4) Collect, Tabulate, Analyze, and Compare with WTC 1, 2 & 7 . . .

SmokeStack TWC.jpg

 

Mick West

Administrator
Staff member
I think it is time to propose a solution:

Next time a high-rise steel reinforced building is to be demolished . . .

1) Do a systematic elastic strength and mass analysis . . . account for the proper parameters, formulae, and data needed to get E1 predicted as close as possible and

2) accomplish a Verinage demolition without weakening the lower floors and foundations prior to detonation or hydraulic removal of the chosen floor or floors . . .

3) Record the speed(s) of fall of multiple target landmarks while recording seismic data from start to finish . . .

4) Collect, Tabulate, Analyze, and Compare with WTC 1, 2 & 7 . . .

Right. You want to contribute the $1,000,000+ required to do this?

The thing is there's no motivation for people to do this, as the vast majority of reasonable engineers agree with the NIST reports general findings. It might seem vastly important to truthers, but there is simply no upside for anyone to spend lots of money on evidence that will IMMEDIATELY be discarded as either faulty, faked, or irrelevant.

And this would obviously do nothing for 7.
 

George B

Extinct but not forgotten Staff Member
Right. You want to contribute the $1,000,000+ required to do this?

The thing is there's no motivation for people to do this, as the vast majority of reasonable engineers agree with the NIST reports general findings. It might seem vastly important to truthers, but there is simply no upside for anyone to spend lots of money on evidence that will IMMEDIATELY be discarded as either faulty, faked, or irrelevant.

And this would obviously do nothing for 7.

Mythbusters, Popular Mechanics, etc. might do it for nothing . . . I would love to contribute to someone who is willing to do it ... and why would it take a million dollars . . . seems most of this could be done with a few volunteer engineers, physicists, seismologists, etc.
 

George B

Extinct but not forgotten Staff Member
George, have you looked over the above two NIST files?

I have looked at NIST files in the past but did not pay any attention to the math, in fact I don't remember any math . . . LoL!!! . . . I will look over the above when I have some time . . .
 

Mick West

Administrator
Staff member
Mythbusters, Popular Mechanics, etc. might do it for nothing . . . I would love to contribute to someone who is willing to do it ... and why would it take a million dollars . . . seems most of this could be done with a few volunteer engineers, physicists, seismologists, etc.

And where are you going to get the building?
 

Cairenn

Senior Member.
A lot of grain elevators are built very solidly. I know that many of the ones around here have had to be demoed by hand, instead of implosion because of that. That has saved a one or 2 of them so they could be repurposed
 

George B

Extinct but not forgotten Staff Member
Cairenn,

That is interesting . . . I suppose the structures are too short and too well constructed . . . but you would think without central support they would fall in a similar fashion as a chimney would since the are rather narrow in construction.
 
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