The Uniqueness of the WTC7 Collapse

A more accurate thought experiment Mick would be to stack ten pop cans on top of one another and perform the same experiment. My bet is you'd likely break your leg cause the cans would guaranteed skip out to the side long before they'd fall straight down through themselves. ;-)
 
Why did the bits of the Windsor tower that collapsed actually collapse then? Why didn't the bits that didn't?

Because it's perfectly reasonable to expect a partial collapse when an entire structure is gutted from top to bottom, lit up like a villager's torch for twenty six hours - it's remarkable more of it didn't collapse in those circumstances - but it did not. The (Windsor) building (which hopefully we agree was an inferior construction to 7), was undergoing remedial works at the time of the fire and was denuded of its fire protection over many floors (7 was intact in that respect) to enable works, allowing the fire to spread from floor to floor unhindered by fire protection design. Can anyone disagree on the disparity of the ferocity and scope of the fires in the two buildings [edit - and the respective results]? And I don't count anything NIST says as a being a reliable source - not until they release all the data we need to see to enable its (the report) entry into the realm commonly known as 'science'.
As for the bits that didn't collapse - well, that would be the building - and one denuded of its fire protection, at that - and it did exactly what all previous observations of such events tells us should have happened - it remained standing, it didn't just fold like a pack of cards.
 
No it was arrested by the elevator shaft and surrounding structure that is designed to provide lateral stability to the building, WTC7 would have had a synonymous structure, likely several for a building that large. Sooooo where did that go and how did it just disintegrate completely right along with everything else in the building regardless of strength characteristics

Another little tid bit is that the WTC building was largely unaffected by fire, whereas everything in the Madrid fire that actuall fell off the building had been totally engulfed in flames for something like 12 hours previous to the collapse.

Feel free to correct me on the 12 hours part, but it was a significant amount of time vs the WTC 7 in which the vast majority of the building wasn't subjected to fire stress at all.


No, actually the total collapse of the upper stories occurred after approx 4-5 hours of burning.

http://www.mace.manchester.ac.uk/pr...Study/HistoricFires/BuildingFires/default.htm

..and NO, the collapse of the upper floors was stopped by the concrete "technical" floor- not an elevator shaft.:

A large portion of the floor slabs above the 17th Floor progressively collapsed during the fire when the unprotected steel perimeter columns on the upper levels buckled and collapsed (see Figure 1). It was believed that the massive transfer structure at the 17th Floor level resisted further collapse of the building.
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http://www.mace.manchester.ac.uk/pr...Study/HistoricFires/BuildingFires/default.htm

Preliminary findings suggest that a combination of the upper technical floor and the excellent passive fire resistance of the tower's concrete columns and core prevented total building collapse.
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No. The 'total collapse of the upper stories' never took place at all.


once again, R resorts to semantics and word play:

The steel columns above the 17th floor suffered complete collapse,
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So, perhaps it wasn't "total"...just "complete" collapse of steel columns due to fire.
 
I clearly see the middle of the building at the top bow in and sag as it falls. How would it do this if the majority of the interior had not fallen away and been left relatively hollow?
 
once again, R resorts to semantics and word play:

The steel columns above the 17th floor suffered complete collapse,
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So, perhaps it wasn't "total"...just "complete" collapse of steel columns due to fire.
once again, R resorts to semantics and word play:

The steel columns above the 17th floor suffered complete collapse,
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So, perhaps it wasn't "total"...just "complete" collapse of steel columns due to fire.

Claim 'total collapse' and expect to be picked up, because it's wrong, innit - the building ended the fire with the same number of floors as it began it with - how does that equal 'total collapse' of anything? I mean, please do explain the 'logic'? The semantics aren't mine, are they. Pictures or it never happened.
 
yep- yer right- way to use your intellect to dismantle that one- good on ya.

doesn't change the fact that there was a "complete" collapse of steel columns due to fire after only 4-5hrs of burning.

The steel-glass façade was completely destroyed, exposing the concrete perimeter columns. The steel columns above the 17th floor suffered complete collapse, partially coming to rest on the upper technical floor. The
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doesn't change the fact that there was a "complete" collapse of steel columns due to fire after only 4-5hrs of burning.

The steel-glass façade was completely destroyed, exposing the concrete perimeter columns. The steel columns above the 17th floor suffered complete collapse, partially coming to rest on the upper technical floor. The
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Just as well 'complete' is 'in' '-', then. Are we saying there was no steel anywhere else in the remaining, uncollapsed parts, ie - the building? Please advise -

And - To say,

the 'total collapse of the upper stories' never took place at all.

is right, and to suggest it in those terms is all the 'semantics' we need to know about? Agenda-a-go-go.
 
I am sorry...what? your agenda is gone??

There was a complete collapse of the steel columns supporting the upper floors...the only thing preventing further collapse was the existence of a concrete technical floor.

Fire caused steel in a high rise building to collapse.
 
I am sorry...what? your agenda is gone??

There was a complete collapse of the steel columns supporting the upper floors...the only thing preventing further collapse was the existence of a concrete technical floor.

Fire caused steel in a high rise building to collapse.

Filling in while Mick takes a break? Crossing the line though, I reckon, with this post. Outright lying is just a bit too extreme to pass inspection.
 
I clearly see the middle of the building at the top bow in and sag as it falls. How would it do this if the majority of the interior had not fallen away and been left relatively hollow?
Even if this were the case, how does it follow that the (damaged on one side) exterior shell must collapse in a remarkably symmetrical fashion?
 
Here's a clue:


If the can had a similar internal structure [to WTC 7], then it would require much more than a light touch to make it collapse.
It requires a light touch in the side and a MASSIVE FORCE ON THE TOP. Perhaps you are suggesting that a man standing on a can is a reasonable representation at scale of the force of gravity on WTC7.
Imagine you were to give it some internal support by filling it with water before standing on it. You then turn it upside down and stand on it. The water will drain out, and then the can will collapse. This simulates the collapse order to wtc7.
I agree: water models the interior structure of a building even more accurately than a man standing on a can models the force of gravity.
The building seems to collapse symmetrically for the reasons NIST gave. The exterior is stronger than the interior.
Exactly why have you and NIST assumed that hypothesising an internal collapse must entail the symmetrical collapse of the exterior shell?
 
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Because gravity is pulling down equally on all of it, and if it's more or less a shell, the thickness would be similar all over - why wouldn't it collapse relatively uniformly?
 
Because gravity is pulling down equally on all of it, and if it's more or less a shell, the thickness would be similar all over - why wouldn't it collapse relatively uniformly?
Can you think of any examples where this naturally happens? Do you think fire is burning equally on all of it too?
 
The 'shell' is a structure that is knitted together - it would more or less act as one cohesive unit.
The penthouse failure initiated the way the rest fell by eviscerating the insides, so an equal presence of fire is not necessary.
A hollowed out termite mound that was subject to a large force going out from it's base would be the only 'natural' structure to compare this to, but the analogy wouldn't be a very good one.
 
Because gravity is pulling down equally on all of it, and if it's more or less a shell, the thickness would be similar all over - why wouldn't it collapse relatively uniformly?

Sure gravitational constant is what it is, however the steal isn't a constant, particularly when subjected to a variety of forces, some of which, like heat for instance impart an uneven alteration in strength characteristics. Ergo its no longer a symmetrical system.

How about this NIST leed investigative engineer outright lying about the existence of molten steal at the site. Would that be denying what the experts said what happened ?

 
It requires a light touch in the side and a MASSIVE FORCE ON THE TOP. Perhaps you are suggesting that a man standing on a can is a reasonable representation at scale of the force of gravity on WTC7.

That's the problem you see, you can't get a "reasonable representation" at this scale. A small object can support many more times its own weight than a large object. What I'm illustrating is the principle, not a direct physical comparison


I agree: water models the interior structure of a building even more accurately than a man standing on a can models the force of gravity.
Again, it's illustrating physical principles, not the actual events.


Exactly why have you and NIST assumed that hypothesising an internal collapse must entail the symmetrical collapse of the exterior shell?

We haven't. That's just what happened in this instance.
 
Was there molten steel there then? How do you know?

Classic denial, so what form of evidence are you willing to accept ?

Me I'm all about film evidence, particularly with the item in question is in the background and reporters are asking questions.


 
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Denial of what? I really don't know whether there was molten steel there or not.
If he was lying, then there was molten steel there, which you can prove.
What form of evidence are you using to prove he's lying? (I'm sorry I didn't watch the video, please explain it if it's in there)
 
Here's an extension of my earlier earlier demonstrations. I have about 170 pounds (77,000 grams) supported by three 15 gram empty soda cans. So each can is supporting about 1700x its own weight.

I bang one can at the end, and all three cans (which are not touching) collapse. The video is shot at 8x normal speed. The delay between the right can collapsing and the left can collapsing is 8 frames, or 0.03 seconds.



This illustrates a rapid progressive collapse, albeit at a vastly reduced scale.

mov file attached if you'd like to step through it.
 

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My attempts at using water to demonstrate loss of internal structure did not work out well, but I got some intersting still frames.

The water is initially forced out of the bottom of the can as it collapses. A pyroclastic flow of dihydrogen monoxide!


 
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Denial of what? I really don't know whether there was molten steel there or not.
If he was lying, then there was molten steel there, which you can prove.
What form of evidence are you using to prove he's lying? (I'm sorry I didn't watch the video, please explain it if it's in there)
Multiple credible witnesses who were directly at the scene (firefighters, police officers, etc.)
 
I think we're getting a bit off track here tho. I'm due at a pub in about ten minutes so I gotta go but I'd like to compare the NIST animation of how they say bldg 7 fell and the actual film evidence, cause there are huge whopping differences.

No visible deformation is seen in the actual film evidence
no visible debris is shedding from the building in the film evidence
no deformation of the roof line is evident in the film evidence
no deformation of the corner is seen in the film evidence
no failure of the complete pent house structure before exterior deformation begins when comparing the two

The list goes on and on but in the end, NIST recreation is entirely inaccurate in pretty much every way. So the question becomes, why do they present it ? Whats the point if they know it doesn't match the observed evidence ?

But lets leave off the ambiguous questions and just stick to whether or not the animation in any way represents the film evidence. Maybe once we establish that its not even close, we can move forward from there.





someone who's good with graphics put that side by side with the real thing so we can all see exactly just how far off that NIST animation really is.
 
yup that looks like molten steel, though it seems still in a solid state as it's being picked up, so not molten as in liquefied.

But I don't know why it's significant, other than it was seemingly denied, as that's a lot of energy in that building. Either he was misinformed, or thought the interviewer meant totally liquid steel, or he was lying.


No visible deformation is seen in the actual film evidence
no visible debris is shedding from the building in the film evidence
no deformation of the roof line is evident in the film evidence
no deformation of the corner is seen in the film evidence
no failure of the complete pent house structure before exterior deformation begins when comparing the two
You're going to have to clarify here. Deformation is definitely seen as it collapses, it bows inward. The corners seems to be slightly delayed compared to the middle.
And the penthouse definitely falls through at least several floors before the whole building goes, you can see its path as the windows smash.

You say Mick should put several cans on top of each other, well maybe if the building was made of several contained units stacked on top of each other, but it's one whole package.
Perhaps a large olive oil can would suit better?
 
But lets leave off the ambiguous questions and just stick to whether or not the animation in any way represents the film evidence. Maybe once we establish that its not even close, we can move forward from there.





someone who's good with graphics put that side by side with the real thing so we can all see exactly just how far off that NIST animation really is.


There are two animations there. The seconds one was done with the known conditions, the first was an idealized version with no impact damage. Conspiracy theorist like to use the first one.
 
Sorry Mick, but you'd want to stack ten or so cans atop one another in order to begin getting an accurate demonstration. Side by side or full of water makes zero impression as to exactly how a complex structure fails

Except in this case the can is the structure. A strong exterior structure that crumples.

Notice in my experiment above, the middle can buckles at the bottom.
 
The 'shell' is a structure that is knitted together - it would more or less act as one cohesive unit.
The penthouse failure initiated the way the rest fell by eviscerating the insides, so an equal presence of fire is not necessary.
A hollowed out termite mound that was subject to a large force going out from it's base would be the only 'natural' structure to compare this to, but the analogy wouldn't be a very good one.
That's right. You'd have to ask how the ants managed to put tiny explosives into the base of their mound without the other ants noticing.

Fact is it's incredibly improbable that the shell would fall straight down, isn't it. Why do you think it wouldn't fall towards a weakened area, or the side where the fire had burned most? That's vastly more probable if it was to happen at all.
 
That's right. You'd have to ask how the ants managed to put tiny explosives into the base of their mound without the other ants noticing.

Fact is it's incredibly improbable that the shell would fall straight down, isn't it. Why do you think it wouldn't fall towards a weakened area, or the side where the fire had burned most? That's vastly more probable if it was to happen at all.
Given the scale, of course it's going to fall straight down. There's not enough structural strength in it for it to have a pivot point that would let it topple over to the side like a fence post. The force acting on it is pulling it directly down. If it were a completely rigid and immensly strong stucture that couldn't break apart then it might fall to the side if a pivot point at it's base transferred the downward energy away from it, but as it is any would-be pivot point just crumbles.

Could you explain why it's incredibly improbable it would fall straight down? That's what it does isn't it?
 
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I appreciate the admission Peter, if we can't at least admit to the visual evidence then there's really no point in discussing it in the first place.

Mick, please, none of the "can" demonstrations thus far even remotely mimic the collapse of WTC 7 why is it we have yet to see some number of cans stacked one on top of another and then recreate the experiment, could it be that the more cans in the stack the less likely it is to illicit a vertical collapse ? Soooo how many floors was bldg 7 ( 47 ) so now stack 47 cans atop one another and try it again, now your beginning to see the complexity of the actual system involved. ;-)

Cairenn really are you seriously going to suggest that those pictures are faked ?

There's no way when placed side by side the NIST recreations actually represent what we see in the WTC 7 collapse. "

Not only that but the NIST text describes buckling at the base of the beams, yet the animation shows failure at the top as well as the inward motion of one corner long before any buckling occurs at the bottom. What it most definitely does not show is a virtical global collapse with simultaneous motion motion directly downwards of all four corners.

Sorry people but the NIST recreation in no way represents what we see in the film evidence.

I'm trying to remain at least somewhat scientifically objecting objective ( sorry but something about this program auto spell ( spells ) what it thinks I want to write and then will not allow me to correct it ) here but wow, the back flips being performed by the some folks desperate to maintain the party line are amazing. Even the NIST recreations, based off there woefully inadequate analysis is clearly in error. No animated visualization NIST offers even remotely resembles what we see in the actual collapse.

Why is that ? ? ? ?

I'll venture a guess, because the NIST assumptions and refusals to analyze "all" the available data prevents them from accurately depicting the events of that day.
 
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To what definition is the metal molten - hot enough to glow white hot, or liquid? If the definition is liquid, is there more definitive evidence of that?
What is the significance?
Do you agree or dispute that the bulldozer arm would not be able to operate in the presence of fully molten metal?

You keep missing the point about the can - it represents the face, the sleeve, of the building, not each separate floor.
Maybe an empty tennis ball container would be closer in scale?

Do you see the penthouse fall and leave daylight in the top windows and then see the lower windows break? Because that seems to be a significant, and clearly observable, event representing a failure inside the building that initiates the final overall one, that is not clear if you see it or not.
Also do you note the sagging in the middle of the facade in the final moments, which seems to indicate a certain 'hollowness'.
 
Mick, please, none of the "can" demonstrations thus far even remotely mimic the collapse of WTC 7 why is it we have yet to see some number of cans stacked one on top of another and then recreate the experiment, could it be that the more cans in the stack the less likely it is to illicit a vertical collapse ? Soooo how many floors was bldg 7 ( 47 ) so now stack 47 cans atop one another and try it again, now your beginning to see the complexity of the actual system involved. ;-)

The can demonstrations are not meant to mimic the collapse of WTC7. As I've said a few times they are to illustrate related principles.

If I added more cans stacked on top then it would be highly unstable. WTC7 had a moment resisting exterior frame - meaning the exterior frame acted as a contiguous skin, all tightly linked together. This is best represented by a single can.

And again, there's this huge problem of scale. The can is hundreds of times stronger than WTC7, relative to its weight. Square cube law.

So scale models can demonstrate principles, but not actuality.
 
Even the NIST recreations, based off there woefully inadequate analysis is clearly in error. No animated visualization NIST offers even remotely resembles what we see in the actual collapse.

Why is that ? ? ? ?

I'll venture a guess, because the NIST assumptions and refusals to analyze "all" the available data prevents them from accurately depicting the events of that day.

Ask NIST:

http://www.nist.gov/el/disasterstudies/wtc/faqs_wtc7.cfm

29. The simulation of the collapse modeling of WTC 7 does not match the video footage of the collapse. In particular, the large inward deformations of the upper exterior walls after the beginning of global collapse are not visible in the video footage. Can NIST explain the difference between the results of its computer model of the collapse and the available video evidence?

NIST conducted two global collapse analyses, one that included damage due to debris-impact from the collapse of WTC 1, and one that did not include any debris-impact damage. These two analyses were conducted to determine the influence of the debris-impact damage on the response of WTC 7 when subjected to the effects of the fires that burned on floors 7 to 9 and 11 to 13. In its comparison of the two analyses (see NIST NCSTAR 1A Section 3.5), NIST showed that the analysis with the debris-impact damage better simulated the sequence of observed events, and it is this simulation that is considered here.

NIST believes that the simulation of the collapse, based on the analysis with debris-impact damage, does capture the critical observations derived from the digital video recording. The critical observations and corresponding failures identified in the structural analysis include: 1) east-west motion of the building beginning at approximately the same time as failure of floors 6 through 14 around Column 79, 2) the formation of the “kink” in the roofline of the east penthouse approximately one second after Column 79 was found to buckle, 3) window breakage on the east side of the north face as the buckling of Column 79 precipitated the failure of upper floors, and 4) the beginning of global collapse (vertical drop of the building exterior) within approximately one-half second of the time predicted by analysis. Both measured time and analytically predicted time, from the start of failures of floors surrounding Column 79 to the initial downward motion of the north face roofline, was 12.9 seconds (see NIST NCSTAR Report 1A, Table 3-1). The collapse observations, from video analysis of the CBS News Archive video, are covered in detail in NIST NCSTAR Report 1A Section 3.5 and NIST NCSTAR Report 1-9, Section 8.3. Only in the later stages of the animation, after the initiation of global collapse, do the upper exterior wall deformations from the NIST analysis differ from the video images.

Uncertainties associated with the approach taken by NIST are addressed in NIST NCSTAR Report 1A, Section 3.5, where it is noted, “Once simulation of the global collapse of WTC 7 was underway, there was a great increase in the uncertainty in the progression of the collapse sequence, due to the random nature of the interaction, break up, disintegration, and falling debris.” The contribution to stiffness and strength of nonstructural materials and components, such as exterior cladding, interior walls and partitions, was not considered in the analyses conducted by NIST. It is well known that such non-structural components can increase the stiffness and strength of a structural system, but their contribution is difficult to quantify. Given these factors, disparities between the video and the animation in the later stages of collapse would be expected.
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Fact is it's incredibly improbable that the shell would fall straight down, isn't it. Why do you think it wouldn't fall towards a weakened area, or the side where the fire had burned most? That's vastly more probable if it was to happen at all.

No, in fact it's literally physically impossible for the unsupported shell of WTC7 to do anything other than fall down. It's a problem of scale.
 
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