How could WTC7 Possible have fallen like it did?

[Heiwa]

Plenty of people have failed. One structure was a glass A with a bowling ball C on top. Dropping C on A crushed A but C didn't break in contact with ground. I explained that the structure should be 9 bowling balls on top of each other - part A - with a 10th ball on top - part C. Or that the structure could also be 9 glasses at the bottom - part A - with one glass on top - part C. Then C never crushed A.
A PhD at Albuquerque, NM, proposed a structure with a 2 m vertical wood rod to which 10 steel rings were attached by matches (so the rings could not slip). The top ring was made loose and it dropped on the ring below, the matches broke and two rings dropped on the third ring from top, its matches broke and after a while 10 intact rings were at the bottom of the intact rod with some broken matches around.
I explained to the PhD to read the rules at http://heiwaco.tripod.com/chall.htm again. Breaking matches with steel rings has nothing to with my Challenge.
Other structures were made of rather strong elements (steel rods) with very weak connections (matches). The top C with the weak connections were difficult to disconnect and when dropped on A below broke up.
Some clown tried with weak elements and very strong connections but again top C could not crush bottom A. One structure was 10 m tall but the 1 m top just bounced off the 9 m bottom part.
I wonder how UBL could come up with such a stupid idea to fly a weak plane into the weak top of a tower and hope that the strong intact tower below would collapse. Maybe UBL has seen to many Hollywood films?

 

[MikeC]

Maybe he had no idea the tower would collapse and that exceeded his wildest dreams?

Collapse of buildings due to gravity si a well known demolition technique called verinage.

Here is an example where 6 floors above the demolition point is sufficient to collapse the structure below that point.

 

[Mick West]

Got a link ? but in short if there was no lateral acceleration how did the top of the south tower tilt in the first place ? It did after all have to move from a stationary position didn't it ? Microspheres only are created in high heat environments, very high heat environments, kinda like white/yellow glowing steel ;-)

It tilted because it initially pivoted. When everything underneath it was collapsing it just sank into it.


http://www.rjlg.com/2011/09/27/dr-richard-j-lee-recounts-rj-lee-groups-involvement-in-wtc-aftermath/
http://www.rjlg.com/litigation-serv...ost-911-environmental-and-damage-assessments/

 

[Mick West]

Plenty of people have failed. One structure was a glass A with a bowling ball C on top. Dropping C on A crushed A but C didn't break in contact with ground. I explained that the structure should be 9 bowling balls on top of each other - part A - with a 10th ball on top - part C. Or that the structure could also be 9 glasses at the bottom - part A - with one glass on top - part C. Then C never crushed A.
A PhD at Albuquerque, NM, proposed a structure with a 2 m vertical wood rod to which 10 steel rings were attached by matches (so the rings could not slip). The top ring was made loose and it dropped on the ring below, the matches broke and two rings dropped on the third ring from top, its matches broke and after a while 10 intact rings were at the bottom of the intact rod with some broken matches around.
I explained to the PhD to read the rules at http://heiwaco.tripod.com/chall.htm again. Breaking matches with steel rings has nothing to with my Challenge.
Other structures were made of rather strong elements (steel rods) with very weak connections (matches). The top C with the weak connections were difficult to disconnect and when dropped on A below broke up.
Some clown tried with weak elements and very strong connections but again top C could not crush bottom A. One structure was 10 m tall but the 1 m top just bounced off the 9 m bottom part.
I wonder how UBL could come up with such a stupid idea to fly a weak plane into the weak top of a tower and hope that the strong intact tower below would collapse. Maybe UBL has seen to many Hollywood films?

You are not accounting for scale, and the square-cube law. So your challenge is meaningless.

 

[Jazzy]

It falls over...it doesn't collapse straight downward. What are you getting at using a sheet of paper as an analogy?

A sheet of card might well fall over. A normal A4 sheet bows, then falls over. That bowing is the buckling of that plane surface. It is its own weight making it bow.



Buckling, as shown here, is about a failure to carry a load due to instability, not due to damage.

The demonstration above can be infinitely repeated, yet it continues to demonstrate failure without being damaged in any way. Yes, I know the load falls off. And yes, if it didn't, those sticks would be toast. But that damage, had it occurred, would have always been preceded by the buckling failure.

A LINE of such columns, when strapped together by ties, acts as a plane surface, and without lateral support to give it stability, will fail like a sheet of thin paper. That is what the fascia of WTC7 did. In effect, the WTC7 collapse video frames the top of the "sheet of paper".

Note that there wasn't a single column in the three WTC buildings that could possibly have remained erect on its own. They were far too slender.

Euler's discoveries on the nature and mathematics of slender vertical column buckling preceded the "modern" world. In my opinion this world doesn't deserve the description "modern" until his work is reasonably understood by the majority of people.

The world economy depends on the efficient use of materials, and this minimal approach leads inexorably towards specific cases of buckling failure. Some compromise is always having to be made, whether it be in ships, buildings, aircraft, bridges, cars, or drink cans.

 

[jomper]

Maybe he had no idea the tower would collapse and that exceeded his wildest dreams?

Collapse of buildings due to gravity si a well known demolition technique called verinage.

Here is an example where 6 floors above the demolition point is sufficient to collapse the structure below that point.

Look at the simultaneous and parallel movement of columns across whole floors of the building that happens here. This is controlled demolition. Could fire and damage possibly replicate this?

 

[Jazzy]

Microspheres only are created in high heat environments, very high heat environments, kinda like white/yellow glowing steel

Nope. "Microspheres" are sparks that have cooled down. This car must have made millions of them:



A hundred and four floors sliding down fifty columns for a quarter of a mile at 120 mph made more, I bet.

 

[Boston]

Maybe he had no idea the tower would collapse and that exceeded his wildest dreams?

Collapse of buildings due to gravity si a well known demolition technique called verinage.

Here is an example where 6 floors above the demolition point is sufficient to collapse the structure below that point.

An excellent example Mike, now can you find any information about rate of descent. Its pretty obvious that its not at free fall speed to me, but lets quantify it if we can, so all can see exactly why so many people have trouble with the free fall speeds seen in the WTC 7 collapse

 

[Boston]

Look at the simultaneous and parallel movement of columns across whole floors of the building that happens here. This is controlled demolition. Could fire and damage possibly replicate this?

not a prayer, what it does show however is a very nice example of how controlled demolition works. It also has great potential to help us inderstand just how much of WTC 7 had to be removed through explosives/controlled substances in order to allow for that 100 + feet of free fall.

 

[Boston]

Nope. "Microspheres" are sparks that have cooled down. This car must have made millions of them:



A hundred and four floors sliding down fifty columns for a quarter of a mile at 120 mph made more, I bet.

sparks aren't cold. Steel wool burns at about 1400C and you can light it with a bic lighter. Thats roughly twice as hot or a bit more than a basic office fire ;-) So what type of metal created those sparks and what makes you think its all that cold ?

The question becomes not that they found iron microspheres at WTC site but how much they found

 

[Steve]

Most of the iron microspheres probably came from the concrete filler fly ash. At a power station when coal is burned it sends residue up and into the stacks which is vacuumed to form fly ash that is sold to the concrete companies.
http://www.nanopowder-technology.com/?page=614

 

[Jazzy]

sparks aren't cold. Steel wool burns at about 1400C and you can light it with a bic lighter. Thats roughly twice as hot or a bit more than a basic office fire ;-) So what type of metal created those sparks and what makes you think its all that cold ?

Sparks start HOT.

But they are made by friction on steel by contact with the road, in the case of the car. Both the road and the car are COLD. Yet the sparks are HOT. And when they cool down to ambient temperature they end up as "microspheres", because the steel is hot enough to be liquid, albeit temporarily. Surface tension pulls the droplets down to spheres, and shortly afterward they solidify in that form.

Similarly, the columns and floors of the towers were COLD, but when the floors slid down the columns (they weren't greased!) the friction between the two would have generated sparks, and thus microspheres, by the ton.

Made of iron in both cases.

Edit. I hadn't thought of the iron content of fly ash. Quite true. Plus the above.

 

[Steve]

So, the basic composition of coal ash:

Easy aluminosilicate cenospheres - 1-2 %

Microspheres (basic composition SiO2, Al2O3, Fe3O4) - 80-85%

Coke - from 1 to 7 %

Magnetite in the spherical form - 3 %

Other minerals of 2 %

 

[MikeC]

An excellent example Mike, now can you find any information about rate of descent. Its pretty obvious that its not at free fall speed to me, but lets quantify it if we can, so all can see exactly why so many people have trouble with the free fall speeds seen in the WTC 7 collapse

It accelerated at 8.5m/sec^2 - see http://philosophers-stone.co.uk/wordpress/2010/08/what-a-gravity-driven-demolition-looks-like/

the Balzac Vitry demolition was, of course, a demolition - all the columns supporting the upper floors were destroyed/cut at he same time so the entire upper structure hits the lower part flat, and everywhere at once - this did not occur in any of het WTC collapses AFAIK - all of the structures there exhibited some tilting which meant that the resistance from any remaining lower structure was minimal - only small parts of it opposed eth collapse at any 1 point in time - this point is illustrated by this pdf/powerpoint - it is mostly about why there is no "jolt" in any of the 9/11 collapses as is clearly evident in the Balzac-Vitry demolition.

 

[Boston]

well you'd need tons to even begin to approach the amount of micro-spheres found at WTC

What's behind the thousands of tons of iron microspheres found in the 9/11 concrete dust?

There were 780,000 metric tons of concrete in the 2 WTC towers. I did not include the third building which collapsed that day (7WTC), but that was only 47 stories tall.

The USGS outdoor samples of concrete dust contained between 0.2 and 1.3% iron microspheres. The mean of all the RJ Lee samples was 5.87%. I'm not certain if this was by weight or by volume. I'm assuming by weight. Please correct me if you know differently. Which would imply an increase over the expected ratio of roughly 4.5 times what would be expected just from the typical fly ash component of concrete

Using the lowest percentage for a conservative estimate: 0.002 (=0.2%) * 780,000 MT = 1560 metric tons!!! That's rough figures. A more accurate calculation would be,

total = 0.002*total + 780,000

.998 * total = 780,000

total = 781,563 metric tons

Minimum estimate of iron microspheres by weight is 1563 metric tons. Maximum estimate is 45,874 metric tons of iron microspheres. The 2 towers contained only 200,000 metric tons of steel beams. So, somewhere between 1-22% of the mass of steel could be found in iron microspheres. Did the iron come from the steel, or somewhere else? And how did it come in the form of microspheres?

What are the implications of this? Even the government reports admitted that the fires in the 2 towers were insufficient to melt steel. Where did 1500 tons of iron microspheres come from? These spheres ranged in sizes from about 1 micron (0.001 mm) to 1.5 mm in size.

And yet, the only way iron could form into such microspheres is through melting and forceful ejection. The steel or iron would have to have been far hotter than the melting point in order to allow the iron to form into spheres before it solidified again.

Steel Wool?

One enterprising investigator considered the idea that burning steel wool could create iron microspheres. Very clever, but with obvious problems. See the video of their efforts here:

Embedded media from this media site is no longer available

The problems are twofold:
(1) The iron microspheres created by burning steel wool have horns -- pieces of the steel threads sticking out of them. These aren't found in the 9/11 dust.

(2) If the thousands of metric tons of iron microspheres were to come from burning steel wool, then there would have to have been thousands of metric tons of steel wool within the fires of the two towers. This proves to be a very unrealistic expectation. It's unlikely that either of the airplanes carried thousands of tons of steel wool for whatever purpose. And that much steel wool is not usually found in the normal business office.

Controlled Demolition?

The only other likely source of iron microspheres is the controlled demolition using thermite or thermate. These use iron oxide (rust) and aluminum. Aluminum is far hungrier for oxygen than iron, so it steals the oxygen creating intense heat, aluminum oxide and elemental iron (metallic). The heat frequently reaches 4500F degrees, far above the 2800F degree melting point, and only 682F degrees below iron's boiling point. Because of the explosive expansion of gases and the constituent materials, reacting thermite will sputter explosively, forcing the iron into the air as tiny droplets -- aerosolized.

So, the question is: Can you think of any other sources for the substantial quantity of iron microspheres found in the 9/11 dust?

If not, then we are left with the unsavory problem of collapse of 3 steel skyscrapers being controlled demolitions. And because all 3 of the WTC buildings which collapsed on 9/11 were highly secure, this means that 9/11 was an inside job. Why? Because it takes weeks or months of unfettered access to buildings of that size to prepare them for controlled demolition. Two Bush family members were executives in the security company which oversaw the WTC. And the CIA was a tenant of 7WTC. I don't think they would've let Al Qaeda rig tons of explosives and thermate cutter charges, unless they were in on it.

Thoughts?

 

[Boston]

It accelerated at 8.5m/sec^2 - see http://philosophers-stone.co.uk/wordpress/2010/08/what-a-gravity-driven-demolition-looks-like/

the Balzac Vitry demolition was, of course, a demolition - all the columns supporting the upper floors were destroyed/cut at he same time so the entire upper structure hits the lower part flat, and everywhere at once - this did not occur in any of het WTC collapses AFAIK - all of the structures there exhibited some tilting which meant that the resistance from any remaining lower structure was minimal - only small parts of it opposed eth collapse at any 1 point in time - this point is illustrated by this pdf/powerpoint - it is mostly about why there is no "jolt" in any of the 9/11 collapses as is clearly evident in the Balzac-Vitry demolition.

Now maybe I've not given this set of papers enough time, I've only read the abstract thus far but maybe you can interpret this differently as it is the link you provided. This is the link you've provided and it clearly states

The official story is that the North Tower of the World Trade Center collapsed due to gravity. This has been critiqued in an analysis by Graeme MacQueen and Tony Szamboti, and in a related analysis by David Chandler (both in the Journal of 9/11 Studies). The Balzac-Vitry demolition was a true gravity-driven collapse. The same analysis that was applied to the World Trade Center is here applied to this known demolition, with contrasting results. This analysis supports the conclusions of both papers referred to above: the North Tower of the World Trade Center was not a natural, gravity-driven collapse.

 

[MikeC]

That wasn't the question - the question was what was the acceleration of the Balzac building and how did it relate to "near freefall" - at 8.5m/sec^2 it is very close to that.

For debunking Chandler's conclusions (as opposed to his measurements) see

 

[muttkat]

The recent NIST report admits that WTC 7 fell at free-fall speed. So you have a brick with nothing beneath it being dropped from 47th floor reaching the ground AT THE SAME TIME as a brick with 40,000 TONS of STEEL resistance beneath it...

How did a FEW pocket fires trigger this kind of free-fall structural collapse?

What temperatures are sufficient to cause such a sudden free-fall collapse?

The damage as you can see was to the SIDE... why didn't it tilt to the side where the damage was and rather have the CLASSIC 'controlled demolition' quirk in the MIDDLE (when they blow out the core columns)?

In an office fire it's IMPOSSIBLE for enough heat to be generated to MELT STEEL... so how do you explain the molten steel that was found?[/quote

For starters people should use the USGS for reference instead of NIST. As far as I know NIST doesn't even touch the temps that the USGS does. It seems to be a very big mystery as to what POSSIBLY cause those type of temperatures.

Look at the simultaneous and parallel movement of columns across whole floors of the building that happens here. This is controlled demolition. Could fire and damage possibly replicate this?

Only on 911 could all these extraordinary events happen and probably will never happen again.

 

[muttkat]

The recent NIST report admits that WTC 7 fell at free-fall speed. So you have a brick with nothing beneath it being dropped from 47th floor reaching the ground AT THE SAME TIME as a brick with 40,000 TONS of STEEL resistance beneath it...

How did a FEW pocket fires trigger this kind of free-fall structural collapse?

What temperatures are sufficient to cause such a sudden free-fall collapse?

The damage as you can see was to the SIDE... why didn't it tilt to the side where the damage was and rather have the CLASSIC 'controlled demolition' quirk in the MIDDLE (when they blow out the core columns)?

In an office fire it's IMPOSSIBLE for enough heat to be generated to MELT STEEL... so how do you explain the molten steel that was found?

Whats amazing is that there were thermal hot spots under WTC 1, 2 and WTC 7. Being 7 wasn't hit by no plane, makes you think something isn't right here.

http://pubs.usgs.gov/of/2001/ofr-01-0405/ofr-01-0405.html

 

[Boston]

That wasn't the question - the question was what was the acceleration of the Balzac building and how did it relate to "near freefall" - at 8.5m/sec^2 it is very close to that.

For debunking Chandler's conclusions (as opposed to his measurements) see

Ah but in that demolition we see a comparison to the top down demolition of WTC 1 & 2 vs the bottom up demolition of WTC 7. In the 7 collapse there was no possible excuse for a top down demolition which they were going to explain away as gravity based. In 7 we have a classic demolition, where the total mass of the building above is used to demolish basically nothing below it, just trying to land it on the pile all nice and neat, and let the building decelerate from there as it contacts the rubble pile, which is far more sponge like than an intact lower half a building . So there would be no jolt per se until the rubble pile itself came into play.

Nice try tho was at least some scientific analysis of at least some remotely similar structure, rather than a slinky or some tooth picks.

 

[MikeC]

A classic demolition - except for the lack of any actual evidence for demolition at all - no plan, no explosives, no hydraulics, no rigging, ...nothing, in fact, except supposition and imagination.

 

[Josh Heuer]

A classic demolition - except for the lack of any actual evidence for demolition at all - no plan, no explosives, no hydraulics, no rigging, ...nothing, in fact, except supposition and imagination.

That same supposition and imagination that created the NIST report? That's all we have aye?

 

[MikeC]

no not at all - eth NIST report had thousands of hours of computer simulation behind it, among other things - if you read it and can comprehend it you would understand that instead of repeating this meaningless mantra of yours.

Whereas the wishful thinking that says there was a demolition has.....

 

[jomper]

thousands of hours of computer simulation

to produce a conclusion that independent experts aren't allowed to verify, and not even one hour of forensic analysis of any of the physical evidence from the building such as the steel FEMA made a preliminary study of in 2002.

Kids spend thousands of hours playing Xbox Mike. Unverifiable computer sims are as scientific as Grand Theft Auto.

 

[Mick West]

That same supposition and imagination that created the NIST report? That's all we have aye?

The NIST report is simply detail on a hypothesis. You can go with the same hypothesis yourself, with a little physics.

Is the hypothesis at all plausible to you? Even a little bit?

 

[Heiwa]

Actually the NIST report of WTC 1/2 suggests that cause of total collapse was that the dropping, intact top part C applied force/energy on the intact bottom part A after some intermediate elements failed that could not be absorbed elastically and the result was that supporting structure of each floor of the intact bottom part A failed POUFF POUFF until the bottom structure A was completely crushed from top down. And then the top structure C collapsed from bottom up.
In my paper that I should have read at EMI yesterday I show that it is the bottom structure A that applies force/energy on the top structure C that either destroys C or stops C dropping. It is simply impossible that a weak top C of any structure can destroy the strong, intact bottom part A.
In WTC7 NIST suggests that removing one supporting element/column (of 27) inside the structure (destroyed by thermal expansion) all elements/connections fail in short time (top part free falls, etc) forgetting that redundancy exists making such event impossible. It is quite easy to make a beam/FEM model of WTC7 and remove one element and show that stresses in adjacent elements increase a little and that nothing serious happens = no failures occur. I have done it.
NIST seems to be supporting terrorism by faulty structural damage analysis.

 

[Alchemist]

In WTC7 NIST suggests that removing one supporting element/column (of 27) inside the structure (destroyed by thermal expansion) all elements/connections fail in short time (top part free falls, etc) forgetting that redundancy exists making such event impossible. It is quite easy to make a beam/FEM model of WTC7 and remove one element and show that stresses in adjacent elements increase a little and that nothing serious happens = no failures occur. I have done it.
NIST seems to be supporting terrorism by faulty structural damage analysis.

Bingo!

</thread>

 

[jomper]

Is the hypothesis at all plausible to you? Even a little bit?

what's supposed to be plausible about a forensic investigation that draws conclusions without examining any physical evidence at all?

 

[Mick West]

Bingo!

</thread>

Heiwa claiming to have done something is not the same as actually having done it.

Demonstrate it.

 

[Mick West]

what's supposed to be plausible about a forensic investigation that draws conclusions without examining any physical evidence at all?

Look, ignoring all questions by saying the same thing over and over is not going to get you anywhere. You have a thread to make that argument. Keep it there.

 

[Alchemist]

WTC 7 had redunancy... just so you know why I think removal of one element would have that result

 

[Mick West]

WTC 7 had redunancy... just so you know

How much did it have?

 

[Alchemist]

WTC 7 had inbuilt redunancy for the entire structure. If one support fails, the others pick the load up.

It had huge 24 steel vertical core columns connected to a mammoth matrix of steel beams & girders.

NIST has you believe that a single column failure in this matrix of steel was able to trigger the core columns to fail in a perfect, systematic fashion as evidenced by the classic "kink"/collapse of the penthouse.

Instead of building on FEMA's research, they chose to move into abstraction, computer simulations and just plain voodoo science. They had to do this because they're openly affiliated with agencies such as Department of Defense and are pressured to provide an explanation which suits the agenda of the agencies they serve. So they REFUSED to examine physical evidence, manipulated data and made a mockery of the scientific method.

9/11 victim family members are correct to push for an unbiased investigation from an independent party.

 

[Boston]

A classic demolition - except for the lack of any actual evidence for demolition at all The photographic evidence is irrefutable, it matches virtually perfect other controlled demolitions in every single side by side comparison I've see so far. If you have some photographic evidence you can place in a side by side comparison that refutes the controlled demolition hypothesis, your welcome to bring it. - no plan, as if I'm required to present a plan in order to establish that the gubment scenario is BS no explosives, as if I need to establish exactly how it happened vs how it could not have happened no hydraulics, as if I'm somehow magically required to know if hydraulics where used, or for that matter, what method was used vs simply pointing out that the gubment BS is entirely implausible no rigging, Again with the assumption that pointing out how it could not have happened is somehow synonymous with knowing how it did...nothing, Other than that the NIST BS is so incredibly implausible that its a virtual impossibility in fact, except supposition and imagination. Which is precisely what the NIST hypothesis is all about except for one thing, no only is it entirely based on supposition and imagination but it also requires that one believe in the least likely vs the most likely, which was never considered.

Sorry but not a single assertion of that last holds one shred of water

 

[Boston]

no not at all - eth NIST report had thousands of hours of computer simulation behind it, among other things - if you read it and can comprehend it you would understand that instead of repeating this meaningless mantra of yours.

Oh so now we're just to ignorant to realize that office fires of max 825C can generate molten steel with temps of 1100~1200C. Very interesting, sooooo your about to explain to us exactly how a fire which most likely burned at a max temp of roughly half what the theoretical maximum ( say 400~500°C )might somehow be magically capable of producing heat of roughly half again its maximum possible potential Best of luck with that

 

[Boston]

The NIST report is simply detail on a hypothesis. You can go with the same hypothesis yourself, with a little physics.

Is the hypothesis at all plausible to you? Even a little bit?

Its a carefully orchestrated web of half truths. What they describe as a progressive collapse is basically exactly what happens in any controlled demolition. Had you argued it correctly I'd have conceded that the interior likely fell first, but you never forwarded your best argument, because you refuse to knowledge that simple fact of controlled demo. You were right of course, in that the penthouse area fell first, we all can see that in the films, but the NIST progressive collapse BS is just a sham to cover the fact that the interior had to be blown first in order to draw the exterior walls inward, and drop the building into its own footprint just like in any other controlled demolition.

The simple reality is any good BS has a modicum truth to it, otherwise you might not fool those gullible enough not to do any of there own thinking.

So what are the odds that three steel framed structures of a type that had never fallen due to fire before, would suddenly all fall, on the same day ?

 

[Boston]

Heiwa claiming to have done something is not the same as actually having done it.

Demonstrate it.

Soooo wouldn't this perfectly apply to the NIST investigation ? which ignored whatever evidence they didn't like and instead just went with computer models that failed completely to reproduce the failure observed ?

 

[Boston]

How much did it have?

Typically about 100% Depends on how tight the engineering is, but there is typically a whopping huge redundancy built in to any structure

 

[jomper]

Buckling, as shown here

demonstrates that the line of least resistance is not straight down through a structure.

 

[Jazzy]

Actually the NIST report of WTC 1/2 suggests that cause of total collapse was that the dropping, intact top part C applied force/energy on the intact bottom part A after some intermediate elements failed that could not be absorbed elastically and the result was that supporting structure of each floor of the intact bottom part A failed POUFF POUFF until the bottom structure A was completely crushed from top down. And then the top structure C collapsed from bottom up.
In my paper that I should have read at EMI yesterday I show that it is the bottom structure A that applies force/energy on the top structure C that either destroys C or stops C dropping. It is simply impossible that a weak top C of any structure can destroy the strong, intact bottom part A.
In WTC7 NIST suggests that removing one supporting element/column (of 27) inside the structure (destroyed by thermal expansion) all elements/connections fail in short time (top part free falls, etc) forgetting that redundancy exists making such event impossible. It is quite easy to make a beam/FEM model of WTC7 and remove one element and show that stresses in adjacent elements increase a little and that nothing serious happens = no failures occur. I have done it.
NIST seems to be supporting terrorism by faulty structural damage analysis.

The "faulty structural analysis" is all yours. Your failure springs from ignoring the consequences of fire.

Before the tower fires took hold, a huge thermobaric blast stripped the foam insulation from inside the affected floors, exposing the floor truss steelwork on the underside of the floors, and ripping off the wallboard cladding on the columns.

When the fire occurred throughout a half-dozen floors it flowed upwards and spread outwards, forming an inverted lake of its hottest gas up against the floor undersides. So immediately the greatest temperatures were being applied to the most heat-sensitive structural elements of the tower.

When the fire played on the steel this way, it heated it to temperatures at least high enough to melt the aluminum of the plane - which is 600 deg C. It heated the floor undersides hotter than that, for pictures show the "ceilings" to be orange. And orange is the color of material heated to over 1000 deg C, which was also the color and temperature of the melted plane alloy as it fell from the corner of tower 2.

Steel is unaffected by such temperatures as long as it isn't loaded in compression or tension (there's also torsion, but it's not applicable here). But it WAS loaded in all cases, and heated way past its phase transition point of 475 deg C.

In such circumstances the steel begins to change shape, deform, in the direction of gravity.

The interior and exterior columns were not equally loaded; the interior ones designed to accept a greater part of the dead load. As heating took place, that load was "evened out" as the interior columns crept downwards.

The end result of that was that the exterior columns were being increasingly stressed in compression, the most overloaded ones being either side of the aircraft entry hole, at the same time as they were being kept above their phase transition point. The settling and evening-out continued, and eventually the members each side of the entry hole would have failed in compression by buckling between two single floors.

They didn't have time to get to that point, because while that was happening the exposed trusses in the floors were having a bad time. They were in the hottest gases, and stretched under their tensile loads, forming catenaries, the steepening angles of their ends pulled out their fixings, and they detached from the columns. They were photographed in that state (collapsed on the floor beneath them) shortly before the towers fell.

The removal of a supporting floor quartered the column's buckling resistance, as the effective column length was now twice as long as it formerly was. It was obviously just capable of holding, otherwise the pictures couldn't have been taken.

(I'm talking about a column, but the external faces were walls of columns quite strongly tied together, and the "unit of failure" was in reality a two-floor-high section of the tower exterior).

When the next nearby supporting floor detached the effective column length was three times greater, and its resistance to buckling fell to one-ninth of its former value. As the strength of the steel was halved by its temperature of >600 deg C, its effective resistance to buckling was one eighteenth of its design resistance, and 1.8 times its 10 : 1 safety factor.

It was toast, and failed in buckling, as a folding plane surface, starting the tilt and the downward motion. The downward momentum continued the job round the corners of the face, and by then the tower top was no longer in line with anything, and could apply the whole of its momentum to the very next thing it met.

What it met next was a whole set of discrete contacts spaced over time, nothing in unison with anything, where the whole momentum of the tower top was resisted at a single contact point until that part of the underlying structure failed, and then the next, and then the next, etc. all the way down.

This explanation is nothing like yours, takes account of the fire, discusses the moment of collapse and the reasons for it, and explains why the tower top was such an effective destructor.

You should try it.