Failure mode in WTC towers

[bofors]

Posted on YouTube by Debunking 9/11 nearly a year ago:
http://www.youtube.com/watch?v=ycP4HTEJXWw

That is the same footage that I just referenced.

It shows practically no pivoting for tens of floors.

 

[Major_Tom]

bofors comments:

Actually, I think I agree with Norseman here.

This means I need to rewrite curioso #1 more carefully. The timing between cause and effect is physically impossible. I will demonstrate this more clearly within a few posts.



Curioso #4: The WTC 1 northwest corner was captured very well in video clips during the "collapse" progression. It is possible to study the dust ejection patterns in detail.


The following clip from the BBC allows us to look down the west facade at the collapse front.

It is clear that the visible ejections along the southwest corner (far corner) are preceeding the same ejections along the northwest corner (near corner) by 10 to 20 floors.

http://www.youtube.com/watch?v=k-jYSy1SxsI

and

http://www.youtube.com/watch?v=Xo7t3XQ2PbM


Therefore, when studying the ejection patterns along the northwest corner in the following video clips, please remember that the collapse progression has already passed these same floors on the southwest corner before these ejections occured.


We established in curioso #3 that this entire west facade is peeling away from the building largely as a single continuous sheet. A few people told me this is "expected" and that the collapse front along this facade is caused by floors failing and piling up on one another.

But that means that, according to them, the southwest flooring is giving way about 10 to 20 stories ahead of the same flooring in the northwest, as visible in the clips linked above.



Within this context lets look at the following video clips:


1) Very good video clip. The camera follows the "collapse" front down the northwest corner. The editor uses slower and slower motion to show dust ejection patterns.
http://www.youtube.com/watch?v=EZeaW4ybejs&feature=related


2) http://www.youtube.com/watch?v=BcKbPEaZ3KU



According to NB and Norseman, the very front of the collapse wave is caused by the perimeter columns of the upper block falling within the perimeter of the lower block, thereby severing the collections between the flooring and the perimeter.

This would mean they are severing the flooring from the perimeter along the southern portion of the west facade 10 to 20 stories ahead of the same flooring on the northern portion?

I am not seeing any evidence of a crushing front as they describe. There is no visible evidence of floors being crushed before dust ejections shoot outwards.

In the first 2 links it is clear that "floors collapse" on the far side of the building considerably sooner than along the northwest corner.

How would you explain these floors building up pressure and causing such forceful ejections considering the same floor gives at noticably different times at different locations?

 

[DGM]

bofors comments:



This means I need to rewrite curioso #1 more carefully. The timing between cause and effect is physically impossible. I will demonstrate this more clearly within a few posts.



Curioso #4: The WTC 1 northwest corner was captured very well in video clips during the "collapse" progression. It is possible to study the dust ejection patterns in detail.


The following clip from the BBC allows us to look down the west facade at the collapse front.

It is clear that the visible ejections along the southwest corner (far corner) are preceeding the same ejections along the northwest corner (near corner) by 10 to 20 floors.

http://www.youtube.com/watch?v=k-jYSy1SxsI

and

http://www.youtube.com/watch?v=Xo7t3XQ2PbM


Therefore, when studying the ejection patterns along the northwest corner in the following video clips, please remember that the collapse progression has already passed these same floors on the southwest corner before these ejections occured.


We established in curioso #3 that this entire west facade is peeling away from the building largely as a single continuous sheet. A few people told me this is "expected" and that the collapse front along this facade is caused by floors failing and piling up on one another.

But that means that, according to them, the southwest flooring is giving way about 10 to 20 stories ahead of the same flooring in the northwest, as visible in the clips linked above.



Within this context lets look at the following video clips:


1) Very good video clip. The camera follows the "collapse" front down the northwest corner. The editor uses slower and slower motion to show dust ejection patterns.
http://www.youtube.com/watch?v=EZeaW4ybejs&feature=related


2) http://www.youtube.com/watch?v=BcKbPEaZ3KU



According to NB and Norseman, the very front of the collapse wave is caused by the perimeter columns of the upper block falling within the perimeter of the lower block, thereby severing the collections between the flooring and the perimeter.

This would mean they are severing the flooring from the perimeter along the southern portion of the west facade 10 to 20 stories ahead of the same flooring on the northern portion?

I am not seeing any evidence of a crushing front as they describe. There is no visible evidence of floors being crushed before dust ejections shoot outwards.

In the first 2 links it is clear that "floors collapse" on the far side of the building considerably sooner than along the northwest corner.

How would you explain these floors building up pressure and causing such forceful ejections considering the same floor gives at noticably different times at different locations?

So? How would you explain it?

You can't expect people to respond to you if you don't respond in kind. A theory on your part would lead to much more commentary. I'm not sure if that's really what you want though.

 

[bofors]

This means I need to rewrite curioso #1 more carefully. The timing between cause and effect is physically impossible. I will demonstrate this more clearly within a few posts.

Just to be more clear, the fireball which I believe you are referring to as "curioso #1" does appear slightly anomalous to me but I do not think it is significant because:

(1) It could have occurred as a result of air pressure wave resulting from the second plane approaching the WTC and its impact.

(2) It seems possible that it could be result of some highly flammable material that was innocently placed in that location.

 

[Major_Tom]

So? How would you explain it?

You can't expect people to respond to you if you don't respond in kind. A theory on your part would lead to much more commentary. I'm not sure if that's really what you want though.

We have seen people make theories about the collapse mechanism involved along the east face of the South Tower without even being aware that the facade had largely peeled of the building as one continuous, connected piece.

What good is such a theory when the actual observable and knowable features of the "collapses" are not even understood and properly recorded?

People are obsessed with theories. If people would simply look at the knowable features of these "collapses" BEFORE theorizing we could have avoided:


1) The Bazant-Zhao simple analysis.

2) The whole Judy Wood fiasco.

3) The thermite cutting devices of Steven Jones.

4) Claims of continued perimeter column buckling.

5) Claims of buckled core columns in the collapse initiation zone.


6) The silly claims of the "top block" being a rigid structure.

7) Claims we are seeing now of the "top block" of the perimeter being responsible for severing the entire west facade (for WTC 1) and east facade (for WTC 2) from the rest of the building.

And so many other theories.



The theories above are the result of poor or inefficient observation.


Considering how we have seen theory after theory fail, why don't we try to accurately describe witnessed events and forensic conditions of objects before spewing out another one?

 

[DGM]

We have seen people make theories about the collapse mechanism involved along the east face of the South Tower without even being aware that the facade had largely peeled of the building as one continuous, connected piece.

What good is such a theory when the actual observable and knowable features of the "collapses" are not even understood and properly recorded?

People are obsessed with theories. If people would simply look at the knowable features of these "collapses" BEFORE theorizing we could have avoided:


1) The Bazant-Zhao simple analysis.

2) The whole Judy Wood fiasco.

3) The thermite cutting devices of Steven Jones.

4) Claims of continued perimeter column buckling.

5) Claims of buckled core columns in the collapse initiation zone.


6) The silly claims of the "top block" being a rigid structure.

7) Claims we are seeing now of the "top block" of the perimeter being responsible for severing the entire west facade (for WTC 1) and east facade (for WTC 2) from the rest of the building.

And so many other theories.



The theories above are the result of poor or inefficient observation.


Considering how we have seen theory after theory fail, why don't we try to accurately describe witnessed events and forensic conditions of objects before spewing out another one?

You forgot to add the stupid controlled demolition nonsense. that would be number (8).

I suspect that was on purpose.

 

[Gravy]

A falling piston that weighs hundreds of millions of pounds causing an increase in air pressure? Impossible, I say!

I wonder when this seemingly interminable meeting of Junior Underachievers will finally be adjourned?

 

[DGM]

Major Tom:
Not using any theories you have shown me a building collapsing with stuff falling off.

Did I get that right? Anything you would like to add?

 

[Furcifer]

We have seen people make theories about the collapse mechanism involved along the east face of the South Tower without even being aware that the facade had largely peeled of the building as one continuous, connected piece.

A few posts back I noticed you were saying this, but I wasn't certain until now. I'm not sure if this is entirely correct. When you say largely, you mean 6-9 story pieces correct?

 

[DGM]

A few posts back I noticed you were saying this, but I wasn't certain until now. I'm not sure if this is entirely correct. When you say largely, you mean 6-9 story pieces correct?

The exterior columns were fabricated as panels and joined in the field. They seem to be breaking away at these weaker field joints and collapsing as panels. For some reason that escapes me he finds this to be strange.

 

[Apollo20]

Major Tom:

Before you come down too hard on all these theories of the WTC collapse, ...... you know, the ones you are so critical of, I think you are misunderstanding the purpose of some of these theories and calculations... at least the way I and others have approched this problem.

I was always interested in the physics of what was possible and what was not possible in the collapse of WTC 1 & 2, and back in 2004 when I really started my research I saw a few people (eg. Jim Hoffman) making wild claims about the energy requirements of the destruction of the towers. I wanted to check these claims out for myself. Today the situation is worse, by the way, because everybody (and his uncle) are putting out papers on the collapse times, the angular momentum, the dust clouds....

Anyway, for me in the context of the collapse of WTC 1 & 2, a theory is an approximation based on a model. It is conceptually useful to start with a SIMPLE model, see what it tells you, and then try to refine the model by minimizing errors in the model's predictions. That's how the scientific method works. My initial model of the collapse was as crude as hell - I know that - but it was a place to start. It showed me that under certain initial conditions a self-sustaining gravitational collapse of a box-like structure resembling a WTC tower WAS ENERGETICALLY POSSIBLE.

I started with an assumed mass of the towers and a constant requirement of energy to collapse one floor. I also assumed that all the mass of each tower remained within the footprint of the tower. From this I obtained collapse times for WTC 1 & 2 that looked reasonable. I have subsequently refined the model to allow for the columns being stronger in the lower floors, and to allow for some mass shedding during the collapse. I find that the collapse still propagates. I have allowed for tilting of the upper sections... the collapse still propagates. I have allowed for the in situ pulverization of the concrete,... the collapse still propagates.

Of course my model is still pretty crude, BUT I believe it helps us to decide what was possible and what was not possible on that terrible day in New York.

It's sure better than saying as some do: "Man those towers fell too fast, man... yeh, the buildings offered no resistance man.. near free fall man.... yeh, that PROVES it was a CD man!"

 

[Furcifer]

The exterior columns were fabricated as panels and joined in the field. They seem to be breaking away at these weaker field joints and collapsing as panels. For some reason that escapes me he finds this to be strange.

It's the use of the terms "largely" and "continuous" that confuses me. Given the size of the panels, the staggering and the splices ALL the exterior facades would have crumbled as 3,6,9 story "chunks", save for possibly the bottom "trees".

 

[DGM]

It's the use of the terms "largely" and "continuous" that confuses me. Given the size of the panels, the staggering and the splices ALL the exterior facades would have crumbled as 3,6,9 story "chunks", save for possibly the bottom "trees".

This seems obvious to me (I'm a builder) too. For some reason this seems strange to him and nothing we say has any effect.

 

[Furcifer]

Of course my model is still pretty crude...

And yes, still better than any offered by NIST. The question of why this is so is certainly one worth asking. I'm personally not of the opinion this was, as we say around here, "nefarious" in nature.

 

[Heiwa]

If people would simply look at the knowable features of these "collapses" BEFORE theorizing we could have avoided:

...

5) Claims of buckled core columns in the collapse initiation zone.


6) The silly claims of the "top block" being a rigid structure.

...

And so many other theories.



The theories above are the result of poor or inefficient observation.


Considering how we have seen theory after theory fail, why don't we try to accurately describe witnessed events and forensic conditions of objects before spewing out another one?

Good observations and suggestion. Major Tom, may I call you General Tom?

Just looking at the WTC1 destruction we see the 'rigid top block' telescoping into itself 30 meters after 2-3 seconds (it gets 30 meters shorter), while the perimeter columns in the so called initiation zone are still intact, i.e. nothing has happened at the initiation zone!! To call something an 'initiation zone' when something else - a top block telescoping into itself - happens before above this 'initiation zone' is evidently dishonest.

According Z P Bazant and K A Seffen (and NIST?) the solid top block (95% air volume wise but still 33 000 tons!) is supposed first to accelerate as one piece and then - after say a 3.7 meters drop (one floor, where all columns buckle 180°) to impact on a 4 000 m² large surface.

So what does it mean? E.g. that a solid 8.25 tons weight drops on each square meter of the floor in the 'initiation zone' and makes an impact? Well, these 8.25 tons consist of a, say, 60 meters high box (the upper block is so tall when intact) so the average density of the upper block box hitting the initiation floor is 0.1375 ton/m3. Not much! Like cotton, actually!

OK, the weight of the cotton is concentrated into the 280+ columns that buckledbent 180° via three hinges in the initiation zone. Any traces of those?

And according Bazant and Seffen then the poor columns in the floors below shall also bucklebend 180° at every floor like an accordion, when the cotton continues to impact, so that the global collapse can ensue down to ground floor. Any traces of 180° buckebent columns there among the forensic evidence? Strange music! Everybody can see that potential energy didn't cause the collapse, probably they heard the same thing but they cannot say it. Reminds me of three monkeys.

 

[Major_Tom]

Apollo20, I agree and I do enjoy your work and your posts.

My basic complaint to an overly theoretical approach is that some people using them seem to have little interest in comparing them to known forensic patterns and known features of these "collapses" in particular.

It is as if people can be so interested in models that they seem to be disturbed, though unaffected, by people pointing out that the patterns their model predicts do not apply in the case of WTC 1 and 2.


It must strike you as curious that after 6 years nobody seemed to notice that huge portions of 2 of the 8 facades peeled off the building as single sheets, meaning that both spandrel connections and column-to-column bolt connections survived the initial peeling intact.

If people don't notice things so large, what else don't they notice?

Here we have people trying to explain this peeling (and "pressure pulses") with some floor collapse model, but they didn't notice that the collapse wave on one side of the west facade, WTC 1, is leading the same wave on the other side of the same facade by 10 to 20 stories.


It is by carefully noting the forensic conditions of supporting columns and distinctive features of the "collapses" that we could NARROW THE POSSIBILITIES even before theorizing begins.

This is what was never done.


3body writes:

And yes, still better than any offered by NIST. The question of why this is so is certainly one worth asking.

It is worth asking. Interesting.




I will argue forcefully. The force of the arguments are not directed at anyones person.

Thanks for the feedback.

 

[Major_Tom]

Just looking at the WTC1 destruction we see the 'rigid top block' telescoping into itself 30 meters after 2-3 seconds (it gets 30 meters shorter), while the perimeter columns in the so called initiation zone are still intact, i.e. nothing has happened at the initiation zone!!

This is one of my future "curiosos".

 

[bofors]

Curioso #4: The WTC 1 northwest corner was captured very well in video clips during the "collapse" progression. It is possible to study the dust ejection patterns in detail.


The following clip from the BBC allows us to look down the west facade at the collapse front.

It is clear that the visible ejections along the southwest corner (far corner) are preceeding the same ejections along the northwest corner (near corner) by 10 to 20 floors.

http://www.youtube.com/watch?v=k-jYSy1SxsI

Excellent clip.

Therefore, when studying the ejection patterns along the northwest corner in the following video clips, please remember that the collapse progression has already passed these same floors on the southwest corner before these ejections occured.


We established in curioso #3 that this entire west facade is peeling away from the building largely as a single continuous sheet. A few people told me this is "expected" and that the collapse front along this facade is caused by floors failing and piling up on one another.

But that means that, according to them, the southwest flooring is giving way about 10 to 20 stories ahead of the same flooring in the northwest, as visible in the clips linked above.

Absolutely.

According to NB and Norseman, the very front of the collapse wave is caused by the perimeter columns of the upper block falling within the perimeter of the lower block, thereby severing the collections between the flooring and the perimeter.

I tried to get NB to spell this out, but he didn't so, so I am not if they actually think the upper block perimeter columns in particular are responsible. They may be thinking more in terms of general debris.

This would mean they are severing the flooring from the perimeter along the southern portion of the west facade 10 to 20 stories ahead of the same flooring on the northern portion?

Absolutely.

I am not seeing any evidence of a crushing front as they describe. There is no visible evidence of floors being crushed before dust ejections shoot outwards.

There is none, of course.

How would you explain these floors building up pressure and causing such forceful ejections considering the same floor gives at noticably different times at different locations?

Once you establish that ejections occur across the entire breath of the west face (not just in the middle), this immediately leads to their problem at the extreme west side of the north face (please correct me if I have these directions confused).

There is absolutely no way that debris can be driving the blow out of the west face, because at the very least we would see some blow out at the extreme west side of the north face (on the same floors).

Congratulations... checkmate.

 

[DGM]

Excellent clip.




Absolutely.




I tried to get NB to spell this out, but he didn't so, so I am not if they actually think the upper block perimeter columns in particular are responsible. They may be thinking more in terms of general debris.



Absolutely.



There is none, of course.



Once you establish that ejections occur across the entire breath of the west face (not just in the middle), this immediately leads to their problem at the extreme west side of the north face (please correct me if I have these directions confused).

There is absolutely no way that debris can be driving the blow out of the west face, because at the very least we would see some blow out at the extreme west side of the north face (on the same floors).

Congraduations... checkmate.

Now all you have to do is explain what it would take to do this. Please be very explicit Mr. engineer.

 

[Furcifer]

Excellent clip.

Whether you believe the acts of 9/11 were a result of some vast government conspiracy or an act of terrorism, that clip, showing the deaths of 1000's of people is not "Excellent". I suggest you remember what exactly you are watching before you make such comments. Have some decency please.