OOS Collapse Propagation Model

[WilliamSeger]

You're missing all the drama and intrigue in M_T's war stories.

I have no interest in drama or intrigue... I made it quote clear why I joined 9/11 discussions and forums.

I have no interest in explaining the thinking or behavior of others or debating them and showing them to be right or wrong.

Okay, then, I think you're completely safe ignoring M_T's war stories.

 

[Crazy Chainsaw]

I am not sure where this crush up thing is going or came from. There was no homogeneous top "block" to have its bottom crushed "up".

What appears to have occurred is that the top section (let's use 1wtc) lost its integrity. By this I mean

It suffered mechanical damage to the structure from the plane strike
Some floor sections broke apart and dropped
It suffered warping from the effects of heat from fires

that led to warping, shearing and breaking or splice connections, mis alignments of columns ends, and additional sections of floors losing support and dropping down​

This damage was probably mostly at and slightly above the plane impact zone. The fires persisted and the damage from them SPREAD. This led to apparently

The loss of support for the center of the hat truss and the collapse of the antenna just preceding what was "left" of the floors above the plane strike zone from dropping
In so doing there were few columns still coupled.... they buckled severely and this may have explained the lateral translation of what was left of the top section as it dropped and engaged in a mutual destruction with the top of the bottom section AND what we identify as the (ROOSD) collapse phase.​

Perhaps crush up refers to the mutual destruction of the bottom of the dropping top and crush down to the top of the standing bottom???

No eular buckling lead to the collapse that is clear from physical evidence.

The floors failing as you say would have formed a homogeneous front.

What I believe happened is Buckling lead to column failure, once the columns buckle until the
Center of gravity was no longer over the columns, the columns fracture.
A sudden drop of the core occurs.
It sparks a large reaction of carbon black dust, and other oxidizing compounds.
The perimeter columns fail and the top block falls.
The hot air created by the revived fire, rises, as it rises and the building falls,
It pushes up the floor slabs, and pans.
This removed the stiffness from the trusses and allows the core to vibrate wildly.
The vibration of the core, and the pealing of the perimeter columns,
Allows for crush up and crush down to be instantaneous, so that the top block is destroyed earlier in the collapses, than BLGB indicates.

 

[JSanderO]

No eular buckling lead to the collapse that is clear from physical evidence.

The floors failing as you say would have formed a homogeneous front.

What I believe happened is Buckling lead to column failure, once the columns buckle until the
Center of gravity was no longer over the columns, the columns fracture.
A sudden drop of the core occurs.
It sparks a large reaction of carbon black dust, and other oxidizing compounds.
The perimeter columns fail and the top block falls.
The hot air created by the revived fire, rises, as it rises and the building falls,
It pushes up the floor slabs, and pans.
This removed the stiffness from the trusses and allows the core to vibrate wildly.
The vibration of the core, and the pealing of the perimeter columns,
Allows for crush up and crush down to be instantaneous, so that the top block is destroyed earlier in the collapses, than BLGB indicates.

vivid imagination. I don't get it but I can't deny it happened as you say. My own imagination is much simpler...

guesses

 

[JSanderO]

Initiation is not the topic of this thread so I will not offer my own crazy thoughts on that.

 

[DGM]

Well, we are now on page 77 of a thread that, in a sane environment, would have lasted about 10 pages.

Oddly enough most of those pages are in response to you not actually making your point.

Do you actually have one? Maybe you need to take a class in communication, clearly you suck at it.

 

[Seymour Butz]

From what I can see MT has done good work about the COLLAPSE phase and that work looks impeccable.

Impeccable?

Lmao

A record of observables means nothing without the indepth engineering analysis that should go along with it.

 

[Crazy Chainsaw]

vivid imagination. I don't get it but I can't deny it happened as you say. My own imagination is much simpler...

guesses

Experimental testing not imagination.

 

[JSanderO]

OT.... CC mentioned failed columns in the section above the collapse (I presume) buckling from Euler forces. For that to have occurred, the column effective length would have had to increase from loss of bracing. (wasn't this the NIST claim for column 79 in 7wtc?. There the bracing beam (girder) was pushed off the beam seat by expansion of the beams framed into it. Is this what you are saying occurred above the plane crash zone in the twin towers? I believe the logic in 7wtc was that the one floor area around the column collapsed, the unsupported length increased, the column buckled and everything above fell down all the way up to the EPH. The massive amount of falling floors from 13 to 41 destroyed everything below 13 including the load transfer structures which then pushed of pulled other girders and load transfer structure out of alignment and the floors above them collapsed and the perimeter columns lost their bracing and or were pulled in or pushed out leaving the perimeter moment frame with no axial coupling to the foundation and it dropped unimpeded for 104' before encountering terra firma and fracturing apart at the bottom.

++++

What testing did you do? Models of the core being heated?

 

[Crazy Chainsaw]

OT.... CC mentioned failed columns in the section above the collapse (I presume) buckling from Euler forces. For that to have occurred, the column effective length would have had to increase from loss of bracing. (wasn't this the NIST claim for column 79 in 7wtc?. There the bracing beam (girder) was pushed off the beam seat by expansion of the beams framed into it. Is this what you are saying occurred above the plane crash zone in the twin towers? I believe the logic in 7wtc was that the one floor area around the column collapsed, the unsupported length increased, the column buckled and everything above fell down all the way up to the EPH. The massive amount of falling floors from 13 to 41 destroyed everything below 13 including the load transfer structures which then pushed of pulled other girders and load transfer structure out of alignment and the floors above them collapsed and the perimeter columns lost their bracing and or were pulled in or pushed out leaving the perimeter moment frame with no axial coupling to the foundation and it dropped unimpeded for 104' before encountering terra firma and fracturing apart at the bottom.

++++

What testing did you do? Models of the core being heated?

Motels heated and a drop test of weighted models that had been subjected to hydrocarbon fires. In the drop tests, a huge reaction occured with carbon black.

If a similar event occured in the core of the world trade center the rising heated air would
Have counter acted D'Alembert's principal and slowed ROOSD to the point it would fit the collapse time.

PS. The falling debris is the only containment needed, the fluid would seek the path of least
Resistance, up along the vibrating core columns.

 

[JSanderO]

If a similar event occured in the core of the world trade center the rising heated air would
Have counter acted D'Alembert's principal and slowed ROOSD to the point it would fit the collapse time.

That is rubbish...

Almost all the ROOSD collapse was in room temp structure with few to no significant fires.

 

[JSanderO]

Crazy I don't get the impression that you are too familiar with the structural system of the twin towers... when you refer to the tops coming down from columns failing from Euler buckling and hot hair in lower part of the building slowing the collapse.

The decent was likely slowed by the air between flows getting pushed out the windows and the energy required to fracture each slab.

 

[Crazy Chainsaw]

That is rubbish...

Almost all the ROOSD collapse was in room temp structure with few to no significant fires.

The upper block had significant fuel loading.

Friction with oxygenation was all that was required to ignite it.

 

[Crazy Chainsaw]

Crazy I don't get the impression that you are too familiar with the structural system of the twin towers... when you refer to the tops coming down from columns failing from Euler buckling and hot hair in lower part of the building slowing the collapse.

The decent was likely slowed by the air between flows getting pushed out the windows and the energy required to fracture each slab.

No just no, the floor slabs were too weak, to slow the collapses.

The windows were too weak also, another force, was at play.

The only available force that could have exerted upward movement into the upper block
Would have to be a hot gas.

 

[JSanderO]

No just no, the floor slabs were too weak, to slow the collapses.

The windows were too weak also, another force, was at play.

The only available force that could have exerted upward movement into the upper block
Would have to be a hot gas.

Doubt that.

The floors slabs destruction would HAVE to slow the collapse even if it was small and barely significant.

The air within the "sealed building" could not be (easily) compressed because the containment (glass) would not "hold" and so it was like forcing the air our between the wood (slabs) of a bellows... There is resistance when you squeeze the bellows and there was resistance from the 18,000 cu yards contained air between each slab.... and it was blasted out the windows and took most of the floor contents and clg tiles and ducts with it. THAT was what was slowing the floor collapse.

Open your eyes! What is being blasted out the windows?

NOT hot air rising!

You are likely wrong.

 

[WilliamSeger]

No just no, the floor slabs were too weak, to slow the collapses.

The windows were too weak also, another force, was at play.

The only available force that could have exerted upward movement into the upper block
Would have to be a hot gas.

Are you assuming that some extra upward force was necessary for concurrent crush up?

The impulse forces delivered to the lower structure were almost exclusively straight down, which is the loading direction the elements were designed to handle, so presumably that's the direction which would require the maximum force to fail. If the top block was tilted, the impulse forces would be at an angle to the framing, so destroying it would presumably require less force. If crush up requires less force than crush down, then both might happen simultaneously, with no need for extra force.

 

[Crazy Chainsaw]

Are you assuming that some extra upward force was necessary for concurrent crush up?

The impulse forces delivered to the lower structure were almost exclusively straight down, which is the loading direction the elements were designed to handle, so presumably that's the direction which would require the maximum force to fail. If the top block was tilted, the impulse forces would be at an angle to the framing, so destroying it would presumably require less force. If crush up requires less force than crush down, then both might happen simultaneously, with no need for extra force.

There should be enough material accumulated between the upper block and the lower block that it should fail the lower structure before crush up would occur.
I
That is the principal of D'Alembert's principal, the mass of the crushed sections should speed downward, failing the floors ahead of the top block.
A fluid movement going up could prevent D'Alembert's principal from having any significant impact.

 

[Crazy Chainsaw]

Doubt that.

The floors slabs destruction would HAVE to slow the collapse even if it was small and barely significant.

The air within the "sealed building" could not be (easily) compressed because the containment (glass) would not "hold" and so it was like forcing the air our between the wood (slabs) of a bellows... There is resistance when you squeeze the bellows and there was resistance from the 18,000 cu yards contained air between each slab.... and it was blasted out the windows and took most of the floor contents and clg tiles and ducts with it. THAT was what was slowing the floor collapse.

Open your eyes! What is being blasted out the windows?

NOT hot air rising!

You are likely wrong.

I could indeed be wrong, but seeing that the energy for the ejections is accounted for,
In BLGB.

 

[JSanderO]

I could indeed be wrong, but seeing that the energy for the ejections is accounted for,
In BLGB.

I have no idea about accounting for energy in BLGB and could care less.

It's pretty obvious that the materials of the building were collapse down inside of the 4 walls. The 4 walls also contained 18,800 x 110 cu yards of air which was clearly forced out of the path of the collapsing mass through that old path of least resistance... the perimeter windows.

A simple back of the envelop calc tells you that the air was moving at speeds as much as 200-400 mph and that a might destructive and powerful blast. And it would easily turn the contents of the floor to rubble in lickity split and take it along out the windows.

Where else would the air go? YOU CAN SEE air movements by the dust the air contains.

And at the end of the show the collapse which was been "pulling a huge down draft behind (above) it hit the hot debris pile... low and behold... it didn't just stop there... but headed off in all directions to regions of lower pressure all around the crash of the building. And of course there were man reports and vids of a blast of debris filled hot air "radiating" from the collapse at the conclusion.

This was all driven by the collapsing floor mass contained by the facade which did a piss poor job of actually containing it and it was cleaved apart and toppled over and away. The "action" and high pressure "front" was at the collapse front... the collapsing slab and the one beneath which survived another 1/8 second before it collapse forcing air out and then reaching in 1/8 second the slab below that. Remember it was no uniform slabs collapsing but section, chunks and so forth in a very compressed time frame so it SEEMS like entire slabs were breaking at once. But they broke apart over a very short span of time.... and it was not seen. But we know they DID very definitely self destruct.

You don't have to do an sophisticated math to understand that the floors simply could not resist the superimposed dynamic loads...it was like tanks raining down on your apartment or house roof. The structure will barely slow this at all. BUT IT will and it has to.

And this left the columns without lateral support and enormous unbraced length and way too slender to stand on their own... and these stacked multipart columns buckled and from "Euler forces" at the end to end connections... the weakest part of the stack

This is a runaway collapse of all known and settled engineering principles.

Now explain how the tops were made to break free from their axial support and send the floor materials down the chute. No there were no A1A tanks or bombs up there.

 

[Crazy Chainsaw]

I have no idea about accounting for energy in BLGB and could care less.

It's pretty obvious that the materials of the building were collapse down inside of the 4 walls. The 4 walls also contained 18,800 x 110 cu yards of air which was clearly forced out of the path of the collapsing mass through that old path of least resistance... the perimeter windows.

A simple back of the envelop calc tells you that the air was moving at speeds as much as 200-400 mph and that a might destructive and powerful blast. And it would easily turn the contents of the floor to rubble in lickity split and take it along out the windows.

Where else would the air go? YOU CAN SEE air movements by the dust the air contains.

And at the end of the show the collapse which was been "pulling a huge down draft behind (above) it hit the hot debris pile... low and behold... it didn't just stop there... but headed off in all directions to regions of lower pressure all around the crash of the building. And of course there were man reports and vids of a blast of debris filled hot air "radiating" from the collapse at the conclusion.

This was all driven by the collapsing floor mass contained by the facade which did a piss poor job of actually containing it and it was cleaved apart and toppled over and away. The "action" and high pressure "front" was at the collapse front... the collapsing slab and the one beneath which survived another 1/8 second before it collapse forcing air out and then reaching in 1/8 second the slab below that. Remember it was no uniform slabs collapsing but section, chunks and so forth in a very compressed time frame so it SEEMS like entire slabs were breaking at once. But they broke apart over a very short span of time.... and it was not seen. But we know they DID very definitely self destruct.

You don't have to do an sophisticated math to understand that the floors simply could not resist the superimposed dynamic loads...it was like tanks raining down on your apartment or house roof. The structure will barely slow this at all. BUT IT will and it has to.

And this left the columns without lateral support and enormous unbraced length and way too slender to stand on their own... and these stacked multipart columns buckled and from "Euler forces" at the end to end connections... the weakest part of the stack

This is a runaway collapse of all known and settled engineering principles.

Now explain how the tops were made to break free from their axial support and send the floor materials down the chute. No there were no A1A tanks or bombs up there.

Gun powder like reaction of carbon black in air.

 

[ozeco41]

Can you suggest an alternate? Would it be better to simply disclaim the use of "fact" as meaning "aspects of the current extant hypothesis which we accept..." Starts to get cumbersome doesn't it..

Doesn't need to be too heavy. How about:

Fact #3 The progression collapse stage for WTC1 and WTC2 appears consistent with a mechanism in which material falling down the office space tube stripped floors leaving perimeter columns to fall away.

Dave

Dave, ozeco, I am not too hung up on the word "fact". I usually treat it as short code for "claim of fact that is supported by evidence and currently agreed upon as most likely true by me plus either my present opponent or by a discernible consensus in the relevant field of study".

So for the sake of brevity, I have no qualms about keeping the label "fact".

Thanks both.

My own position is full agreement with Oystein's and with the spirit of your comment Dave "Doesn't need to be too heavy" - which also aligns with my concern about "cumbersome".

My own position is that I have run out of patience with the general reluctance to address the actual topic of the thread. Throughout my involvement I have held that certain core "facts" were true (true current or extant hypotheses to be pedantic).

Meanwhile some members have responded to my own reasoned arguments with opposing bare assertions leading to false challenges on details. Bare assertions do not counter reasoned argument. And all of those questionable issues of details are subsumed under my final "fact"

Fact #6 "The later papers by Bazant et al are wrong if and whenever they apply 1D simplification models to the WTC real event".

If anyone wants to argue against that point - by reasoned argument NOT bare assertion - be my guest. I may respond.

I will continue my discussion with Oystein to resolve some secondary issues of disagreement - probably via a channel other than this thread.

Again - thanks both.