OOS Collapse Propagation Model

[jaydeehess]

Progression of understanding time then.

I watched the live event of 9/11 on TV. At the time I was in a crew tasdked with moving a cable TV head end and we had already disassembled one of two dishes for the move. That meant the town had only about 20 channels working on cable. Called the boss who said to wait and go back to finishing it starting at noon.

When the south Tower went down, although I was sreaming "NO!" in my mind, I knew it was really happening. My first thought was "how many people got out in time". I knew then, in an undetailed way, that the dynamic load , having not been lowered by mass ejections, was what drove collapse to the ground. Never even considered bombs.
Was posting on the Blackvault then. One poster commented on bombs in the towers and that started my journey in this arena. From BV to Pravda English, through Physics forum and then to Pilots For 9/11 Truth, where I was called a government loyalist and a plant from the govt loyalist website. Finally, after many entreaties to state with they were talking about, I ended up here. Yes, I found JREF because Rob Balsamo informed me of it being the bane of his existence, a point I find rather ironic.

WRT Bazant, the first paper I read he had calculated that floor loading was 30+ times greater than required to fail the floor. He made it clear that with such a margin, that his simplifications of such an event would not change the fact that floor overloading would collapse the structure. I had no problem deducing ( since he came right out and said it) that this was a simplification of a collapse mechanism.
Next Bazant paper I read wasa best case limit of all the dynamic loading being an axial load on the column tops of a lower block. Again, I had no problem deducing that this was even less "real" than the previous paper since it was patently ridiculous to expect all that load to be taken on by the columns.

Both however gave some flesh to my original thought that dynamic forces built due to added mass and velocity and that mass ejections could not reduce dynamic overloading to the point that collapse could arrest.

When Verniage was introduced I did understand that Bazant's math was confirmed, placing an enormous overload on columns would collapse a structure. Yet just how this applied to the towers, I was confused as to how that occurred. Perhaps on columns already having some vertical separation due to aircraft severing.

When "pancake" was introduced I saw the relevance, learned about Euler buckling but understood that the PBS graphic and the term,"pancakeing" were no t very accurate.

Skip ahead, skip ahead, past therm?the, nukes, no planes/fake planes/substituted planes, CiT idiocy, WTC "smoking gun" and free fax=CD nonsense, and here I am.

 

[ozeco41]

Not wrong. As a non-engineer, I just don't see the point of discussing "progression" much when the building was doomed to fail.

I fully comprehend that position.

You, MT and others find it interesting, while I find it akin to discussing the number of angels dancing on the head of a pin.

You have your classification - I have a different one. And the difference is one of the two/three key issues being discussed in this thread.

As an engineer I have difficulty accepting that trivialising of the key reason for the most dramatic aspect of the Twin Towers collapses. I have on many occasions explained the Twin Towers collapses to persons - engineers and others - "normal" community members who are not involved in 9/11 CT debates. Takes me about thirty seconds to explain that stuff falling down the "tube space" stripped the floors off, let the perimeter columns fall over, and bypassed he columns. And they universally see that "down the tube" PLUS "miss the columns" are the two key features. Without any of the jargon.

We can agree to disagree on the "angels dancing" metaphor. Even tho I respect your position I simply cannot view the key feature of the collapse mechanics as a trivialised minor detail.

The video analysis in particular bores me to tears. Let alone the pop psychology, frames vs. fields, and other nonsense.

I loathe the pseudo psychology and false logic. I find it amusing that those who disagree with the detailed technical research done by alleged truthers don't make the same comments over on the Dust and Microspheres threads when debunkers are doing similar detailed research. For reasons I have already stated.

I imagine the world's biggest Jenga game. You pulled a piece, and it fell. How exactly did it fall? Well, you lose no matter what. You could videotape it in slo-mo, you could measure how far and fast the pieces bounced off of each other, but why?

Couldn't care less about the jenga game myself. But the discussion is not about a jenga game. And we have both made our different perspectives clear.

 

[ozeco41]

As a structural engineer, I'm not interested in studying the collapse progression of a building where the majority of the columns failed over several stories. I'm not going to design a skyscraper to arrest a collapse of this nature because it's simply not possible within reasonable economics.

Spot on Newton. The hard realities of "commercial viabilty". Post 9/11 should buildings be designed, can buildings be designed to withstand any form of terrorist attack? If the fire fighting and occupant escape provisions are made more robust - the two failings of WTC which resulted an a lot of deaths - can the building itself be economically protected against extreme terrorist actions.

I doubt it.

Disproportionate collapse, such as Ronan Point, is of interest.

But those are two completely different scenarios.

Yes.

 

[carlitos]

I find it amusing that those who disagree with the detailed technical research done by alleged truthers don't make the same comments over on the Dust and Microspheres threads when debunkers are doing similar detailed research. For reasons I have already stated.

It's a fair point. I have largely cured myself of participating in those threads, although I was guilty of helping to fund the "dust" research. I tend to agree with ... I believe it was you? ... that it matters not whether there was thermXte all over the place on 9/11, since it obviously wasn't used for anything. I believe that I have re-iterated that point as of late, but I'm probably still guilty of a little hypocrisy on the subject.

 

[ozeco41]

It's a fair point. I have largely cured myself of participating in those threads, although I was guilty of helping to fund the "dust" research....

Thanks. Me too. Me too.

I tend to agree with ... I believe it was you? ... that it matters not whether there was thermXte all over the place on 9/11, since it obviously wasn't used for anything....

I plead guilty. And plead the following argument in mitigation of sentence:
1) The only relevance of thermXte to 9/11 discussion is as partial support for CD;
2) There is not and never has been an hypothesis to prima facie standard in favour of CD;
3) Even if presence of thermXte is proven it means nothing without proof of CD;
4) Proving thermXte by itself is a dead end track. Truthers would be better served proving CD THEN if there was thermXte they have an hypothesis which it supports;
5) I describe the truther process of argumentation as "arse about"; AND
6) That is before I carve them up into mince because of their reliance on reversed burden of proof. Or reversed burden of disproof as they usually deploy the trick.

I believe that I have re-iterated that point as of late, but I'm probably still guilty of a little hypocrisy on the subject.

No royalties or fees apply - I put it in the public domain. I sometimes breach the relevant rules such as:
1) "don't feed trolls"; and
2) "why contribute to derails which favour truther evaders?"

...usually I rationalise my sinful ways by finding some "better for the overall good" reason.

 

[Major_Tom]

Another common accusation throughout the thread from the first page is that there is insufficient mathematics presented in support of the ROOSD concept. It is a recurring 'meme' multiplied, propagated, and sincerely believed by some posters thoughout the thread, reaching a crescendo in any of the one sentence comments by Beachnut which include the word 'math' or 'physics'.

There is a common belief that Bazant is 'math heavy' and the OOS model 'lacks math' and therefore the Bazant comments in BV, BL, and BLGB have a 'reality' that the OOS model somehow lacks.




Mathematical Basis of ROOSD Propagation in WTC1 and 2


This information has been available since 2010, but this time I'll write it as a simple 5 step process so no regular readers cam claim they never noticed it later, as has been the case since 2010.



Mathematical approach to the study of ROOSD propagation:


Step 1: GAIN AN OVERALL CONCEPTUAL AND VISUAL UNDERSTANDING OF WHAT ONE IS LOOKING AT

Step 2: RESEARCH AVAILABLE LITERATURE ON THE SUBJECT OF FLOORS IMPACTING FLOORS

Step 3: MEASURE THE COLLAPSE PROPAGATION RATE AS ACCURATELY AND COMPLETELY AS POSSIBLE

Step 4: EXAMINE A VARIETY OF PHYSICS-BASED MATHEMATICAL APPROACHES TO THE COLLAPSE OF STACKED SYSTEMS

Step 5: COMPARE MODELS IN STEP 4 TO INFORMATION IN STEPS 1 - 3 to see which models could match propagation behavior or teach something about it.







Each step in detail:



Step 1: GAIN AN OVERALL CONCEPTUAL AND VISUAL UNDERSTANDING OF WHAT ONE IS LOOKING AT

I'd recommend using parts 2.1 and 2.2 in my book.







Step 2: RESEARCH AVAILABLE LITERATURE ON THE SUBJECT OF FLOORS IMPACTING FLOORS


General Conditions of ROOSD mechanics will take the form:

for rubblized driving mass > M(1) moving at a downward velocity > V(1) , the runaway process is assured. (threshold limits to initiate ROOSD)

If driving mass M is large enough and the downward velocity V is large enough the conditions will probably escalate. (conditions in which ROOSD is sustained)


A process very similar to the ROOSD description of progressive floor collapse has been modelled mathematically by A.G. Vlassis, B.A. Izzuddin, A.Y. Elghazouli and D.A. Nethercot. The paper "Progressive Collapse of Multi-story Buildings Due to Failed Floor Impact" is available at this link.

Progressive Collapse of Multi-Storey Buildings due to Failed Floor Impact, linked:
http://spiral.imperial.ac.uk/bitstream/10044/1/1466/1/EngStr09 - AGV_BAI_AYE_DAN.pdf

From the paper a deforming slab responding to impact:

From the introduction:

"It is concluded that such structures are susceptible to progressive collapse initiated by impact of a failed floor, mainly due to insufficient ductility supply under combined bending and axial deformation modes. Moreover, the development of shear failure modes is identified, thus further increasing the observed vulnerability of the studied floor system. Since these shear modes of failure are expected to be even more pronounced when the actual dynamic rather than the static response of the impacted floor is considered, the need for further research work focussing on the shear capacity of a variety of connection types subject to extreme events is established. Finally, practical design recommendations that can improve the impact response of floor systems exposed to impact from the floor above are made."

page 24: "Hence, it can be easily concluded that in the event of failure and subsequent impact of a single floor plate onto the floor plate below, the lower impacted system, modeled using a grillage-type approximation, is highly unlikely to possess sufficient dynamic load carrying capacity to resist the imposed dynamic loads and prevent progressive collapse."

page 26: "Thus, although assessment is based on a simplified grillage-type approximation rather than a detailed slab model, the explicitness of the results leads to the conclusion that a floor system within a steel-framed composite building with a typical structural configuration has limited chances to arrest impact of an upper floor. This is particularly true when the falling floor completely disintegrates and falls as debris without retaining any residual strength or spanning capability."

page 27: "To conclude, although there is room for further improvements with respect to its accuracy and applicability, the proposed assessment methodology provides an effective platform to rationally tackle the scenario of floor impact, which is one of the most prevalent progressive collapse initiation mechanisms."



Also consider the Ph.D thesis by the same author: Vlassis, A.G. (2007). Progressive Collapse Assessment of Tall Buildings, PhD Thesis, Department of Civil and Environmental Engineering, Imperial College London.








Step 3: MEASURE THE COLLAPSE PROPAGATION RATE AS ACCURATELY AND COMPLETELY AS POSSIBLE: A collapse front down the west face of WTC1 remained visible and measurable down to the lower floors. The movement shows a relatively constant velocity after quickly leveling off after collapse initiation. The velocity is approximately 25m/s, or about 8 floors per second being destroyed. To the author's knowledge this is the first time that the propagation rate of a progressive floor collapse was measured.



Initial data for linear ejecta traversal from West face of WTC 1:

http://femr2.ucoz.com/photo/linear_2/6-0-217
http://femr2.ucoz.com/photo/6-0-217-3 (1280x720px/74.6Kb)

Source video in H264 format (1280x720x25fps):
http://femr2.ucoz.com/ffdemhd_264.avi

Crop of West Face Ejecta:

http://www.youtube.com/watch?v=BMeTGfCZWMI
http://www.youtube.com/watch?v=2F5Tw2ITMF8

Position⁴:

http://femr2.ucoz.com/photo/6-0-219-3 (1234x731px/67.0Kb)

Velocity:

http://femr2.ucoz.com/photo/6-0-220-3 (1224x730px/87.3Kb)








Step 4: EXAMINE A VARIETY OF PHYSICS-BASED MATHEMATICAL APPROACHES TO THE COLLAPSE OF STACKED SYSTEMS



Here are a few different ways to set up the basic physics to the collapse propagation of a stacked system of masses in 1 dimension:

Study of a Simple 1 Dimensional Stacked System

Models of Inelastic Accretion


WTC Asynchronous Impact Crush-Down Model




It is also important to be aware of and review the approaches taken to collapse progression in the following papers in light of the new information gathered in steps 1 - 3 and compare them to the models linked above:

All 4 Bazant papers BZ, BV, BL and BLGB, linked and reviewed here
Frank Greening, Energy Transfer in the WTC Collapse, linked and reviewed here
Keith Seffen, Progressive Collapse of the World Trade Centre: a Simple Analysis, linked and reviewed here
Gordon Ross: Momentum Transfer Analysis of the Collapse of the Upper Storeys of WTC 1 linked here







Step 5: COMPARE MODELS IN STEP 4 TO INFORMATION IN STEPS 1 - 3 to see which models could match propagation behavior or teach something about it.








Step 6: As a final step, I suggest a careful and open examination of all claims being floated about the public concerning the collapse progression processes of WTC1 and 2 in light of what has been learned in the first 5 steps.

 

[DGM]

Step 6: As a final step, I suggest a careful and open examination of all claims being floated about the public concerning the collapse progression processes of WTC1 and 2 in light of what has been learned in the first 5 steps.

Just so I'm clear. If someone is clear on models vs reality, can he/her just skip this step?

I'd also like to hear your comments on claims your work is more or less just a more detailed look at something that has been suggested (and accepted) since very early on (pre-truther).

 

[ozeco41]

Just so I'm clear. If someone is clear on models vs reality, can he/her just skip this step?

Yes. And that applies to those who genuinely are clear as well as those who think they are clear.

Ackcherly I would like to see persons from all four "sides" being taken here define what they think the actual topic under current discussion is. But that isn't going to happen is it?

...I'd also like to hear your comments on claims your work is more or less just a more detailed look at something that has been suggested (and accepted) since very early on (pre-truther).

It's "more" but he doesn't seem to want to explain why. F'rinstance this opening paragraph of his latest post:

Another common accusation throughout the thread from the first page is that there is insufficient mathematics presented in support of the ROOSD concept. It is a recurring 'meme' multiplied, propagated, and sincerely believed by some posters thoughout the thread, reaching a crescendo in any of the one sentence comments by Beachnut which include the word 'math' or 'physics'.

IMO is true...

...BUT he then loses that plot and tries to prove the maths.

Nonsense.

OOS and ROOSD are explanations - definitions - of a mechanism. They are not subjects for "proof' by maths or FEA (which is only a complicated special purpose calculator).

Anyone calling for maths or FEA when the topic is definition of a mechanism is off the track. Maths and FEA are tools which are applied to solving a problem once the problem is defined. Sadly some engineers are not good at defining which problem they are solving. T Sz a classic example with "Missing Jolt" And in Tony's case, the multiple times I have pointed out an error in his logic and he responds "Where is your math or your FEA". Ludicrous. Neither math nor FEA are definers of problems NOR correctors of false logic. They are both subject to GIGO - feed in garbage models/assumptions/mechanisms and math or FEA will blithely respond with garbage results. OR even worse - results that are close to realistic but wrongly derived. We've seen a lot of those over the years. AND, in case anyone thinks I'm drifting, look at all the Bazantian energetics based calculations of likely collapse speeds/accelerations which were based on "columns in line" and came up with near enough right numeric answers. When the foundation premises were faeces.

[/EndMiniRant

 

[rwguinn]

Yes. And that applies to those who genuinely are clear as well as those who think they are clear.

Ackcherly I would like to see persons from all four "sides" being taken here define what they think the actual topic under current discussion is. But that isn't going to happen is it?
It's "more" but he doesn't seem to want to explain why. F'rinstance this opening paragraph of his latest post:
IMO is true...

...BUT he then loses that plot and tries to prove the maths.

Nonsense.

OOS and ROOSD are explanations - definitions - of a mechanism. They are not subjects for "proof' by maths or FEA (which is only a complicated special purpose calculator).

Anyone calling for maths or FEA when the topic is definition of a mechanism is off the track. Maths and FEA are tools which are applied to solving a problem once the problem is defined. Sadly some engineers are not good at defining which problem they are solving. T Sz a classic example with "Missing Jolt" And in Tony's case, the multiple times I have pointed out an error in his logic and he responds "Where is your math or your FEA". Ludicrous. Neither math nor FEA are definers of problems NOR correctors of false logic. They are both subject to GIGO - feed in garbage models/assumptions/mechanisms and math or FEA will blithely respond with garbage results. OR even worse - results that are close to realistic but wrongly derived. We've seen a lot of those over the years. AND, in case anyone thinks I'm drifting, look at all the Bazantian energetics based calculations of likely collapse speeds/accelerations which were based on "columns in line" and came up with near enough right numeric answers. When the foundation premises were faeces.

[/EndMiniRant

What the hells?

That makes even less sense to me the more I read it.
Manager-speak?

If you can't describe a mechanism mathematically, then it is not engineering-or science.

 

[JSanderO]

What the hells?

That makes even less sense to me the more I read it.
Manager-speak?

If you can't describe a mechanism mathematically, then it is not engineering-or science.

I think Ozzie pretty much nailed why this "discussion" is going no where... To mathematically model a complex process such as the collapse or ROOSD requires all manner of precise data input. This data is not available. I suppose one could use some assumed data and build an FEA.. which could look like the real world event. Then one might declare... see here is a proof of how the tower collapse. That's not a proof... only a conceptual demonstration based on assumed inputs.

The basic concepts of ROOSD are settled engineering/physics... such as dynamic loads which exceed capacity of slabs will destroy the slabs.... or columns which depend on lateral bracing for stability will become unstable if they lose their bracing.

It seems that ROOSD is almost self evident if one looks at what happened... mass was driving down behind / inside the facade... it created over pressure forcing material out the windows (weaker than the steel columns of the facade)... left columns which required bracing... unbraced and unstable and they toppled over from... Euler buckling forces (settled engineering).

What's to prove? Euler's done the work on columns.... materials testing has done the work on slabs systems... AISC has done the work on bolted and welded connections and strength of steel sections.

So Mr B tells us that X force (mass) can destroy Y assembly... lovely...

ROOSD is a process... where several mechanisms are in play and they result in destruction of a system of several sub systems...

Get it?

 

[tsig]

Another common accusation throughout the thread from the first page is that there is insufficient mathematics presented in support of the ROOSD concept. It is a recurring 'meme' multiplied, propagated, and sincerely believed by some posters thoughout the thread, reaching a crescendo in any of the one sentence comments by Beachnut which include the word 'math' or 'physics'.

There is a common belief that Bazant is 'math heavy' and the OOS model 'lacks math' and therefore the Bazant comments in BV, BL, and BLGB have a 'reality' that the OOS model somehow lacks.




Mathematical Basis of ROOSD Propagation in WTC1 and 2


This information has been available since 2010, but this time I'll write it as a simple 5 step process so no regular readers cam claim they never noticed it later, as has been the case since 2010.



Mathematical approach to the study of ROOSD propagation:


Step 1: GAIN AN OVERALL CONCEPTUAL AND VISUAL UNDERSTANDING OF WHAT ONE IS LOOKING AT

Step 2: RESEARCH AVAILABLE LITERATURE ON THE SUBJECT OF FLOORS IMPACTING FLOORS

Step 3: MEASURE THE COLLAPSE PROPAGATION RATE AS ACCURATELY AND COMPLETELY AS POSSIBLE

Step 4: EXAMINE A VARIETY OF PHYSICS-BASED MATHEMATICAL APPROACHES TO THE COLLAPSE OF STACKED SYSTEMS

Step 5: COMPARE MODELS IN STEP 4 TO INFORMATION IN STEPS 1 - 3 to see which models could match propagation behavior or teach something about it.







Each step in detail:



Step 1: GAIN AN OVERALL CONCEPTUAL AND VISUAL UNDERSTANDING OF WHAT ONE IS LOOKING AT

I'd recommend using parts 2.1 and 2.2 in my book.







Step 2: RESEARCH AVAILABLE LITERATURE ON THE SUBJECT OF FLOORS IMPACTING FLOORS


General Conditions of ROOSD mechanics will take the form:

for rubblized driving mass > M(1) moving at a downward velocity > V(1) , the runaway process is assured. (threshold limits to initiate ROOSD)

If driving mass M is large enough and the downward velocity V is large enough the conditions will probably escalate. (conditions in which ROOSD is sustained)


A process very similar to the ROOSD description of progressive floor collapse has been modelled mathematically by A.G. Vlassis, B.A. Izzuddin, A.Y. Elghazouli and D.A. Nethercot. The paper "Progressive Collapse of Multi-story Buildings Due to Failed Floor Impact" is available at this link.

Progressive Collapse of Multi-Storey Buildings due to Failed Floor Impact, linked:
http://spiral.imperial.ac.uk/bitstream/10044/1/1466/1/EngStr09 - AGV_BAI_AYE_DAN.pdf

From the paper a deforming slab responding to impact:

[qimg]http://www.sharpprintinginc.com/911/images/photoalbum/13/1316386655_Capture.PNG[/qimg]


From the introduction:

"It is concluded that such structures are susceptible to progressive collapse initiated by impact of a failed floor, mainly due to insufficient ductility supply under combined bending and axial deformation modes. Moreover, the development of shear failure modes is identified, thus further increasing the observed vulnerability of the studied floor system. Since these shear modes of failure are expected to be even more pronounced when the actual dynamic rather than the static response of the impacted floor is considered, the need for further research work focussing on the shear capacity of a variety of connection types subject to extreme events is established. Finally, practical design recommendations that can improve the impact response of floor systems exposed to impact from the floor above are made."

page 24: "Hence, it can be easily concluded that in the event of failure and subsequent impact of a single floor plate onto the floor plate below, the lower impacted system, modeled using a grillage-type approximation, is highly unlikely to possess sufficient dynamic load carrying capacity to resist the imposed dynamic loads and prevent progressive collapse."

page 26: "Thus, although assessment is based on a simplified grillage-type approximation rather than a detailed slab model, the explicitness of the results leads to the conclusion that a floor system within a steel-framed composite building with a typical structural configuration has limited chances to arrest impact of an upper floor. This is particularly true when the falling floor completely disintegrates and falls as debris without retaining any residual strength or spanning capability."

page 27: "To conclude, although there is room for further improvements with respect to its accuracy and applicability, the proposed assessment methodology provides an effective platform to rationally tackle the scenario of floor impact, which is one of the most prevalent progressive collapse initiation mechanisms."



Also consider the Ph.D thesis by the same author: Vlassis, A.G. (2007). Progressive Collapse Assessment of Tall Buildings, PhD Thesis, Department of Civil and Environmental Engineering, Imperial College London.








Step 3: MEASURE THE COLLAPSE PROPAGATION RATE AS ACCURATELY AND COMPLETELY AS POSSIBLE: A collapse front down the west face of WTC1 remained visible and measurable down to the lower floors. The movement shows a relatively constant velocity after quickly leveling off after collapse initiation. The velocity is approximately 25m/s, or about 8 floors per second being destroyed. To the author's knowledge this is the first time that the propagation rate of a progressive floor collapse was measured.



Initial data for linear ejecta traversal from West face of WTC 1:

[qimg]http://femr2.ucoz.com/_ph/6/2/995880143.jpg[/qimg]

http://femr2.ucoz.com/photo/linear_2/6-0-217
http://femr2.ucoz.com/photo/6-0-217-3 (1280x720px/74.6Kb)

Source video in H264 format (1280x720x25fps):
http://femr2.ucoz.com/ffdemhd_264.avi

Crop of West Face Ejecta:

[qimg]http://femr2.ucoz.com/_ph/6/2/760729846.gif[/qimg]

[qimg]http://femr2.ucoz.com/_ph/6/2/139901890.gif[/qimg]

http://www.youtube.com/watch?v=BMeTGfCZWMI
http://www.youtube.com/watch?v=2F5Tw2ITMF8

Position⁴:

[qimg]http://femr2.ucoz.com/_ph/6/2/730189522.jpg[/qimg]
http://femr2.ucoz.com/photo/6-0-219-3 (1234x731px/67.0Kb)

Velocity:

[qimg]http://femr2.ucoz.com/_ph/6/2/185125992.jpg[/qimg]
http://femr2.ucoz.com/photo/6-0-220-3 (1224x730px/87.3Kb)








Step 4: EXAMINE A VARIETY OF PHYSICS-BASED MATHEMATICAL APPROACHES TO THE COLLAPSE OF STACKED SYSTEMS



Here are a few different ways to set up the basic physics to the collapse propagation of a stacked system of masses in 1 dimension:

Study of a Simple 1 Dimensional Stacked System

Models of Inelastic Accretion


WTC Asynchronous Impact Crush-Down Model




It is also important to be aware of and review the approaches taken to collapse progression in the following papers in light of the new information gathered in steps 1 - 3 and compare them to the models linked above:

All 4 Bazant papers BZ, BV, BL and BLGB, linked and reviewed here
Frank Greening, Energy Transfer in the WTC Collapse, linked and reviewed here
Keith Seffen, Progressive Collapse of the World Trade Centre: a Simple Analysis, linked and reviewed here
Gordon Ross: Momentum Transfer Analysis of the Collapse of the Upper Storeys of WTC 1 linked here







Step 5: COMPARE MODELS IN STEP 4 TO INFORMATION IN STEPS 1 - 3 to see which models could match propagation behavior or teach something about it.








Step 6: As a final step, I suggest a careful and open examination of all claims being floated about the public concerning the collapse progression processes of WTC1 and 2 in light of what has been learned in the first 5 steps.

If you overload a floor it will collapse, OK, now what?

 

[Major_Tom]

If you can't describe a mechanism mathematically, then it is not engineering-or science.

A physical mechanism can have both qualitative and quantitative attributes. Mathematics can be used to find physical relations between quantitative attributes.

Descriptive as well as mathematical models can be used to shed light on what is being observed during the collapse progression processes.

 

[Major_Tom]

OOS and ROOSD are explanations - definitions - of a mechanism. They are not subjects for "proof' by maths or FEA (which is only a complicated special purpose calculator).

Anyone calling for maths or FEA when the topic is definition of a mechanism is off the track. Maths and FEA are tools which are applied to solving a problem once the problem is defined.

This is why step 1 is essential when approaching the application of mathematical models to the WTC1, 2 collapse progressions.

Sadly some engineers are not good at defining which problem they are solving. T Sz a classic example with "Missing Jolt" And in Tony's case, the multiple times I have pointed out an error in his logic and he responds "Where is your math or your FEA". Ludicrous. Neither math nor FEA are definers of problems NOR correctors of false logic. They are both subject to GIGO - feed in garbage models/assumptions/mechanisms and math or FEA will blithely respond with garbage results. OR even worse - results that are close to realistic but wrongly derived. We've seen a lot of those over the years. AND, in case anyone thinks I'm drifting, look at all the Bazantian energetics based calculations of likely collapse speeds/accelerations which were based on "columns in line" and came up with near enough right numeric answers. When the foundation premises were faeces.

[/EndMiniRant

All that is true.


That is why it is nice to see both OneWhiteEye and Femr2 approach the subject with far more care and intelligence in 2009 and 2010.

The variety of models introduced in step 4 are:


Study of a Simple 1 Dimensional Stacked System (OneWhiteEye, 2009-10)

Models of Inelastic Accretion (OneWhiteEye, 2010)


WTC Asynchronous Impact Crush-Down Model (Femr2, 2009)


They provide an excellent lens through which to look at the collapse mechanics literature of:

All 4 Bazant papers BZ, BV, BL and BLGB, linked and reviewed here
Frank Greening, Energy Transfer in the WTC Collapse, linked and reviewedhere
Keith Seffen, Progressive Collapse of the World Trade Centre: a Simple Analysis, linked and reviewed here
Gordon Ross: Momentum Transfer Analysis of the Collapse of the Upper Storeys of WTC 1 linked here



Many mistakes within the written technical history can be spotted in this way.

 

[Reactor drone]

Many mistakes within the written technical history can be spotted in this way.

Such as?

 

[rwguinn]

If you overload a floor it will collapse, OK, now what?

If you push something hard enough, it will fall over?
But there is mathematics and physics implied in "push" and "hard" , just as there is in "overload", therefor it can't be a description of a mechanism....

 

[DGM]

Another common accusation throughout the thread.......................

I'm sure Tom has just been busy. Any time you're ready buddy.

Just so I'm clear. If someone is clear on models vs reality, can he/her just skip this step?

I'd also like to hear your comments on claims your work is more or less just a more detailed look at something that has been suggested (and accepted) since very early on (pre-truther).

 

[beachnut]

I think Ozzie pretty much nailed why this "discussion" is going no where... ...

Get it?

I thought you were a big NIST guy. Many, maybe most who fell for 911 truth failed to read and comprehend NIST. I don't need NIST, my mom said i should be an engineer... I think 911 truth are the NISTians, a 911 truth projection due to their inability to do math, engineering and science.

JREF is populated by ill mannered NIST bots who can't think for themselves... and can't carry on a discussion with anyone expect other NISTians which consists of back slapping each other.

There goes your beer.

Nope, you were a Gage guy. Wow, NIST confirmed what I knew on 911, 911 truth are late to figure out much.

Do you think MT still thinks the gravity collapse was an illusion? 911 truth members should have read NIST before signing up to be in 911 truth failed groups with claims based on ignornace - yet they must be well mannered, being nice to fool the gullible.

 

[JSanderO]

Do you think MT still thinks the gravity collapse was an illusion? 911 truth members should have read NIST before signing up to be in 911 truth failed groups with claims based on ignornace - yet they must be well mannered, being nice to fool the gullible.

Shoulda coulda woulda... Why should I know what MT's thoughts are? Ask him... not me. I could care less what NIST says... My interest in 9/11 was to satisfy my own curiosity about how those collapses might have happened. I don't need proof and I don't intend to offer any. My curiosity is satisfied...

The continuing debate is more revealing about how people think (or don't or won't or can't) and relate to each other around this issue. The key "players" are quite the study in human psychology and behavior.

 

[carlitos]

I could care less what NIST says...

How much less?

 

[beachnut]

Shoulda coulda woulda... Why should I know what MT's thoughts are? Ask him... not me. I could care less what NIST says... My interest in 9/11 was to satisfy my own curiosity about how those collapses might have happened. I don't need proof and I don't intend to offer any. My curiosity is satisfied...

The continuing debate is more revealing about how people think (or don't or won't or can't) and relate to each other around this issue. The key "players" are quite the study in human psychology and behavior.

What a load of BS, however why are you here when you make up the dumbest claim in history, as you project your study in human psychology and behavior - like the poster who was writing a book, not MT's book another book never done.

JREF is populated by ill mannered NIST bots who can't think for themselves... and can't carry on a discussion with anyone expect other NISTians which consists of back slapping each other.

Are you a NIST bot, or a what? Who are the NIST bots, and where is the evidence, and how does that dovetail with OOS? NIST bots?

Do based on human psychology and behavior, is that why you joined Gage, he was not ill mannered but a smooth talking "used car salesman" with the special "financing plan"? Do manners manner with respect to truth?

With respect to human psychology and behavior, why can't Major Tom answer if he has dropped the "gravity collapse is an illusion" inside job mentality? You mentioned human psychology and behavior, why is Major Tom unable to debunk his illusion stuff? You must be into human psychology and behavior study, you keep heading that direction.

The human psychology and behavior that has someone who joins Gage would be interesting. Did OOS help you wake up and see Richard Gage was a fraud?

OOS is not new, it is how the WTC would fail, as Robertson explained; It is how it was built - in addition, NIST's explain a floor can hold 29,000,000 pounds puts math to the OOS beginnings, per floor. I find it amusing MT mocks engineering models, yet only has observation as his model. Why does 911 truth mock things they don't understand? You have insight into this you failed to believe NIST, or your own eyes on 911, what is the human psychology and behavior behind your joining 911 truth? Yes, human psychology and behavior is interesting, what is the truth? Why can't Major Tom answer questions.

Based on human psychology and behavior, why does 911 truth mock engineering models? How long have you been studying human psychology and behavior? And can you list the NIST bots, now that you are a JREF poster? What was the name of the thread you exposed JREF was infested with NIST bots? Do the bots get money from NIST? Was that post BS, and how does that relate to human psychology and behavior?