OOS Collapse Propagation Model

[carlitos]

What is the purpose of the OOS model?

A clue:

Absurd? No.

What is with your fascination with trying to psychoanalyze people and groups of people? I thought you were interested in discussing how the towers came down?

Since many people (most?) were in "disbelief" that a seemingly very well built and strong structure could collapse so rapidly NIST was given the task to explain it... and stand as the "official explanation"

The is so little truth in the above sentence, I don't know where to start. Where do you get these ideas? Who are these "most" people that were in "disbelief" with what they all saw live on television?

Perhaps the "math" behind ROOSD is trivial and so some felt why bother to model it... but to leave the explanation to "implication" seems to me a "fail" by NIST.

Oh, please please please show us the "math" behind ROOSD.

 

[Myriad]

A few points... I don't really care about the history of the collapse discussion... who said what when...

Okay. Maybe I can believe that, let's see if it holds true for a few paragraphs.

9/11 was a conspiracy because it involved multiple parties... 4 planes etc.

So? Has that fact caused confusion, do you think, about what phrases like "9/11 conspiracy theories" mean?

Since many people (most?) were in "disbelief" that a seemingly very well built and strong structure could collapse so rapidly NIST was given the task to explain it... and stand as the "official explanation"

That is not a remotely accurate description of NIST's mandate or purpose for NCSTAR. NIST is not a public relations firm, it's not PBS or the Discovery Channel.

The Bazant papers appear to not be related to the real world event so they hardly "qualify" as demystifying the collapse to the public even if they show that there was a theoretical possibility.

The Bazant papers were not written for "the public."

Many organizations (including the aforementioned PBS and other cable TV channels) frequently take on the task of demystifying technical matters to the public. The problem with "demystifying" is that it pretty much by definition, it requires choosing easier-to-understand explanations over more-accurate ones. Special Relativity and quantum mechanics have been around for over a century, but every magazine article, book, and video documentary "demystifying" these subjects for the public have been filled with simplifications and inaccuracies. It's inherent in the goal.

It appears to me that NIST missed the explanation of the progressive collapse... might have (likely missed the mechanisms of initiation) and implying a "global collapse" which occurred is hardly an explanation.

It might appear that way to you but it is not the case.

I've used the analogy before, of a technical report explaining why a dam broke. If such a report omits an explanation of why, once the dam broke, the water spilled out of it and rushed down the valley and washed away objects in its path, would you say the report "missed" that?

And then, if someone came along and wrote an essay explaining that water is liquid and dense, and hence gravity caused it to flow down the valley and its momentum caused it to exert differential pressures on objects in its path, would you hail that as filling in some crucial gap in the original report?

The irony of this multi year discussion... appears to be that the explanation was right there in the vids and still images and it seems that until work similar to Tom's was done which appears to be a fairly rigorous analysis... the discussions seemed to miss a clear concise explanation. Why would NIST "imply" something that they could have described and SHOULD have described (wasn't that their mandate?).

You started out saying you don't care about who said what when, but here you are making claims about who said what when. It appears that what you don't care about is other people's understandings of who said what when. Sorry, the claim you started out with isn't holding up.

My sense is that we see a battle of egos here... And it looks rather childish.

Silly ad hom. "It's so childish when other people challenge my claims. It's only not childish when I challenge their claims."

Perhaps the "math" behind ROOSD is trivial and so some felt why bother to model it... but to leave the explanation to "implication" seems to me a "fail" by NIST. I will never understand why all these "professionals" failed to come up with ROOSD by any name or acronym in the year following the collapse. And with the core surviving the floor collapse all discussions about core capacity seem to completely miss what happened.

You have elected to put the word professionals in scare-quotes. Are you suggesting that the NIST authors were not actually professionals or not acting in professional standards? If so, please specify which authors of NCSTAR were not professionals or which professional standards that were violated and how.

Failing to include an explanation, in a report for other professionals, of something that by your own admission in the next paragraph is completely obvious even to many non-professionals, does not qualify as such a lapse. Please indicate something that was.

The collapse was not about 2 blocks... and was not about column crushing. This is a obvious as the nose on your face.

I suppose it is probably embarrassing that the "experts" missed "the obvious" and fragile egos seem to now get in the way.

You have used the scare-quotes again, on the word experts. How amusing.

But the experts did not miss the obvious. That you dismiss the evidence of that as ego-related, or uninteresting to you personally, doesn't make it go away.

Personally I find all attempts to produce scale models silly. Any engineer should know that the floors will fail when their load exceeds their capacity all settled knowledge in load tables engineers use all the time... and that is how the progressive run away collapse occurred.

Many scale models were so poorly designed (usually with a complete disregard for the effects of scale, which is rather important in scale modeling) that they were indeed quite silly.

If you really want to see a silly model, though, take a look at the other model that ended up being discussed in my "proposed model" thread: Heiwa's "funny m" model. In that model, all forces on the floors (which are invulnerable) are automatically transferred to the columns, and only the columns (modeled as springs) can break. With no scale of mass or size at all. And yet, I showed analytically that even that unrealistically modeled structure would undergo progressive collapse, given the few parameters Heiwa did specify. (In response, he changed those parameters to indicate that the "columns" would have to be compressed by 10% of their original height before they'd break; a model of a rubber building.) Now that was funny, and silly, but I did my best to explain why, in the hopes that someone would benefit.

Heiwa and numerous others were not capable of understanding that floors would fail when their load capacity was exceeded, or that such failure would lead to progressive collapse. As much as you might wish to revise history to the contrary, that's representative of the segment of the "public" that was offering truther arguments in this forum at that time.

 

[Newtons Bit]

Just in case no one else says it, I'm really glad you're posting here, Myriad. I always enjoy your posts.

 

[LSSBB]

For reference:

Thanks, however I already have those papers.

As mentioned earlier, were I to sum up this forum in one word, I would choose the word 'smear'

That's an interesting way to frame it. Why not 'validation', or 'verification'?

I could also sum up the purpose of this forum in a single sentence. It is to downplay or ignore all contradiction to a particular world view expressed among regular posters here.


Anyone who challenges or identifies contradictions within this world view is 'smeared'.

Is that really true, or are they seeking validation for your ideas, and you have just not met the challenge? How is your 'interpretation' any more correct than mine?

Consider the comments linked below on BV, BL, and BLGB by each listed person:

Newtons Bit
R Mackey
Dave Rogers and Myriad


David Benson, co-author of BLGB


Do they accurately portray statements within these papers and comments by David Benson or are we witnessing the dynamics of historic revisionism in action within this thread?

Are the comments intelligent and insightful or are they simply a type of 'meme' processing and propagation, an establishment and repetition of a common 'meme' through multiple parties?

Those are 4 instances selected by you. How are they indicative of the 'forum'? Is your sample size adequate to draw your conclusion? Are you prepared to include yourself in an Attribute Agreement Analysis with other forum members and casual readers to see if your interpretation is in line with others, using a large enough sample size of posts.

Out of curiosity,why do you evade questions regarding comparison of purposes? Is it to merely bog down the rhetoric and stave off an inevitable conclusion? How long can we continue this merry-go-round?

 

[beachnut]

...
Perhaps the "math" behind ROOSD is trivial and so some felt why bother to model it... ...

Make the day, show the math.

"I am not satisfied with the explanation given. The explanation raises more questions than it answers."

What were the more questions? Do you have a list? And did ROOSD solve those questions?

 

[tsig]

A few points... I don't really care about the history of the collapse discussion... who said what when...

9/11 was a conspiracy because it involved multiple parties... 4 planes etc.

Since many people (most?) were in "disbelief" that a seemingly very well built and strong structure could collapse so rapidly NIST was given the task to explain it... and stand as the "official explanation"

The Bazant papers appear to not be related to the real world event so they hardly "qualify" as demystifying the collapse to the public even if they show that there was a theoretical possibility.

It appears to me that NIST missed the explanation of the progressive collapse... might have (likely missed the mechanisms of initiation) and implying a "global collapse" which occurred is hardly an explanation.

The irony of this multi year discussion... appears to be that the explanation was right there in the vids and still images and it seems that until work similar to Tom's was done which appears to be a fairly rigorous analysis... the discussions seemed to miss a clear concise explanation. Why would NIST "imply" something that they could have described and SHOULD have described (wasn't that their mandate?).

My sense is that we see a battle of egos here... And it looks rather childish. Perhaps the "math" behind ROOSD is trivial and so some felt why bother to model it... but to leave the explanation to "implication" seems to me a "fail" by NIST. I will never understand why all these "professionals" failed to come up with ROOSD by any name or acronym in the year following the collapse. And with the core surviving the floor collapse all discussions about core capacity seem to completely miss what happened.

The collapse was not about 2 blocks... and was not about column crushing. This is a obvious as the nose on your face.

I suppose it is probably embarrassing that the "experts" missed "the obvious" and fragile egos seem to now get in the way.

Personally I find all attempts to produce scale models silly. Any engineer should know that the floors will fail when their load exceeds their capacity all settled knowledge in load tables engineers use all the time... and that is how the progressive run away collapse occurred.

Yet here you are in full armor, lance firmly placed under the arm, riding to the windmills.

 

[waypastvne]

It appears to me that NIST missed the explanation of the progressive collapse...

NIST describes what happens after collapse initiation in this paper, Sept 2007

However, over 90% of floor truss connections at or below the impact floors of both buildings were either bent downward or completely sheared from the exterior wall suggesting progressive overloading of the floors below the impact zone following collapse initiation of the towers.

http://www.aws.org/wj/supplement/wj0907-263.pdf

 

[tsig]

I am no expert and don't make such a claim. I have no idea what Bazant et al papers were "trying to do"... My recollection is that they were cited as explaining that the towers could collapse in the "early years" of the discussion.

Thought experiment:

Let's toss out the Bazant el al papers... pretend they didn't exist... So... what was the plausible explanations to how these massive structures collapsed in those "early years"?
PBS's pancakes? I realize that the pancake is used as a term of art... because it's virtually impossible to an entire floor plate to drop like a record on a record changer (do you remember them?) So pancake is poor choice of words... but PBS seems to show them as entire slabs dropping... (kinda stupid of them no?) What was dropping was MASS of broken floor slabs and contents... this destroyed the floor below and so on... no PANCAKES.

I don't recall... and I was not active in the discussions back then... any decent explanation for what we saw... And I don't care what Bazant et al were trying to do... their papers were cited many times back then...

No?

They were hit by large planes full of fuel, the fires started by the fuel weakened the remaining columns till the columns buckled leading to complete collapse.

 

[jaydeehess]

NIST describes what happens after collapse initiation in this paper, Sept 2007

Quote:
However, over 90% of floor truss connections at or below the impact floors of both buildings were either bent downward or completely sheared from the exterior wall suggesting progressive overloading of the floors below the impact zone following collapse initiation of the towers.

http://www.aws.org/wj/supplement/wj0907-263.pdf

I think NIST understates this in using "suggesting".

Bent downward means that they were moved in a downward direction while the columns they connected to were stationary. That goes beyond 'suggesting' that these truss connections failed before the columns did, at the very least.

What would be the utility of then running calculations on each floor collapse? how could one simplify that situation enough so that a supercomputer could even do that for 90 floors?

 

[jaydeehess]

I think he's truly interested in taking nuance denial to the highest level possible.

by gum you may have nailed it.

 

[Newtons Bit]

The is so little truth in the above sentence, I don't know where to start. Where do you get these ideas? Who are these "most" people that were in "disbelief" with what they all saw live on television?

He's confusing "surprise" with "disbelief". The average person doesn't understand how buildings behave, nor do they understand why the fail and what happens afterwards. The average person does, however, watch a lot of Hollywood action movies where buildings sustain incredibly damage, but don't fall. Or when they do fall, they topple sidewalls.

Most people saw the manner in which the towers collapsed and were surprised. However most of these people aren't so arrogant that they believe that their close working knowledge of Hollywood special effects makes them experts on how buildings should collapse when hit by planes. Instead, these people altered their understanding of building behavior.

Truthers, on the other hand, couldn't alter their understand of building behavior. Instead, they're trying to alter reality. Hence the confusion between "disbelief" and "surprise".

(This, I think you know. JSanderO probably didn't)

 

[jaydeehess]

When WTC2 came down as I watched on TV, the word that came out of my mouth was"No!".
It was shock, surprise and denial, certainly not a reasoned technical expression of doubt.

 

[rwguinn]

When WTC2 came down as I watched on TV, the word that came out of my mouth was"No!".
It was shock, surprise and denial, certainly not a reasoned technical expression of doubt.

2 words frome and my colleagues, separated by a comma. First word was "Oh"...

 

[DGM]

This is an interest set of questions.... Presumably all these papers and theories were meant to make the collapse understandable the the public. And NIST was the official "speaker" for the explanation.

Why would you think this? If memory serves, "truthers" actually are the ones that started arguing this as fact. I think it falls into the same group as there actually being an "official story" on this.

Come on boys... swallow your pride... you will not die... it is not poison. Give credit where credit is due. It hardly matters who saw described it first... or what the acronym is... right?

Right back at you. Are you ready to accept the fact these papers were not intended for the general public? Do you really think any of these are worded in a way the average Joe/Jane would understand?

The PBS special was "close enough" for the average public (and that in no way is an insult).

The vast majority of this argument is of no interest to anyone, pros and laymen alike.

 

[ozeco41]

For reference:

Thanks for the references Major_Tom. I already have copies of the papers and have read all of them. More importantly IMO I comprehended them all. And it was some years ago hence my reluctance to claim from memory - I have re-read the BV paper and BV is not a limit case NOR validly applicable to the real event. You are right. But don't lose sight of the fact that your opponents are agreeing with you on a lot of things.

So rather than both sides persisting in the snide personal commentary - whether true, partially true or outright false. Let's focus on the technical issues and issues of technical reasoning. Your opponents are agreeing with you on a lot - I suspect much of it without realising it. Sure there is a hell of a lot of constructive missing the point going on and "they" are variously wrong on some details. Why not "sort the wheat from the chaff"?

Here I'll try a couple of clear cut cases:

Yes,¹ as mentioned before, Bazant' papers are limiting cases² and the OOS model attempts to more exactly model behavior³. Don't you see that incompatibility?⁴ If not, please explicitly state how they may be directly compared.⁵ Better yet, explain why the comparison matters.⁶

According to your statement they cannot. They can both be simultaneously true.⁷
You see no contradiction between Bazant statements in BV, BL, and BLGB and the OOS model.⁸

(Code: Green - he is agreeing with you; Orange Talking at cross purposes OR missing the point you are making; Red - he is (IMHO) technically wrong.)

1 He agrees with you that he can "....see incompatibility issues between BV, BL, and BLGB and the OOS model." You are half way there - he differs on the basis of the incompatibility.
2 The Bazant papers other than B&Z are not "limiting case" papers as has been explained and proved ad nauseam. (Proof outlined in my previous post - more details on request.) That misunderstanding is one of the big problems underpinning these recent discussions. B&Z was a limit case for valid reasons. Later Bazant papers run off the rails when in BV and later they try to apply the 1D B&Z concepts to the strictly 3D event of the real collapse. I'll describe that as "technical conflation" and will explain later if there is any interest - IMO a lot of people are still confused.
3 He agrees with you again. So two big points of agreement on one of the two issues under contention. Why ignore the start of agreement and post more aggression???

4 He is agreeing with you - you are the one alleging "incompatibility" - but he is clearly seeing you coming from the opposite direction. No point arguing the issue - the problem is that he doesn't see where you are coming from. Has you arse about.
5 He is agreeing with you - you are the one alleging they CANNOT be "directly compared" - but he is clearly seeing you coming from the opposite direction. No point arguing the issue - the problem is that he doesn't see where you are coming from. Again he has you arse about.
6 Same as above except his challenge "...explain why the comparison matters" should be "..explain why the difference matters" because your opponents are effectively arguing either that there is no difference OR that the difference does not matter.

7 You misread him - misread that he was misunderstanding your position....need I say more? Talk about feedback loops of misunderstanding.
8 Again you miss the point. He has already agreed that (or most of it) - take the discussion forward not back into conflict after he has gone a long way agreeing. Or, being pedantic, actually agrees with you but doesn't know he is agreeing. Because he perceives you coming from the opposite direction on some of your key points. Ball in your court - be clearer.

And this second one:

According to your statement they cannot. They can both be simultaneously true...

And that is why you fail. Bazant's papers aren't models of what actually happened.¹ This has been explained to you over and over and over and over and over and over and over again.² It's like you don't want to understand that Bazant set out to model something other than what actually happened.³

1 Which is one of the two main points which Major_Tom keeps asserting. M_T he is agreeing with you on that point.
2 Which is one of the big problems here - both sides" not comprehending what the others are saying. M_T is well aware that the Bazant papers do not model reality. He is also aware that the later Bazant papers - after B&Z - are NOT "limit cases" as applied to the WTC Twins. (I think I'm the only one who has said that explicitly in these recent discussions)
3 Missing the point he is trying to make. Several inaccurate slants including:
(a) Bazant in the later papers (BV for certain) did set out to develop - as per BV - a "...simplified one-dimensional analytical solution of the collapse front propagation". NOTE "simplified" and "one-dimensional".
(b) Major_Tom could not be more explicit - nor could I - that Bazant did not model "what actually happened".

So: The contentions still being discussed include:

(1) People still being confused about the limits of applicability - to the real events - of Bazant's later - non-limit case - papers;
(2) Denials that there has been confusion over "limits of applicability of Bazant" despite the very same confusions being replicated here in this thread over recent days;
(3) Resurrection of the false interpretation of BV as being a limit case" - it isn't - and I'm confident that the others are not limit case either - but I still need to check; AND
(4) Failure to recognise that all the later Bazant papers which purport to apply energy based analysis to WTC real event collapses - are probably wrong. (Same disclaimer - I will re-read the papers - then probably remove the "probably" ). BV is wrong as applied to WTC real event. It is a one-dimensional approximation of a three-dimensional event where the assumptions involved in simplifying to 1D are not valid as support for real event maths.

The only "new" claim I have made relates to BV - and probably the other papers - not being valid limiting cases. If everyone could read BV it would save me having to explain again why that is so. In fact how about some other members re-reading the other papers and telling us if they are "limit case or not".

And there are a lot of "interesting" side tracks being raised....as usual.

I've tried to keep this post tightly focused on the what IMO are a couple of the key issues.

 

[Newtons Bit]

Several inaccurate slants including:
(a) Bazant in the later papers (BV for certain) did set out to develop - as per BV - a "...simplified one-dimensional analytical solution of the collapse front propagation". NOTE "simplified" and "one-dimensional".
(b) Major_Tom could not be more explicit - nor could I - that Bazant did not model "what actually happened".

So: The contentions still being discussed include:

(1) People still being confused about the limits of applicability - to the real events - of Bazant's later - non-limit case - papers;
(2) Denials that there has been confusion over "limits of applicability of Bazant" despite the very same confusions being replicated here in this thread over recent days;
(3) Resurrection of the false interpretation of BV as being a limit case" - it isn't - and I'm confident that the others are not limit case either - but I still need to check; AND
(4) Failure to recognise that all the later Bazant papers which purport to apply energy based analysis to WTC real event collapses - are probably wrong. (Same disclaimer - I will re-read the papers - then probably remove the "probably" ). BV is wrong as applied to WTC real event. It is a one-dimensional approximation of a three-dimensional event where the assumptions involved in simplifying to 1D are not valid as support for real event maths.

Post #3 from this thread:

Bazant and Verdue states that, "The kinetic energy of the top part of the tower impacting the floor below was found to be about 8.4 larger than the elastic energy absorption capability of the underlying story," and the the purpose of the Bazant and Verdue paper is not to describe the WTC collapse, but rather to create "a theory describing the progressive collapse dynamics" as this would be "very useful for other purposes, especially for learning from demolitions".

Most of us here are aware of the differences between BV and BZ. However if you'd care to look at Major_Tom's responses to the above quote from 2010, he disagrees. I presume he still disagrees. But I can't follow what argument he thinks he's trying to make anymore as he won't explain anything.

This is why I keep getting annoyed at his comments of "they can both be true" or "there is an incompatibility". His ideas and Bazant's ideas aren't addressing the same things. And we've explained that to him. But he keeps saying his silly slogans again an again and won't elaborate on why he thinks we're wrong.

 

[ozeco41]

Post #3 from this thread:

Yes -- I've read the early posts sequence several times in recent days.

The two main issues I have then and now are:
1) Major_Tom is IMO his own worst advocate because:
(a) His style of personal snide comments wins no friends. His opponents just as bad or worse but I don't give a damn who started it - personal commentary and insults add nothing to debate of legitimate technical issues;
(b) He refuses to make his own claims - instead he plays irritating "JAQing" - rather than state simply and explicitly that the various Bazant papers except B&Z are in conflict with the real event he asks other members for their view. Irritating to say the least.

2) I agree fully with where he is coming from on the two issues which I believe are central to the discussion BUT I do not want to make M_T's arguments for him when he is reluctant to do so himself. And my agreement goes only to those central technical issues. I detest the pseudo-psychology, the self aggrandisement and the atrocious logic of his interpersonal comments which is riddled with false generalising.

HOWEVER overall I think the problem is that both sides of the current "conflict" in this thread are making far too many broad generalised statements or diversionary side tracks which are prolonging the angst.

HENCE my previous post where I tried (yet again) to focus some specifics where there is in fact agreement OR talking at cross purposes. Accepting the first and resolving the second of those aspects should help us move discussion forward. BUT the focus remains on finding nits to pick IMO rather than building on agreed points.

Sure I'm an experienced conciliator in both industrial and contractual dispute situations. So I'm probably "odd man out" wanting to build on and move forward from agreement rather than forever keep finding fault.

[/end personal frustration rant. ]

So let me address your comments from my own perspective:

Most of us here are aware of the differences between BV and BZ. However if you'd care to look at Major_Tom's responses to the above quote from 2010, he disagrees. I presume he still disagrees. But I can't follow what argument he thinks he's trying to make anymore as he won't explain anything....

OK - so I tracked the posts following yours until you made this statement:

Bazant and Verdue sets out to model and understand progressive collapse¹. Not prove how the WTC collapsed². It uses the WTC only as a paradigm³. I.e. an example, a model, a pattern, etc etc⁴. It then applies the conclusions of this model to other buildings, as that is the stated purpose of this model⁵.

1 I understand and agree that was their stated intent.
2 Same comment - that was their stated intent.
3 Again their intent. I think it was a lousy paradigm to attempt to use.
4 I understand the meaning of the word. The problem I see is that using a "columns in line model" WHILST proclaiming that it uses the WTC collapses as a "paradigm" is false. In fact at the level of academia that these folks occupy it is borderline professionally dishonest. The real WTC collapse was a totally different model to what they use as a "paradigm" WHILST claiming it uses the WTC as that paradigm. Tut Tut.
5 I have no problem whatsoever with applying the one-dimensional approximation to a "normal" building with a grid of columns where the collapse behaviour is reasonably approximated by the 1D model.

And that is the central issue where members opposing Major_Tom are conflating the issues - not differentiating when conflation is wrong and differentiation is essential. The progression collapse of the WTC Twins was different. It was not the same as would occur with a more conventional building. The Bazant claim that a 1D model is a suitable paradigm of the WTC collapse is simply false. Bazant acknowledges that is is "simplified" - is is actually "oversimplified".

And bigger problem here is that people are not even recognising the issue I have once more identified. Whether they agree or not. Recognise what I am saying clearly. Then either agree with me or show me where I am wrong. Recognise that is is part of what M_T is implying or saying - possibly not so clearly. Then challenge me or M_T and seriously discuss the technical issues rather than play tit for tat with snide personal comments or partial truths or simply missing the points being made or...(all the other evasive nonsense)

And maybe members would get more mileage out of challenging me on the same issues as M_T is raising. I would tightly focus the specific issues and not be fooled by ambiguous foggy generalising. They would find it hard to dismiss me as a truther or shake me off with irrelevant personal comments.

This is why I keep getting annoyed at his comments of "they can both be true" or "there is an incompatibility". His ideas and Bazant's ideas aren't addressing the same things. And we've explained that to him. But he keeps saying his silly slogans again an again and won't elaborate on why he thinks we're wrong.

One side or the other has to break out of that circling game. History says that "we" will not get Tom to stop playing his JAQing innuendo personal comments style. So ball in our court. I've tried nibbling at the central issues several times. No response. Seems it's easier to simply dismiss him as a truther - avoiding the fact that he is right on those two central issues. Viz (A) Bazant post B&Z does not apply to WTC real collapse events and (B) there has been, still is, a lot of confusion as to the limits of Bazant.

IMO All the rest of the mini-arguments could, should and possible would fall into place if we resolved those two. But maybe baiting the "truther" is more fun.

 

[Major_Tom]

Most of us here are aware of the differences between BV and BZ.

The comments linked:

Newtons Bit
R Mackey
Dave Rogers and Myriad


FIrst, this is no random list of average JREF posters.

R Mackey is an engineer working for NASA, I believe.
Doesn't Dave Rogers have a Ph.D. in physics?
Newtons Bit, you are a structural engineer with a masters degree, is that true?
I am not sure about Myriad, but I respect the desire for privacy.

TFK is a mechanical engineer and his comments are available for anyone to see.


Lastly, David Benson has a Ph.D. in mathematics and Bazant has a Ph.D in structural engineering(?).






Let us start with the case of R Mackey. He starts out by confusing BZ with BL for the first few pages of this thread and he states in his second to last quoted post, months later:

Bazant and Zhou's "crush down / crush up" model is a model. It represents the best case from the standpoint of structural survival. It is not an accurate representation of the precise blow-by-blow collapse, nor could it be. It was written on September 13, 2001!

Crush down / crush up is first introduced by Bazant in 2007 in BV.




If anyone wishes to defend this bumbling set of posts by R Mackey, please do so now.


Next, we can check out by Myriad.

 

[MileHighMadness]

Yes...the Major_Tom do loop...around in circles we go.

 

[Reactor drone]

Let us start with the case of R Mackey. He starts out by confusing BZ with BL for the first few pages of this thread and he states in his second to last quoted post, months later:

Bazant and Zhou's "crush down / crush up" model is a model. It represents the best case from the standpoint of structural survival. It is not an accurate representation of the precise blow-by-blow collapse, nor could it be. It was written on September 13, 2001!

Crush down / crush up is first introduced by Bazant in 2007 in BV.




If anyone wishes to defend this bumbling set of posts by R Mackey, please do so now.

I'm not finding this case particularly compelling. Neither paper purports to model the specifics of the WTC collapses so what difference does it make if someone mixed them up 4 years ago?

What bearing does discussing simplified models of collapse progression have on your collection of observations? Wouldn't your collection of observations be better compared to another collection of observations, such as the one in the NIST reports?