Debunked: 9/11 truth experts are knowledgeable professionals and their judgments are to be trusted

[Jeffrey Orling]

Some good points Jeffrey. These three the most important in my opinion:

<< My personal special focus as you know. BUT it only works if the "layman" is interested in learning and is prepared to read, follow and discuss the steps of explanation. Very few are. (Do you remember "Jango"?)

<< Which poses a special challenge for many engineering or applied physics specialists. It makes argument in generic qualified (descriptive) form the necessary method. And most engineers are left brain details focused. They are not comfortable arguing without precise numbers and specific structural details.

<< To adequately explain Twin Towers collapses needs understanding of four distinct stages - each with a different mechanism. Very few persons attempting to provide explanations even recognise the two main stages of "initiation" and "progression". And, consequently, they get confused when they conflate different stages.

The truther experts appear to disregard the details/mechanism which enables heat to cause a steel frame to fail.... which of course would only initiate a (runaway) progression of non heat related failures. So truthers will claim there was in adequate heat to destroy the frame in part and make the false claim there was melted steel indicating the heat destruction was not from jet fuel or office fires.

My sense is not enough attention was given to the importance of the"progression" of failures and how these escalated, spread through the structure and were "unstoppable" and led to total collapse. So yeah... it would be a educated guess at best at how loads were redistributed to other columns beams and so on which exceeded their capacity. Load "redistribution" for sure is not an intuitive concept. How does that work? Without this there would have been no collapse. Has any expert drilled down into this? We know NIST punted and said.... an "global collapse ensued" or words to that effect. Oh goodie... I get it NIST!

Load distribution... or the "frame managing the loads is also key and mysterious. There was obviously no new loads and the structures were not operating at the limit of their load bearing capacity... But somehow... the loads which didn't grow in size were able to wreck the frame and cause the collapse. Just how does that happen? And how does "residual capacity" come in to play.... was there enough? (obviously not)....how is it determined and what where should that residual capacity applied?

How would a local failure be "arrested" and confined and not "domino" to other regions of the structure. Was this "anti domino" something engineers consider? If so what were they in these structures? What are other anti domino strategies used in other high rise designs....

Engineers... speak out!

YES there were stages with different mechanisms dominating or defining them... YES there were periods of transitions from one stage to another. It seems "obvious" but also not explained at all in my opinion. The "explosion" notion is easy to grasp even when not detailed... everyone knows explosions destroy things.

 

[Thomas B]

The trust the expert "problem" with respect to the WTC may be due to several things...

Are any of the things you mention unique to the WTC collapse, i.e., not present in some equivalent way the Paris Concorde crash? There, the experts were able to determine that the accident was caused by a small piece of titanium that had fallen off another plane.

1. Explaining the engineering and the physics requires technical expertise and making the arguments such that laymen can understand.

BUT it only works if the "layman" is interested in learning and is prepared to read, follow and discuss the steps of explanation.

The problem that we're discussing here is not whether the layman can understand the expert's explanation but whether there is a coherent body of expert opinion to understand at all. In the case of the Paris crash, investigators and pilots understand what happened, and some of them have the rhetorical skills to communicate this to the public.

Mentour Pilot doesn't make any demands on the viewer to be "interested in learning and prepared to read, follow and discuss..." He just goes ahead and explains everything in a clear and detailed manner. But the crash investigators didn't go about their work with the layman in mind, trying to find an explanation the layman could understand. They were just trying to find out what happened.

We seem to be reaching the conclusion that engineers (FEMA/NIST/Bazant) never really answered the question of how the WTC collapsed, never got the "real story", as in the case of the Paris crash. The WTC investigators never found the equivalent of the titanium strip and the ruptured fuel tank, because, as Jeffrey puts it,

4. There is no precise data about the fires and heat, duration and location.

(among other difficulties)

It's as if the investigation in Paris had determined only that two engines failed, leading to a stall, after which a crash was inevitable. If this is the state of the science on the WTC, I don't think it's any wonder that some laypeople don't find the debunking we do compelling, and give the truthers and their "experts" their attention a little longer than they deserve.

 

[Jeffrey Orling]

Are any of the things you mention unique to the WTC collapse, i.e., not present in some equivalent way the Paris Concorde crash? There, the experts were able to determine that the accident was caused by a small piece of titanium that had fallen off another plane.


The problem that we're discussing here is not whether the layman can understand the expert's explanation but whether there is a coherent body of expert opinion to understand at all. In the case of the Paris crash, investigators and pilots understand what happened, and some of them have the rhetorical skills to communicate this to the public.

Mentour Pilot doesn't make any demands on the viewer to be "interested in learning and prepared to read, follow and discuss..." He just goes ahead and explains everything in a clear and detailed manner. But the crash investigators didn't go about their work with the layman in mind, trying to find an explanation the layman could understand. They were just trying to find out what happened.

We seem to be reaching the conclusion that engineers (FEMA/NIST/Bazant) never really answered the question of how the WTC collapsed, never got the "real story", as in the case of the Paris crash. The WTC investigators never found the equivalent of the titanium strip and the ruptured fuel tank, because, as Jeffrey puts it,

(among other difficulties)

It's as if the investigation in Paris had determined only that two engines failed, leading to a stall, after which a crash was inevitable. If this is the state of the science on the WTC, I don't think it's any wonder that some laypeople don't find the debunking we do compelling, and give the truthers and their "experts" their attention a little longer than they deserve.

Thomas.... This discussion may be identifying some glaring problems in the 911 collapse discussions.
Unlike a single piece of metal... or out of spec temp for an o-ring to seal properly... the WTC had multiple causal mechanisms factors for the collapse.
I have "argued" for years that they actual designs contained the "genes" for the form of their collapse. Not all high rise buildings have the same structural attributes. I think some "traditional" designs might have not gone to total collapse. Just a guess.

In complex systems failures.... it is almost always a chain of events.... one thing leads to another or two and so on... failures escalate and go "domino" as I called it. Some times the path of the dominoes is obvious... other times it's not very clear.

The shuttle exploded because the O ring didn't seal... let fire "escape" and ignited a nearby fuel tank. Not many dominoes... the WTC collapse were much more complex. Different dominoes and of different sizes. Heat was very important in the "initiation" stage... even before any "movement" was observed from the outside. Heat play no role once "observable" movement had begun... then it became all mechanical failures.

There are coherent explanations out there. There is not a coherent body of them nor has any expert comprehensively "detailed" how the collapses evolved a static structure to a pile of rubble.

Scientists can explain how a heated WF beam would perform under estimated temps at the WTC. But no one can tell which beam did what and when it did it.

So NO there was no "straw" that broke the camel's back.

Now in 7wtc we were led to believe that a single 2 story tall column.... 79 could have a problem/failure at one low level and the entire building would collapse. The explanation goes something like this:
Heat caused beams to push on a main girder framed into col 79. That girder was pushed off the "beam seat" at the column and fell. When it fell it took with it the floor slabs and contents on them with it. The beams/girder not only supported the floors, but provided crucial bracing to the column. Without the bracing... the load bearing of the column is reduced as well. We are told that the column then buckled and all the columns above this level dropped down, took the floors attached to them down as well, But damage was not localized to the area around col 79 ground to roof. That collapse caused adjacent columns and floors to also collapse. And rather quickly the building was "hollowed out" from floors collapsing. It's likely that a few things resulted. The transfer structures at floors 5-7 collapsed from the impacts of the falling 40 stories of mass on them... and the moment frame was the exterior "tube"had its support undermined when all the floor materials piled up at the base and "pushed" the columns supporting the moment frame "over". Moment frame/tube came down like a hollow container with nothing bracing it on the inside.
So perhaps the straw for 7WTC was the fires on the floor where the girder was pushed off its seat.
And then there are those who claim the fires were no hot enough to do that.

 

[Thomas B]

There are coherent explanations out there. There is not a coherent body of them nor has any expert comprehensively "detailed" how the collapses evolved a static structure to a pile of rubble.

This also suggests that even a very good engineering student at university cannot learn "how the WTC collapsed" from reading the literature on the subject. They must engage in same conjecturing and "reasoning from first principles" that you and @econ41 model for us here.

I think that's simply appalling! Shame on the engineering community for leaving us in this mess! It seems that the "experts" that really need their knowledge and trustworthiness "debunked" are the mainstream ones -- Bazant et al.

 

[Jeffrey Orling]

This also suggests that even a very good engineering student at university cannot learn "how the WTC collapsed" from reading the literature on the subject. They must engage in same conjecturing and "reasoning from first principles" that you and @econ41 model for us here.

I think that's simply appalling! Shame on the engineering community for leaving us in this mess! It seems that the "experts" that really need their knowledge and trustworthiness "debunked" are the mainstream ones -- Bazant et al.

Let me take a leap to a place no one seems to want go there.
My "journey" to understand got me to examine the structures and their rather unique design features. I am an architect but do not work on high rises and so use only basic structural principles I learned ages ago in college. That was more than adequate.

The most obvious thing about the WTC is that is was not a collection of "garden variety" high rise structures.

The twin towers employed perhaps for the first time or certainly were early examples of Tube designs... with column free floors. The column free floors were presumably a marketing feature giving no restraints to the interior design or "partitions and office spaces". 7WTC designed much later used the same open office column free concept.

The column free floor designs were intended to not only be more flexible for the interiors but offered construction savings and reduced erection time. WTC had many factory built components hoisted into place and bolted together. It also used very very light weight concrete for the floors and lobbied for and got the code requirement lowered for design loading. This reduced weight and strength and cost. The lightweight steel bar trusses allowed for mechanicals to be run easily and no pencil rods were needed for the ceilings which could be attached to the tracks screwed to the lower flange of the bar trusses.

The old style grid frames with small "bays" were actually somewhat structurally independent. A failure would be isolated within a single and not involve a very area. So in a sense these floors were kinda like pancakes .... square donut shapes suspended along their edges.
The inside of the square donut was not connected "directly" to the perimeter columns of the core. they were 24 and very stout. But 24 points was too few to support a large light weight floor. So the perimeter columns had large "belt girders" bolted on short beam stub cantilevers.

Because of the manufacturing or the floors being all the same spec... the belt girders attachments... the beam stub cantilevers were of different lengths... because the columns they attached to shrunk in plan dimension as you go from bottom to top.

The beam connections of the floor to the columns were to the webs and flanges. Beams did not rest ON columns but were bolted or welded to the sides of them and to facilitate construction short beam stubs were employed with plates spliced/bolted to make the connections. The failed girder at 7WTC rest on a beam seat which in turn was welded to the column... again to facilitate erection. But this also meant that the girder could move laterally at the column... and apparently move it did... pushed by expanded heated beams.

None of the column ends at the WTC were restrained laterally by more than relatively thin steel plates used to facilitate erection. In the 3 story high twin column... floors were attached at about 8', 20' and 32' feet from the bottom... again this was done to facilitate erection.

My "assertion" is that the very clever erection and design elements played a significant role in how they collapsed.. and how the frame performed on the stress of fire (expanding beams). Unrestrained column ends means that the upper and lower columns are more "prone" to laterally translate independently as erection splices are not robust enough to resist the magnitude of lateral forces that presented.

I am not going to go on about these details. But the take away.... is that the unique elements of those structural designs was barely noted and never identified as playing any role in the collapses.

The collapse were more complex than the shuttle disaster or maybe the paris jet... both of which had an identifiable straw to break the camel's back

 

[JMartJr]

It is unsatisfying to the layman to see that the experts can't seem to agree on exactly what was happening to cause the building collapse with specificity.

I get what you are saying, but maybe this can be an opportunity for the "laymen" to get a better understanding of how complex, unusual and catastrophic events sometimes, in the real world, are going to leave us unable to ever be sure of exactly what happened, second by second. In such situations the truth, or at least our knowledge of it, may always contain some areas of ambiguity, and the public's learning to be skeptical of the artificially simple answer might be a Good Thing.

 

[Jeffrey Orling]

"Indeterminate system

In mathematics, particularly in algebra, an indeterminate system is a system of simultaneous equations (e.g., linear equations) which has more than one solution (sometimes infinitely many solutions).[1][2] In the case of a linear system, the system may be said to be underspecified, in which case the presence of more than one solution would imply an infinite number of solutions (since the system would be describable in terms of at least one free variable[3]), but that property does not extend to nonlinear systems (e.g., the system with the equation {\displaystyle x^{2}=1}

)."

I think the complexity of the structural systems and the complexity of fire and absence or incompleteness of the data renders a "single" or linear solution almost impossible to identify. You can study an single tree in the forest... but this does not mean the other trees are experiencing the same "things"... But when you see a dying forest it may not be possible to know the cause of death of each tree as there could be many causes.

 

[Thomas B]

the unique elements of those structural designs was barely noted and never identified as playing any role in the collapses.

The collapse were more complex than the shuttle disaster

Or perhaps Shyam Sunder simply had no one to play Richard Feynman to his William Rogers?

 

[Mendel]

The weight of prevailing expert opinion including NIST relies on A is FALSE. (And that much is readily demonstrated to be factually correct.) However Professor Bazant has published - formally - peer reviewd - not challenged - an explanatory hypothesis that relies on A is TRUE. Both those opposing views are "in the wild" of the published world of professional expertise and the conflict not formally recognised. The Wikipedia article accepts Bazant's "A is TRUE" as fact.

The NIST report is citable, and its findings should be reflected in the Wikipedia article. Are they?

 

[Mendel]

The fact that this sort of public performance of knowledge and expertise doesn't exist for the WTC collapses yet (and remember that the Paris crash is just a little older than 9/11) is a serious embarrassment for us.

Accident investigations in passenger aviation used to shrouded in mystery and guesswork until Flight Data Recorders and Cockpit Voice Recorders were installed; the bright orange "black boxes" give investigators insight into the state of the aircraft leading up to the crash, and the state of the mind of the pilots.

The Challenger disaster had lots of telemetry as well, and cameras from every angle observing many aspects of the launch.

People who investigate a high-rise collapse have much less data to work with, which makes obtaining a detailed sequence of events much more difficult. (Compare with the investigation into the Kobe Bryant crash in January 2020 that involved crowdsourcing weather data and ADS-B data because the helicopter lacked flight data recorders.) You can't demand knowledge into existence if the data to base that knowledge on is not there.

 

[econ41]

Engineers... speak out!

I'm an engineer, with sufficient understanding of the topics I comment on. And as you are well aware I have "spoken out" many times across on-line Forums and FaceBook Groups. This is the only Forum were I have been explicitly told that I do not meet the criteria as an acceptable "expert" BECAUSE the preferred goal here is that the answers be in accepted forms of formally published literature and written by authors who have recognised standing in THAT domain.

YES there were stages with different mechanisms dominating or defining them... YES there were periods of transitions from one stage to another. It seems "obvious" but also not explained at all in my opinion.

Same situation. And you should be aware that I have many times clearly defined the stages and explained the mechanisms. With sufficient detail and rigour of argument needed for discussion in this form of debate and on this medium.

 

[econ41]

The NIST report is citable, and its findings should be reflected in the Wikipedia article. Are they?

Yes the NIST findings are reflected in most of the Wikipedia articles. As I said in response to Thomas B's original request..

The Wikipedia article is, in my opinion a good generalised overview. Accurate in most of what it says but does not delve deeply into some details.
But I identify two flaws that are relevant to our current discussion. I will explain the most blatant one which is in the section addressing Total progressive Collapse.

The "good generalised overview" reflects NIST. The one exception - the "[flaw that is] relevant to our current discussion" is where the paper calls up the Bazant & Verdure "Crush Down/Crush UP" hypothesis. THAT aspect is not in my opinion consistent with NIST. The central point I have offered to explain.

And be warned - BOTH the NIST and the Bazant explanations are "accepted wisdom" in the domain of formal published professional opinion. The inconsistency apparently not recognised. Which brings us back to the central point I have identified: "What do we do when the body of expert opinion is alleged to be wrong?"

 

[econ41]

I get what you are saying, but maybe this can be an opportunity for the "laymen" to get a better understanding of how complex, unusual and catastrophic events sometimes, in the real world, are going to leave us unable to ever be sure of exactly what happened, second by second. In such situations the truth, or at least our knowledge of it, may always contain some areas of ambiguity, and the public's learning to be skeptical of the artificially simple answer might be a Good Thing.

EXACTLY. There are probably two variable factors involved; First the level of sophistication needed by the audience. Second the level to whch ambiguity can be removed or resolved. For this specific example - the "Wikipedia Article" - I think the article is sufficiently accurate for most of the intended audience which I judge to be lay persons. The one issue I identify as problematic would almost certainly not be of concern to most of that lay person audience. BUT if a slightly more sophisticated person was attempting to build a more comprehensive understanding of the applied physics mechanisms THAT single issue could lead them astray.

 

[econ41]

The problem that we're discussing here is not whether the layman can understand the expert's explanation but whether there is a coherent body of expert opinion to understand at all.

That is what YOU want to discuss. We have already answered it in this and two preceding threads. There is no uniform, cohenrent, homogeneous and totally agreed, consistent "body of expert opinion".

 

[Jeffrey Orling]

Back to the thread topic.... can experts be trusted.

The default is to trust people with technical knowledge AND credentials.

BUT

Experts can be and often are wrong.
The "presentation" or analysis must be informed by data and correct information... observations are the best "data" to work with.
There are no high rise "black boxes"
I doubt their is a field of "high rise forensics"
The expertise required includes: physics, structural engineering, fire science engineering, video analysis, knowledge of the engineering details of the buildings

None experts with sufficient technical background, excellent observation skills, knowledge of the structures and fire science can produce "sound" explanations and analyses.

What is important is not the credential, but the quality and competence of the analysis.

Presentation skill can make the work available to their target "audience".

It appears to me that the "truther experts" target audience is the lay public not the engineering or science community

It appears to me that the "non truther experts" target audience is the engineering and science community and decidedly NOT the lay person. However NIST's work is "intellectually" accessible to non experts... ie lay persons.

Econ is a stellar example of a qualified engineer to has provided explanations of the collapses which lay persons can understand. His media is the internet and does not publish in engineering journals. He skillfully engages misinformed experts who make a presence on the www "forums".

Mick West has done very good experiments and demos about the physics of the collapses which are intellectually accessible to the lay person.

 

[econ41]

This also suggests that even a very good engineering student at university cannot learn "how the WTC collapsed" from reading the literature on the subject. They must engage in same conjecturing and "reasoning from first principles" that you and @econ41 model for us here.

That is exactly how the "very good engineering student" should be understanding the collapses. The "literature" is the secondary source which points the learning student or experienced newcomer to the topic in the right directions. The learning is complete when the person is able to fully reason through the problem.

You are looking for the literature to spoon feed a layperson. A legitimate goal. Not the only goal. The engineer who needs to analyse problems needs to be able to pursue reasoned understanding. There is a legitimate place for rote learning follow the book application to routine engineering problems. Forensic analysis of complex one-off events is not such a place.

 

[econ41]

Back to the thread topic.... can experts be trusted.

The default is to trust people with technical knowledge AND credentials.

BUT

Experts can be and often are wrong.
The "presentation" or analysis must be informed by data and correct information... observations are the best "data" to work with.
There are no high rise "black boxes"
I doubt their is a field of "high rise forensics"
The expertise required includes: physics, structural engineering, fire science engineering, video analysis, knowledge of the engineering details of the buildings

None experts with sufficient technical background, excellent observation skills, knowledge of the structures and fire science can produce "sound" explanations and analyses.

What is important is not the credential, but the quality and competence of the analysis.

Presentation skill can make the work available to their target "audience".

It appears to me that the "truther experts" target audience is the lay public not the engineering or science community

It appears to me that the "non truther experts" target audience is the engineering and science community and decidedly NOT the lay person. However NIST's work is "intellectually" accessible to non experts... ie lay persons.

Econ is a stellar example of a qualified engineer to has provided explanations of the collapses which lay persons can understand. His media is the internet and does not publish in engineering journals. He skillfully engages misinformed experts who make a presence on the www "forums".

Mick West has done very good experiments and demos about the physics of the collapses which are intellectually accessible to the lay person.

Blush. Thank you.

If we set aside the penultimate paragraph your post is an excellent summary of the status of the topic.

 

[Thomas B]

There is no uniform, cohenrent, homogeneous and totally agreed, consistent "body of expert opinion".

Then how do you expect someone who is trying to decide whether to become a truther to make up their mind about whether the "official story" makes sense?

 

[Jeffrey Orling]

Blush. Thank you.

Well deserved. Speaking for myself I am hardly an expert. More on the "level" of someone like Gage. I have a better grasp about structure and the engineer design at the WTC than a lay person.

I have approached understanding by looking closely at the structure for "vulnerability" of the design or elements/features of the design.

I realized early on that the process was dynamic and different "forces/processes" dominated at during the course of the collapse. The twin towers were damaged by the planes which also delivered a healthy supply of fuel. That fuel easily spread.

I also realized that the processes involved were very complex... and in a sense unknowable with precision. This was very much like a black box. We more or less know the "inputs". We know the result.... we know the rules of mechanics and physics inside the black box...but we can't reduce this to "recipe".

I believed as a starting point that the unique design SHOULD be the starting point for understanding the dynamic progressive failure process. And that this should not be ignored as Bazant seems to. My own contributions were supported by my own graphics and notes... obviously not targeted at the engineering community which had little to no presence on the 911 forums online.

I completely agree that the quality is way way way more important the the person's who makes it credentials.

There were many other brilliant "scientist" types who added immeasurably in my mind to my understanding such as "OneWhite Eye, Major Tom to name a few others.

edited to add:

Also Oystein and femr2... Hat tip to Econ for reminding me and pointing out my memory is dimming.

 

[Jeffrey Orling]

Then how do you expect someone who is trying to decide whether to become a truther to make up their mind about whether the "official story" makes sense?

My short answer.... it is one good plausible explanation... it is not the only one... in a sense many roads leading to Rome. Ergo there is no single explanation that is THE one. Bummer but even this notion was not made clear by the "experts".

 

[econ41]

Then how do you expect someone who is trying to decide whether to become a truther to make up their mind about whether the "official story" makes sense?

The $64.000 question. Way beyond the scope of the current topic. If you seriously want discussion - OP a thread. And what part of the "official story" do you refer to? Because WTC collapse is only part of the topic. However - lets stay with WTC collapse for this post.

The range of potential "new truthers" has historically been broad - from those who were simply ignorant of why the Twin Towers collapsed across to the other extreme of those who were CT obsessed and pre-set to disbelief of anything "official". With a lot of "shades of grey" between the two extremes.

The Layperson "Dummies Guide" book would have been an ideal introduction for those who genuinely wanted to learn. We agreed that much in both the previous threads. And we agree there is no book. You don't accept my opinion that such a book is both unlikely to be written and too late to be of much success AT THIS LATE STAGE viz 2022 onwards.

Whilst, for those who CT obsession is the root problem, the need is to resolve the underlying psychological pathology. A "book" MAY be of some secondary value. But CT obsession is beyond help from reasoned technical argument. Read Mick West's excellent "Escaping the Rabbit Hole" https://www.amazon.com.au/Escaping-Rabbit-Hole-Conspiracy-Theories-ebook/dp/B077YS5G2N

 

[Mendel]

Then how do you expect someone who is trying to decide whether to become a truther to make up their mind about whether the "official story" makes sense?

Most people are actually able to reason under some amount of uncertainty.
Certainly it is the case that the uncertainties in the official account/on the wikipedia page are much fewer than those in the conspiracy theory!

 

[econ41]

I completely agree that the quality is way way way more important the the person's who makes it credentials.

There were many other brilliant "scientist" types who added immeasurably in my mind to my understanding such as "OneWhite Eye, Major Tom to name a few others.

Add "Oystein", "femr2" and all those pioneers of both JREF and The911Forum. Leaders from both "sides". And input from those like Dwain Deets, T Szamboti who kept the rest of us on our toes and honest.

PS several others - like "Stundie" -who was grades too clever for the debunker claque.

 

[econ41]

Most people are actually able to reason under some amount of uncertainty.

One of my constant frustrations. Many can reason in uncertainty. A lot of engineers cannot. I misuse the metaphor but I call it "left brain" thinking - they cannot process without numbers or specific details. Neither of which are accessible for much of the explanation of WTC collapses.

EXAMPLE., The "initiation" stage mechanisms for Twin Towers collapses is near enough a 5 dimensional dynamic problem scenario. (3 orthographic dimensions of geometry PLUS two dynamic overlays - the structural dynamics and the heat motion dynamics - those two move differently hence they are effectively separate dimensions)

The key process of that stage of collapse was a "cascading sequence failure of columns" ( driven by heat weakening and load re-distribution.)

It is reasonably straight forward to explain in terms of "The first column to fail, followed by the second then the third...."n"th" BUT the usual engineer's first question "Which column was first?" Which we will never know. We know one column was first. We don't know which column it was. Doesn't change the logic of explanation but the "details and numbers" mind set simply locks-up - cannot progress the logic in generic terms. Has to know that it was the 5th column in the 7th row or similar.

And it is the same with the heat weakening aspects. "How hot did the column get?" The engineer wants degrees C. The "uncertainty logic" only need to know "Hot enough to be weak enough to fail". Try arguing THAT with a typical engineer.

Certainly it is the case that the uncertainties in the official account/on the wikipedia page are much fewer than those in the conspiracy theory!

Yes. The Wikipedia and most other arguments supporting the accepted narratives are based on coherent overall hypotheses. Most CT side claims are about anomalies - usually single issue anomalies and bereft of any "fit" to context. e.g. "thermite can cut steel and was fond at Ground Zero THEREFORE that proves CD" << a few missing links in that logic.

 

[Jeffrey Orling]

It is reasonably straight forward to explain in terms of "The first colmn to fail, followed by the second then the third...."n"th" BUT the usual engineer's first question "Which column was first?" Which we will never know. We know one column was first. We don't know which column it was. Doesn't change the logic of explanation but the "details and numbers" mind set simply locks-up - cannot progress the logic in generic terms. Has to know that it was

I went of on a different tangent.

The planes took out the "first" core and some of the perimeter columns. And we saw that the towers stood because the loads those columns supported has "handled" or transferred to other columns.
Looking at 1 WTC the planes took out several columns in row 500. I made the following diagram wherein I proposed the sequence of core column failures in the crash zone. Above and below those columns were intact. It needs to be noted that the OOS floor loads were supported by the belt girder which intern was connected to the 8 columns of row 500. So unless the girder went down with the failed column it would likely remain supporting the floor and handing the loads off the the 4 strongest columns in row 500, Row 600 and 600 "framed" elevator shafts, the distance and spans between them were small and the beams larger (that bar trusses)

I think the hat truss ultimately lost axial support collapse taking the mech floors with them destroying the top "block" and displacing the columns at the facades.
edit
another graphic

Maybe

 

[econ41]

I went of on a different tangent.

The planes took out the "first" core and some of the perimeter columns. And we saw that the towers stood because the loads those columns supported has "handled" or transferred to other columns.

Yes. BUT... we are talking about different "sub-stages". The first column I am describing was the first one to fail in the cascading sequence which started about 1 hour after the initial damage. NOT the load re-distribution associated with the initial damage from the aircraft impact.

(And - side comment - note how important it is to be clear as to which stage we are discussing. Even you and I can get "crossed up" and after ~10 years (??) discussion we should be able to read each other's minds. )

And I'm jealous of your architects skill at presenting good graphics. You have seen my "first effort" from 2007. Lousy graphics but the first attempt to describe the situation that is subject of the error I have alleged in the Wikipedia article. << crude attempt to make sure we are "on-topic".

 

[Gib]

Article:

Painted Steel Joists

In dry interior-use conditions, fireproofing can be applied directly to primed/painted joists without use of metal lath. No bond testing is required.

Painted Structural Steel

Spray Applied Fire Resistive Materials are almost always fire tested on unprimed/unpainted structural steel. The presence of any unknown substance on the steel, such as unlisted paints/primers, may affect both the ambient and high temperature bond of fireproofing and its ability to remain in place during the design life of the building and during a fire. The front of the UL Fire Resistance Directory (Section II.9. Coating Materials) details the requirements related to the ambient bond and lath requirements when primers or paint is present on structural steel.

Source: https://nfca-online.org/GI1002%20Primed%20or%20Painted%20Steel.pdf

So it's definitely possible that the steel was painted with primer before being fireproofed, though that's not evidence that it actually was.

The point about the "peer review" struck me as well, because it means very little when the study hasn't been published in a reputable journal.

And why isn't McCoy able to spell the name "Marc" correctly?

"And why isn't McCoy able to spell the name "Marc" correctly?"
I could provide an answer to that, but it might not get through the censors.

 

[Thomas B]

And I'm jealous of your architects skill at presenting good graphics.

Me too! I wish they were the centerpiece of an hour-long podcast in which @Jeffrey Orling interviews Shyam Sunder or Ronald Hamburger or, yes, Zdenek Bazant and has them say what they think happened to the structure as described in those drawings.

 

[Thomas B]

Most people are actually able to reason under some amount of uncertainty.
Certainly it is the case that the uncertainties in the official account/on the wikipedia page are much fewer than those in the conspiracy theory!

The issue for me at this point is that the uncertainty seems to exist in the minds of professional engineers, not just the laypeople who are trying to understand them.

If @econ41 is right, then the Wikipedia article contains at least one "fatal flaw", which means that if a reader identifies the article with "the official account" (as you seem to here, Mendel) then they would seem to have a point when they say "the official account is wrong". That's where trutherism about the WTC begins, i.e., the feeling that the official explanation can't possibly be how it happened.

But at this point I have another non-rhetorical question. Is Bazant's account wrong in the sense that it didn't happen the way his model suggests or in the sense that it couldn't have happened that way? I think that makes an important difference for how we think and talk about it, as well as what we think of Bazant's expertise and how credible the truther's experts are when they dismiss the official account of progressive collapse as represented by Bazant.

 

[Thomas B]

there is no single explanation that is THE one. Bummer but even this notion was not made clear by the "experts".

Well, I hope we agree that each building failed in one particular way. (And both of them failed in roughly the same way.) This isn't Schrödinger's Skyscraper or something. It's completely implausible to me that engineering science wouldn't have figured out what the actual, if somewhat general, mechanism of collapse of those buildings was.

I don't mean that they have to be able to specify every column and floor failure individually. (Just as an aircrash investigation doesn't have to tell you how every passenger seat detached from the floor, bolt by bolt.) All that is needed is a hypothesized series of structurally/physically possible failures that explains the visual evidence.

To avoid the controlled demolition conclusion, each of these progressive failures must be explained by the gravitational energy that was released above them and before they happend. The model cannot introduce energy below what Bazant calls the "collapse front", nor after it has passed (as in the case of the spire). The energy must come from above, even if it did not come in the form of a single, rigid descending "block".

Like I say, I think engineers should be able to explain this using Jeffrey's excellent drawings. Which could be arranged in a second-by-second series, for example, providing a twenty-second stop motion animation, for each tower that corresponds to what we can see on video but removes the dust clouds and lets us focus on what (yes, with some uncertainty) happened to the structure.

The non-existence of such an "animation" for each tower, with deference to Bazant's underwhelming diagrams, is, in my opinion, a scandal that the engineering community must own and fix. The absence of a fully fleshed-out "accepted wisdom" about the collapses is, for all intents and purposes, the basis of AE9/11T's credibility. It's what lets their "experts speak out" with a (dis)semblance of authority.

 

[econ41]

But at this point I have another non-rhetorical question. Is Bazant's account wrong in the sense that it didn't happen the way his model suggests or in the sense that it couldn't have happened that way?

Both. Didn't happen the way Bazant and Verdure's "CD/CU" hypothesis says. Couldn't because the scenario could not be set up even by deliberate design. And certainly not as an outcome of the actual collapse initiation mechanism.

The technical scenario is relatively easy to explain - with my usual proviso - "to anyone who is prepared to engage in honest reasoned discussion of my explanation." It involves issues of technical fact which can be seen in the visual record.

The academic/professional social dynamics as to why no one has formally identified the issue is more complex. And would by highly speculative.

 

[Thomas B]

Couldn't because the scenario could not be set up even by deliberate design.

But if we distinguish sharply between initiation and progression, and asked,

"If for the sake argument the top block had moved freely straight down onto the bottom section "through the height of one floor" then would/could the collapse have progressed as a series of column failures, each localized to the story immediately below the collapse front?"

would the answer here be that yes, Bazant would be right in this (impossible-to-initiate) "limit case"?

That would go directly to the truthers' "What if we lifted the top section the height of one story with a crane and dropped it?" scenario. It would debunk their intuitions about "the path of most resistance" etc.

 

[Jeffrey Orling]

The issue for me at this point is that the uncertainty seems to exist in the minds of professional engineers, not just the laypeople who are trying to understand them.

If @econ41 is right, then the Wikipedia article contains at least one "fatal flaw", which means that if a reader identifies the article with "the official account" (as you seem to here, Mendel) then they would seem to have a point when they say "the official account is wrong". That's where trutherism about the WTC begins, i.e., the feeling that the official explanation can't possibly be how it happened.

But at this point I have another non-rhetorical question. Is Bazant's account wrong in the sense that it didn't happen the way his model suggests or in the sense that it couldn't have happened that way? I think that makes an important difference for how we think and talk about it, as well as what we think of Bazant's expertise and how credible the truther's experts are when they dismiss the official account of progressive collapse as represented by Bazant.

First thanks to @econ41 and @ThomasB for the compliments.
Please understand that my "participation in the online 911 discussions was selfish. I wanted to satisfy my curiosity about the event. I never had the intention to make any presentation in any formal way,. give any talks, YouTubes, write papers and so on to make my ideas available to the "public", the truthers, NIST or anyone. I made and used my diagrams to graphically "think" and "talk" to the other people in the forums.
++++
Back to the "Experts". B&V and other non truther explanations were good science and engineering I suppose but not reflecting, in my opinion, what happened. I think almost all non truther engineers acknowledge that heat was the main "driver" that led to the towers collapsing (aside from B&V). NIST looked at the steel floor trusses in the twin towers and how they could have caused the outer "tube" to displace/buckle. So this concept is valid. My problem with it... is that is would seem to get the entire outer tube to move you would have to have almost all trusses involved... heated the same, same elongation or whatever at more or less the same time... And that would be like "cinching" the entire perimeter in a continuous bucking event. I don't see this in any video or photos. I do see this locally. And then there is the thorny problem of the 4 corner quadrants. My hunch is that if the trusses in the corner were significantly heated and expanded,,, there was no significant restraint at the end OPPOSITE from where they connect to the facade. So this would most likely deform the bar truss girder they were framed into... not the much stronger facade. AND the short span bar trusses would expand differently than the long span ones. So when you look at this "using a graphic" such as I use you would see this explanation has problems. Their basic concept.... floor trusses expand from heat is correct. Their application to the ACTUAL plan is a fail. And it most certainly doesn't account for 2WTC tip and drop to the SE.
++++
Again... engineers can and do identify failure modes "in isolation" but seem to fail in the "big picture" matching to the actual real world videos and structure.
Another example.... Failure at the truss seats at the perimeter. So let's look at the plan. Note that the plan shows the hat truss location and its outriggers which connected to the facade. Initial destroyed columns are in green bubbles. Likely core column failures shown in diamonds... red, magenta and green. These diamonds indicate likely sequence of column failures red first, purple next and finally green, Antenna base location is shown.
This diagram shows 3D in a a sense on a 2 D diagram...

What makes no sense to me in the NIST explanation (fantasy)... is that the short span would move the facade with half the "pull in force" than the long span. The 4 corners would most like deform the "truss girders" framed into the belt girder at the corners of the core.... and likely not deform the facade at the short side of the cores in the corners quadrants.
Note the observed bowing. It appears to be "below" one outrigger of the hat truss and partially within a corner quadrant. I suppose lots of fuel was transported to that quadrant heated the most and led to the IB. Here is my depiction of the likely fuel disburment through the floor. It has enormous momentum and perhaps columns and walls caused it to deflect laterally.

It not likely that a lot of jet fuel would end up on the North side... or more accurately the East and West side... heating the floor trusses. I would expect the "bowing" at the center of the South wall... if this was an actual process of "deformation". I doubt it was for a number of reasons.

YET the engineering supporting the floor trusses expanding from heat is correct. It just doesn't seem to "Fit" the actual event.

These diagrams are crude and not intended to be "engineering" explanations. They are intended to show to me... what happened on those floors. MAYBE. And this seems to make sense to me.

++++

So next how do I take this and produce a "theory" that might explain the collapse of the top block and the ROOSD that was observed? "

I am not an expert and the OP is not about layman theories of the collapse. I post the graphic to, in my opinion demonstrate what was missing in the "experts'" presentations.... graphics which make sense, show real world as best fit approximations and are supportable with fire science, engineering etc. And most importantly, perhaps, are understandable by ANYONE.

 

[Jeffrey Orling]

But if we distinguish sharply between initiation and progression, and asked,

"If for the sake argument the top block had moved freely straight down onto the bottom section "through the height of one floor" then would/could the collapse have progressed as a series of column failures, each localized to the story immediately below the collapse front?"

would the answer here be that yes, Bazant would be right in this (impossible-to-initiate) "limit case"?

That would go directly to the truthers' "What if we lifted the top section the height of one story with a crane and dropped it?" scenario. It would debunk their intuitions about "the path of most resistance" etc.

Sure there would be more than enough force to buckle columns on impact. Of course a one story lift of the facade columns would mean impacts at 3 different levels because the columns were staggered.

Have a look at this graphic... hardly seems like the floor trusses were the culprit. Rather few pulling at the much stronger facade in few places.... Makes NIST truss pull in look silly.

 

[Jeffrey Orling]

So no one... truther or non truther would deny that things that collapse do so because of the force of gravity which pulls everything on earth down. Structured resist gravity... and this allows real estate to use multiple floors on a footprint.

The supposed mystery is how did Mr Gravity get to "do his thing"?

Truthers shout structures are too strong to collapse from fires... fuel or office materials. Only way to defeat the incredibly strong frame is to explode it apart. They are not precise and when they wandered down the thermite path they claimed melted steel would not perform.... so maybe the CD was some sort of device which melts steel. There evidence for this was pretty shabby and wrong. There was no evidence of melted steel... only melted aluminum.

Non truthers need to explain how load paths were "destroyed" or interrupted. Gotta have load paths to get the gravity forces down to the ground... columns are load paths. Beams and girders are horizontal load paths... but they must move the loads to the columns.

One way to mess up load paths would be to interrupt them or get the column ends to misalign. B&V is theoretical and they do not show how to have mass drop without "erasing" columns to create a gap to fall though. Fail.

We got to learn about Euler buckling. A column's strength is related to its "slenderness ratio"... Same cross section as weaker when it is more slender. Bracing reduces the slenderness ration. WTC columns were over course "multi story". segments... 2 stories in 7WTC and 3 stories in the twin towers..

The explanation for 7wtc involves a reduction in capacity of col 79 when it lost bracing and slenderness ratio changed so that its capacity dropped below service loads... it buckled.

Twins column failures by NIST are the fantasy that the floor trusses were able to "distort" sufficient number of the staggered 3 story tall 3 column "assemblies" such that they buckled and the entire top block came crashing down. Does this makes sense?

So some other "lost of column capacity" explanations are required.

Would floor collapses cause slenderness ratios to increase and lead to the same sort of bucking that happened to col 79 wtc7? How many columns... how much capacity had to be lost? How much capacity could be lost from heat? Again...how many columns would have to lose capacity from heat?

How about "displacement" of the column connections. This would reduce bearing area and could induce buckling. Could column ends be "displaced" ...translated laterally? How many columns and how much translation would drop the capacity below what was required? Did you see any non truther experts tackle this?

Identify the mechanism(s) of non truther experts which explain the "loss of capacity" of the columns.

 

[Mendel]

If @econ41 is right, then the Wikipedia article contains at least one "fatal flaw", which means that if a reader identifies the article with "the official account" (as you seem to here, Mendel) then they would seem to have a point when they say "the official account is wrong". That's where trutherism about the WTC begins, i.e., the feeling that the official explanation can't possibly be how it happened.

It's still very close to how it happened, much closer than the CTs, and the mistakes are the result of an honest quest for knowledge.

It's like finding out how a car got moving, and someone says, you push on the accelerator and then turn the key in the ignition, and then someone says "you're wrong, it won't work that way" and then concludes an invisible elephant must have pushed it because Elephants are strong enough to push cars.

If someone says, "I won't believe what you say unless you are 100% correct and can answer any question you ask, otherwise I'll uncritically believe everything in this conspiracy theory video", stop trying to convince that person; you never will as long as they want to believe.
It's not your responsibility to ground them in reality, it's their own.

 

[Edward Current]

It's completely implausible to me that engineering science wouldn't have figured out what the actual, if somewhat general, mechanism of collapse of those buildings was.

I dunno, y'all. As an informed layman, I tell people that each building got destroyed by a descending debris shield that blew away everything in its path. How much detail does the general population need to know? It's like, people generally accept that an object from space did away with the dinosaurs, and they don't go asking what was the composition and altitude of the ejecta or the exact environmental conditions that followed.

 

[Jeffrey Orling]

I dunno, y'all. As an informed layman, I tell people that each building got destroyed by a descending debris shield that blew away everything in its path. How much detail does the general population need to know? It's like, people generally accept that an object from space did away with the dinosaurs, and they don't go asking what was the composition and altitude of the ejecta or the exact environmental conditions that followed.

It's mostly confusion about how it started. It wasn't the energy from the plane impact...The towers stood. It was what followed which was what all "experts" agree on... extreme heat. But there is no consensus about how the heat did what it did... where is was acting... I think people are confused and think... OK heat can make steel weaker... it can even go "soft" and bendy... Were the columns heated hot enough to go bendy and weak? Think the answer is no... certainly not "enough of them" and there was no evidence of that in the debris... which would be held up as evidence.
It was something else.
In 7wtc it was expanding beams and a girder... and the floor trusses in the twins... Public had a hard time understanding this... understandably so. How do expanding beams get columns to "fail".
Once tops started dropping... the avalanche of destruction was not hard to understand... you can almost see it.

 

[Thomas B]

I said:

It's completely implausible to me that engineering science wouldn't have figured out what the actual, if somewhat general, mechanism of collapse of those buildings was.

To which Edward replied:

How much detail does the general population need to know?

I get it. But it's not the primary job of engineering science to inform the public about buildings collapses. When I say it's a "scandal" that a comprehensive, established explanation of the (progressive) WTC collapses doesn't exist, I don't mean that the "general population" should already have been informed. I mean that any given member of the population who is curious about how those buildings collapsed should be able to satisfy that curiosity, without having to go down a "rabbit hole".

The worry I have these days is that the progression of the WTC collapses is actually not known by engineering science. (It may be known by an engaged community of enthusiasts who have been developing the ROOSD model outside the confines of "academic" engineering research.) That is, I worry that engineers, as a profession, don't understand what happened to the structures of the of Twin Towers after the collapses initiated.

I hope I'm wrong about this. If I am, there will be a handful of engineering professors who can set me straight. Who are they?

 

[Jeffrey Orling]

I said:

To which Edward replied:

I get it. But it's not the primary job of engineering science to inform the public about buildings collapses. When I say it's a "scandal" that a comprehensive, established explanation of the (progressive) WTC collapses doesn't exist, I don't mean that the "general population" should already have been informed. I mean that any given member of the population who is curious about how those buildings collapsed should be able to satisfy that curiosity, without having to go down a "rabbit hole".

The worry I have these days is that the progression of the WTC collapses is actually not known by engineering science. (It may be known by an engaged community of enthusiasts who have been developing the ROOSD model outside the confines of "academic" engineering research.) That is, I worry that engineers, as a profession, don't understand what happened the structures of the of Twin Towers after the collapse initiated.

I hope I'm wrong about this. If I am, there will be a handful of engineering professors who can set me straight. Who are they?

So let me help you out.
A progressive collapse is like one domino knocking another down. But over and over again Engineers understand the mechanics of the first domino fall... so progression is trivial and not a mystery, THEY UNDERSTAND. All the WTC floors collapsed because they were all the same spec.

There are some issues.... arresting collapse and isolating a local collapse.

Arresting collapse would requiring much stronger floors... instead of failing.... collapsing and shattering from having 3 floor masses fall on the top intact floor.... it might not collapse if the falling mass were 3 floor masses and the floor was designed for loads of 4 or more... for example... then the 3 floors masses would end up sitting on the floor they collapsed on... and it's clean up time.

The "driving mass" initially far exceed the capacity of the floor. Maybe by 5 or 10 times... or more as it was a dynamic not a static load. Arrest was not even remotely possible and this would be the case for almost every high rise. Settle engineering.

Isolation would only be possible if the floors were divided into structural grids of bays. A local collapse could continue right to the ground.... only collapsing the floors in that bay..... adjacent floor areas would / could survive. WTC did not use grid or bays... too expensive to build...they used column free office floors.... the "pancakes".

So... image the antenna was made to collapse... would it cause the entire building to collapse? Maybe not it might mess up the interior of the core... even plunging to to the ground.... leaving the OOS floors intact if the core's perimeter columns were not involved.

No engineer should have been puzzled by the runaway floor collapse.

++++

But "progressive failure" also involved the progression of failures laterally through the frame as failed column loads were transferred to adjacent columns and this was a progressive process... similar to how a sink hole often grows in diameter.