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

[Keith Beachy]

This is not a rhetorical question. How does a structure that was designed to carry 250,000 tons provide "no significant resistance" when, let's say, 60,000 tons is dropped on it from about 10 feet?

I get that there were "chaotic interactions", so it's not just one solid mass falling on another. But "no significant resistance"? I mean, the cores were completely destroyed. How does a structure that was designed to carry 250,000 tons get completely destroyed by some fraction of that mass without prodividing significant resistance?

It sounds really strange to talk that way.

I know that's how it looked. But surely the structure that was actually destroyed by the falling debris significantly resisted it? Otherwise it would it not itself have been destroyed.

Like I say, this is not a rhetorical question. If you have the patience to explain it, please do.

"no significant resistance" from the core? Because the floors are hanging on the core and shell. The core and shell share the gravity load of the towers. A floor only holds up a floor. A floor fails essentially instantly when overloaded, the connections to the core and shell fail, essentially instantly. The falling towers will fall at about the rate/speed based on simple momentum transfer of falling debris adding mass at each floor in a gravity field. As seen, the core was stripped of floors, as nearly 70 stories of partial core remained standing for seconds, and failed because the lateral support was the shell which was ripped up by the mass of falling floors.

https://www.nist.gov/world-trade-ce...on capacity-,(29,000,000 pounds,-) of a floor

 

[econ41]

It may sound awkward, but I can't think of a better way to explain it. The issue is that the word "floor" could mean the height on the building where an event occurred or it could mean the actual floor plate at that level. If you have a suggestion for a better way to express what I meant, I would be happy to edit my comment.

I would still offer those cautions:
First - we are drifting off topic AND second - there is a long history of attempts to explain the collapse mechnisms to Thomas B using various approaches.

Then - third - I doubt that generalised simplifications and references to analogous collapses expecting Thomas B to work from base principles is the way to go. Best of luck if you want to take that path. Again - it may help to check the several previous threads.

I would still recommend working from what actually happened to the Twin Towers on 9/11. The history of debate is littered with errors and confusions arising from inappropriate generalistations or approximations. Plus those AE911 stalwarts - Szamboti, Chandler and Coste all fell for the same trap - not comprehending the actual WTC collapse mechnaisms. (So did J Cole - I'm not sure if he is affiliated with AE911 but he makes the same mistake.)

And there is a lot missing between "...the misaligned columns at the plane crash floor buckled.." and "...the floor directly below was instantly overloaded.." I suggest that neither premise "instantly" nor "directly below" is accurate. (Even if we assume you are referring to the NIST version of "misaligned columns" AND NIST was right.)

 

[econ41]

"no significant resistance" from the core? Because the floors are hanging on the core and shell.

Your comments are true enough @Kieth Beachy EXCEPT they do not fit the context in which the assertion "no significant resistance" was made. You could go back a few posts to this at Post #30. The context was no significant resistance from columns during the progression stage of collapse.

Bottom line - for Twin Towers there was no significant resistance from core columns.

 

[Thomas B]

The issue is that the word "floor" could mean the height on the building where an event occurred or it could mean the actual floor plate at that level. If you have a suggestion for a better way to express what I meant, I would be happy to edit my comment.

Is the distinction between "floor" and "story" what you need? I understand why the individual floor systems would not have significantly resisted the falling mass of the upper stories. It's harder to understand how to the lower stories (the floor + column systems) did not significantly resist the falling debris.

 

[Keith Beachy]

Is the distinction between "floor" and "story" what you need? I understand why the individual floor systems would not have significantly resisted the falling mass of the upper stories. It's harder to understand how to the lower stories (the floor + column systems) did not significantly resist the falling debris.

All the floors will fail in turn as the mass falls, even the lower floors, the core can't stop the floor failures.

https://www.nist.gov/world-trade-ce...on capacity-,(29,000,000 pounds,-) of a floor

 

[Thomas B]

The video shows a 14-story building under demolition when part of the roof accidentally broke loose resulting in a succession of floor failures all the way down to the basement.

I like this video. It looks like columns (i.e., vertical structures running the length of the building) are destroyed in the process. If a wider area of the upper floors had failed, it's plausible that the building would have been totally destroyed. I'll use this as a model for thinking about it (and building physical models) going forward. Thanks.

 

[Thomas B]

There have been several credible estimations of the momentum effect on rate of descent. (And, incidentally, from "both sides".) They vary in quantification but seem to put the order of magnitude of the effect in the same order of magnitude as the "lost" 1/3rd "G".

HENCE Although both shearing forces and friction are "column resistance" their magnitude is less significant than momentum. And that was the relevant part of my reason for claiming:
"Bottom line - for Twin Towers there was no significant resistance from core columns."

I think this clears it up for me. The cores resisted the collapses by about one third of what would have been needed arrest the collapses (i.e., a scenario in which the collapses "lost" 3/3 G). That seems "significant" to me, but that's a semantic issue. We don't need to spend more time on it for me.

 

[Marc Powell]

I like this video. It looks like columns (i.e., vertical structures running the length of the building) are destroyed in the process. If a wider area of the upper floors had failed, it's plausible that the building would have been totally destroyed. I'll use this as a model for thinking about it (and building physical models) going forward. Thanks.

Your welcome. However, from what I see in the video, it looks like the accident only involved the pancaking of floors. No columns (i.e., vertical structures running the length of the building) were crushed... just like none were crushed in the twin towers.

 

[Thomas B]

nearly 70 stories of partial core remained standing for seconds, and failed because the lateral support was the shell

This is also helpful. It suggests that I'm wrong to think that the falling mass actually destroyed the core. Most of it was not destroyed in the collapse itself. The cores failed for lack of lateral support after the shell and floor system was destroyed. Those 70 stories of core would, of course, not have resisted the collapse at all.

I still need to get my mind around the need of the cores for lateral support from floors to even remain standing. But that thread has been closed so I'm working on that elsewhere. Thanks.

 

[Thomas B]

No columns (i.e., vertical structures running the length of the building) were crushed

OK. It looked like the collapsed sections included vertical features on the facade, but I guess they might not have been part of the load-bearing system. At the end of the day, I need to understand how both the floors and the columns failed (even if the latter didn't buckle or crush but just snapped from shear forces). But I'm in no rush. A few things are falling into place. (Is that a bad joke?) Thanks.

 

[Bruce Lansberg]

It suggests that I'm wrong to think that the falling mass actually destroyed the core.

Indeed it didn't. Maybe the thing to remember is that the core wasn't cross braced and therefor needed the floors for lateral support.

I still need to get my mind around the need of the cores for lateral support from floors to even remain standing.

If you look at pictures of the construction of the towers, you will not see either core or perimeter being built any higher than the length of their individual elements, being 3 stories tall in most cases, over the highest floor. That's not coincidental.

 

[Bruce Lansberg]

It looked like the collapsed sections included vertical features on the facade

Correct, but they didn't get crushed. They simply fell away from the floors and core. Sometimes in a sheet of connected panels, sometimes as individual panels 3 stories tall.

but I guess they might not have been part of the load-bearing system.

They were. The perimeter carried about 40% of the tower's weight.

I need to understand how both the floors and the columns failed

Floors should be obvious by now.
The floors were an integral part of the construction and were what gave the towers lateral stability. No floors, no stability. Try stacking 50 beer crates on top of eachother without lateral support and see what happens. Pleas bear in mind that each inidividual part of the core columns only existed of 3 story lengths, bolted to the part above and below.

 

[econ41]

Correct, but they didn't get crushed. They simply fgell away from the floors and core. Sometimes in a sheet of connect panels, sometimes as individual panels 3 stories tall.

And in one example an humongous sheet of perimeter about 1/3rd the height of the Tower toppled over and swiped the WFC. Leaving its top members stuck in the corner of WFC whilst other parts of the top of the sheet landed on Wintergarden.

And the visual evidence of that is - as far as I am aware - the only example of visual evidence which "disproves" truther claims for explosive projection of those 6-7-8 "outlier" beams which impaled in buildings.

 

[Thomas B]

If you look at pictures of the construction of the towers, you will not see either core or perimeter being built any higher than the length of their individual elements, being 3 stories tall in most cases, over the highest floor. That's not coincidental.

I had thought that that was mainly the most convenient way to build it, not to prevent the core and perimeter from collapsing during construction. But if we go down this road, I fear the thread will be closed. PM me if you want to talk it through. I have some thought experiments (and some math) I need help with. (This invitation for a PM discussion is open to anyone else on this thread too. I'm happy to discuss it, just wary of the moderators.)

 

[Landru]

The topic is

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

Discussions about the collapse and its causes are covered in other threads.

 

[Jeffrey Orling]

The topic is

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

Discussions about the collapse and its causes are covered in other threads.

My sense is that an opinion from a "professional" must include someone who has done their homework and is well aware of the details. I want to believe that any competent professional who knows all the facts would pretty much have the same "read"/opinion about the "thing" they are offering their professional opinion on.

I also believe that MOST truther people do not understand the engineering... and few are aware of the many technical discussions online about the mechanisms of the collapse... and I find this willful ignorance and it's troubling.

 

[Marc Powell]

And in one example an humongous sheet of perimeter about 1/3rd the height of the Tower toppled over and swiped the WFC. Leaving its top members stuck in the corner of WFC whilst other parts of the top of the sheet landed on Wintergarden.

And the visual evidence of that is - as far as I am aware - the only example of visual evidence which "disproves" truther claims for explosive projection of those 6-7-8 "outlier" beams which impaled in buildings.

Here is a picture of the humongous sheet of perimeter columns you referred to:

https://ia801303.us.archive.org/2/items/NIST_9-11_Release_08/International_Center_for_911_Studies_NIST_FOIA/Release_08/Release 8/42A0007 - 1of3/Police Overheads/166.JPG

9/11 Truth "experts" claim that the columns sticking out of the WFC got there by being hurled hundreds of feet by explosives and that, except for the few stories worth of columns left standing at the lobby level, the frame of each tower was completely shattered down to individual structural components. Here is what David Hooper said at the 55:57 mark in his film:

I could pretty much rule out a gravitational progressive collapse because of the physical dynamics I'd seen with my own eyes, and I found it ironic that the only part left standing was the base of the building. Even though the whole building landed on it, it was the only part of the building whose columns did not become dismembered. Perhaps that said something about the difficulty in wiring the atrium of the towers, and maybe these columns at the base did what the rest of the building should have done, and that is stay together in some way, just a personal observation I made at the time.

Do the columns seen in the picture, laid out on the ground, still mostly bolted together, look to be "dismembered"? Does it look like they didn't "stay together in some way"? Does the sheet of exterior columns look like the rubble from a massive explosion or like what would be expected when a skyscraper peels apart in a "gravitational progressive collapse"? It is beyond belief that anybody could trust anything those guys (Hooper and Gage) say after they try to trick their audience by concealing evidence like this.

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[econ41]

Here is a picture of the humongous sheet of perimeter columns you referred to:

Thanks- I lost my references to where to link it. The problems of recycling topics which were addressed 10+ years back. I never kept the source material - assuming that once issues were addressed the debate would move forwards. Silly me. Never kept copies of my own explanatory posts NOR links to the few sources I could have used. Not the only naive misjudgement. In the first weeks of my on-line posting I recognised that the real issues of 9/11 concern were in the politics. So I decided my goal was to "sort out this CD nonsense so we can move onto the real issues". Mmmmm...

 

[Jeffrey Orling]

Thanks- I lost my references to where to link it. The problems of recycling topics which were addressed 10+ years back. I never kept the source material - assuming that once issues were addressed the debate would move forwards. Silly me. Never kept copies of my own explanatory posts NOR links to the few sources I could have used. Not the only naive misjudgement. In the first weeks of my on-line posting I recognised that the real issues of 9/11 concern were in the politics. So I decided my goal was to "sort out this CD nonsense so we can move onto the real issues". Mmmmm...

It's unfortunate that no one has put together a comprehensive... step by step of how each building likely came down with graphics and gifs and so forth. And of course a bibliography and references. Online technical discussions moved from one detail to another and it seems there was no need to produce anything resembling a "summary". Even Major Tom's site is more like resource than a summary.
I suspect those who followed the discussions over the years do not need a summary presentation. But it would be useful to those who are curious and faced with the NIST reports, AE911Ts presentations, films like Hooper's and discussion forums like JREF, Metabunk and 911FF. The slick presentations are easiest to digest. No wonder that truthers take this sales approach.

 

[Thomas B]

I also believe that MOST truther people do not understand the engineering... and few are aware of the many technical discussions online about the mechanisms of the collapse... and I find this willful ignorance and it's troubling.

Some truthers are probably willfully ignorant. But I think there are lots of people who are just never really able to get their minds around the collapses, try as they might. Though I have independent reasons not to become a truther, I consider myself one of these not-willfully ignorant people about the engineering issues. I just don't understand how the buildings could both stand and collapse the way they did.

As we discussed last summer, that may be partly because very few engineers talk to popular audiences about the collapses in a detailed way. Almost never unless they're helping to debunk conspiracy theorists. So anyone who begins with curiosity about the engineering inevitably finds themselves in one of "the many technical discussions online about the mechanisms of the collapse," all of which (I don't think there are exceptions, but I'm happy to be shown one) are in forums about conspiracy theories. (Like this one.)

I think it's simply a statistical inevitability that some of those people will end up truthers and some will end up debunkers and some will just give up and go back to their lives still not understanding the engineering. The people who decide that AE911T's "experts" are *not* especially konwledgeable or trustworthy, don't really have anyone else to turn to. One day I'm going to try to find out how undergraduate engineering students learn about the WTC collapses. How are they explained to people who are learning the engineering principles as well?

 

[Marc Powell]

Thanks- I lost my references to where to link it. The problems of recycling topics which were addressed 10+ years back. I never kept the source material - assuming that once issues were addressed the debate would move forwards. Silly me. Never kept copies of my own explanatory posts NOR links to the few sources I could have used. Not the only naive misjudgement. In the first weeks of my on-line posting I recognised that the real issues of 9/11 concern were in the politics. So I decided my goal was to "sort out this CD nonsense so we can move onto the real issues". Mmmmm...

Once all the evidence is laid on the table, it should at least be obvious that 9/11 Truth Movement leaders are hiding inconvenient truths that conflict with their theories. They are not just willfully ignorant of the facts... they are knowingly deceitful in how they present them. Early in my research into the events of 9/11, it became clear that politics was the only area where issues were unresolved and debate was reasonable.

 

[Jeffrey Orling]

My experience with AE911T up close was that they start from the notions:
Government and media can be counted on to cover up some inconvenient truth. The cover up has no bounds including out lies and false technical reports.
They then conclude that the gov's "official story", being a cover up and lies means that "they"... the government had a hand in the events. Some truthers assert that out of control "agents" pulled it off. But the official story amounts to a causus belli to ramp up defense appropriations... attack a ME country. They love the idea that 911 was a "Pearl Harbor-like" event which would enable all manner of constitutional repression as well as a war...great for the MIC. To truthers this makes perfect sense. And anyone who questions truthers are gov agents suppressing embarrassing info.
Gage et al then look anything about the event to frame as supporting "evidence" for their thesis which includes... steel high rises cannot collapse from fire of plane strikes. And of course anything that supports the planes led to uncontrolled fires that weakened and warped the frame causing runaway floor collapse which led to all columns to drop.
Melted aluminum is misrepresented as melted steel... and that is evidence of nano thermite technology and new CD devices.
What is shameful and disturbing is the ignorance of "professionals" who support AE's fantasy. But that is how they sell it...Don't trust me.. trust all these building experts. Sadly these people are smart enough to understand the event... they choose not to because of their political agendas.
It's true that the mechanism and engineering are too complex for the lay person. Turning these into cartoons will fail as the "pancake collapse" did.
Unfortunately there were no videos or slide shows explaining the best fit engineering explanations along the line of "Loose Change" or "Blueprint for Truth" and Hooper's recent film. In reality why is an everyman YouTube or similar necessary? Who is the target audience? Does the AE911T false narrative need to be refuted?
In fact.... anyone who is curious can find out about the collapse by using google which will lead them to this site, JREF, or the 911freeforum and many other online resources. These are "technical discussions" so some work is required.
People like Econ had generously walked through people who honestly wanted to learn about the collapses. Mick has done some instructive experiments as well. But the bottom line is... if someone is not interested in learning... they are willfully ignorant.
++++
Understandably we live in a world of PR and marketing which are simply not JUST the facts. We all take advertising with a grain of salt. We all expect pols to avoid inconvenient truths and spin. But there are scientists with no agenda other than explain the world... They will have no "political" affiliations as the "'truth experts" clearly seem to have.

 

[econ41]

Once all the evidence is laid on the table, it should at least be obvious that 9/11 Truth Movement leaders are hiding inconvenient truths that conflict with their theories. They are not just willfully ignorant of the facts... they are knowingly deceitful in how they present them. Early in my research into the events of 9/11, it became clear that politics was the only area where issues were unresolved and debate was reasonable.

Your identification of "politics" is similar to my position. I've detailed my own reasons for involvement many times. Put simply - my main interest in these discussions has been in explaining the physics of WTC collapses in lay person language to persons who want to learn. Several aspects of my career make 9/11 Topic a glove fit. An engineer manager with both civil and military qualifications. Plus emergency management, regulatory management of high rise building water supply and fire sprinkler design, interfacing and conflict resolution with diverse "stakeholder" groups including policy advice to Government.

So when I first came to 9/11 discussion in 2007 the hot topic was "CD at WTC" which I saw as a technical misunderstanding which formed a barrier to the real issues which were in the politics. I joined a serious Forum which was not mainstream for 9/11 debate. The former Richard Dawkins Forum. So biological science oriented. Top grade professional science contributors BUT one lone engineer.. me. My goal was simple "Let's clear up this CD nonsense so we can discuss the real issues which are in the politics". I thought it would take a couple of weeks discussion. Mmmm possibly I was a bit naive?

Back to where you - we - are today. I've not changed my position on the importance of politics. I think there were - still are - some issues worthy of discussion in the political domain. But most of the debate has been kept on the technical issues. With AE911 putting the focus on CD at WTC which must be a loser long term. There is a handful of serious researchers interested in the political history but - IMNSHO - no one capable of strategic leadership. And, overall, I think it is far too late for 9/11 based debate to change track.

And I think you have well and truly proved your main claims which are: "They are not just willfully ignorant of the facts... they are knowingly deceitful in how they present them." Your excellent series of technical example threads all support those two claims. Do we need more proof of "wilful ignorant and deceitful intent"? Because that is the main thrust of debate. The technical issues are only support - we know "they" are wrong and "we" are near enough right.

 

[econ41]

People like Econ had generously walked through people who honestly wanted to learn about the collapses. Mick has done some instructive experiments as well. But the bottom line is... if someone is not interested in learning... they are willfully ignorant.

Thanks Jeffrey. Would you believe May 2015 was the last time I "walked" a willing "want top to learn" member through some of the physics on a serious forum. Had a couple on FaceBook about 4 or 5 years ago. 3 or 4 truthers and two debunkers who were deep into the politics but needed to understand the WTC Physics. Serious interest from truther side long dead.

 

[Jeffrey Orling]

Thanks Jeffrey. Would you believe May 2015 was the last time I "walked" a willing "want top to learn" member through some of the physics on a serious forum. Had a couple on FaceBook about 4 or 5 years ago. 3 or 4 truthers and two debunkers who were deep into the politics but needed to understand the WTC Physics. Serious interest from truther side long dead.

So it seems that to those on the 911 technical forums... there is nothing of substance left to "demystify" about the destruction of the WTC collapses and interested persons have moved on. I do believe the discussions were thin about the progression of failures leading to "release". I attribute this to the fact that these discussions need more actual data and without it the discussions are just "what ifs" and best informed guesses. NIST settled on their best guess and punted on "global collapse". Frankly I was disappointed that interest in the "imitation" periods and transition to the collapse phase was not discussed very much. I doubt one could "prove" or take a position that X was "the"initiation mechanism. Yet it seems that discussion about the "straw that broke the camel's back" was at the heart of perhaps mitigating a building collapse in the future. My take away is that more or better fire suppression might have saved those towers... and saved more lives.

++++

I did attempt to present a core led collapse what if... but it was met with little interest for the twin towers. So yeah... other than "helping" confused people understand a bit there is nothing more to do.... so WTC technical discussions are largely silent/ended.

 

[Jeffrey Orling]

Once all the evidence is laid on the table, it should at least be obvious that 9/11 Truth Movement leaders are hiding inconvenient truths that conflict with their theories. They are not just willfully ignorant of the facts... they are knowingly deceitful in how they present them. Early in my research into the events of 9/11, it became clear that politics was the only area where issues were unresolved and debate was reasonable.

I question whether the 911truth "professionals" are even aware of the technical discussion aside from the NIST reports, and Popular Mechanics and perhaps a PBS presentation. The only professionals who was a 911truth supporter who ventured into the tech discussions online were Tony Sz and Gerry. It was like you can lead a horse to water but you can't make her drink (think) sort of thing.

 

[econ41]

I do believe the discussions were thin about the progression of failures leading to "release". I attribute this to the fact that these discussions need more actual data and without it the discussions are just "what ifs" and best informed guesses.

I have many times explained in layman language. In face of much reluctance from debunkers who think NIST and Bazant are infallible - thereby setting themselves a glass ceiling. As you know from our many discussions I do not agree that availability of data is the limiting factor. There is more than enough data available to describe the mechanisms of collapse for Twin Towers without excess speculation. The limitations are in the reasoning skills needed to process the data

The biggest barrier I have met is what I describe as "left brain thinking". One example - it is only moderately challenging to explain the cascading failure of columns which was the dominating feature of Twin Towers collapse "initiation" stage. The explanation can be expressed in terms of "the first column failed by xyz, then load redistribution caused the second column to fail etc etc.." And reasoned discussion halts right there because 90% or more engineers, who think "left brain", ask "which was the first column". They need specifics .. cannot process generics.

And we will NEVER know the exact sequence. but that does not invalidate the logic - other than for those who cannot process the reasoning without knowing which specific column was #1, #2 etc... They think via their FEA. And that is only one of a number of self imposed limitations on thinking. Many persons of a "trade" background are more adaptable but implicitly lack the credibility to take on the professionals. Stalemate results.

I doubt one could "prove" or take a position that X was "the"initiation mechanism.

Is that a challenge? It is not hard to describe it in much detail for Twin Towers. WTC7 probably only plausible in broader brush - generic - terms.

So yeah... other than "helping" confused people understand a bit there is nothing more to do.... so WTC technical discussions are largely silent/ended.

"Helping" confused people was always my primary goal .. not "debunking". Or "arguing". Or even helping "them" out of the Rabbit Burrow.

The last "pushing the limits" technical discussion I was engaged in was about 2013. I was discussing with a couple of engineers how we may be able to help Bazant achieve his goal of inventing a generic model of high rise progressive collapse. By fixing up the error in the Bazant & Verdure "Crush Down/Crush Up" modelling. My two partners in discussion r ealised I was saying Bazant was wrong. Committing unforgivable "lèse-majesté". And they abandonned ship. Bailed out... Thats just one example but over the intervening years there have been very few attempts at serious discussion.

 

[econ41]

The only professionals who was a 911truth supporter who ventured into the tech discussions online were Tony Sz and Gerry.

W Coste has engaged with Oystein and me on FBook using our other aliases. D Chandler also participates but in "no threat" echo chamber groups on FBook. Then for many years C Sarns appeared solo or in tag team with T Szamboti on some forums. Tho he is not "professional" and Chandler is marginally so.

 

[Jeffrey Orling]

I have many times explained in layman language. In face of much reluctance from debunkers who think NIST and Bazant are infallible - thereby setting themselves a glass ceiling. As you know from our many discussions I do not agree that availability of data is the limiting factor. There is more than enough data available to describe the mechanisms of collapse for Twin Towers without excess speculation. The limitations are in the reasoning skills needed to process the data

The biggest barrier I have met is what I describe as "left brain thinking". One example - it is only moderately challenging to explain the cascading failure of columns which was the dominating feature of Twin Towers collapse "initiation" stage. The explanation can be expressed in terms of "the first column failed by xyz, then load redistribution caused the second column to fail etc etc.." And reasoned discussion halts right there because 90% or more engineers, who think "left brain", ask "which was the first column". They need specifics .. cannot process generics.

And we will NEVER know the exact sequence. but that does not invalidate the logic - other than for those who cannot process the reasoning without knowing which specific column was #1, #2 etc... They think via their FEA. And that is only one of a number of self imposed. Many persons of a "trade" background are more adaptable but implicitly lack the credibility to take on the professionals. Stalemate results. limitations on thinking.

Is that a challenge? It is not hard to describe it in much detail for Twin Towers. WTC7 probably only plausible in broader brush - generic - terms.

"Helping" confused people was always my primary goal .. not "debunking". Or "arguing". Or even helping "them" out of the Rabbit Burrow.

The last "pushing the limits" technical discussion I was engaged in was about 2013. I was discussing with a couple of engineers how we may be able to help Bazant achieve his goal of inventing a generic model of high rise progressive collapse. By fixing up the error in the Bazant & Verdure "Crush Down/Crush Up" modelling. My two partners in discussion r ealised I was saying Bazant was wrong. Committing unforgivable "lèse-majesté". And they abandonned ship. Bailed out... Thats just one example but over the intervening years there have been very few attempts at serious discussion.

Sure... you don't need a complete data set. You do need to establish that there were fires with temps high enough to impact the steel frame... and that would most likely be in the core region. The facades were seeing heat but unlike the core which was "engulfed" or parts were... the facade could only face heat on one side. I believe NIST postulated the perimeter was pushed pulled but the floor trusses where the fire was... "on the floor slabs".
Both plane strikes were above the sky lobby levels and much of the core up there was not elevator shafts but used as office space and those floors surfaces allowed for fires over a large area where bracing beams... like the floor trusses likely became heated, expanded and warp and could push the core columns ends laterally, reducing bearing area and causing a buckling situation. Maybe.

I always thought that the dropping antenna was a tell that the center of the hat truss and the columns that supported it had failed "first" and those core column failures may have triggered the top blocks' descent. The tipping of 2WTC is a tell that the SE side failed more/first and so the blocked tipped and fell favoring the SE side.

The columns could not acquire more loads except if some columns were unloaded and their load redistributed. This makes perfect sense and leads to a progressive/runaway column failure sequence. We can't know the sequence, but we can guess that this is is what happened. Any "asymmetry" of the top blocks' collapse is a tell that the column failure/buckling was not "symmetrical". Maybe.

Since we can't pin down the sequence... but we know the outcome there are likely several "paths" to arrive at the initiation... top blocks coming down.

 

[Jeffrey Orling]

Some truthers are probably willfully ignorant. But I think there are lots of people who are just never really able to get their minds around the collapses, try as they might. Though I have independent reasons not to become a truther, I consider myself one of these not-willfully ignorant people about the engineering issues. I just don't understand how the buildings could both stand and collapse the way they did.

As we discussed last summer, that may be partly because very few engineers talk to popular audiences about the collapses in a detailed way. Almost never unless they're helping to debunk conspiracy theorists. So anyone who begins with curiosity about the engineering inevitably finds themselves in one of "the many technical discussions online about the mechanisms of the collapse," all of which (I don't think there are exceptions, but I'm happy to be shown one) are in forums about conspiracy theories. (Like this one.)

I think it's simply a statistical inevitability that some of those people will end up truthers and some will end up debunkers and some will just give up and go back to their lives still not understanding the engineering. The people who decide that AE911T's "experts" are *not* especially konwledgeable or trustworthy, don't really have anyone else to turn to. One day I'm going to try to find out how undergraduate engineering students learn about the WTC collapses. How are they explained to people who are learning the engineering principles as well?

My journey into understanding the collapse of the towers involved of course reading and responding in discussions. Not being an engineer, but an architect I chose to present my ideas in graphics... and narrative explanations which I would post. Bellow is one such example which attempts to show how core column failure might progress in 1WTC.

and how the block might have dropped:

 

[Marc Powell]

W Coste has engaged with Oystein and me on FBook using our other aliases. D Chandler also participates but in "no threat" echo chamber groups on FBook. Then for many years C Sarns appeared solo or in tag team with T Szamboti on some forums. Tho he is not "professional" and Chandler is marginally so.

In your interaction with AE911Truth mouthpieces, have you had the experience of having your publicly visible comments censored? I have given up making comments for videos on the AE911Truth YouTube channel because any comment I made that revealed the tricks behind their smoke and mirrors was deleted within hours. When I first started watching AE9/11Truth videos, I couldn't understand how it could be that almost every comment was flattering and supportive. I suspected that it was because people with an understanding of physics and the actual evidence were just not drawn to videos like that. When I posted my first comment offering a more reasonable explanation for the evidence cited by Gage and company, I thought that the voice of reason could finally be heard. Later that evening, after discovering that my comment had been removed by the channel host, I realized what was going on.

Incidentally, I have also had a discussion with Chris Sarns some years back. When I provided a reasonable explanation for the iron-rich microspheres found in WTC dust, he started to act stupid and to change the subject... as if he didn't understand what I was talking about. To me, that is a sure sign of tacit acknowledgement that he actually did know what I was talking about.

 

[Keith Beachy]

I had thought that that was mainly the most convenient way to build it, not to prevent the core and perimeter from collapsing during construction. But if we go down this road, I fear the thread will be closed. PM me if you want to talk it through. I have some thought experiments (and some math) I need help with. (This invitation for a PM discussion is open to anyone else on this thread too. I'm happy to discuss it, just wary of the moderators.)

It is things covered in this thread which exposes the 9/11 truth "experts" lack knowledge

 

[econ41]

In your interaction with AE911Truth mouthpieces, have you had the experience of having your publicly visible comments censored? I have given up making comments for videos on the AE911Truth YouTube channel because any comment I made that revealed the tricks behind their smoke and mirrors was deleted within hours.

I've not run into censorship as a routine practice. But I rarely post on the high profile Facebook groups like AE911 and have never posted on YouTube. Partially because of choice I made which, in hindsight, I regard as a strategic error. I've been active on forums for about 14 years - First posted Nov 2007. Totaled over 40k posts before I stopped counting. Mostly on 9/11 matters but I was a moderator and active in other topics for several years. I went to FaceBook by invitation of a friend and never thought - posted on my personal account. Should have adopted an alias account.

Now censorship was never an issue on serious forums. The ones I've posted on R Dawkins Forum then JREF/ISF - both since transplanted. Then The911Forum and Debate Politics... I have visited a couple of "echo chamber" truther FaceBook Groups. Got insulted but never censored. BUT I've never gone "boots and all" into rebuttal or argumentative conflict.

Incidentally, I have also had a discussion with Chris Sarns some years back.

It may surprise you but Chris Sarns was for a couple of years a very persuasive troll on what was then JREF. He was far better at "playing the crowd" than T Szamboti. One of his tricks was that he would occasionally concede a point in argument - and fooled many debunker members. A simple trick and effective. However in more recent times I've seen him arguing topics like microspheres and he is EITHER not as subtle as he used to be OR I've matured my interpretive skills.

To me, that is a sure sign of tacit acknowledgement that he actually did know what I was talking about.

Yes. It is not easy to "read" how much is ignorance, how much is obsessive "genuine belief" and how much is plain lying. Have you realised that all the AE911 stalwarts - Szamboti, Coste, Cole (?), Chandler, Sarns share one common fundamental problem? They do not comprehend the actual models - the mechanisms of WTC collapses. Specifically the Twin Towers. Remember that for years both "sides" - as they were emerging and polarising - made the same fundamental errors. All related to "not understanding the mechanism". Easiest seen with Szamboti's "Missing Jolt". He made two big errors. Most debunkers recognised one of them. (He applies Bazant & Zhou's limit case scenario as if it actually happened.) And fell for the second...(The assumption that the "Top Block" fell to impact on Lower Tower. It didn't but try telling anyone that.... Many are still lost.)

Then if you want some real fun try telling debunkers that Bazant & Verdures "Crush Down/Crush Up" is wrong... And THAT also results from the same error - not understanding the actual mechanism of collapse.

I'll [/EndRant] before I get too far off the rails... I see a page full of spelling "errors" - all my "s's" when the US dictionary wants "z's". Took me years to remember that 9/11 is not ninth of November....

 

[Jeffrey Orling]

In your interaction with AE911Truth mouthpieces, have you had the experience of having your publicly visible comments censored? I have given up making comments for videos on the AE911Truth YouTube channel because any comment I made that revealed the tricks behind their smoke and mirrors was deleted within hours. When I first started watching AE9/11Truth videos, I couldn't understand how it could be that almost every comment was flattering and supportive. I suspected that it was because people with an understanding of physics and the actual evidence were just not drawn to videos like that. When I posted my first comment offering a more reasonable explanation for the evidence cited by Gage and company, I thought that the voice of reason could finally be heard. When I discovered my comment removed later that evening, I realized what was going on.

Incidentally, I have also had a discussion with Chris Sarns some years back. When I provided a reasonable explanation for the iron-rich microspheres found in WTC dust, he started to act stupid and to change the subject... as if he didn't understand what I was talking about. To me, that is a sure sign of tacit acknowledgement that he actually did know what I was talking about.

Some years ago there was a presentation about the history of emergency responses at Fordham U in Manhattan which included a segment on 9/11. I attended because I wanted to learn about issues related to design input as it related to disaster preparedness. Were the WTC buildings lacking adequate fire protection and egress paths. It was a good presentation.
Wayne Coste attended and set up an "AE911T table" to distribute their literature promoting their CD fantasy. He may have been selling CDs and collecting petition signers. That stuck me as inappropriate.

 

[Thomas B]

for years both "sides" ... made the same fundamental errors ... (The assumption that the "Top Block" fell to impact on Lower Tower. It didn't but try telling anyone that.... Many are still lost.)

What is your take on the Wikipedia article? It might be the reason so many people think the "top block" model captures the basic mechanism.

[Edit to comply with no-click rule:]

After the planes struck the buildings, but before the buildings collapsed, the cores of both towers consisted of three distinct sections. Above and below the impact floors, the cores consisted of what were essentially two rigid boxes; the steel in these sections was undamaged and had undergone no significant heating. The section between them, however, had sustained significant damage and, though they were not hot enough to melt it, the fires were weakening the structural steel.

Source: https://en.wikipedia.org/wiki/Collapse_of_the_World_Trade_Center#Collapse_initiation

From there collapse proceeded through two phases. During the crush-down phase, the upper block destroyed the structure below in a progressive series of column failures roughly one story at a time. Each failure began with the impact of the upper block on the columns of the lower section, mediated by a growing layer of rubble consisting mainly of concrete from the floor slabs. The energy from each impact was "reintroduced into the structure in [the] subsequent impact, ... concentrate[d] in the load-bearing elements directly affected by the impact."[26] This buckled the columns of the story immediately beneath the advancing destruction down to the next point of lateral support, usually the floor trusses of the given story. After the columns buckled the block was once again unsupported and fell through the distance of that story, again impacting the columns of the story below, which then buckled in the same way.

This repeated until the upper block reached the ground and the crush-up phase began. Here, too, the columns buckled one story at a time, now starting from the bottom. As each story failed, the remaining block fell through the height of the story, onto the next one, which it also crushed, until the roof finally hit the ground.[6] The process accelerated throughout, and by the end each story was being crushed in less than a tenth of a second.[31]

Source: https://en.wikipedia.org/wiki/Collapse_of_the_World_Trade_Center#Total_progressive_collapse

Perhaps that would be a place to invest some effort? As I understand it, the truthers have been completely run off that article.

 

[Jeffrey Orling]

What is your take on the Wikipedia article? It might be the reason so many people think the "top block" model captures the basic mechanism.

Perhaps that would be a place to invest some effort? As I understand it, the truthers have been completely run off that article.

The article is a decent summary of the attempts to describe how the towers came down. I found the wiki article fails to clearly articulate how heat from fires led to the collapses in the twin towers. Heat caused failure around col 79 leading to floor collapse is credible but what is not articulated is how that progressed to the interior collapse and the perimeter moment frame collapse which appear to not be one and the same with the moment frame collapse following the interior collapse and likely caused by it. One gets the impression that the failure of columns was largely weakening cause by heat not buckling cause by displacement cause by heated beams.

 

[Edward Current]

What is your take on the Wikipedia article? It might be the reason so many people think the "top block" model captures the basic mechanism.

Perhaps that would be a place to invest some effort? As I understand it, the truthers have been completely run off that article.

I encourage improving the Wikipedia article, but any changes/improvements to the section need to be rigorously referenced to either a reliable secondary source (e.g. a paper in a peer-reviewed general engineering journal) or a notable author with relevant expertise (e.g. a tall-building engineer with their own Wikipedia article, like Guy Nordenson).

I've been watching the 9/11 Wikipedia articles for years. Truthers get immediately and summarily run off if they attempt any shenanigans, which they constantly are — for example, trying to replace all instances of the phrase "conspiracy theory" with "scientific hypothesis."

 

[Marc Powell]

What is your take on the Wikipedia article? It might be the reason so many people think the "top block" model captures the basic mechanism.

[Edit to comply with no-click rule:]

Source: https://en.wikipedia.org/wiki/Collapse_of_the_World_Trade_Center#Collapse_initiation

Source: https://en.wikipedia.org/wiki/Collapse_of_the_World_Trade_Center#Total_progressive_collapse

Perhaps that would be a place to invest some effort? As I understand it, the truthers have been completely run off that article.

Another good place to invest some effort might be to offer NIST assistance with rewording some of the answers on their Towers FAQ webpage ( www.nist.gov/world-trade-center-investigation/study-faqs/wtc-towers-investigation ) so as to eliminate ambiguities that truthers take advantage of in their false narratives. In particular, FAQ No. 28, which only talks about conditions that initiated the collapse, is so poorly worded that it is used by David Chandler and others to claim that NIST scientists dismissed progressive floor failure as the mechanism that sustained the collapse after it had started. Below is Question 28 and part of NIST's poorly worded response.

28. Why didn't NIST consider a "controlled demolition" hypothesis with matching computer modeling and explanation like it did for the "pancake theory" hypothesis?

NIST's findings do not support the "pancake theory" of collapse, which is premised on a progressive failure of the floor systems in the WTC towers (the composite floor system—that connected the core columns and the perimeter columns—consisted of a grid of steel "trusses" integrated with a concrete slab; see diagram). Instead, the NIST investigation showed conclusively that the failure of the inwardly bowed perimeter columns initiated collapse and that the occurrence of this inward bowing required the sagging floors to remain connected to the columns and pull the columns inwards. Thus, the floors did not fail progressively to cause a pancaking phenomenon.

A better wording for that part of the response might be the following:

NIST's findings do not support "pancake theory" as the initiating cause of the WTC tower collapses. This theory is premised on massive fires weakening the structure and inducing a progressive failure of the floor support systems in the floors at and above the airplane impact (the composite floor system—that connected the core columns and the perimeter columns—consisted of a grid of steel "trusses" integrated with a concrete slab; see diagram). Instead, the NIST investigation showed conclusively that collapse was initiated by the buckling of inwardly bowed perimeter columns and that the occurrence of this inward bowing required sagging floors to remain connected to the columns and pull the columns inwards.

The answers to Questions 18 and 31 discuss the overloading of floors that resulted in the progressive "pancaking phenomenon" that took place after collapse initiation discussed in Question 28.

 

[econ41]

What is your take on the Wikipedia article? It might be the reason so many people think the "top block" model captures the basic mechanism.

I'm concerned that we are drifting "off topic" - the thread topic is the unreliability of 9/11 Truther "side" professionals. We are discussing identified flaws with the legitimate professional explanations associated more with the "debunker" side. And clearing up the confused issues can lead to extended debate going further "off-topic". So I will try to keep comments brief - we may need a separate thread or threads.

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.

From there collapse proceeded through two phases. During the crush-down phase, the upper block destroyed the structure below in a progressive series of column failures roughly one story at a time. Each failure began with the impact of the upper block on the columns of the lower section, mediated by a growing layer of rubble consisting mainly of concrete from the floor slabs. The energy from each impact was "reintroduced into the structure in [the] subsequent impact, ... concentrate[d] in the load-bearing elements directly affected by the impact."[26] This buckled the columns of the story immediately beneath the advancing destruction down to the next point of lateral support, usually the floor trusses of the given story. After the columns buckled the block was once again unsupported and fell through the distance of that story, again impacting the columns of the story below, which then buckled in the same way.

This repeated until the upper block reached the ground and the crush-up phase began. Here, too, the columns buckled one story at a time, now starting from the bottom. As each story failed, the remaining block fell through the height of the story, onto the next one, which it also crushed, until the roof finally hit the ground.[6] The process accelerated throughout, and by the end each story was being crushed in less than a tenth of a second.[31]

Source: https://en.wikipedia.org/wiki/Collapse_of_the_World_Trade_Center#Total_progressive_collapse

That explanation is the "Crush Down/Crush Up" hypothesis published by Bazant & Verdure in their 2007 paper "Mechanics of Progressive Collapse: Learning from World Trade Center and Building Demolitions."

I say that explanation is wrong. It has four fatal errors when applied to WTC Twin Towers collapses. And I'm well aware that most debunkers regard Bazant as infallible and that the CD/CU hypothesis is accepted wisdom by many. Here is the outline of my explanatory proof:
1) I believe that B&V fell for the mistake that many debunkers had made by misapplying the "limit case" modelling of the Bazant & Zhou papers of 2001-2. The specific error being the assumption that columns remained inline resisting collapse and were crushed (buckled) as the collapse progressed. And a second associated error - that the collapse started by the "Top Block" dropping so that the upper part of each column impacted on its lower part.

The following are specific examples of false aspects in the quote from Wikipedia:
2) "upper block destroyed the structure below in a progressive series of column failures roughly one story at a time." >> That did NOT happen. The falling debris missed the columns allowing the perimeter columns to fall away and topple and fall away in "sheets" of various sizes. Not "buckled".

3) "Each failure began with the impact of the upper block on the columns of the lower section.." >> Didn't happen. (See #5 below)

4) "This buckled the columns of the story immediately beneath the advancing destruction.." >> Same error - didn't happen that way. Columns were not buckled. Debris fell on floor areas and sheared floors off columns.

5) "This repeated until the upper block reached the ground and the crush-up phase began..." >> Not so - the Top Block was dismantled at the start of progression collapse. (Separate proof available of that assertion.)

The fundamental error is that B&V assumed "columns in line" resisting collapse. The error that B&Z did NOT make 5 years earlier but one that most early truther v debunker discussions got wrong. And was one of the two foundation errors of T Szamboti's "Missing Jolt" paper.

I will pause there - members will realise that what I am explaining opposes current "accepted wisdom". And I'm committing "lèse-majesté" - having the unmitigated gall to disagree with Bazant. So I'll await comments. Possibly discussion in another thread?

And I haven't forgotten my earlier reference to "...two flaws that are relevant to our current discussion..". The second flaw can wait.

 

[econ41]

I encourage improving the Wikipedia article, but any changes/improvements to the section need to be rigorously referenced to either a reliable secondary source (e.g. a paper in a peer-reviewed general engineering journal) or a notable author with relevant expertise (e.g. a tall-building engineer with their own Wikipedia article, like Guy Nordenson).

Whilst I endorse "..improving the Wikipedia article.." I doubt it is pragmatically achievable. Certainly not by comments from a retired Water and Sewerage Engieer - bachelors degree - Australian - with ZERO "publishing" record. Being "correct" wont count for much in the status games of academia. Nor trying to correct the seried ranks of academic status hierarchy from the platform of Wikipedia. Just read Bazant's patronising put downs in the published formal discussion of Bazant's works by those who dared to question "the King".

I've been watching the 9/11 Wikipedia articles for years. Truthers get immediately and summarily run off if they attempt any shenanigans, which they constantly are — for example, trying to replace all instances of the phrase "conspiracy theory" with "scientific hypothesis."

Understood. However my current focus is more on the errors made by and disagreements between those in the debunker professional ranks. When the focus is on "truthers are always wrong" it is easier to overlook the errors made by debunkers. Possible misguided "loyalty" to "our side". Or pragmatics - I've made that call myself not wanting to get offside with both sides when both are wrong. Often when the truther side was definitely wrong, the debunker side was better but still a bit short of "correct".