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

Marc Powell

Active Member
9/11 conspiracy theorists have amassed a cadre of professionals in fields such as physics, civil engineering, architectural design and comic acting who claim that the collapse of the buildings in New York City on 9/11 could not have been due to the effects of damage, fire and gravity alone and must have been assisted by pre-planted explosives. Many of these “experts” appear in the 2014 David Hooper film, The Anatomy of a Great Deception (viewable in its entirety at youtube.com/watch?v=l0Q5eZhCPuc ), where they offer their opinions and share their wealth of scientific knowledge. However, each and every professional who appears in the film can be proven to be either misinformed, mistaken, lying or offering information that is trivial. Below are a few examples:

1. At the 16:14 mark, Robert Podolsky, M.S., Engineering and Physics says:

So, if you have a flame at 750 degrees, you could hold that flame under a steel beam forever and you will never reach a high enough temperature to bend steel, let alone melt it.

R Podolsky.jpg

Obviously, the temperature of the steel beam is never going to exceed the temperature of the flame heating it. However, Master of Science holder, Robert Podolsky, certainly must be aware that the yield strength of structural steel is reduced to less than 20% of its room temperature value at a temperature of 750 degrees centigrade. So then, 750 degrees is not hot enough to melt steel but it certainly is hot enough to weaken it and allow it to yield to stresses. See the chart below from NIST NCSTAR 1, page 30:
Steel Sterength vs Temp.jpg

2. At the 15:42 mark, civil engineer Jonathan Cole says:

But there is a problem, office and open air jet fuel fires cannot melt steel.

J Cole.jpg

Nobody, except members of the 9/11 Truth community, has ever suggested that steel structural members in the twin towers had to melt to initiate the collapses. The steel structure only needed to be heated sufficiently to weaken it and cause floor trusses to sag and columns to be pulled out of alignment. The fires were certainly hot enough to accomplish that. Below is a picture from NCSTAR 1, page 33 showing the columns of the North Tower bowed inward due to the pull of sagging floors:

Bowed Columns.jpg
3. At the 15:47 mark, high-rise architect Les Young tells us:

A lot of things in these kinds of buildings have to be fire resistant by nature. It's required by code. So there really isn't a whole lot of fuel in there to begin with.

L Young.jpg

Each of the Twin Towers contained more than ample fuel, (including almost the entire wreckage of a Boeing 767 airliner and its contents) to sustain fires adequate to weaken the structure as can plainly be seen in photographic evidence of the massive raging and spreading fires. Below is a picture of the North Tower taken by a member of the NYPD Aviation Unit shortly before it collapsed:

gjs-wtc027.JPG

4. At the 16:27 mark, high-rise architect Robert McCoy tells us:

NIST would have us to believe that this was, these were typical office fires, scattered office fires, if you will, that brought this building down. Since the mid-sixties I have tried to follow high-rise fires and I'm not aware of any high-rise buildings that have come down as a result of fires.

As McCoy is heard in voiceover, David Hooper presents the video below taken shortly after the collapse of the North Tower when the fires in WTC 7 had not yet widely spread and flames could only be seen in a single window on its east side:



However, the un-fought fires quickly spread. Here is a video of the east side of WTC 7 taken later in the afternoon that shows just how massive the fires became:




Does that look like a building with a few wastebasket fires that firefighters should have been able to quickly defeat as David Hooper implies? While the collapse of the building was unprecedented (at that time), its unusual design as well as the massive damage and extensive un-fought fires it experienced were also unprecedented. There is a first time for everything.

5. At the 40:29 mark, actor Ed Asner says the following as videos of the collapsing WTC 7 are shown alongside videos of controlled demolitions for comparison:

Explosives are used to demolish buildings like this in just seconds. Okay, so it's a controlled demolition, what's the problem with that? Let's just think about this. Controlled demolitions cannot be engineered and rigged in a day. It takes months and therefore this event must have been planned in advance.

Below is the video of the collapsing buildings presented in Hooper's film:



The "problem with that" is that the collapse of Building 7 was not a controlled demolition and therefore the “event” required no engineering, rigging or advance planning. Incidentally, it should be noted that, in Hooper’s film, all videos of the collapse of Building 7 as well as other buildings destroyed by controlled demolition are presented without their soundtrack so as to allow the audience to only compare their visual appearance. If presented with soundtrack, the silence of the collapse of building 7 would contrast sharply with the staccato roar of demolition charges heard with the buildings that were brought down by controlled demolition.
 
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Mendel

Senior Member.
comic acting
Ed Asner, who died 11 days ago, was also recognized for his dramatic acting; it feels unfair to single out his comedic career.
Article:
Eddie Asner (/ˈæznər/; November 15, 1929 – August 29, 2021) was an American actor and president of the Screen Actors Guild. He is best remembered for playing Lou Grant during the 1970s and early 1980s, on both The Mary Tyler Moore Show and its spin-off series Lou Grant, making him one of the few television actors to portray the same character in both a comedy and a drama. He is the most honored male performer in the history of the Primetime Emmy Awards, having won seven – five for portraying Lou Grant (three as Supporting Actor in a Comedy Television Series on The Mary Tyler Moore Show and two as Lead Actor in a Dramatic Television Series on spin-off Lou Grant). His other Emmys were for performances in two television miniseries: Rich Man, Poor Man (1976), where he won for Outstanding Lead Actor for a Single Performance in a TV series, and Roots (1977), for which he won for Outstanding Single Performance by a Supporting Actor in a TV series.[1]

Asner's best-remembered character, Lou Grant, is a journalist; it feels to me like that's the role the audience would be most likely to assign to him in his appearance in AoaGD, not that of an "expert".
 

FatPhil

Senior Member.
The top arguments (presented and debunked) are of a different type from the final one. The top are supposed factual claims that can be countered with simple facts. The final one drops more into a class of illogic, as it's dependent on something that's not known to be true ("If A, then B, therefore not just A, but B too!!!1").

The Bayesian in me takes this approach to such statements: If such great effort was necessary to rig such a CD, then why was none detected? Absence of detection of such great effort, in a heavily surveiled environment, inside and out, should decrease our belief that it happened. And therefore, as A demands B, our belief in A should be weakened too. So it's a slippery one - their own argument *should* weaken their own argument, but if one makes the right (wrong) assumptions (A), then one gets to conclude even wronger things. It's ouroboros all the way round.
 

Mendel

Senior Member.
Absence of detection of such great effort, in a heavily surveiled environment, inside and out, should decrease our belief that it happened.
Well, if you go in with a strong prior that there was a conspiracy, then that's not enough evidence to disbelieve that. And if you still think a CD likely, then the fact that the preparations were covered up reinforces the prior that there was a conspiracy.

Bayesian analysis is codified prejudice, its results are only as good as the prejudice you begin with.
 
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Marc Powell

Active Member
Ed Asner, who died 11 days ago, was also recognized for his dramatic acting; it feels unfair to single out his comedic career.
Article:
Eddie Asner (/ˈæznər/; November 15, 1929 – August 29, 2021) was an American actor and president of the Screen Actors Guild. He is best remembered for playing Lou Grant during the 1970s and early 1980s, on both The Mary Tyler Moore Show and its spin-off series Lou Grant, making him one of the few television actors to portray the same character in both a comedy and a drama. He is the most honored male performer in the history of the Primetime Emmy Awards, having won seven – five for portraying Lou Grant (three as Supporting Actor in a Comedy Television Series on The Mary Tyler Moore Show and two as Lead Actor in a Dramatic Television Series on spin-off Lou Grant). His other Emmys were for performances in two television miniseries: Rich Man, Poor Man (1976), where he won for Outstanding Lead Actor for a Single Performance in a TV series, and Roots (1977), for which he won for Outstanding Single Performance by a Supporting Actor in a TV series.[1]

Asner's best-remembered character, Lou Grant, is a journalist; it feels to me like that's the role the audience would be most likely to assign to him in his appearance in AoaGD, not that of an "expert".
I meant no disrespect for Ed Asner, although I have to question his judgment for throwing in with the truthers and lending his good name to their enterprise.
 

Marc Powell

Active Member
The top arguments (presented and debunked) are of a different type from the final one. The top are supposed factual claims that can be countered with simple facts. The final one drops more into a class of illogic, as it's dependent on something that's not known to be true ("If A, then B, therefore not just A, but B too!!!1").

The Bayesian in me takes this approach to such statements: If such great effort was necessary to rig such a CD, then why was none detected? Absence of detection of such great effort, in a heavily surveiled environment, inside and out, should decrease our belief that it happened. And therefore, as A demands B, our belief in A should be weakened too. So it's a slippery one - their own argument *should* weaken their own argument, but if one makes the right (wrong) assumptions (A), then one gets to conclude even wronger things. It's ouroboros all the way round.
The Ed Asner statement was included to highlight its faulty logic as well as to demonstrate how Hooper and Gage present incomplete evidence intended to mislead their audience.
 
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Edward Current

Active Member
Believers positively swoon over advanced degrees and impressive job titles (provided those "experts" are supporting their beliefs). There's nothing actually impressive about a Master's degree or Ph.D. other than the person's endurance for staying in school and writing an extremely narrow thesis. And, neglecting that architects know almost nothing about structural or fire engineering, I would love to know more about the "high-rise architects" in the film. People have a way of puffing up their bona fides; I recently met a guy who said he "owned a cannabis business," and it turned out he was just a weed dealer.
 

Marc Powell

Active Member
Believers positively swoon over advanced degrees and impressive job titles (provided those "experts" are supporting their beliefs). There's nothing actually impressive about a Master's degree or Ph.D. other than the person's endurance for staying in school and writing an extremely narrow thesis. And, neglecting that architects know almost nothing about structural or fire engineering, I would love to know more about the "high-rise architects" in the film. People have a way of puffing up their bona fides; I recently met a guy who said he "owned a cannabis business," and it turned out he was just a weed dealer.
I recently had an exchange of comments on Quora with high-rise architect Robert McCoy, the guy in David Hooper's film. His lack of understanding of basic issues regarding steel frame construction and his adherence to the AE911Truth agenda were astonishing. I can provide quotes of what he said or a link to the Quora item if you are interested.
 
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Jeffrey Orling

Senior Member
I would assert that the "knowledgeable" professionals who appear in Gage and Hooper presentations are in fact not knowledgeable about the event. These people are used simply because they have "credentials" which would lead naive viewers to trust what they say. Ronald Regan, said..."trust but verify" and I am almost certain that there was no verification of the statements of these "professionals".
Curious that Gage and Hooper never include engineers or fire science professionals who believe that the conditions present in those buildings were sufficient to weaken, warp, distorted and render the structural frame incapable of supporting the design loads.
The collapses were runaway progression of failures rapidly spreading through the frame... not a single explosive event. The was no evidence of CD found.
So they made it up out of whole cloth and flawed reasoning.
 

Jeffrey Orling

Senior Member
So I will throw out some questions.

From my ramblings around the web and especially on this website.... virtually all the false statements and misconstrued "evidence" advanced by the "truth movement" has been "debunked". While the NIST work may not be precise/complete in every detail, it seems largely correct and sensible and well supported by engineering and physics.

Truthers don't seem to make an effort to "debunk" engineers, physicists etc. who offer "explanations" for the collapse of the WTC buildings. It appears that this work is ignored. I do see that some ridicule the work of Bizant... which clearly is correct on the physics but not applicable to the towers.

Why don't truthers who advance incorrect ideas/theories/explanations acknowledge or respond to those who have debunked their work? It feels like AE911T, for example, simple ignores the debunking. Their advocates largely seem to refuse to engage in "debates" or discussions with non truther engineers and physicists with the exception of Tony Szamboti... who did engage on websites such as JREF, 911FF for a number of years but as I recall never admitted his work was basically bull puckey. Perhaps he has simply stopped his advocacy?

Hulsey was the last "engineer" on the truther side of the debate that I recall. He tried to prove that fire cannot cause a steel frame high rise to collapse... specifically 7WTC. His work was demonstrated to be wrong. Has he responded?

Are truther engineers/professionals reading critiques of their work? Or ignoring them?

Do you know of any truther debunking the debunking?
 

Marc Powell

Active Member
Believers positively swoon over advanced degrees and impressive job titles (provided those "experts" are supporting their beliefs). There's nothing actually impressive about a Master's degree or Ph.D. other than the person's endurance for staying in school and writing an extremely narrow thesis. And, neglecting that architects know almost nothing about structural or fire engineering, I would love to know more about the "high-rise architects" in the film. People have a way of puffing up their bona fides; I recently met a guy who said he "owned a cannabis business," and it turned out he was just a weed dealer.
Since you gave me a "LIKE" vote for my previous response, I thought I would go ahead and tell you about my conversation at Quora with high-rise architect Robert McCoy, but first I should give you some background about what he had to say in David Hooper’s film. I have already mentioned in my OP how McCoy was quoted at the 16:27 mark. At the 22:52 mark he is again quoted as saying the following about the collapse of Building 7:

The buildings actually accelerated as they came down meaning they were not getting resistance from these massive columns in the center of the core of this building. And when it's all finished, the outside walls from the lower floors are piled one on top of the other right in above the top of the building.

Robert McCoy seems to be confused. His first sentence seems to be a description of the twin towers. Then, in the second sentence, he is either talking about Building 7 or has a misconception about where the “outside walls” of the twin towers ended up. They certainly were not “piled one on top of the other right in above the top of the building.” They were either splayed out on the ground on all four sides of each tower or, in the case of the bottom few floors, they remained standing. At any rate, Hooper should not have inserted a quote regarding the twin towers to backup claims about Building 7.

Finally, at the 23:20 mark, Robert McCoy gives the audience his opinion about the NIST hypothesis for the Building 7 collapse mechanism:

It doesn't add up.

Now, about my conversation with Robert McCoy on Quora, you can read the entire conversation at www.quora.com/Does-the-WTC-7-Hulsey-report-definitively-prove-that-fire-was-not-the-cause-of-the-collapse-as-NIST-purported . McCoy offered the fourth answer to the question, which elicited our brief exchange. In our conversation, McCoy offered only speculation while groundlessly denigrating the official investigations and accusing me of being the one giving out “misinformation.” Upon receiving his last communication, I was left with the impression that McCoy is not an architect I would want to hire to design any structure that I or my family should ever be required to enter or stand under. After you have read what McCoy had to say, I would love to get your take on it.
 

Mendel

Senior Member.
Article:
image.jpeg Robert McCoy, former Architect for Many Tall Buildings Up to 44 Storie (1965-2010)
Answered 1st June 2020

First, let me state that I have designed many tall and important buildings during my career. At least 6 have employed Dynamic Analysis in the final design, the first a 34 story building in the late 60’s, and the last a 1,000,000 sf building at LAX.

Secondly, I was the Board Chair at AE9/11Truth and negotiated and signed the contract with the University of Alaska Fairbanks for the study undertaken by Dr. Hulsey. We both agreed that this would be a completely independent peer review study, no interference from AE or anyone else. UAF would not undertake the study without that being a condition. Additionally, when I was with AE, no one else even had a clue what was really involved is such a study. It was just “A good idea” to do it was the general consensuses. Dr. Hulsey and I are still in contact but our only discussions have related to how was it going. I am an Architect, not an Engineer.

Third, the final report, peer reviewed, was published a few months ago along with all the supporting data and misc other studies connected with his work. And that work was based upon over 2,000 sheets of Shop Fabrication Drawings prepared by Frangle Steel Fabricators and Erectors. These are the drawings from which Building #7 was built. The original steel design drawings were also available for review. All of the above is on line for public review.

Fourth, the analysis by fire was considered and is discussed in the report. Additionally, all reasonable scenarios were also analyzed in order to simulate what was captured on the videos we have all watched. This included studies of the building after it was damaged by debris from Buildings #1 and #2. Ultimately the only scenario that worked, or resembled what we have all seen, involved removing the interior core columns followed shortly thereafter by removing the exterior columns. And then progressing upward as the building descended.
The only logical explanation for such a collapse at the acceleration of gravity, which has been measured by many, and the results of Dr. Hulsey’s study, is controlled demolition.

Keep in mind, the building was fully fireproofed, had fire sprinklers throughout, and that the steel frame and connections are designed to withstand approximately 4 times the ultimate strength of the steel.

I hope this puts this question to rest. And I urge you to read the final report.


Marc Powell

The UAF study does not address the fact that the collapse was silent… except for the clatter of a crumbling steel frame building. There is no way that all 82 columns over eight floors could be simultaneously explosively severed without so much as making a peep. That alone should be a clue that fire actually did cause the collapse.

Dr. Hulsey also ignores the gentle east-west swaying of the building that began a few seconds before the falling of the east penthouse and continued until the beginning of global collapse. It is covered in depth in the NIST report and is clearly visible to anyone with access to the CBS video of the collapse taken from West Street. The swaying was an indication of internal failures that NIST scientists determined to have resulted in external columns between the 7th and 14th floors becoming insufficiently braced so as to buckle. That is what resulted in the short interval of free fall that truthers like architect Robert McCoy go on and on about but in actuality is trivial.

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Robert McCoy
9th August 2021

Mark,

Actually the explosives used, and well documented by others, were of the incendiary type that produce the necessary heat to melt, and or soften, the steel so as to cause the collapse. Very little sound, if any, would have escaped the building enclosure itself because the type of explosive used produces very little sound. Fire alone does not produce sufficient heat to cause the steel to fail. Additionally, there was most likely an ample amount of ambient sound/noise a the time of the collapse. And don’t forget, the building has a design safety factor of between 3 and 4 times the anticipated dead load, live load, and wind, plus it was fully fireproofed to between 2, 3 and 4 hour protection depending on where the steel and decking is in the building.

As for the swaying, all tall buildings sway naturally with the wind. I would not be surprised if Building 7 were to sway 18″ or more naturally at any time on any given day. And from the videos we know the wind was blowing that day.

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Marc Powell
9th August 2021

Mr. McCoy,

I have seen your interviews in various 9/11 truth films and know you to be a reasonable person. So, I can’t understand how you can make such speculative statements in this forum with such conviction. You, of all people, should know that there is no explosive or incendiary in existence that is capable of silently and without flash or blast wave instantly cutting through thick structural steel. I am aware of the paper that was published several years ago claiming that unreacted thermite (thermate, nano-thermite, etc.) was found in the WTC dust and have read it in its entirety. However, I found it to be unconvincing. The tests performed by scientists on the suspicious “red/gray chips” were flawed and showed the heavy influence of confirmation bias and disregard for conflicting evidence. And if you read the paper very carefully you will find only one brief mention that the red layer on the red/gray chips they tested (the part alleged to contain thermite) was only between 10 and 100 microns thick, and much of that material was an inert polymer binder. Now, there is no way that a film of exploding paint as gossamer thin as a baby's hair can blow through 4"-thick structural steel. It's thermodynamically impossible, and that alone should have clued the scientists in that what they were looking at really was nothing more than paint flakes. And, in fact, an independent researcher (James Millette) tested red/gray chips found in dust samples in his possession and found them to be flakes of ordinary primer paint with an adherent layer of mill scale… exactly what might be expected in the dust from the collapse of a steel structure. So, incendiary explosives are not well-documented, there is no evidence of their use on 9/11 and there is no scientific validity in speculation that they offer any kind of reasonable explanation for the collapse.

With regard to the utter silence of the Building 7 collapse, please watch this video:

Source: https://www.youtube.com/watch?v=_5XAUUnBYpY


The collapse was so silent that an EMT being interviewed on camera didn't know anything was happening behind her until it was pointed out by others. You can’t seriously be proposing that the collapse seen but not heard in the video was the result of explosive controlled demolition. Why do you suppose it is that videos of the collapse presented in 9/11 truth films (some of which feature your interview) do not include the soundtrack?

Now, regarding the swaying of WTC 7 that NIST documented but that Dr. Hulsey ignored, please take a look at this video:

Source: https://www.youtube.com/watch?v=nqbUkThGlCo


If you mark the upper right corner of the building you will be able to clearly visualize the east-west swaying of about 12 inches that occurred between the falling of the east penthouse and the start of global collapse. NIST analysis determined that the swaying actually started several seconds before that. Does it seem likely to you that sudden wind gusts caused the building to start oscillating right before it collapsed or does it seem more likely that Dr. Hulsey ignored the movement of the building because it conflicts with his hypothesis? By the way, Dr. Hulsey claims that the three columns under the east penthouse gave way first at about the 44th floor level causing the penthouse to descended only a few stories into the building. The area where the explosive demolition of the columns supposedly occurred is in direct line-of-sight with the camera which was less than a half-mile away. Do you really think such an event would not be audible on the soundtrack and would not cause windows to break? I don’t think so and you shouldn’t either.

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Robert McCoy
14th August 2021

Dear Mark,

I have reviewed your response of 080821 to my previous responses regarding your comments. I have several questions and responses to your comments.

First, I would like to know to whom I am responding. Your Quora Bio lists you as a ‘former Civil Engineer’. That tells me nothing. I have been quite open about my background as an Architect and experience with tall buildings. However, I know nothing about yours. As a ‘former civil engineer’ what does that mean? Are you retired? Were you licensed and where? If so, why the word ‘former’ in your background description. And what branch of civil engineering were you involved in? And for how long? And what are/were your significant accomplishments?

Secondly, I could not get the videos you included to play, initially. They were blocked and cited as non-factual information, in essence, they were cited as misinformation. However, the videos themselves were included in the response today and I could play them.

The first video of the lady not being able to hear the collapse behind her, is misleading. She is obviously several blocks away and there are buildings between her and Building 7. Plus, the fact that she was standing in a street with busses, cars, fire engines, and other ambient noise generators that would have muzzled the sound at her obvious distance from the event. Remember, the collapse was initiated at the lower floors and continued at the lower floors as the mass of the building descended into the rubble pile.

The second video does not indicate to me any movement of the tower to the east, again, the video was shot from a distance that would make it impossible to detect any movement in Building 7, even 18” as I indicated before as a potential movement due to wind. And you must remember there was some wind blowing that day.

As for the explosives used, the incendiary characteristics would not make as much sound, as say dynamite would make. Secondly the larger charges would have been on the columns in the center of the building, the smaller charges at the perimeter, and all sound would have been shielded, or muffled, by the building enclosure itself. In addition, the steel was enclosed in fireproofing that would have contributed to the muffling/suppressing of the sound.

You next discussed the red/grey chips found in the rubble. And yes, there are multiple tests on such sample. And they all do not agree. However, your statement that the flakes were paint is simply not true. The steel is not painted prior to applying the fireproofing. I have only one building where the steel was not painted. And the paint used was green in color. Steel, or I should say, miscellaneous iron, in any building is generally painted with a red paint as a rust inhibiter. But it does not receive fireproofing.

One more point, the steel in some instances exhibits a significant amount of erosion from the explosives. That is the result of the steel being oxidized, or burned, due to the explosives used. In fact, it is a characteristic of the incendiary explosives used. It is not a characteristic of other types of explosive charges.

And one final point on this issue; the fireproofing was noticeably absent from the steel in the rubble and as it was being hauled away. In fact, there was very little fireproofing in the debris pile. BUT we did see a large plume of ash drift away from the buildings as they collapsed. And there was a significant amount of dust everywhere. That dust and ash were the fireproofing, concrete deck, and other concrete and materials. It was caused by the fireproofing ‘encapsulated’ to keep the asbestos contained, and the ‘encapsulating’ material contained incendiary material. Additionally, the metal decking and the concrete topping were also missing in the debris pile, another sign of the type of incendiary explosive used.

Please do not split hairs with your interpretation of the videos or the lab reports. There is enough misinformation, and patently false information already out there. We do not need more.

Robert

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Marc Powell
14th August 2021

Robert,

I prefer not to divulge too much personal information. However, I will say that I am semi-retired and work in a field of civil engineering unrelated to structural engineering. That said, I did take college courses in design of reinforced concrete structures and indeterminate steel structures. So, I am not exactly a babe in the woods when it comes to technical issues such as the building failures in NYC on 9/11.

The YouTube videos I referenced in my previous post are in the public record and are entirely accurate and unaltered. The movements of Building 7 in its lead-up to the collapse are well documented in the NIST Building 7 Investigation, Appendix C. The building was initially at rest. The east-west oscillations began six seconds prior to the falling of the east penthouse and continued for an additional seven seconds until the start of global collapse. They were a reaction to internal failures and not due to wind gusts as you suggest. The oscillations are readily visible in the CBS video if you place a marker on your monitor at the upper right (northwest) corner of the building. The final oscillation before the beginning of global collapse took the building only six inches to the east and eight inches to the west, so don’t expect to see a lot of movement. But, whatever movement there was is a major clue to what was going on inside the building and cannot be ignored. Wouldn’t you agree that any analysis that concludes that all the columns were removed almost simultaneously (by something other than fire) should also be able to explain the oscillations leading up to the collapse? Dr. Hulsey failed to address this issue… or even acknowledge it in his exhaustive investigation and the reasons for that should be obvious.

I will address the other issues you raised in additional posts as my time allows.

Marc Powell
14th August 2021

Robert,

Continuing with my response to your response.

It is my understanding that steelwork used in the construction of steel frame buildings leaves the factory with a prime coat finish. The World Trade Center twin towers were no exception. Here is a picture that shows how the steel looked prior to the application of SFRM:


Here is a picture of the bar trusses after the application of SFRM:


I have only seen red iron oxide paint used as a prime coat on structural steel. That is what was used on the twin towers and flakes of it were claimed to contain “thermitic material” by 9/11 truth scientists.

As you said, “There is enough misinformation, and patently false information already out there. We do not need more.” That being the case, please vet information you provide and avoid offering opinions and speculation for which there is no evidence.

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Robert McCoy
20 August 2021

Dear Mark,

I am surprise, but not really, at your reluctance to disclose your CV. However, your response did tell me what I needed to know to evaluate your comments. As such, I will respond this one last time.

To Quote you, however, which included a quote from me, “As you said, ‘There is enough misinformation and patently false information already out there. We do not need more.’ That being the case, please vet information you provide and avoid offering.” If you mean following the NIST report, then you are welcome to it. However, I know, based upon my extensive experience designing and constructing tall buildings, that it is a ‘propaganda’ document, designed to deliberately mis-lead the public. And in all the comments you have made to me so far, all you have done is attempt to cast doubt on what I have said, all without anything factual to back up your comments. Please use a little common sense the next time you try to cast doubt on someone else’s comments.

Please do not comment to me again as you have nothing further to add to our understanding of what happened on the fateful day.

Several factors were not considered by you, CBS, or NIST as well as Hulsey re the perceived alleged oscillation of the Building 7. All of which really add nothing to the discussion. For instance:

1.

The distance of cameras, including the one you cited, could easily have vibrated imperceptivity at the moment the collapse ensued. That movement could have been caused by any one of a number of factors, such as the traffic on the street next to the camera. There is a heavy fire engine passing in the photo captured. Or the operator having his or her hand resting on the camera or tripod. Or simply the wind.

2.

Keep in mind that even the slightest movement of a camera will magnify the movement of any object as far away at WTC7 was when It began the collapse.

3.

Additionally, air movement, such as heat rising, or a sudden movement caused by the exhaust of a passing vehicle could easily have distorted the image as recorded. Or simply a heat wave passing between the camera and WTC7.

4.

Or as you allege, the movement was caused by initiation of the collapse itself.

5.

Keep in mind, as I commented previously, all tall buildings move laterally naturally. Some caused by wind, some by earthquakes, or just the sun on one face vs. cold air on the opposite face. The distance you allege is insignificant and had no effect on the collapse.

We really do not know, nor do we have enough factual or scientific evidence to adequately explain any perceived movement such as you allege.

You are simply splitting hairs to make a point, that truthfully cannot be made from the evidence. However, it is entirely possible the penthouse collapse did cause some movement. How much, if any, we cannot adequately determine from the evidence we have to date.

And please do not cite the NIST report as factual. From my perspective and knowledge, it is no more factual than a Dr. Zuss book would be explaining 9/11.

Also keep in mind that the NIST studies for all of the buildings were to only investigate up to the moment of the start of the collapse, nothing further. Nor were they required to state the cause of the collapse. They simply were tasked with determining a ‘possible’ cause of the collapse.

Next you stated that “…steelwork used in construction of steel frame buildings leaves the factory with a prime coat finish.” Yes, some steel does leave the fabrication shop with a prime coat of rust inhibitor paint. BUT NOT ALL! Especially steel for tall buildings. That coating interferes with the adhesion of the fireproofing and the welding. The photos you included do appear to be prime coated. However, the photo on the right shows’ signs of oxidation or some other material such as dust or salt build up. I do not know how those outside columns were fireproofed. If the fireproofing was done with say fiberglass insulation, I would have expected the steel to be coated with a rust inhibitor paint.

Additionally, we do not know how long before erection the steel was fabricated or where it was stored. All of these would have been contributing factors.

The erection photos I have seen, however indicate to me that most of the steel was not coated with a rust inhibitor paint. One further note on these two photos; they seem to have a reddish cast to everything. Notice the grey concrete mat foundation has a reddish cast to it and the sky appears to be red, or pink as well.

I have never had the steel for a tall building leave the fab shop with a rust inhibitor paint, with the one exception I mentioned earlier. In fact, the weld joints are polished so as to receive the weld material and seal the construction joint tighter and stronger when welded.

On the other hand, I have seen 3 and 4 story wood and steel frame buildings with the steel coated in a rust inhibitor paint. That steel will not receive spray-on fireproofing. It will simply be covered with gypsum board for the fireproofing rating required. I suspect those are the buildings you are familiar with.

The second photo showing the fireproofing on the interior adds nothing to this discussion.

One final note: I have designed a number of buildings with structural steel used in the roof framing and it has been furnished to the job site with a rust inhibitor paint finish. We subsequently painted the steel with a protective coat of exterior paint. The exposed steel contributed to the overall character and grace of the building. Steel, when used appropriately can be very handsome.
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Mendel

Senior Member.
His final answer shows McCoy flailing. His idea of "camera shake" ignores that the building in the foreground are rock steady. His idea of the shaking caused by wind etc. ignores that it only started seconds before the collapse. Point 4 may refer to the building or to the camera, but the movement starting seconds before the building collapses means it proves a major flaw in the Hulsey report either way.

I don't really understand how he can mention 4-hour-rated fireproofing as evidence that the building couldn't have been damaged by fire and collapsed almost 7 hours after it started burning.
 

Marc Powell

Active Member
His final answer shows McCoy flailing. His idea of "camera shake" ignores that the building in the foreground are rock steady. His idea of the shaking caused by wind etc. ignores that it only started seconds before the collapse. Point 4 may refer to the building or to the camera, but the movement starting seconds before the building collapses means it proves a major flaw in the Hulsey report either way.

I don't really understand how he can mention 4-hour-rated fireproofing as evidence that the building couldn't have been damaged by fire and collapsed almost 7 hours after it started burning.
Thanks for posting my Quora conversation with Robert McCoy.

If I didn't think our conversation was endlessly looping, I would have brought up to McCoy the point about other buildings in the video not shaking along with WTC 7. Clearly, he could never admit that there is evidence that contradicts his speculation or that casts aspersions on the validity of Dr. Hulsey's findings.
 

Jeffrey Orling

Senior Member
David Chandler was on the radio this evening hawking his free fall means CD myth and referring to the excellent work of Hulsey and Szamboti. I have seen the 911truth "thinking" soundly debunked over the years.... detail by detail, point by point.
So how is it that this has no impact on them? Do they ignore the "debunking" as if it's not there? Have they refuted the science/engineering that shows their thinking flawed?
Credentials often led credibility to a person's argument and we think of someone with them as an "expert". But more important that the CV are the arguments. And truther arguments don't stand up to scrutiny.
So who is the audience for these truther so called experts? Would it be NIST or Popular Mechanics? Are they expecting the engineers who work at NIST and PM to respond and or retract their reasoned arguments supported by settled engineering and evidence?
Behind the flawed/false truther engineering claims lies the main thesis... 9/11 was an "inside job" not the work of radical Islamic terrorists. Who did the inside job is never defined. But sometimes we hear of rogue intel inside gov working for the MIC or the "deep state". They supposedly have the means, motive and opportunity to do "big things" like the 9/11 CDs. But I digress...

How is it possible that the truth engineers never retract their false claims, incorrect "science"/ engineering and misread evidence?

Unfortunately technical explanations seems to be turned into simple cartoons probably because the public cannot understand the science or the engineering involved. We got the "pancake theory" for just this reason. It has elements of truth but for the most part is not an accurate depiction of the twin tower collapses.

And then there are the completely wrong ideas like structural steel melted as the cause of its failure. There was no melted steel at the WTC. There was melted aluminum. Aluminum was not used for structure.

All three towers experienced a process over time of structural "deterioration" which was "driven" by heat. Heat both weakens steel and causes it to expand. We know that and see the strategies for dealing with this in expansion joints in bridges, roads and even building elements.

It also seems that truther engineers don't understand the collapses we all saw.
What collapsed for the most part were the floors and contents, not the columns. In fact much of the core's of the twin towers survived the collapse of the floors and the peeling away of the structural perimeter. You can't reach a correct understanding of something with flawed observations along with insufficient technical background to inform your understanding of the observations. This is clearly what is happening in the lay public. And you see reason such as... it looks like X so it must be X as well.

But the more educated truthers should be able to understand the technical explanations, especially those that debunk the false claims... such as... it is impossible for the twin towers to collapse with CD involvement. Why are they denying science, engineering and fact?

++++

Years ago circa 2009 I attempted to introduce some contrary ideas to AE911T about the collapse. I suggested they embark on a building performance study to explain how the buildings could collapse. I was called a cognitive infiltrator by Griffin... a spy... a plant and someone sent to destroy the truth movement. Pretty crazy stuff. The truth movement was not destroyed and their "professionals" continue to prattle on (in the media) about their false claims and junk science. I suspect engineers and scientists can't be bothered with them... but the lay public seems to fall for their false claims.

Does it even matter?
 

Oystein

Senior Member
I was surprised to see McCoy claim that structural steel is either painted or fire-proofed, but not both. I was surprised to see him speculate that explosives were in the fireproofing. His having-it-both-ways on silent explosives that don't explode but are explosives, they melt, like explosives ... very confused.
The talk of "independent peer review" - LOL what? AE911truth paid for the study and provided the peer-reviewers based on their already agreeing with the conclusion, a conclusion Hulsey had already come to even before he had done the modelling.
 

Mendel

Senior Member.
I was surprised to see McCoy claim that structural steel is either painted or fire-proofed, but not both.
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.

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?
 

Edward Current

Active Member
I love how he immediately challenges Marc's qualifications -- Who are you and how are you qualified to challenge an architect with zero engineering training? Oh, you have engineering training? Since you won't say exactly what kind, this will be my last reply. :rolleyes:

Of course this is a pattern with fringe believers and pseudo-skeptics of all kinds: intense scrutiny of the qualifications of anyone supporting the "official story," but zero scrutiny or skepticism over the qualifications of anyone supporting the fringe belief (e.g. Hulsey, an expert on bridges who had never done a fire analysis).

But it was peer reviewed.... :rolleyes:
 

Oystein

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

Here is the proof for the Twin Towers' core:
Turn to NIST NCSTAR 1-6A, page 288 of the PDF-file, which is in Appendix A. This describes how damaged fireproofing was to be repaired in 1995 - recommendations made after a survey carried out by Leslie Robertson from the elevator shafts. The key quote: "prior to re-fireproofing steel, paint with a zinc-rich paint."
NCSTAR 1-6A p236 Repair fireproofing in 1995.jpg

Here is proof for the external wall panels, as produced by Pacific Car & Foundry Company:
Turn to the same report above, page 302f of the PDF. It's a letter dated March 5, 1968, describing the paint job PC&F. The important quote is that "we" [i.e. PC&F, factoryside, as opposed to onsite construction teams] "are about to paint our first production [wall] panels ...".
NCSTAR 1-6A p250 Letter from PCF concerning paint on wall panels.jpg
The next page specifies "Tnemec Red 99 Red Metal Primer" as the paint for that project (the wall panels), a "Texaco #LB [? difficult to decipher] rust proofing compound" for field welds (i.e. where in the process of onsite assembly corrosion protection has gone missing, and the "Tnemec 99-G Green Metal Primer ... for all stenciled marks".
NCSTAR 1-6A p251 Letter from PCF concerning paint on wall panels.jpg

And here is proof for the floor trusses:
Turn to NIST NCSTAR 1-6B, page 158 of the PDF, which contains the 1967 paint specification for the joists (trusses):
NCSTAR 1-6B p157PDF PaintSpecification LaCledeJoists.jpg
The key is that all trusses are painted at the factory, before delivery to the WTC site for assembly.

In all three cases I think it should be clear that the paint is not removed from the steel before spraying on fire proofing, and that fireproofing is thus applied to the painted steel surface.
 

Oystein

Senior Member
...
Of course this is a pattern with fringe believers and pseudo-skeptics of all kinds: intense scrutiny of the qualifications of anyone supporting the "official story," but zero scrutiny or skepticism over the qualifications of anyone supporting the fringe belief (e.g. Hulsey, an expert on bridges who had never done a fire analysis).
...
Oh the irony: Hulsey and AE had invited members of the public - not just expert public but general public - to follow the study's progress and to submit comments on the draft report.
But when I had submitted my comments, and they didn't show up at first in the Public Comments document, I wrote Hulsey - and as soon as he became aware that my criticism was thorough, extensive and devastating, he went for the "...and your qualifications are?" ploy. My reminder that members of the public were invited to comment, and that each comment should be judged by its merits, he stopped responding.
 

Marc Powell

Active Member
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.

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?
The trusses in the towers definitely had a prime painted finish before the application of SFRM. Here is a picture taken from NCSTAR 1, Page 71 where the red iron oxide primer is visible in spots where the thermal insulation is missing:

Painted and Insulated Trusses.jpg

From the way that the bar trusses ended up in a jumbled mass after the collapse, there must have been massive amounts of paint flakes ("red/gray chips") generated.
 
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Marc Powell

Active Member
I love how he immediately challenges Marc's qualifications -- Who are you and how are you qualified to challenge an architect with zero engineering training? Oh, you have engineering training? Since you won't say exactly what kind, this will be my last reply. :rolleyes:

Of course this is a pattern with fringe believers and pseudo-skeptics of all kinds: intense scrutiny of the qualifications of anyone supporting the "official story," but zero scrutiny or skepticism over the qualifications of anyone supporting the fringe belief (e.g. Hulsey, an expert on bridges who had never done a fire analysis).

But it was peer reviewed.... :rolleyes:
I received the exact same response when I tried to communicate with David Chandler. He demanded to know my background and qualifications and then refused to discuss his analysis of the North Tower collapse because I preferred to protect my anonymity. By the way, in YouTube comments, I have received death threats from those who fancy themselves to be patriots for supporting people the likes of Gage, Hooper and Chandler. So, I have good reason to not give out too much personal information.
 
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At the 22:52 mark he is again quoted as saying the following about the collapse of Building 7:
The buildings actually accelerated as they came down meaning they were not getting resistance from these massive columns in the center of the core of this building. And when it's all finished, the outside walls from the lower floors are piled one on top of the other right in above the top of the building.
There another thing I don't get. How does acceleration means there's no resistance (apart from the fact that any resistance wouldn't have come from the columns in the first place)? A lot of people I have engaged with online seem to believe that less acceleration means deceleration. So does McCoy, which really surprises me. Shouldn't architects have a basic understanding of physical principles?
 

Jeffrey Orling

Senior Member
There another thing I don't get. How does acceleration means there's no resistance (apart from the fact that any resistance wouldn't have come from the columns in the first place)? A lot of people I have engaged with online seem to believe that less acceleration means deceleration. So does McCoy, which really surprises me. Shouldn't architects have a basic understanding of physical principles?
Of course they should,
The velocity of the collapses concerns two different observations,
The facade of 7wtc appears to drop as if there is "nothing supporting it/in the way". This is because the axial structures... columns and belt truss on floors 5-7 was pushed out from under the 40 stroy tall moment frame of 57 columns above. This is like kicking out the legs of a table and having the top drop. A total collapse of the interior preceded the drop of the moment frame. The moment frame "began" at floor 8 which was 108 feet from the the ground.. that explained to 2.25 seconds.
The rapid collapse of the floors inside the structural exterior tube... can be measured by "timing" the ejections of debris at the collapse front coming through blown out windows... these were measured at something like 100' feet / second. That speed did not increase. There was no acceleration. Of course all things which were "at rest" and then are moving... have to accelerate from 0 feet/ sec to whatever speed they do reach... So there always will be a period of acceleration in the beginning. The structural facades peeled away.... the core columns toppled from instability absent the bracing that the floors supplied to the columns. Nothing unusual about the motion or its speed.
 

econ41

Senior Member
There another thing I don't get. How does acceleration means there's no resistance (apart from the fact that any resistance wouldn't have come from the columns in the first place)?
There has, over the years of these discussions, been a lot of confusion from "both sides" and not always the result of deliberate truther mendacity. Much of the base level confusion arises from a cluster of issues including:
1) The handful of "truther tropes" which are accepted as fact by the TM and are all false. Including (a) free fall proves CD - that one relevant to this discussion then (b) falling in own footprint and (c) falling "symmetrically" >> neither relevant at this time BUT all three are features of a collapse mechanism. NOT of CD which is a means of starting (or helping to start) a collapse.

2) Failing to distinguish between the STATE of "free fall" and the resulting MOTION at Free Fall Acceleration. ["FFA"]. That aspect compounded by two other isues. First the presumption that FFA can only result from a state of free fall. Not so. It will result if there are external forces applied but the NET sum of those forces other than gravity is zero. Second the practice of many professionals of saying "free fall" - even "free fall speed" - when they mean FFA. Assuming that fellow professionals will know which is meant. "We" usually do but it can confuse lay-persons.

So reverting to your specific questions:
(i) Correct. The amount of acceleration reflects the net resistance. Any net resistance and acceleration will be less than "G". (And "NET" is IMO vital to comprehending the acceleration of the WTC7 facade subject of the controversy between Chandler and NIST.) (The fact that the motion "averaged" "G" is IMO strong indication that it was NOT Free Fall. I'm aware of better measuremnts that suggest actual measurable over "G" which would be conclusive of "not Fee Fall" >> a side track we need not take at this time.)
(ii) I'm unclear as to what columns you refer to as producing no resistance. (Side issue but the 2/3rds "G" during the Twin Towers progression stage - the "missing" 1/3rd "G" is to first order approximation explained by the need to accumulate momentum as each impacted floor added to the mass of debris. Structural resistance had minimal effect.)
A lot of people I have engaged with online seem to believe that less acceleration means deceleration. So does McCoy, which really surprises me. Shouldn't architects have a basic understanding of physical principles?
Yes. That is one of the common confusions. Understood that you find it surprising. At this level even informed professionals occasionally make errors. Yes - both architects and engineers should understand the basics BUT most practicing professionals become accustomed to routine application of established practices. Contemporary engineers are protected by their FEA suite from making many errors. Forensic applied science often requires working from basic principles in a way that most practising professionals have not done since undergrad study days.
 
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econ41

Senior Member
McCoy, like @Marc Powell suggested, seems to be a bit confused. The first sentence of his discussed quote seems to refer to the Twin Towers. So my best guess would be McCoy believes the core of both towers should have provided resistance during the collapses.
Thanks. Without chasing back through all the who said what material this is the situation for the Twin Towers and WTC7 scenarios:

For Twin Towers the collapses were in two distinct stages with two very different mechanisms. To accurately complete the explanation actually needs four "sub" stages - but two are all we need for this explanation. Remember the question is "would the core columns resist the collapse" and I'm saying "No!".

The dominant process of the "initiation stage" was a cascading failure of columns losing strength to carry vertical loads. Easily seen with WTC 2 where columns failing more one side than the other caused tilting of the top block. Same scenario with WTC1 tho' the tilt was less - not as obvious The details readily analysed >> load redistribution as each column (or column cluster) fails its load is taken by other columns which fail in sequence. (And that much is true whether or not truther claims for CD are true >> all CD would do is add more "clear cut" columns into the mix >> plane impact had already clear cut some columns.) And the load redistribution cascading failure was possibly assisted by heat weakening. Note that NIST hypothesis that column inward bowing was the trigger. I agree it is most probable. And the net result of "inward bowing" is that the column loses vertical load carrying capacity >> consistent with what I am saying. NET bottom line - the initiation stage allowed the Top Block to start to descend AND guaranteed that the falling material missed the columns both perimeter and core. << That may need more "proof". This graphic shows why the Top Block columns were misaligned with their bottom parts. It is the most extreme case but the other three views - one for WTC2 and both options for WTC1 are analogous. Falling top part of columns miss their bottom part
ArrowedROOSD.jpg


and the next graphic shows how falling debris missed the perimeter columns as the collapse went into "progression stage". And the situation was analogous for the inner "end" of the office space floor joists. Also for the core though there would be more chaotic interactions in that area - more columns in a more confined space::

003c350.jpg

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

I'll be much briefer with WTC7. The core fell first so there was no significant core column resistance to slow down the dropping of the perimeter shell. >> Further discussion if needed. Note: There is plausible argument that inner stucture elements were "pulling down" the facade perimeter shell at the zone subject of "controversy" between D Chandler and NIST. But that is NOT resistance from columns - if it is correct it is pulling down not resisting.

Overall summary: If "McCoy believes the core of both towers should have provided resistance during the collapses." he is misinformed or misunderstanding the mechanisms of all three collapses.
 
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econ41

Senior Member
Yeah, I am aware of that. Hence my earlier suprprise :).
No problem. You may also be aware that early research and on-line debate for many years took a false trail. Misapplication of Bazant & Zhou's 2001-2 "limit case" paper saw most explanations assuming "columns in line" as part of the resistance to collapse. Remnants of those early misunderstandings of mechanism still arise quite often. The related error - assumptions that the "Top Block" dropped to impact the lower tower still distorts reasoning.
 
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Thomas B

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

Mendel

Senior Member.
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'm fairly sure we discussd this here a short while ago,and your numbers are off.
The floors could take a static load of 3-6 other flosors or something like that, but they had a much greater weight dropped on them. Look up the nmbers and then ask again, please.
 

econ41

Senior Member
"significant" is a no-true-scotsman enabler.
Blame me - not @Thomas B I first used the term because, logical pedantry aside - I can explain in SUFFICIENT ( ;) ) detail if there is any SERIOUS ( ;) ) interest. Except we are drifting of topic.

Put as simply as I can and not even attempting to be 100% pedantic with either logic or quantifying the maths. - I'll flag the "naughty words":

(a) The progression stage collapse of both Twin Towers moved at about 2/3rds "G". So it wasn't free fall;
(b) There were three main sources of resistance which contributed to the "loss" of about 1/3rd "G". In order of probable magnitude they are;
____(i) the effects of momentum accumulation as successive floors were sheared and debris added to the falling mass.
____(ii) structural resistance as the floor to column connections were sheared. NOTE Those forces are resisted by the columns supporting those floor connections; AND
____(iii) Some friction as the falling debris "rubbed" on the face of the still intact columns NOTE also contributing some column resistance.

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."

;)
 

econ41

Senior Member
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?...........................
If you have the patience to explain it, please do.
In the interest of transparency we should acknowledge that I have on several previous occasions attempted to engage you in discusion to support explanation. And attempted the same by PM. To put it diplomatically we ran into some problems.

And explaining what did happen does not fit comfortably with the ethos of Metabunk which is focused on debunking bunk.

However if there is interest I am prpared to present my explantion of Twin Towers collapse mechanisms. Such explantion needs to be by coherent argument in a step by step process working from agreed facts and from "broad brush" "big picture" down into as much detail as is necessary for the parties. Such a process does not lend to intrusion of derailing half baked ideas taken out of the context of another ill defined fantasy scenario.
 

Marc Powell

Active Member
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.
Let me try to help you understand what happened to each of the twin towers. After the misaligned columns at the plane crash floor buckled, the floor directly below was instantly overloaded and collapsed onto the floor below it. This video might help you visualize the progressive collapse of floors that followed.


www.youtube.com/watch?v=wFp4S4Ey-sU

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. Although the building was much shorter than the WTC towers and the walls remained standing, the near free-fall acceleration of the collapsing floors and the dust and debris expelled from windows looked just like the twin tower collapses. Somehow, truthers just can't seem to grasp the simple physics involved in this phenomenon. Their engineers, architects and even a physics teacher (David Chandler) in 9/11 “truth” videos declare that it would be impossible for a building to "fall through itself in the path of greatest resistance" as the towers did on 9/11 without the assistance of precisely timed explosives clearing a hole for the rubble to fall into. But when you understand the basic laws of motion and transfer of momentum that were in play, what happened that day should be no mystery.
 
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Marc Powell

Active Member
what? did you misword that?
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.
 
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