6 ms·

15 Years Later: on the physics of high-rise building collapses [pdf]

17 points by 2a0c40 10y ago

xpaqui 10y ago
> Meanwhile, unreacted nano-thermitic material has since been discovered in multiple independent WTC dust samples [13] http://www.911research.wtc7.net/mirrors/bentham_open/ActiveThermitic_Harrit_Bentham2009.pdf http://www.911research.wtc7.net/mirrors/bentham_open/ActiveT... Suspicious Indeed.
nwp 10y ago
FYI: Truther article
- myrion 10y ago
  Yeah, with lots of weasel words and written by people who are not qualified on the topic.
  - woah 10y ago
    It's written by a professor of physics, a professor of civil engineering and a mechanical engineer.
    - jcranmer 10y ago
      The physicist in the group should be classified as a particle physicist, not a structural mechanics expert. That's as worlds different as saying that someone who studies compiler research is qualified to talk about recurrent neural networks.
- codeduck 10y ago
  This needs to be tagged as such, I started reading this believing that it was a reputable paper.
- deleted 10y ago
  [deleted]
- woah 10y ago
  Is an article that comes to a conclusion different than the one you believe automatically false? That seems to be your only complaint.
  - jcranmer 10y ago
    Conspiracy theorists (in general) have been known to make stuff up, and non-experts who believe in them can easily parrot this stuff thinking it's true. A great example of this in history is the "Magic Bullet Theory" of JFK's assassination, which holds that the single bullet is false because the bullet would have had to make sharp turns to get to its next target, which is almost entirely based on made-up positions in a fake film. Thus, for an article which is espousing that the towers came down only via controlled demolition, it is necessary to find independent sources of all facts mentioned, even ones as pedestrian as the expected weight of a floor of a building. (I haven't done the math myself, so I hold no opinion as to whether or not the numbers in the article are correct).
    - mlvljr 10y ago
      How about this guy: https://www.youtube.com/watch?v=T2XV3Edd2dc https://www.youtube.com/watch?v=T2XV3Edd2dc
    - 20yrs_no_equity 10y ago
      Your characterization of the Magic Bullet Theory is inaccurate. The error is in not realizing the car was of an unusual geometry (I believe JFK was elevated, and the seats were different widths apart between the front and the back- unusual for cars of the time.) So assuming the car was normal, and all the seats were the same distance apart and the same height, you would need a magic bullet. Applying deeper understanding of the setup of the car accounts for that, reducing it to the improbable bullet theory. That doesn't mean they were wrong, that means they didn't have access to the car to do direct measurements. When the government locks down the evidence (or in the case of 9/11 immediately ships it off to china, before the investigation begins, literally shipping buildings across the ocean to be recycled) it's not the fault of the conspiracy theorists if they come up with wrong hypothesizes when denied access to the evidence every legitimate researcher should have access to. Regarding "fake film" you seem too be referring to Oliver Stones "JFK" which is not the source of the Magic Bullet Theory, or any of the theories there, it is merely a collection of the theories prominent at the time, and then fictionalized.
Tycho 10y ago
It doesn't talk much about the damage from impact and also jet fuel.
- woah 10y ago
  This is about WTC7, which was not hit by a jet, and did not come into contact with jet fuel. It's the only skyscraper ever to have collapsed from fire.
  - jcranmer 10y ago
    ... after getting a front-row seat to two massive buildings collapsing. There was some serious damage to the building from the collapse of the towers, which was after all responsible for starting many of the fires. Also, as far as I'm aware, almost all skyscrapers with major fire damage are largely uncontrolled fires on one or two floors, rather than uncontrolled fires throughout the entire building. Also: http://www.sfgate.com/bayarea/article/Tanker-fire-destroys-part-of-MacArthur-Maze-2-2575285.php http://www.sfgate.com/bayarea/article/Tanker-fire-destroys-p... --that's a steel structure (overpass, not a skyscraper) being collapsed entirely due to an out-of-control fire (due to a crashed gasoline truck).
    - 20yrs_no_equity 10y ago
      I know paper burns at fahrenheit 451 (thanks Ray Bradburry)... what temperature does jet fuel burn at? Or that gasoline truck? I presume it's a much higher temperature. The jet fuel that hit the twin towers was mostly expelled in massive fireballs, with some of it draining into the towers. I don't see a reason to believe WTC 7 was saturated in jet fuel. So WTC 7 was a paper & wood and fabric fire, right?
woah 10y ago
There are several half-formed complaints from people who did not read the article in this comment thread. I'm guessing that the commenters are having a knee-jerk reaction to the fact that there are a lot of conspiracy theorists out there who think that the US government did 9/11 etc. This article is not about that. It revisits a disaster (the collapse of WTC7) which appears to have happened under very unique circumstances. If the accepted explanation is correct, WTC7 is the only high rise to ever have collapsed from fire, and the collapse resulted from a long string of coincidences. The article is a critique of this analysis.
- lb1lf 10y ago
  >...and the collapse resulted from a long string of coincidences. -Most, if not all spectacular, unexpected events are the result of a long string of coincidences. Otherwise, they'd be common occurrences.
  - loup-vaillant 10y ago
    That would work with one building. A long string of coincidences (failures upon failures…), such as the ones that causes some big server outage, or blackout, or plane crash, could have been a good explanation for the fall of one building. Here however the "string of coincidences" hypothesis would have to apply pretty much simultaneously to three buildings, one of which wasn't even hit by a plane. No. freaking. way. That's just too damn improbable.
    - jcranmer 10y ago
      You're ignoring correlation. The twin towers are, for almost all purposes, virtually identical, and experienced largely identical scenarios. For them to behave differently under such circumstances would be less extraordinary than for them to behave similarly. To my knowledge, the twin towers are the only buildings in history to have been hit with a four-engine plane full of fuel (El Al Flight 1862 apparently had only two engines left when it struck the apartment building. Note that the building fully collapsed at point of impact). Again, to my knowledge, with WTC 7, they were the only high-rises to have experienced serious, out of control multi-floor fires for hours after receiving major structural damage--Deutsche Bank received serious damage but no fires so far as I can tell. If 100% of similar structures in similar circumstances have failed in a similar manner, is that improbable?
lb1lf 10y ago
I find the conspiracy theories surrounding 9/11 somewhat amusing. With regards to controlled demolition - how on earth would anyone be able to rig the buildings for controlled demolition without anybody noticing? And why use slow-acting thermite when shaped charges would be more efficient and harder to detect (both before, during and after the event) Not to mention - how have They(tm) been able to keep their conspiracy under wraps? Seriously - you pull off a massive gig like this, hardly the work of a couple of lone wolves - and no-one talks?
- colejohnson66 10y ago
  It's best not to think about it. Conspiracy theorists have a tendency to take confirmation bias to an extreme. If you provide a counter argument, they don't respond to that argument, they attack your character by "realizing" that you're part of the conspiracy too.
  - 20yrs_no_equity 10y ago
    Isn't calling them "conspiracy theorists" itself an attach on their character? Personally, I like to play devils advocate, and I'm curious about what happened on 9/11. It doesn't add up for me. So I have taken the "conspiracy theorist" side several times... I don't see people making arguments against the theorists data. I see the same common fallacies, most often variations of appeal to authority. "Popular science debunked that" for example in response to an argument that Popular Science didn't address. "If it were a cover up it would have gotten out" in response to people pointing "it getting out" is my favorite, of course. Sort of a "I don't believe it, therefore it can't be right". Not sure what fallacy that is.
    - colejohnson66 10y ago
      > Isn't calling them "conspiracy theorists" itself an attach on their character? I've never thought of it like that. For me, I've always looked at it as a literal definition. They theorize that there is a conspiracy. However, I guess it could be seen as an attempt on someone's character because it does have a negative connotation.

17 points by 2a0c40 10y ago

> Meanwhile, unreacted nano-thermitic material has since been discovered in multiple independent WTC dust samples [13] http://www.911research.wtc7.net/mirrors/bentham_open/ActiveThermitic_Harrit_Bentham2009.pdf http://www.911research.wtc7.net/mirrors/bentham_open/ActiveT... Suspicious Indeed.

nwp 10y ago

FYI: Truther article

myrion 10y ago
Yeah, with lots of weasel words and written by people who are not qualified on the topic.
- woah 10y ago
  It's written by a professor of physics, a professor of civil engineering and a mechanical engineer.
  - jcranmer 10y ago
    The physicist in the group should be classified as a particle physicist, not a structural mechanics expert. That's as worlds different as saying that someone who studies compiler research is qualified to talk about recurrent neural networks.
codeduck 10y ago
This needs to be tagged as such, I started reading this believing that it was a reputable paper.
deleted 10y ago
[deleted]
woah 10y ago
Is an article that comes to a conclusion different than the one you believe automatically false? That seems to be your only complaint.
- jcranmer 10y ago
  Conspiracy theorists (in general) have been known to make stuff up, and non-experts who believe in them can easily parrot this stuff thinking it's true. A great example of this in history is the "Magic Bullet Theory" of JFK's assassination, which holds that the single bullet is false because the bullet would have had to make sharp turns to get to its next target, which is almost entirely based on made-up positions in a fake film. Thus, for an article which is espousing that the towers came down only via controlled demolition, it is necessary to find independent sources of all facts mentioned, even ones as pedestrian as the expected weight of a floor of a building. (I haven't done the math myself, so I hold no opinion as to whether or not the numbers in the article are correct).
  - mlvljr 10y ago
    How about this guy: https://www.youtube.com/watch?v=T2XV3Edd2dc https://www.youtube.com/watch?v=T2XV3Edd2dc
  - 20yrs_no_equity 10y ago
    Your characterization of the Magic Bullet Theory is inaccurate. The error is in not realizing the car was of an unusual geometry (I believe JFK was elevated, and the seats were different widths apart between the front and the back- unusual for cars of the time.) So assuming the car was normal, and all the seats were the same distance apart and the same height, you would need a magic bullet. Applying deeper understanding of the setup of the car accounts for that, reducing it to the improbable bullet theory. That doesn't mean they were wrong, that means they didn't have access to the car to do direct measurements. When the government locks down the evidence (or in the case of 9/11 immediately ships it off to china, before the investigation begins, literally shipping buildings across the ocean to be recycled) it's not the fault of the conspiracy theorists if they come up with wrong hypothesizes when denied access to the evidence every legitimate researcher should have access to. Regarding "fake film" you seem too be referring to Oliver Stones "JFK" which is not the source of the Magic Bullet Theory, or any of the theories there, it is merely a collection of the theories prominent at the time, and then fictionalized.

Tycho 10y ago

It doesn't talk much about the damage from impact and also jet fuel.

woah 10y ago
This is about WTC7, which was not hit by a jet, and did not come into contact with jet fuel. It's the only skyscraper ever to have collapsed from fire.
- jcranmer 10y ago
  ... after getting a front-row seat to two massive buildings collapsing. There was some serious damage to the building from the collapse of the towers, which was after all responsible for starting many of the fires. Also, as far as I'm aware, almost all skyscrapers with major fire damage are largely uncontrolled fires on one or two floors, rather than uncontrolled fires throughout the entire building. Also: http://www.sfgate.com/bayarea/article/Tanker-fire-destroys-part-of-MacArthur-Maze-2-2575285.php http://www.sfgate.com/bayarea/article/Tanker-fire-destroys-p... --that's a steel structure (overpass, not a skyscraper) being collapsed entirely due to an out-of-control fire (due to a crashed gasoline truck).
  - 20yrs_no_equity 10y ago
    I know paper burns at fahrenheit 451 (thanks Ray Bradburry)... what temperature does jet fuel burn at? Or that gasoline truck? I presume it's a much higher temperature. The jet fuel that hit the twin towers was mostly expelled in massive fireballs, with some of it draining into the towers. I don't see a reason to believe WTC 7 was saturated in jet fuel. So WTC 7 was a paper & wood and fabric fire, right?

woah 10y ago

There are several half-formed complaints from people who did not read the article in this comment thread. I'm guessing that the commenters are having a knee-jerk reaction to the fact that there are a lot of conspiracy theorists out there who think that the US government did 9/11 etc. This article is not about that. It revisits a disaster (the collapse of WTC7) which appears to have happened under very unique circumstances. If the accepted explanation is correct, WTC7 is the only high rise to ever have collapsed from fire, and the collapse resulted from a long string of coincidences. The article is a critique of this analysis.

lb1lf 10y ago
>...and the collapse resulted from a long string of coincidences. -Most, if not all spectacular, unexpected events are the result of a long string of coincidences. Otherwise, they'd be common occurrences.
- loup-vaillant 10y ago
  That would work with one building. A long string of coincidences (failures upon failures…), such as the ones that causes some big server outage, or blackout, or plane crash, could have been a good explanation for the fall of one building. Here however the "string of coincidences" hypothesis would have to apply pretty much simultaneously to three buildings, one of which wasn't even hit by a plane. No. freaking. way. That's just too damn improbable.
  - jcranmer 10y ago
    You're ignoring correlation. The twin towers are, for almost all purposes, virtually identical, and experienced largely identical scenarios. For them to behave differently under such circumstances would be less extraordinary than for them to behave similarly. To my knowledge, the twin towers are the only buildings in history to have been hit with a four-engine plane full of fuel (El Al Flight 1862 apparently had only two engines left when it struck the apartment building. Note that the building fully collapsed at point of impact). Again, to my knowledge, with WTC 7, they were the only high-rises to have experienced serious, out of control multi-floor fires for hours after receiving major structural damage--Deutsche Bank received serious damage but no fires so far as I can tell. If 100% of similar structures in similar circumstances have failed in a similar manner, is that improbable?

lb1lf 10y ago

I find the conspiracy theories surrounding 9/11 somewhat amusing. With regards to controlled demolition - how on earth would anyone be able to rig the buildings for controlled demolition without anybody noticing? And why use slow-acting thermite when shaped charges would be more efficient and harder to detect (both before, during and after the event) Not to mention - how have They(tm) been able to keep their conspiracy under wraps? Seriously - you pull off a massive gig like this, hardly the work of a couple of lone wolves - and no-one talks?

colejohnson66 10y ago
It's best not to think about it. Conspiracy theorists have a tendency to take confirmation bias to an extreme. If you provide a counter argument, they don't respond to that argument, they attack your character by "realizing" that you're part of the conspiracy too.
- 20yrs_no_equity 10y ago
  Isn't calling them "conspiracy theorists" itself an attach on their character? Personally, I like to play devils advocate, and I'm curious about what happened on 9/11. It doesn't add up for me. So I have taken the "conspiracy theorist" side several times... I don't see people making arguments against the theorists data. I see the same common fallacies, most often variations of appeal to authority. "Popular science debunked that" for example in response to an argument that Popular Science didn't address. "If it were a cover up it would have gotten out" in response to people pointing "it getting out" is my favorite, of course. Sort of a "I don't believe it, therefore it can't be right". Not sure what fallacy that is.
  - colejohnson66 10y ago
    > Isn't calling them "conspiracy theorists" itself an attach on their character? I've never thought of it like that. For me, I've always looked at it as a literal definition. They theorize that there is a conspiracy. However, I guess it could be seen as an attempt on someone's character because it does have a negative connotation.