[Merged]New Paper on WTC 7 in Structure Magazine

[Norseman]

Single Point of Failure

How the Loss of One Column May Have Led to the Collapse of WTC 7

http://www.structuremag.org/Archives/2007-11/SF-WTC7-Gilsanz-Nov07.pdf

Since I am not sure that all the regulars here care to follow the never ending thread 10 story hole in WTC 7 by Christopher7, I lifted out this post by bje since it could be of interest to a broader audience.

Both the authors have been involved in the FEMA investigation and one in the NIST investigation. There is nothing new in the article, it focuses on how a collapse of column 79 could have brought down the whole building. What is noteworthy is that the article appears so close to the expected release of the draft report on WTC 7 by NIST. Therefore there is no reason to expect any sunrises from NIST in the final report, as expected.

Thanks bje for bringing attention to this article. :)

Norseman

PS
The article says that the final collapse of WTC 7 occurred over 8.2 seconds. But I am pretty sure the authors meant the time from the east penthouse started to move until the west penthouse disappeared, and global collapse ensued. That is the time given in table L-1 in the interim NIST (http://wtc.nist.gov/progress_report_june04/appendixl.pdf) report on WTC 7.

[bofors]

Thanks for posting this.

I reading this paper now.

However, I do not see a single equation in this paper

[JamesB]

Thanks for posting this.

I reading this paper now.

However, I do not see a single equation in this paper

Wow, you are actually reading a paper before attacking it? When did you start doing that? :D

[Drudgewire]

However, I do not see a single equation in this paper
It does have some pretty pictures though. :)

[1337m4n]

However, I do not see a single equation in this paper

Didn't somebody on your side try to debunk the NIST report without calculations and without even reading it?

[slyjoe]

Thanks for posting this.

I reading this paper now.

However, I do not see a single equation in this paper

Well, that should save you some embarassment ala Bazant & Zhou, equation 1 now shouldn't it?

[Gravy]

I spot one error in the paper. They say the collapse took 8.2 seconds, but they're probably using NIST's time of 8.2 seconds between the start of the east mechanical penthouse collapse and the start of the roofline movement.

[Norseman]

Thanks for posting this.

I reading this paper now.

However, I do not see a single equation in this paper

According the to STRUCTURE magazine Author's handbook (http://www.structuremag.org/downloads/Author%20Handbook%202007%20v070102.pdf) the articles are supposed to be more casual reading for structural engineers, it is a magazine and not a journal. In fact mathematical equations are to be avoided.

And the authors very clearly draws upon the work done in connection with the FEMA and the NIST investigations. So you will have to wait for the NIST draft report due at the end of the year for all the technical details, expect thousands of pages to read.

[bofors]

Wow, you are actually reading a paper before attacking it? When did you start doing that? :D

Nice...

[bofors]

I spot one error in the paper. They say the collapse took 8.2 seconds, but they're probably using NIST's time of 8.2 seconds between the start of the east mechanical penthouse collapse and the start of the roofline movement.

That's right Mark, let's focus on the irrelevant details and ignore the important ones. Nobody here will notice...

[Bell]

That's right Mark, let's focus on the irrelevant details and ignore the important ones. Nobody here will notice...

Troof movement in a nutshell.

[Quad4_72]

Nice...

AND true at the same time...

[Par]

That's right Mark, let's focus on the irrelevant details and ignore the important ones. Nobody here will notice...


Which important ones did you have in mind?

[BenBurch]

Thanks for posting this.

I reading this paper now.

However, I do not see a single equation in this paper

Equations aren't needed if you can show that there is a single column that bears enough of the load to cause failure if you take it out.

You are just upset that it proves your fairy tale wrong.

[Bell]

Which important ones did you have in mind?

My guess would be the "pull it" comment.

[bofors]

In fact mathematical equations are to be avoided.

Yes, by all means. It would be absurd to put equations in a magazine for structural engineers.

Moreover, even referencing basic laws of physics which would so obviously conflict with the nonsense promoted here, clearly would disrupt the "casual" level of analysis being done here.

http://img124.imageshack.us/img124/5665/911jh0.jpg



And the authors very clearly draws upon the work done in connection with the FEMA and the NIST investigations. So you will have to wait for the NIST draft report due at the end of the year for all the technical details, expect thousands of pages to read.

True, but on the other hand, put up or shut up. These clowns put up this crap analysis with showing any of there models.

This is shear propaganda, very unscientific. You are supposed to published the real work first, so it can be picked apart, then issue the press releases after words.

Other than givening a overview of WTC 7 structure, this paper is totally useless. They might as well have said the collapse of Building 7 was an act of God.

Their refusal to even consider controlled demolitions shows that this work fatally flawed on its face.

[bofors]

AND true at the same time...

Actually I draw the line on prereading 10,000 page reports that are inherently flawed, this was only 4 papes.

I know it is hard, but it makes sense if you think about it. Give it a try...

[BenBurch]

Stop with your focus on equations. You cannot analyze everything that happened here with them because a simple equation does not capture the structure or the structure as damaged. For that you need a full dynamic simulation of the collapse, and its not clear that state of the art allows that yet. And in any case though we know the structure as built fairly well (based on plans) we do not know the structure as damaged with the same accuracy.

[bofors]

Equations aren't needed if you can show that there is a single column that bears enough of the load to cause failure if you take it out.

And you think this paper shows that?

Did you even read it?


You are just upset that it proves your fairy tale wrong.

Proves? Not even the authors of this junk claim to have proven anything.

Yah, this paper hurts my feelings... whatever.

[DGM]

Actually I draw the line on prereading 10,000 page reports that are inherently flawed, this was only 4 papes.

I know it is hard, but it makes sense if you think about it. Give it a try...
And who's opinion are you stating this time?

[dudalb]

This is shear propaganda, very unscientific.

A wonderful description of Almost all Truther material.

[Bell]

Yes, by all means. It would be absurd to put equations in a magazine for structural engineers.

Moreover, even referencing basic laws of physics which would so obviously conflict with the nonsense promoted here, clearly would disrupt the "casual" level of analysis being done here.

Yes, by all means, show where the basic laws of physics contradict with this report?

http://img124.imageshack.us/img124/5665/911jh0.jpg

And what the hell is up with this picture?

True, but on the other hand, put up or shut up. These clowns put up this crap analysis with showing any of there models.

Feel free to start a new 'critical analysis' thread. Your last one went well.

This is shear propaganda, very unscientific. You are supposed to published the real work first, so it can be picked apart, then issue the press releases after words.

Supposed to? By whom? Who made that rule?

Other than givening a overview of WTC 7 structure, this paper is totally useless. They might as well have said the collapse of Building 7 was an act of God.

That's closer to the truth than controlled demolitions.

Their refusal to even consider controlled demolitions shows that this work fatally flawed on its face.

And why should they have EVEN CONSIDERED controlled demolitions? What is there to lead to the assumption for a CD beside the tiresome "pull it" quote?

[BenBurch]

And you think this paper shows that?

Did you even read it?

Proves? Not even the authors of this junk claim to have proven anything.

Yah, this paper hurts my feelings... whatever.

Yep, I read it, and its an ARTICLE, not a PAPER. I know that is probably a distinction lost on you.

I read ARTICLES about steam boilers and locomotives all the time. There are equations that describe them, but the articles typically do not use any of them because they are not required to understand and safely operate the machine, or even to rebuild and repair it. And I don't need them to know why a crown sheet failed when the water got too low.

What these authors say is that they HAVE identified a single point of failure. They aren't trying to prove it to YOU, because the REAL structural engineers who read this piece don't have any trouble accepting that the authors are telling them the Truth!

[cmcaulif]

Yes, by all means. It would be absurd to put equations in a magazine for structural engineers.

Moreover, even referencing basic laws of physics which would so obviously conflict with the nonsense promoted here, clearly would disrupt the "casual" level of analysis being done here.

which laws of physics would that be?

I suppose you missed the part about casual reading and 'not a journal' as well. If you want a method to analyze the potential of WTC 7 to arrest progressive collapse by the observed mechanism, I suggest reading this paper by dunesberry and Hamberger:

Practical Means for Energy-Based Analyses of Disproportionate Collapse Potential
J. Perf. Constr. Fac., Volume 20, Issue 4, pp. 336-348 (November 2006)

It is not about WTC 7 in particular, but it lays out a general method


True, but on the other hand, put up or shut up. These clowns put up this crap analysis with showing any of there models.

This is shear propaganda, very unscientific. You are supposed to published the real work first, so it can be picked apart, then issue the press releases after words.

Other than givening a overview of WTC 7 structure, this paper is totally useless. They might as well have said the collapse of Building 7 was an act of God.

Wow, I honestly hope that you are not going to sit there and try to say that the construction of the building did not play a major role in the collapse. transfer trusses especially put a building at a very high risk for progressive collapse.

Their refusal to even consider controlled demolitions shows that this work fatally flawed on its face.

Why would they consider controlled demolitions if they provide an alternate explaination that is clearly superior in terms of explanatory power and not to mention much more likely scenario?

Although regarding CD, I posted these questions for some CTs on another forum, they have not answered one of them, maybe you can do better

If the building was demolished in a controlled fashion:

How could your charges and their wiring survive the impact from being pelted with debris?

How could your charges survive being heated for 7 hours?

How could your charges survive compression as the building is displaced downward over the evolution of the fire?

Why are there no sequential, extremely loud bangs immediately before collapse initiation, like would be expected in a CD?

The scaled distance, Z, from an explosive charge is given by

$$ Z = \frac{R}{W^{1/3}} $$

where R is the distance to the charge and W is the weight the charge in kg TNT. the peak overpressure at scaled distance Z for 1< Z < 10 is:

$$ \frac{55.6}{Z} + \frac{405}{Z^2} - \frac{328.8}{Z^3} $$

So if a 3 kg TNT equivalent charge went off 14m(which is in the core area) from a window of the building, it would produce a peak over pressure of 9.67 kPa (this is just the peak, not the total impulsive load)

It takes 3.4-6.9 kPa to break a window, so the notion of windows broken from explosives seems valid, so why, if there were bombs going off in the building, was there no sudden window breakage immediately before collapse initiation?

[BenBurch]

Actually, you know, seven hours of uncontrolled fire before collapse is not bad.

[jackob]

Yes, by all means. It would be absurd to put equations in a magazine for structural engineers.

Moreover, even referencing basic laws of physics which would so obviously conflict with the nonsense promoted here, clearly would disrupt the "casual" level of analysis being done here.

http://img124.imageshack.us/img124/5665/911jh0.jpg




True, but on the other hand, put up or shut up. These clowns put up this crap analysis with showing any of there models.

This is shear propaganda, very unscientific. You are supposed to published the real work first, so it can be picked apart, then issue the press releases after words.

Other than givening a overview of WTC 7 structure, this paper is totally useless. They might as well have said the collapse of Building 7 was an act of God.

Their refusal to even consider controlled demolitions shows that this work fatally flawed on its face.

a magazine for structural engineers wouldn't need to have equations and basic physics referenced, because as engineers they know it already so they dont need to reference the law of gravity in every thing they write, because it can be assumed that as some one with a degree in engineering would know it.

[Gravy]

Folks, please don't rise to bofors' bait. He has amply demonstrated that he will not or cannot discuss these issues rationally. We can't keep him from trolling, but we can deprive him of attention.

[Newtons Bit]

Thanks for posting this.

I reading this paper now.

However, I do not see a single equation in this paper

Structure is a magazine, not a journal. They post interesting articles like this not to show the math, but just to give an idea. Structure does focus alot on code issues and how things change and new resources etc and can get math heavy.

I know this because I have a subscription to this magazine and read it every month.

[beachnut]

Only nut cases seriously believe in controlled demolition on 9/11. Only a few people who are unable to think rationally follow those few idiots in 9/11 truth.

As an engineer and a pilot both for over 34 years, I can not believe anyone is so void of knowledge and logical thinking to come up with CD as an idea. I was not suprised Jones was fired for making up thermite. I understand some engineers are politically biased enough to suspend the truth and make up lies about 9/11
http://forums.randi.org/imagehosting/12447460d8430f0ca9.jpg
Not one fact or piece of evidence to support CD; Why are people in 9/11 truth unable to figure out 9/11?

[BenBurch]

Not one fact or piece of evidence to support CD; Why are people in 9/11 truth unable to figure out 9/11?

"Language Limits Thought" - because they think of themselves as being in the TRUTH movement, how is it even possible for them to be wrong? Such things happen deep in the subconscious and cause all sorts of epistemological absurdities in some afflicted persons.

[rwguinn]

Thanks for posting this.

I reading this paper now.

However, I do not see a single equation in this paper
Considering your inability to comprehend a simple equation (in the thread you started and abandoned (http://forums.randi.org/showthread.php?postid=3121844#post3121844)), WHAT DIFFERENCE DOES IT MAKE?

[BenBurch]

Considering your inability to comprehend a simple equation (in the thread you started and abandoned (http://forums.randi.org/showthread.php?postid=3121844#post3121844)), WHAT DIFFERENCE DOES IT MAKE?

I wonder if he knows where it went, though?

[rwguinn]

I wonder if he knows where it went, though?
He posted on it after it was moved, as I recall...

[BenBurch]

He posted on it after it was moved, as I recall...

Ah!

$SET VOICE="Emily Latella"
Never Mind!
$SET VOICE="Ben Burch"

[bofors]

which laws of physics would that be?


Again,

(1) The WTC buildings disintegrated straight down, they did not topple over, the 2nd Law of Thermodynamics (entropy, randomness) tell us that this can not be simply result of imperfect aircraft impact and random fires.

(2) The WTC buildings disintegrated at near free fall speed, basic laws of mechanics tell that controlled demolition has to have caused this result.

These two points should be immediately clear to anyone looking the videos of the WTC building demolitions.


I suggest reading this paper by dunesberry and Hamberger:

Practical Means for Energy-Based Analyses of Disproportionate Collapse Potential
J. Perf. Constr. Fac., Volume 20, Issue 4, pp. 336-348 (November 2006)

It is not about WTC 7 in particular, but it lays out a general method

Thank you, that sounds like a great reference so I will certainly be looking at it.


Wow, I honestly hope that you are not going to sit there and try to say that the construction of the building did not play a major role in the collapse. transfer trusses especially put a building at a very high risk for progressive collapse.

I am saying that WTC 7 was demolished.


Why would they consider controlled demolitions...

Good science practice requires it, to the extent they are ignoring all the claiming controlled demolition, they are indulging in "junk-science".


... if they provide an alternate explaination that is clearly superior in terms of explanatory power


Again, NIST does not even attempt to explain why the towers "globally" collapse, they merely point to Bazant & Zhou 2002 which itself fails to offer an detailed mechanical explanation.


.... and not to mention much more likely scenario?


NIST fails to proposes any scenario that details "global collapse" and what NIST proposes is not likely, in fact it is impossible.


Although regarding CD, I posted these questions for some CTs on another forum, they have not answered one of them, maybe you can do better

If the building was demolished in a controlled fashion:

How could your charges and their wiring survive the impact from being pelted with debris?


Charges are commonly set off by radio wave, they do not need to be wired.


How could your charges survive being heated for 7 hours?

I don't think they were.


How could your charges survive compression as the building is displaced downward over the evolution of the fire?


I do not think the fire evolved and otherwise the charges were not compressed before they blew.


Why are there no sequential, extremely loud bangs immediately before collapse initiation, like would be expected in a CD?


Some of the WTC7 witness testimony suggests there were such explosions.


It takes 3.4-6.9 kPa to break a window, so the notion of windows broken from explosives seems valid, so why, if there were bombs going off in the building, was there no sudden window breakage immediately before collapse initiation?

I suspect some windows did break when the "kink" was formed in Building 7.

[Jonnyclueless]

Folks, please don't rise to bofors' bait. He has amply demonstrated that he will not or cannot discuss these issues rationally. We can't keep him from trolling, but we can deprive him of attention.

I think I found the conspiracy he's talking about:

http://www.foxnews.com/story/0,2933,308841,00.html

[Jonnyclueless]

2nd law of thermodynamics says they should topple over?? Again, must be the rotation of the earth that causes it to topple over.

And disintegrate at free fall speed? Can you show us that basic law of mechanics that says its a CD? I forget which law that was.

[CHF]

Their refusal to even consider controlled demolitions shows that this work fatally flawed on its face.

No it shows that they're not willing to waste time on stupid theories that can be debunked in five seconds.

[bofors]

He posted on it after it was moved, as I recall...

I have not even looked at thread since my last post in it.

Instead, I am preparing a written critique of Bazant & Zhou 2002, which of course will detail the problems with their Equation 1 and their "Elastic Dynamic Analysis", among other things.

I will post a copy in this forum when my paper is done.

[beachnut]

How can they find idiots who believe them; Architects & Engineers for 9/11 Truth? The OP points to independent work done to study 9/11, including WTC7.

Funny, this is an independent study of 9/11, even building 7. Which makes the idiots at, Architects & Engineers for 9/11 Truth, who say
Join ae911truth.org in calling upon Congress for a truly independent investigation into the 3 WTC High-rise "collapses" on 9/11! Our voices will be louder and more resonant in the halls of Congress when joined together as one voice of hundreds of architects and engineers!
; Obsolete, stupid for not know there are many independent investigation already complete on 9/11. Sad we have a group of people unable to function in a real world on 9/11 topics.

Unable to understand reality must be the problem with people who join Architects & Engineers for 9/11 Truth. A group who wants what has already been done; may times. Architects & Engineers for 9/11 Truth have failed.

How can truther nuts be so gullible?

[BenBurch]

Seems to me that there were more than three high rise collapses on 9/11!

http://www.kolumbus.fi/totuus/img/wtc7-area.jpg

[Corsair 115]

(1) The WTC buildings disintegrated straight down, they did not topple over, the 2nd Law of Thermodynamics (entropy, randomness) tell us that this can not be simply result of imperfect aircraft impact and random fires..You really shouldn't take your expectations of how a building would collapse from Hollywood movies and TV shows. They are not good sources for depictions of realistic physics.

Do you think that when someone gets shot they should be hurled backwards by the force of the bullet?

[Cl1mh4224rd]

Again,

(1) The WTC buildings disintegrated straight down, they did not topple over, the 2nd Law of Thermodynamics (entropy, randomness) tell us that this can not be simply result of imperfect aircraft impact and random fires.

(2) The WTC buildings disintegrated at near free fall speed, basic laws of mechanics tell that controlled demolition has to have caused this result.

These two points should be immediately clear to anyone looking the videos of the WTC building demolitions.


I'm sorry, but have you already forgotten that this article was about WTC7, not the Twin Towers? Did you actually read it, or just skim over it looking for something you could complain about?

Also, this is worthy of repeating, I think:

Structure is a magazine, not a journal. They post interesting articles like this not to show the math, but just to give an idea. Structure does focus alot on code issues and how things change and new resources etc and can get math heavy.

I know this because I have a subscription to this magazine and read it every month.


bofors, please feel free to pick up an issue of Sky & Telescope magazine and complain about the lack of equations in an article about astronomers' most recent discoveries about the universe. I'm sure your "critique" will be as well researched and presented as any other you've attempted recently...

[leftysergeant]

The scaled distance, Z, from an explosive charge is given by

$$ Z = \frac{R}{W^{1/3}} $$

where R is the distance to the charge and W is the weight the charge in kg TNT. the peak overpressure at scaled distance Z for 1< Z < 10 is:

$$ \frac{55.6}{Z} + \frac{405}{Z^2} - \frac{328.8}{Z^3} $$

So if a 3 kg TNT equivalent charge went off 14m(which is in the core area) from a window of the building, it would produce a peak over pressure of 9.67 kPa (this is just the peak, not the total impulsive load)

It takes 3.4-6.9 kPa to break a window, so the notion of windows broken from explosives seems valid, so why, if there were bombs going off in the building, was there no sudden window breakage immediately before collapse initiation?

Uh....yeah, what he said.

Now let's put this into perspective. Magazines, as opposed to scholarly journals, are not aimed at just the professionals. They also can be assumed to reach the hands of persons outside the profession who have not the math skills to understand stuff like what cmcaulif posted. I can't make heads or tails of the math, but I do know enough about explosives to tell you that the windows, for the stated reasons, do not look a bit like they would have in a controlled demolition. I would, then ,benefit more from someone's saying, the windows just broke as the building fell. The glass would have wound up half-way to Central Park had they used sufficient explosives to demolish the building.

It's a horses-for-courses thing.

You take yourself too seriously, bofors.

[cmcaulif]

Again,

(1) The WTC buildings disintegrated straight down, they did not topple over, the 2nd Law of Thermodynamics (entropy, randomness) tell us that this can not be simply result of imperfect aircraft impact and random fires.

Wrong, the second law of thermo merely states that entropy in a closed system that is not in equilibrium will increase over time.

I don't think there is a person on the planet that thinks that the pile of rubble 7 was left in was somehow more ordered than the standing building. The law clearly has not been violated.

If you can demonstrate how the remaining supports of the building could survive the bending moments and shear forces caused by rotation, thus allowing the building to topple, then you would have a leg to stand on.

This is even more difficult for you since the video record shows the east penthouse dropping well before global instability. This means that failures will propagate to horizontally to nearby columns, which will fail in shear(we see the result of this happening in the video as well as the roof falls).

(2) The WTC buildings disintegrated at near free fall speed, basic laws of mechanics tell that controlled demolition has to have caused this result.

completely wrong, again. WTC 7, which is the building being discussed in this thread, collapsed in aprrox 18 seconds. Your conclusion is based on a false premise.

Good science practice requires it, to the extent they are ignoring all the claiming controlled demolition, they are indulging in "junk-science".

I laid out a few simple questions for why the notion of CD can be tossed out right away, your answers are amusing at best, as we shall see.

Again, NIST does not even attempt to explain why the towers "globally" collapse, they merely point to Bazant & Zhou 2002 which itself fails to offer an detailed mechanical explanation.

this is a thread on building 7.


Charges are commonly set off by radio wave, they do not need to be wired.

Now how about the charges themselves? That was part of the original question too, and surely you can't have a CD without them


I don't think they were.

thats great, I hope you realize your opinion is worth nothing though. Here is what the people who were there have to say:
http://wtc7lies.googlepages.com/eyewitnessaccountsofwtc7fires

The fires were quite large, they burned for about 7 hours, and many of those hours uncontested. To add to this, when the building was hit with debris, at the very least many windows were blown out, providing better ventilation than in a normal office fire.

These charges need to be able to survive about 7 hours of high heat before exploding silently, figure out a way to make it work.


I do not think the fire evolved and otherwise the charges were not compressed before they blew.

see above



Some of the WTC7 witness testimony suggests there were such explosions.

I asked for explosions similar to that of a demolition, since its so obvious right? Specifically, numerous, extremely loud, and sequential bangs immediately before collapse. Can you provide evidence of such explosions that match a CD? Other random explosions are easily explained by smoke explosion, which are a type of fire gas ignition, and occur naturally in a fire, and other secondary explosions that occur in a fire from things like aerosols, transformers, fire extinguishers, etc.

Clearly, unless there were explosions in a testimony or heard in the video record, a random explosion is extremely unimpressive in terms of your theory.



I suspect some windows did break when the "kink" was formed in Building 7.

The kink was formed as a result of the failure of the columns supporting the east penthouse. I'm assuming that you would say that these failures were caused by explosives rather than fire, and if this was true we would expect to see broken windows before the kink formed, in fact before the penthouse dropped.

[BenBurch]

Of course in a real CD, the windows would have all been removed first along with doors, interior non-loadbearing walls, etc.

[leftysergeant]

Good science practice requires it, to the extent they are ignoring all the claiming controlled demolition, they are indulging in "junk-science".

A simple examination of the steel and the air and dust samples is all that was really needed. No positively identifiable combustion products of explosives, no damage consistant with demolition charges= no CD. That simple. It is not good science to go testing for everything that some immature or nefarious twit pulls out of his butt.

NIST fails to proposes any scenario that details "global collapse" and what NIST proposes is not likely, in fact it is impossible.

Steel buildiongs do collapse all the time in fires. Once local failure occurred, the lower structure was unable to stop it, thus global failure is inevitable, unless there is something I am missing here, like a mecahnism by which the lower structure could stop it.



Charges are commonly set off by radio wave, they do not need to be wired.


Not at all accurate. True enough, the charges COULD be set off by radio signal, but it is rarely done for saftey and timing reasons. Direct wiring gives you better control over the timing, but there are safety issues, especially in a tall building which could suffer lightning strikes while you are setting your charges. Detcord is safer and much more precise. Of course, both detcord and wires tend to melt in heat and that kind of screws up a well-laid plan.

As for the safety of radio-initiated detonation, I don't know of any demolitions expert, military or civilian, who would even think of allowing a radio within a mile of his location while he removed the ferrules from a blasting cap. He would probably give you one strangely-shaped supository if he saw you with a cell phone out and opened.

And right there on top of one of the towers was this humongous radio and cell phone tower and a couple of telecom buildings within easy walking distance, and an emergency response office right there in WTC 7.

Yeah, I would sure volunteer for the rigging of that one....
NOT!

I do not think the fire evolved and otherwise the charges were not compressed before they blew.

There were fires all over the place that were caught on video, and you can count on a lot that were not. No way detcord, wires or cutting charges would have lasted five hours in there. They would all have melted or deflagrated uselessly or been found still attached to beams during cleanup.

Some of the WTC7 witness testimony suggests there were such explosions.

There were also audio and video recording devices up the wazoo all over the area, and none of them picked up an identifiable explosive detonation inside the towers before collapse. That gives us some pretty long odds against there having actually been such charges and detonations.

Sorry, but this is a handful of diddly.

[Minadin]

How can they find idiots who believe them; Architects & Engineers for 9/11 Truth? The OP points to independent work done to study 9/11, including WTC7.

Please do not consider these folks to be indicative in any way of the general competance in the industry.

[Rika]

I dunno, I'm looking forward to his paper. If nothing, it'll give me a reason to look up basic physics.

[Dave Rogers]

Thanks for posting this.

I reading this paper now.

However, I do not see a single equation in this paper

Good, then you'll be able to understand it all.

Dave

[Dave Rogers]

Moreover, even referencing basic laws of physics which would so obviously conflict with the nonsense promoted here, clearly would disrupt the "casual" level of analysis being done here.


Given that you have clearly demonstrated that you don't understand the mechanics of a weight connected to a perfectly elastic spring, one of the simplest problems of Newtonian mechanics, what makes you think that your understanding of the basic laws of physics is sufficient for you to tell whether or not they conflict with this analysis?

Dave

[chillzero]

Just a reminder not to get derailed, and not to focus on individual posters; discuss the argument.

The topic in this thread is the article on WTC7, and specifically how it focuses on how a collapse of column 79 could have brought down the whole building.

Thanks

[Dave Rogers]

(1) The WTC buildings disintegrated straight down, they did not topple over, the 2nd Law of Thermodynamics (entropy, randomness) tell us that this can not be simply result of imperfect aircraft impact and random fires.

Your understanding of the Second Law of Thermodynamics is in error. WTC7 evolved from a highly ordered structure to a highly disordered pile of rubble, therefore its entropy increased in the collapse; this is enough to satisfy the Second Law. You seem to believe that every individual aspect of the collapse should have shown a localised increase in disorder. This is not true. Let's look at the proper form of the Second Law, in the Clausius formulation - as a chemist, this should be familiar to you:

In an isolated system (http://en.wikipedia.org/wiki/Isolated_system), a process can occur only if it increases the total entropy of the system.

By implying that the direction of collapse must be more disordered than the structure of the building, you are treating the directionality of the collapse as an isolated system, independent of the structural integrity of the building. Since the direction of collapse is a result of the detailed processes by which the structural integrity of the building is destroyed, the direction of collapse is therefore in no sense isolated from any other aspect of the collapse. The Second Law of Thermodynamics therefore makes no predictions whatsoever concerning the direction in which the building collapses. This is an expected result, as thermodynamics generally determines the overall characteristics of the initial and final state of processes, and does not in general concern itself with the fine details of the evolution of those processes.

Therefore, your contention that the collapse of WTC7 violated the Second Law of Thermodynamics is erroneous.

Dave

[westprog]

This is shear propaganda,

If that's intentional, it's quite witty.

[westprog]

Given that you have clearly demonstrated that you don't understand the mechanics of a weight connected to a perfectly elastic spring, one of the simplest problems of Newtonian mechanics, what makes you think that your understanding of the basic laws of physics is sufficient for you to tell whether or not they conflict with this analysis?

Dave

To be fair, the level of misunderstanding he demonstrates for mechanics isn't quite as profound as his total miscomprehension of thermodynamics.

[Lurker]

Thanks for posting this.

I reading this paper now.

However, I do not see a single equation in this paper

Are you expecting to see some basic engineering formula like s=Mc/I ? Or perhaps you want to see F=PA? F=kx?

I noted in the paper that they mentioned a kinematic model. I am assuming that they used CAE for their model and the engineering formulas you are desirous of seeing are embedded in the code. So you won't see the equations as every engineer would know them already and the actual formulas would be too complex to reqrite in a short paper anyways (since they involve plenty of simultaneous equations and matrices). What might be of interest to an engineer would be to see the boundary conditions of their model. I think that is the question you should be asking not a rather silly request for formulas.

[Lurker]

Again,

(1) The WTC buildings disintegrated straight down, they did not topple over, the 2nd Law of Thermodynamics (entropy, randomness) tell us that this can not be simply result of imperfect aircraft impact and random fires.
Care to show your work? I don't see a single equation in this statement. Crack open a thermo book, copy down the 2nd law equationa dn then tell us the rough values for each variable. Then you will have provided better evidence instead of the vague claim of violating a law.

Lurker

[Mancman]

Again,

(1) The WTC buildings disintegrated straight down, they did not topple over, the 2nd Law of Thermodynamics (entropy, randomness) tell us that this can not be simply result of imperfect aircraft impact and random fires.

(2) The WTC buildings disintegrated at near free fall speed, basic laws of mechanics tell that controlled demolition has to have caused this result.

These two points should be immediately clear to anyone looking the videos of the WTC building demolitions.



If you are so insistent on equations, why not produce some to prove the above comments?

1) How far would each of the top sections have had to lean in order for toppling to be physically possible?
1a) Could the building withstand the lean shown in Q1?

2) How long should the WTC buildings have taken to collapse in a 'natural' event?

[BenBurch]

To be fair, the level of misunderstanding he demonstrates for mechanics isn't quite as profound as his total miscomprehension of thermodynamics.

He's obviously seen these problems some time in his past, but paid only enough attention at the time to pass the course.

[BenBurch]

I have written the authors of this article with the link to this discussion in the hope that they will show up and tell us about their fine work.

[Lurker]

He's obviously seen these problems some time in his past, but paid only enough attention at the time to pass the course.


Yeah, I am profoundly amazed that he seems to think the 2nd law of Thermo seems to go along the lines of "...following the path of least resistance...".

I took a whole freaking year of thermo and never encountered that phrase in thermo, although I did in EE and Fluids classes.

[Dave Rogers]

Yeah, I am profoundly amazed that he seems to think the 2nd law of Thermo seems to go along the lines of "...following the path of least resistance...".

I think there is a genuine misconception about the nature of the Second Law of Thermodynamics at the heart of a lot of the truther arguments about symmetrical collapse, and that misconception is that any symmetrical state is always more ordered than any asymmetrical state. The problem is, when stated it's plainly shown up as absurd, but it's never explicitly stated.

Dave

[Molinaro]

(1) The WTC buildings disintegrated straight down, they did not topple over, the 2nd Law of Thermodynamics (entropy, randomness) tell us that this can not be simply result of imperfect aircraft impact and random fires.

(2) The WTC buildings disintegrated at near free fall speed, basic laws of mechanics tell that controlled demolition has to have caused this result.

These two points should be immediately clear to anyone looking the videos of the WTC building demolitions.


If we were discussing a Bugs Bunny cartoon I may agree. However, we are talking about reality instead and your fantasies about what should have hapened are entirely meaningless.

1) How could a building topple over? Picture what would have to hapen at the pivot point. The upper portion of the building has to either, hold it's shape, and thereby RAISE it's centre of mass in order to topple. Or, the base of the upper portion would have to crumble away as it pivoted about that point. However, as soon as the base were to crumble in any way, there is no longer a basis for any pivoting to occur. Where is the energy suposed to come from for that to hapen? Did anyone see any rocket engines on the side of the building pushing it over?

2) The videos of the collapse clearly show debis free-falling ahead of the collapse. The building did not fall in bulk at free fall speed. The video proves this point. You pretend not to have heard this before. Hence, you are basing everything you say on your imagination.

There is no reason whatsover to give any credence to your imagination and cartoon based physics.

[Lurker]

I think there is a genuine misconception about the nature of the Second Law of Thermodynamics at the heart of a lot of the truther arguments about symmetrical collapse, and that misconception is that any symmetrical state is always more ordered than any asymmetrical state. The problem is, when stated it's plainly shown up as absurd, but it's never explicitly stated.

Dave


I guess they only believe in laminar flow and turbulent flow just does not exist....

[slyjoe]

I think there is a genuine misconception about the nature of the Second Law of Thermodynamics at the heart of a lot of the truther arguments about symmetrical collapse, and that misconception is that any symmetrical state is always more ordered than any asymmetrical state. The problem is, when stated it's plainly shown up as absurd, but it's never explicitly stated.

Dave

The other problem most people have with thermo (see the creationists) is that they don't know what a closed system is.

[BenBurch]

I guess they only believe in laminar flow and turbulent flow just does not exist....

And as a result, automobiles owned by Truthies get better gas milage!

Wait.

They don't?
:eek:

[Dave Rogers]

The other problem most people have with thermo (see the creationists) is that they don't know what a closed system is.

Oh, that's a classic one. Excluding the sun from the system is quite popular, isn't it?

Dave

[Dirburke]

Hi Everyone, First time poster.

bofors,

your comment on the 2nd Law of Thermodynamics tell me that you simply don't know what the 2nd Law of Thermodynamics is about. You may want to go to wikipedia next time to look it up before you post something like that. Also since when has NYC been at closed system?

Also how do you conclude that since the "artice" is bunk because it doesn't have equations in it? The wtc was not a rigid body, so your knowledge of Physics I cannot be used in this sector. Because thousand of different varibles are to be used in every aspect of this collapse, simply stating that a equation simple enough for a truther to understand is ridiculous.

If any mathmatical system that needs to be looked at, you may question whether finite element analysis is done to it to find out weakness of the wtc (it may have been done, I dunno).

[slyjoe]

Welcome to the forum Dirburke :)

bofors has said he has a mental illness, but has supposedly provided evidence he was a doctoral candidate in mechanical engineering at one time. Search the forum for his posts before you become too engaged with this guy - it will give you a headache and no information.

[twinstead]

your comment on the 2nd Law of Thermodynamics tell me that you simply don't know what the 2nd Law of Thermodynamics is about.

He either doesn't know what he is talking about, or more likely is simply parroting what another conspiracy theorist told him or something he read on a conspiracy website.

[Good Lt]

Don't know if this was posted here recently (I've been in and out traveling for the past week or so), but most of this article appears to be old news.

From this month's STRUCTURE Magazine:

How the loss of 1 column may have led to the collapse of WTC7 (http://www.structuremag.org/Archives/2007-11/SF-WTC7-Gilsanz-Nov07.pdf)
by Raymond Gilsenz, P.E., S.E., and Willa Ng


Still, it's another nail in the Troofer coffin, from a reputable trade publication.

[OldTigerCub]

I had not seen that article. It makes a lot of sense to a layman like myself, as it is well illustrated and appears to put the required elements of the collapse into a context that a non-engineer can understand.

Thanks, Good Lt.!:D

[JimBenArm]

How can you take it down a peg when it's laying prostrate on the floor?
(That's not "prostate" ConspiRaider!)

[Good Lt]

Well, then it pulverizes Troofer science into dust faster than freefall speed with thermite.

Or something.

[Norseman]

Earlier thread on the article:
http://forums.randi.org/showthread.php?p=3128720#post3128720

[Good Lt]

Thanks - my bad.

I was looking for it, but did a poor job of finding it.

[GregoryUrich]

This in no way negates controlled demolition. In fact, given 7 hrs, a strong guy with a hacksaw (and a few extra blades) could have made and angle cut.

Any body remember linebacker Jack "Hacksaw" Reynolds? I think he cut his Volkswagen in half. I thought I recognized that guy coming out of building 7...

[Good Lt]

This in no way negates controlled demolition.

There was no controlled demolition.