The Progressive Top Down Collapse Challenge

[spooked911]

http://911research.wtc7.net/wtc/analysis/challenge.html

You've heard that the Twin Towers pancaked, crushing themselves completely. The experts gave us a fancy-sounding term for this: progressive collapse . If you search with the phrase "progressive collapse" you will find numerous articles, most of them written since 9/11/01 about things like assessing and retrofitting existing structures against progressive collapse. It seems that the only examples of progressive collapse of buildings cited are the Twin Towers, Building 7, and the Murrah Federal Building in Oklahoma City.

A TV documentary which purported to explain the collapses of the Twin Towers featured a demonstration in which a house-of-cards like structure representing one of the towers was supposed to collapse from the top down. The documentary showed only the beginning of this simulated building collapse, since the producers were apparently unable to achieve progressive total collapse. This raises the question: If this newly discovered mode of structural failure is so likely to happen, why is it so difficult to reproduce?


THE PROGRESSIVE COLLAPSE CHALLENGE

The challenge is in 5 parts, from the easiest to the most difficult.

All five require building a structure that will undergo top-down progressive total collapse -- i.e.: when disturbed near the top, it will collapse from the top down to the bottom, leaving no part standing. The disturbance can include mechanical force, such as projectile impacts, and fires, augmented with hydrocarbon fuels. Explosives and electromagnetic energy beams are not permitted.

Your structure can be made out of anything: straws, toothpicks, cards, dominoes, mud, vegetables, pancakes, etc.

The designers of the Twin Towers were able to meet all 5 challenges using steel and concrete.



CHALLENGE #1:

Build a structure with a vertical aspect ratio of at least 2 (twice as tall as it is wide) and induce it to undergo top-down total progressive collapse.

CHALLENGE #2:

Build a structure with a square footprint and a vertical aspect ratio of at least 6.5 (6.5 times as high as it is wide), and induce it to undergo top-down total progressive collapse.

CHALLENGE #3:

Build a structure as required by CHALLENGE #2 which, in the process of collapsing, will throw pieces outward in all directions such that at least 80% of the mass of the materials ends up lying outside of the footprint, but their center of mass lies inside the footprint.

CHALLENGE #4:

Build a structure as required by CHALLENGE #2 which is capable of remaining intact in 100 MPH cross wind.

CHALLENGE #5:

Build a structure that meets the requirements of both CHALLENGES #3 and #4.
------------

There IS no precedent for what happened on 9/11 to the twin towers.

So why are so many people here so god-danged bent on declaring it a pure structural-failure "collapse"?

WHAT IS THE EVIDENCE THAT ANY TOWER CAN UNDERGO GLOBAL PROGRESSIVE COLLAPSE BESIDES WHAT HAPPENED ON 9/11?

[MervinFerd]

1. Declined.

1. There is absolutely no question as to possibility of progressive collapse. http://wtc.nist.gov/pubs/factsheets/faqs_8_2006.htm

2. Tiny models may be useful for -illustrating- certain phenomena, but they are fundamentally different from 110 story skyscrapers and their behavior proves nothing.

Now, please stop wasting everybody's time.

[John Q. Citizen]

2. You can waste your own time Mervin, but I don't think you can pin that on spooked.

Time to cowboy up and take some responsibilty instead of blaming others for your actions.

Sheesh!

[greyl]

3. Post #2, and already totally off of the OP and getting personal. Fyi. nt

[John Q. Citizen]

6. Is it logical and rational to you that a poster on a discussion board should

be attacked for wasting anybody elses time?

We are all free to spend our time anyway we see fit, unless we are at work. Then it's the bosses time. It doesn't make any logical or rational sense to blame someone else because we decide to read or respond to a post.

I'm not taking the challenge because I don't have the time to put into it. Are you going to take the challenge?

If you feel it's a waste of time to reply to me, I will understand if you don't. Or, if you want to put the time into a reply then that's up to you and please don't blame me because you decided to reply. OK?

I can't waste your time. Only you can do that.

I decided to waste a little of my time replying to you. I take full responsibilty for the time I spent.

[greyl]

7. reply

jqc: "Is it logical and rational to you that a poster on a discussion board should be attacked for wasting anybody elses time?"

Yes. Would you prefer if they were encouraged? Anyway, you're taking the phrase a tiny bit too literally.
The post you replied to addressed the OP. You didn't. You didn't spend your time offering a meaningful rebuttal to post #1, you spent it attacking the person who posted post #1. Whatever.

[spooked911]

4. what is your friggin problem?

Man, do you have an attitude.

NIST proves NOTHING.

[John Q. Citizen]

5. That's for sure. NIST doesn't have a shred of physical evidence to back up

their primary hypothisis. Funny that.

NIST proposes after all the evidence is disposed of.

[petgoat]

8. NIST doesn't even have the decency to express regret

about the destruction of the steel that could have told the tale.

[Bolo Boffin]

9. NIST eats babies and hides the bones. n/t

[MervinFerd]

18. NIST eats babies and ships the bones to Taiwan. Without a forensic study.

BAD NIST.

[greyl]

11. Forensic Expert Studying WTC Steel

Forensic Expert Studying WTC Steel

(architecturalrecord.com- 01/10/02)

By Deborah Snoonian, P.E.
Last September, Astaneh-Asl was part of a team from the American Society of Civil Engineers that convinced the city of New York to delay recycling the WTC steel so that some of it could be studied for clues to the collapses. At a scrapyard in Jersey City he has helped identify the steel pieces to be saved.

The most important structural steel members to study are those severed by the planes and those that sustained the heaviest fire damage. The severed members will be studied to determine the speed and force of impact. Fire-damaged steel will be examined under an electron microscope for changes to its crystal structure; material scientists can then determine how long fires burned and at what temperature the steel failed.

Astaneh-Asl will also study structural members relatively unaffected by the crash or fires. “There were lots of different types of steel used in the towers—both high- and regular-strength—and we can learn things from pieces that fell hundreds of feet as the buildings collapsed,” he explains. Tests can measure the robustness of bolts and connections, for example, and identify the types of steel adequate for various structures.
http://www.construction.com/NewsCenter/Headlines/AR/20020110r.asp

Other rarely linked 9/11 articles and updates here.

[DoYouEverWonder]

12. So he went to NJ

but he didn't go to Hanger 17 at Kennedy?

Makes it hard to do an accurate analysis if you don't include the items that were separated and taken to Kennedy.

[MervinFerd]

16. And he didn't go to Area 51 either!!

Such a goof.

[petgoat]

37. Dr. Asl jumped on the "pancake" bandwagon before the

debris pile had even cooled.

He still hasn't released his final report. In his testimony before
Congress he expressed frustration at his inability to save all the
steel he wanted from recycling.

Your invocation of Area 51 and baby eating is a juvenile tactic commonly
indulged in open forums, and rarely here at DU.

[AZCat]

38. Rarely here at DU?

Sheesh - wait until the primaries. Remember 2004? Ugh...

[MervinFerd]

40. NIST eats pancakes and ships the plates to New Jersey.

Jesus f'ing Christ wearing sneakers on a boat trailer!

Get over the f'ing "Pancake theory" already. Hypotheses are presented, tested against evidence, and sometimes rejected and replaced by better ones. "Pancake theory" did not fit the facts; another theory did fit; NIST adopted the better theory.

--Nobody-- qualified to evaluate these theories has even considered any hypothesis that did not involve progressive collapse --in some form--.

Massive amounts of explosives are an unnecessary hypothesis.


Eating babies? In a discusion --this-- bullshit stupid, some humor is necessary.

Now, run along Mr. Goat.

[DoYouEverWonder]

95. Dr Asl also admitted

that he couldn't get all the floor plans for all the floors in the WTC, so he took one (I believe the 78th floor) and assumed all the floors above in the impact zones were the same. However, the floors were not all the same and he omitted some important differences in his modeling.

[MervinFerd]

98. Did he now? And the differences were? And they were important because?

You don't know, do you?

[DoYouEverWonder]

44. In a hangar at JFK, World Trade Center artifacts are treated as sacred

Yes, of course, investigating 9-11 is a big joke to you.

In a hangar at JFK, World Trade Center artifacts are treated as sacred

By Brian Williams
Anchor & “Nightly News” managing editor
NBC News
Updated: 7:25 p.m. ET Sept 11, 2006


Brian Williams
Anchor & “Nightly News” managing editor
• Profile
NEW YORK -

We have a special look tonight at all of the wreckage that was taken from ground zero. All of it is sacred and it's all awaiting a home — a permanent memorial. For now, it's all being cared for in a hangar at New York's JFK airport.

They don't want us to show you the outside, but we can say this: if you've flown out of Kennedy, you've taxied by it.


http://www.msnbc.msn.com/id/14789146/

Yet Astaneh-Asl, didn't bother to go there?

[MervinFerd]

45. I thought it was all sent to Taiwan.

What does Astaneh-Asl accomplish by going there? He's going to look at steel beams?

BAD ASTANEH-ASL! BAD!

And it is not "investigating 911" that is a joke to me.

Some of the investigators, however........

[DoYouEverWonder]

48. Important evidence was recovered and stored there

and the main structural engineer for NIST didn't bother to go look at the steel there? Give me a break. Gee, why would he want to go there?

Why would he even be interested in seeing this:



Or this:



Or this:



No, nothing to see here.

[MervinFerd]

49. And -looking- at this would have accomplished, what?

I presume there is some wild-ass theory woven around these photographs?

Perhaps our structural engineer was operating in the world of reality-based evidence?

[DoYouEverWonder]

50. Can't imagine why a structural engineer

would want to look at the structure.

:sarcasm:

[MervinFerd]

75. Maybe he'd already seen it? Maybe more qualified experts...

had already studied it? Maybe the steel was from completely random parts of the structure that had no relation to the cause of the collapse? Maybe the origin of the steel was unknown, and so useless for study? Maybe he'd already carefully studied steel that -was- from the region of the collapse?

OR,

maybe he was just deliberately leaving a CLUE that Conspiracy Hobbyists could find, but the rest of the world would be just too dense to understand? Secret Shadow Government operatives do that ALL the damn time.

[DoYouEverWonder]

96. He claims he went to Fresh Kills

He never mentions Hanger 17.

Maybe not.

[MervinFerd]

99. Well, we'd better check out that vital fact! It was NOT investigated by the....

911 Commission. Or the FBI.

Coverup!

[petgoat]

106. Can you explain that hairpin column? Do you see any sign of

heating on that piece of steel?

[MervinFerd]

110. No. Can you. With an -explicit- hypothesis about the collapse?

Didn't think so.

Unexplained is just unexplained. Doesn't mean wild-assed theories are true.

[petgoat]

111. I presented no theory. I asked an answerable question involving empirical data.

Samples from that hairpin would show if it was heated or not.

If it was heated, it might prove the fires were hot enough to weaken steel,
which has not yet been demonstrated.

If it was not heated, we have to wonder what forces could have bent it like
that without causing its anchors to fail.

Unexplained is just unexplained.

You're not very curious, are you? You've got all the answers you need, and
questions don't interest you one bit.

[MervinFerd]

120. What's your hypothesis? Assume it was -not- heated. What would that mean?

It might have been from a part of the building far removed from impact and fire.



<<You're not very curious, are you? You've got all the answers you need, and
questions don't interest you one bit.>>

I"m -very- curious. But, an unexplained fact does not prove any damn thing. It's just unexplained.



Now, run along Mr. Goat.

[petgoat]

127. If it was not heated, I think it would be very difficult to explain

how it got bent into a bobby pin.

an unexplained fact does not prove any damn thing.

An unexplained fact is a mystery. You seem to regard it as
useless and uninteresting.

[AZCat]

128. You need to read up on this stuff.

You fail to understand the effect heating has on steel, and you don't grasp the forces involved and how they relate to plastic deformation. I understand that not everyone has the time or inclination to study this sort of stuff, but perhaps if that is true in your case then you could avoid making such uninformed statements.

[MervinFerd]

130. "Difficult to explain": REALLY STRONG invisible elves? Hypothesis?

Yes, but do you have an hypothesis that would explain how it got bent into a bobby pin? Really strong invisible elves? In what way would "controlled demolition" bend a steel beam into a bobby pin?

It's a mystery, but in the powerful and violent chaos of the building collapse, the beam could've been jammed into a bobby pin shaped hole. Who the fuck knows?

UNLESS THIS PARTICULAR FACT SUPPORTS SOME BIGGER HYPOTHESIS, IT IS JUST AN UNEXPLAINED FACT. It may be fun, and even educational, to imagine mechanisms, but other than that it's just idle effort.

[petgoat]

53. I certainly have a question about that bobby pin.

Does the metal show signs of heating?

If not, what could have bent it like that?

[William Seger]

19. You must not know what NIST's primary hypothesis is

There certainly is ample physical evidence -- videos and stills -- of the columns bending inward on both walls where the collapses were initiated. And, once again, here's my favorite physical evidence that it was the buckling of those columns that initiated the collapse: http://video.google.com/videoplay?docid=-5405555553528290546&q=wtc+south+tower

There is absolutely no way the colums could bend inward like that if the floor diaphragms were still intact. This buckling happened slowly, over a period of at least half an hour in both towers, not suddenly as would be the case if explosives had caused it. In WTC2, at least, there are clear pictures of floor slabs above the collapse level hanging loose from the perimeter, which would make it easier for the floors below, still attached, to pull the columns inward.

> NIST proposes after all the evidence is disposed of.

Also wrong. There is still, to this day, plenty of evidence at that landfill and in the steel samples that were preserved.

It must be hard to pack so much wrong in such a short post.

[spooked911]

22. THAT'S your evidence that proves the NIST model?

Are you kidding me?

That video can be interpreted many ways, but it certainly doesn't show long-term, slow inwards bowing of the columns. They clearly bent inwards right before the tower was destroyed, but beyond that not much.

And you guys always complain that CTers rely on ambiguous video and extrapolate too much!

[William Seger]

28. Read the NIST report, if you're going to criticize it

It has some pictures showing the bowing in well before the collapse, and if you look around the web, there are plenty more.

[John Q. Citizen]

26. Ha ha, You don't know the difference between physical and photgraphic evidence, do

you, Mervin?

I'm not a bit surprised.

NIST has no metal from the WTC fire floors or collapse floors that shows temperature exposures that are assumed in their primary hypothisis.

Why not?

[William Seger]

29. OK, videos are "documentary evidence", your honor

So? Does you entire argument rest on semantics?

But there were about 250 or so pieces of steel saved by the FEMA investigators. They found steel that had been heated to at least 600^oC, but the technique they used (paint analysis) meant that a lot of the steel couldn't be tested.

[MervinFerd]

15. "NIST proves nothing" ? ??? Can you support this claim with any sort...

of rational argument?

Or is this just a part of the catechism?

Attitude? Not particularly. I just refuse to play by Conspiracy Rules. I play by the standard rules of rational discourse. In that world your challenge is not worth of discussion for the reasons I stated.


Now, please stop wasting our time.

[spooked911]

20. how have they proven that top-down progressive collapse can occur

especially in the absence of demolition?

[MervinFerd]

33. Can you prove today is Monday? Can you prove the Earth is Round?

Holy Jesus on a boat trailer wearing galoshes!

---WHY--- should anyone --need-- to prove a possibility that has never been doubted by even one qualified person? And that has been explained to --you-- at least a dozen times?

Stop wasting everyone's time.

[greyl]

36. You're implying it can occur with demolition. Show the evidence.

[vincent_vega_lives]

79. I suppose they should prove that

along with proving that aircraft can crash, fuel can burn, and steel can weaken in fire. Then when their done they can publish the report in a pop-up book promoted by Bob-The-Builder.

[William Seger]

80. LOL!

[spooked911]

140. do you REALLY not understand the point here?

I know this is all a game to you, but still... again--
where is the evidence-- BESIDES FROM 9/11-- that a strong tower can undergo top-down global progressive collapse?

Maybe a model of a strong tower doing this would be useful.

Will you try it?

[vincent_vega_lives]

78. "NIST proves nothing"

It requires no support. It is a sacred 9-11 TRUTHISM.

If the National Institute of Standards and Technology were considered credible or competent, that would completely render any evil-empire conspiracy theory null and void.

Of course all these folks are incompetent, money grubbing cowards.

http://wtc.nist.gov/pi/

[spooked911]

114. They are government workers who for the most part do the best they can

under the circumstances of the cover-up.

Maybe they don't feel like ruining their career by questioning the "collapses" too much.

And they still haven't PROVED the progressive global collapse mechanism

[cherokeeprogressive]

109. "There IS no precedent for what happened on 9/11 to the twin towers."

Given that, I ask you: Is there ANY precident for THE TWIN TOWERS? What would you compare them to? What other building has their mass? What other FLOOR in ANY other building has the mass of a floor of the WTC?

[KJF]

10. The towers did not pancake and NIST accepts this

For example, it says:

NIST’s findings do not support the “pancake theory” of collapse, which is premised on a progressive failure of the floor systems in the WTC towers (the composite floor system—that connected the core columns and the perimeter columns—consisted of a grid of steel “trusses” integrated with a concrete slab; see diagram below). Instead, the NIST investigation showed conclusively that the failure of the inwardly bowed perimeter columns initiated collapse and that the occurrence of this inward bowing required the sagging floors to remain connected to the columns and pull the columns inwards. Thus, the floors did not fail progressively to cause a pancaking phenomenon.
http://wtc.nist.gov/pubs/factsheets/faqs_8_2006.htm

NIST now backs the piledriver theory.

[spooked911]

25. are you saying there was no progressive collapse?

[KJF]

34. No, I'm saying...

... there was no pancaking, at least according to NIST. NIST thinks the buildings were destroyed by a piledriver, so you should not say NIST says the buildings pancaked, as this is misrepresenting their position.

btw, my personal opinion is that they blew them up.

[William Seger]

43. You're misunderstanding what the "pancake theory" means

Read the paragraph you quoted again. It's talking about what initiated the collapse, where the "pancake theory" was one hypothesis, and the paragraph describes what that hypothesis was. The paragraph also describes what NIST decided was the actual initiating event: the floors pulling the columns in until they buckled. But after the collapse got started, the floors did "pancake" or "piledriver" or whatever similar term you want to use for a progressive vertical collapse.

[KJF]

69. NIST thinks the floors pancaked?

NIST clearly states that the floors did not pancake:

NIST’s findings do not support the “pancake theory” of collapse, which is premised on a progressive failure of the floor systems in the WTC towers.

Pancaking is no longer the official theory - the piledriver is. Do you understand the difference between pancaking and the piledriver?

[Bolo Boffin]

70. William has it right. n/t

[William Seger]

71. Last time

The "pancake theory" has a very specific meaning in that paragraph you're quoting: It was an early hypothesis that the event that initiated the collapse was a floor pulling away from the perimeter wall and falling onto the floor below, after which the columns buckled and allowed the top of the tower to fall. What NIST says in that paragraph is that their study did not support that particular theory as the initial cause, and the paragraph then states what the study showed as being more probable. The term "pancake" itself, outside that paragraph and on its own, is simply a non-technical, imprecise term for one floor collapsing on another, which then itself collapses because of the impact. "Progressive vertical failure" really means the same thing to most people, but the NIST team didn't want to use that term because some of the engineers want to use that term to have a certain technical meaning, while some didn't think that it has any precise technical meaning at all. So, NIST used the term "global collapse." "Pile driver" is simply an analogy for what happened -- it's not really a technical term, any more than "pancake" is.

You're trying to make a semantic issue that doesn't really mean anything, but worse, it appears you're doing it with your own misunderstanding of what NIST specifically meant by the "pancake theory" in that paragraph. When the the top of the tower collapsed onto to the floor below, that floor and the columns supporting it couldn't absorb the impact, so they collapsed, too. And so on, all the way down the building. Use whatever term you like for that kind of failure, but implying that NIST doesn't think that's what happened is just dead wrong.

[KJF]

72. I'll take that as a no, then

I asked:

Do you understand the difference between pancaking and the piledriver?

It is clear you do not.

This is the pancake theory (explanation taken from your post):

When the the first floor collapsed onto to the floor below, that floor and the columns supporting it couldn't absorb the impact, so they collapsed, too. And so on, all the way down the building.

This did not happen and NIST has now stated this, despite your assertion NIST still beleives in pancaking. For example, it states:

Thus, the floors did not fail progressively to cause a pancaking phenomenon.

This clearly does not relate to only the initial event. Why do you feel a need to promote a theory you don't even understand?

[William Seger]

76. I take that as a yes, then

... that you are trying to create (or more likely, parrot something you read) a totally pointless semantic difference out of you own misunderstanding about how NIST is using the term "pancake theory." That sentence, "Thus, the floors did not fail progressively to cause a pancaking phenomenon" is simply restating that the first floor did not fall on its own, nor was it just the floors that pancaked; they're now saying the first floor fell with the entire top of the tower when the columns buckled. They're still referring to what initiated the collapse, which had become widely known as the "pancake theory" and which had become the major issue that NIST was attempting to settle. And again, "pancake" is not any kind of precise technical term that in itself necessarily implies the distinction you're pointlessly trying to make. But since it's a pointless semantic difference and it's not a precise technical term, you're free to not call what happened after the columns buckled "pancaking" if you don't want to, and I'm free to call it that if I want to, as will many others. But you, like many "truth" sites, said "the towers did not pancake and NIST accepts this" as if there is some mystery or uncertainty about what happened when the columns buckled. (As nearly as I can tell, those sites are apparently hoping to create enough ambiguity to leave the impression that explosives must have been required. Since you didn't actually make any point relevant to the discussion, you seem to be just parroting something you read without understanding that "pancake theory" is a specific reference, "pancake" is not.) No, the floors did not pancake on their own, but yes, the towers pancaked after the columns buckled; the term is inherently ambiguous enough to support that usage. No, the floors did not fail progressively to cause a pancaking phenomenon on their own, but yes the entire tower structure failed progressively.

My point is, there is no mystery about what happened after the collapse got started, whether you call it "pancaking," a "pile driver," a "progressive vertical collapse," or a "global collapse."

But please feel free to prove me wrong that you aren't simply trying to create a pointless semantic difference: Take your assertion that "the towers did not pancake" and make some actual point that actually has some bearing on the discussion at hand.

[MervinFerd]

73. I think Mr. F is pulling our legs here.

Your explanation was admirably clear and precise.

--Nobody-- could have misunderstood it as thorougly as Mr. F pretends to do.

He is, perhaps, working with Mr. Goat on this.

[MervinFerd]

13. "Rebuttal": A --rational-- explanation of the errors in an argument.

Statements such as "NIST offered no physical evidence." Or "NIST never proved its claims," are NOT rebuttals.

They are just passing of gas.

REBUT NIST.

[spooked911]

24. show me where NIST proves that progressive top-down collapse can destroy a tower in the absence

of controlled demolition.

[MervinFerd]

32. Sigh... WTC.NIST.Gov. You really should read it. nt

[spooked911]

81. show me the page number where they PROVED this

[MervinFerd]

83. Read the damn report. Then explain to me what errors are there.

God DAMN IT! It is not the job of NIST to "prove" that every damn fool conspiracy theory than every damn fool comes up with is false.

JESUS CHRIST ON A POGO STICK, DRIVING A BOAT TRAILER THROUGH NEW JERSEY.

[spooked911]

85. One of the MAJOR ERRORS in the reports is that they don't explain how the

progressive collapse occurs.

They just say it happens.

I am asking for proof of principle for progressive global collapse.

Otherwsie, demolition is a perfectly valid hypothesis to explain what happened, as well as that there are aspects of what happened that are NOT explained by the reports.

Why do you think NIST is so wonderful?

You don't think there were any political concerns in their report?

[MervinFerd]

87. "How progressive collapse occurs"?

Well, they --do-- provide quite a bit of explanation. But it ---REALLY--- is not a mystery.

----YOU---- (and perhaps some website you are vastly fond of) are the only person in the entire known universe that sees this as a problem. Progressive collapse from the top is --most certainly-- a physical possibility. Besides the NIST report, we have engineers RIGHT HERE ON THIS THREAD who have explained the mechanism to you. OVER AND OVER AND OVER. ----I myself-----, no structural engineer, have given you examples of structures that will progressively collapse from any point you want--houses of cards and Jenga blocks. Structures built of dominoes would have the same properties. Try it.

<<"Why do you think NIST is so wonderful?">> Wonderful? I don't know about wonderful. Competent and professional? Yes.
--Read-- the resume's of the personnel. These people actual know and understand the physics that you are butchering.

<<You don't think there were any political concerns in their report?>>
Not to the point of writing nonsense. This report is read by thousands of --other-- competent engineers. If the explanation of the collapse were -really- impossible or incoherent, there would be a major uproar.

[spooked911]

115. example please of a strong tower undergoing progressive global collapse

not jenga block, not a house of cards. A REAL tower where the pieces are fastened together.

Please.

You think I'M butchering physics?

[MervinFerd]

116. WTC 1 , WTC 2

Fortunately, no other skyscrapers have been hit by jetliners.

Praise God.

[spooked911]

138. I thought you said they were a house of cards, now you say they were strong?

in any case, the example was clearly for towers besides WTC1, 2 and 7.

[MervinFerd]

142. "Strong" is not a technical term. And is relative to the force in question.

And, yes, I know what your question was. The answer is that there -are- no examples of towers (strong or otherwise) that have collapsed quite that way,

--- or that have been hit by jetliners.

It's just a meaningless question. But you know that already.

There are plenty of examples of progressive collapses--both real buildings and illustrative models. This is hardly a novel phenomenon invented for purposes of deception.

Now, will you--please-- answer the questions about the "connections" between prominent Truthers and Nazi White Supremacist Nutcases?

Should not be very hard.

[spooked911]

143. plenty of examples of progressive collapses

Examples of top down progressive collapse with real buildings?

Care to name one?

As far as your "question" I know nothing about what you ask. I suspect your question is somewhat along the lines of "when did you stop beating your wife?"

[MervinFerd]

144. Posts 118 through 126: Regarding connections between...

prominent Truthers and White-supremacist neonazi nutcases.

Simple to answer.

Progressive Collapses: WTC1, WTC2. No other comparable buildings have been hit by jetliners.

[MervinFerd]

14. "Towers did not pancake" and NIST is covering this up...

by stating that clearly on their public web site.

They then describe the mechanism they consider most plausible--which is not controlled demolition.

What a horrid bunch of deep-cover underhanded conspirators NIST is!

BAD NIST!

[spooked911]

23. Yes, they are bad for many reasons. One of which is not examining all

possibilities seriously. But their game is cover-up, not the truth.

In any case, please show me where NIST proves that progressive top-down collapse can destroy a tower in the absence of demolition?

[MervinFerd]

31. NIST eats babies and sends their bones to Taiwan? Bad NIST! BAD!

Examine --all-- possibilities seriously?

NO! No investigation can, or should, examine -all- possibilities. The only requirement is to examine --plausible-- hypotheses. Controlled Demolition is not a reasonable possibility, for reasons NIST explains. No Plane theories are not generally considered by sane individuals.

""show me where NIST proves that progressive top-down collapse can destroy a tower in the absence of demolition?"

Sigh.... Have you read the NIST report? The link is -real- easy to find. Might even be on this thread.

This -really- is not a rational question. The structure is designed to support only the expected --static-- loads. If the upper 20-odd floors develop any substantial velocity, there isn't any other possibility than a progressive collapse. This is the universal opinion of experts who actually know something. Why is this difficult?

If you disagree with the consensus of expert opinion it is --your-- responsibility to prove your case. Not mine.

[MervinFerd]

17. Did you ever actually build a "house of cards"? Evidently not.

Beyond the first few layers, its damn nigh impossible to stop it from a "global progressive collapse". Try it.

You could also try this game: http://www.hasbro.com/jenga/ .

Build your structure more open than the one illustrated. Then begin removing blocks from the middle.

[spooked911]

21. So the WTC was a "house of cards"? Do you really think that?

[MervinFerd]

30. No. --You-- think that. --YOU-- asked for a model system.

I explained that such was not meaningful.

But -your- claim was that a progressive collapse is a physical impossibility at any scale.

That is plainly a false claim.

QED

[spooked911]

82. I didn't say that it was a physical impossibility at any scale

those are your words.

The question is: how can any STRONG tower undergo progressive global collapse?

That was the point of the original CHALLENGE.

[MervinFerd]

88. You are moving the goal post again.

What's a "strong" tower? How do you define "strong"? You mentioned nothing about "strong" in the original challenge.

You said:
<<Your structure can be made out of anything: straws, toothpicks, cards, dominoes, mud, vegetables, pancakes, etc.>>
How is that "strong"?

What we've been trying to tell you OVER and OVER, is that the towers were not "strong". They were carefully designed to support their own weight + a little more. They were NOT designed to be tilted over to the ground or tossed against the wall like a chicken-wire tower.

They were more like a house of cards (or Jenga blocks) than they were like a chicken wire tower.

With substantial damage to their structure, they collapsed in a heap. Like a house of cards when you remove a couple of the card supports.

[spooked911]

112. yes, a house of cards that could swallow a 767 impact and show no loss

of integrity. Yes, that makes PERFECT sense.

:eyes:

In any case, part of the challenge was to build a tower that held up in a 100 mph per hour wind. That means STRENGTH.

[MervinFerd]

121. 100 mph wind? That's Goal 4. Have I met Goals 1 through 3?

Who said anything about swallowing a 767 without loss of integrity.

A house of cards falls down if you look at it meanly. But it undergoes a progressive collapse. Its a very common phenomenon.

As to a tower that will withstand 100 mph winds and collapse in a heap: WTC1 WTC2.

For reasons that have been explained --repeatedly-- its just not possible to model a 110 story tower with a tiny model. You can -illustrate- certain phenomena, but no model is going to be a realistic simulation.

Do you ever actually read the answers to your questions?

[William Seger]

27. Counter-challenge

Come up with a rational theory for what would stop a total progressive collapse if the impact of a falling section exceeds the ability of the structure below to absorb the impact. Since that's a hot topic among structrural engineers now, I'm sure they'll be relieved to know it can't happen.

By the way, what's the prize for accepting your challenge? Since it certainly wouldn't change CTers mindsets about 9/11, there would have to be some other reason for doing it.

[MervinFerd]

35. There's money to be made here. We'll need a patent attorney.

If Mr. Spooked can come up with a structural system that totally prevents collapse, he will need a patent on the concept.

[petgoat]

39. The core was designed to take all the gravity loads.

Most of the mass of your piledriver was outside the core area.

The core should have resisted the limited amount of mass attacking
it in the core area. Piledriver hits on the core would have been rare.
Sliding-friction hits would have been more common. Much of the energy
would have been absorbed by core columns poking holes in heavily braced
core floors.



I agree that a progressive collapse, once initiated, might have brought
down the floors. But the core should have remained standing until
a several hundred foot section toppled to damage one of the surrounding
buildings.

[Name removed]

41. Deleted message

Message removed by moderator. Click here to review the message board rules.

[William Seger]

42. How?

>The core was designed to take all the gravity loads.

No, it was designed to take about 60% of the gravity loads, with about a 1.67 factor of safety, but we're talking about impact forces now, not gravity loads. And again, the core could only take on its design load if the structure was intact, not if the joists and beams holding it vertical were being disconnected at the the same time that falling debris was pushing stuff around chaotically rather than coming straight down on the columns.

> Most of the mass of your piledriver was outside the core area.

Outside the core area, perhaps, but not outside the building. Watch any of the videos again. At least for the first few floors, it's clear that "most of the mass" is not being ejected. After that, you've got a debris pile that's over 200 feet wide, and very likely being funneled inward somewhat by the perimeter walls. How does "most of the mass" get ejected out the side when most of the mass is trapped under that 200' wide pile?

There isn't any way to tell from the videos how much of the mass is being ejected, since mostly what you see is dust. And, you can't tell anything by just looking at the final debris pattern, because it would have hit the ground with a lot of excess kinetic energy that wanted to go somewhere.

> Piledriver hits on the core would have been rare. Sliding-friction hits would have been more common. Much of the energy would have been absorbed by core columns poking holes in heavily braced core floors.

Some of the mass hitting the floors probably broke through without transferring a great deal of force to columns, but certainly a lot of it hit squarely enough on the floor joists and beams to transfer a lot of force to the columns before they broke free. When that happened, the core columns could be pushed over to the side with much less force than that required to cause them to fail under compression. There are multiple factors involved here in addition to the raw kinetic energy of that much mass falling: there's also the loss of structural integrity at the same time that the kinetic energy is chaotically trying to find someplace to go. (Yes, I'm going to keep saying this until it starts to sink in.)

> But the core should have remained standing until a several hundred foot section toppled to damage one of the surrounding
buildings.

Well, there is at least one photo -- actually I believe I've seen a couple -- that seem to show a few hundred feet of core standing for a few seconds -- I'll dig it up if you honestly haven't seen it -- but it didn't topple over like a tree because it wasn't rigid enough for that. It probably collapsed from somewhere near the ground up, more like a conventional CD, when the lower columns buckled.

Those photos and the fact that small pieces of the core were still standing when it was all over pretty much rule out the "mini-nuke in the basement" hypothesis, by the way. (Not that I'm accusing you of being nutty enough to believe that one; I just thought I'd mention it.)

[MervinFerd]

46. The safety factor is really less than 2?

Doesn't give me much confidence in the friendly local skyscraper.

[petgoat]

51. 69% * 1.67 = 100%. The core was designed the take the

gravity loads.

That the mass of the (non-pulverizable) debris remains within
the building footprint is irrelevant to the point that it
remains outside the core area. The majority of the debris was
engaged in taking down the weakest part of the building--the
floors and perimeter columns.

the kinetic energy is chaotically trying to find someplace to go.

The kinetic energy is expended in friction forces in the core, in punching
holes in the core floors, and in tearing the floors loose from the core.

[AZCat]

52. No, it wasn't.

It was designed to take ~60% of the gravity loads. The concept of a safety factor has been gone over many times here yet you seem to have failed to grasp it. It is not to be used as you claim.

[petgoat]

54. I don't believe the safety factor was only 1.67.

Maybe the individual columns had a safety factor of 1.67.

But then you'd have a redundant design that used three times
as many columns as necessary.

[LARED]

55. Huh? A redundant design that used three times

as many columns as necessary.

What in God's green earth are you talking about?

[MervinFerd]

56. Do you have a factual basis for this opinion? Or just pulling out of your ass?

I don't doubt the original post. William generally knows what he is talking about.

My surprise was that this leaves rather little margin for error--bad calculations, bad construction, big airplanes hitting the side...

Would not take very much for those building to just collapse in a heap.

I prefer my buildings be built like the proverbial brick shithouse--indestructible.

[William Seger]

60. 1.67 is fine for a steel structure

For "non-ductile" structures like concrete, it can be anywhere from 2 up to 5 for different types of structural elements, how much earthquake protection is required, etc.

[petgoat]

61. If 1.67 is fine, why is the Dagu Bridge built to a safety factor of 4?

http://www.pubs.asce.org/ceonline/ceonline06/0306feat.html

If 1.67 is fine, and if the WTC was built twice as strong as it would
have been built in Chicago, then we have 3.34 at least.

[Name removed]

63. Deleted message

Message removed by moderator. Click here to review the message board rules.

[petgoat]

66. Is an office building not half a bridge?

Rather more challenging structurally than a full bridge.

Given that it was much more heavily populated than a bridge,
and that the consequences of failure were greater than a bridge,
that the hurricane wind loading was much greater than that of a
bridge, you'd think that the safety factors of the WTC would be
greater than those of a mere bridge.

NYC code was also 1.67

But the WTC was not built to NYC code. It was engineered.

[AZCat]

67. Please, please, please...

Learn more about this concept before continuing to base your arguments on it. Taking the time to do so will be rewarding for you, IMO.

[William Seger]

68. No, it's half a battle ship

I really don't care what "you'd think" about such things when I know what the ASCI recommendation is for office buildings.

> But the WTC was not built to NYC code. It was engineered.

The first statement is just wrong, and the second is a just a non-sequitur. The WTC wasn't required to conform to NYC code because of a legal technicality involving its Port Authority ownership, but it was built to code in almost every respect anyway. Specifically, according to the NIST investigation, the original design documents indicated that the core had been designed to the 1.67 code standard. But let's cut to the chase once again: NIST reverse-engineered the design and found the numbers they published in the document I referred you to. When you have those actual numbers, what "you'd think" about what they were or should have been are totally irrelevant.

And let's try this one more time: When structural integrity is lost, the theoretical load calculations are nearly irrelevant, anyway. Obviously, you simply don't appreciate the significance of that, so your "birds nest on a fence post" and "meatball on a stick" analogies and "sliding-friction hits" make sense -- to you! The question is, why should anyone take you seriously and ignore the experts who actually understand these things? Sorry, but I don't, and not just because they're the experts; it's also because they make a lot more sense than you do.

[petgoat]

91. The experts made more sense to you than the tinfoil hatters

when the experts were still yammering about steel melting in jet-fuel infernos
and still making detailed animations about their absurd zipper theory.

Your invocation of credentials simply constinues to obscure the point:

There was no monolithic piledriver pounding the entire building flat.

There was a structurally compromised top section coming apart around a
rugged steel core. The floors and the perimeters were weak and subject to
progressive collapse once that got started. The core was strong and
extensively cross braced. Core debris from the top section would soon
have started falling onto the trussed floor section, hastening the collapse
of the floors ahead of the resistant core.

[William Seger]

94. Tinfoil hatters have never made any sense to me, period.

For example:

> The experts made more sense to you than the tinfoil hatters when the experts were still yammering about steel melting in jet-fuel infernos and still making detailed animations about their absurd zipper theory.

Your misconceptions have no bearing on the actual issues.

> Your invocation of credentials simply constinues to obscure the point:
There was no monolithic piledriver pounding the entire building flat.

Did you throw in "monolithic" just to be technically accurate? Good job, there was no "monolithic" pile-driver; a non-monolithic pile-driver pounded the entire building flat. Glad we finally got that straight.

[petgoat]

107. A non-monolithic pile driver is not a pile driver. It's a birdsnest. nt

[MervinFerd]

123. A 1000 ton birdsnest travelling 100 mph. nt

[AZCat]

77. I've read the article you linked to...

and I don't see where you got that the bridge in question was built to a safety factor of 4. Perhaps you could point it out to me?

[petgoat]

92. Dagu safety factor

"The bridge behaves basically linearly up to an overload equal to about 400 percent of the total load, defined as all permanent loads plus full live load, on the bridge deck."

http://www.pubs.asce.org/ceonline/ceonline06/0306feat.html

[AZCat]

101. That's what I thought.

It is important to understand that this not quite what you think it is. While the article isn't very clear, my interpretation of it is that the behavior you have quoted (linear response up to ~400% total load) is a result of certain design decisions, not a design criteria itself. The next line after your quote is telling, IMO - it says, "This far exceeds the factor of safety required for such structures." This implies that the design factor of safety was far lower than the results showed.

[MervinFerd]

74. The building fell; therefore, it was not strong enough.

I would add a smiley, if the subject were not so grim.

Seriously, there is a public issue obscured by the nutcase Conspiracy Theories. -Are- these buildings adequately safe? And could they be made safer for some feasible expenditure of money?

We had a bomb at the base of the WTC once. If that had been a bigger bomb, or better placed, would the building have collapsed? Is fire protection adequate?

I gather the engineering community is debating these issues internally, but pressure from the "occupant community" might move the discussion in the direction of greater safety.

[petgoat]

84. Post Hoc Ergo Propter Hoc, eh? The dead man's skull was

battered in, a hammer was found on the ground. Occam's razor tells
us it was suicide by hammer.

[MervinFerd]

89. Whatever, Mr Goat.

[AZCat]

58. You don't quite grasp the concept.

The safety factor is determined by the design load and the design strength (yield strength in this particular case). If you triple the number of columns in a design, the design load will decrease for each column on average by 1/3. In other words, the number of columns partly determines the safety factor.

Extremely simplified example:

I have a column that has a yield strength of 1x10^6 lbs. If I load this column with 0.6x10^6 lbs, my design has a safety factor of (1x10^6 lbs)/(0.6x10^6 lbs), which equals 1.67.

Now let's say that I triple the number of columns in my design. Each column is now loaded with 0.6x10^6/3 = 0.2x10^6 lbs. My new safety factor for all my columns (assuming the load is shared equally) is (1.10^6 lbs)/(0.2x10^6 lbs), which equals a safety factor of 5, quite different from the previous result.

[William Seger]

59. I already showed you that 1.67

... is the recommendation of the ASCI, which is incorporated into most US building codes, and I pointed you to NIST's "reverse engineering" of the individual columns, which showed numbers greater than that only for some of the smaller columns.

> But then you'd have a redundant design that used three times as many columns as necessary.

Complete nonsense on the face of it, as AZCat already pointed out, but also disproved by the NIST study; they didn't count only one-third of the columns. Nobody builds commercial building with three times the number of columns that it needs, or three times as much steel as it needs, because that part of the building would cost three times more than it needs to. The WTC design was more than adequate for its intended purpose.

And anyway, the discussion here is about the ability of the core to withstand the top section falling on it, not it's ability to carry dead load when intact. I see that now you're trying to convince yourself that all that kinetic energy would just be dissipated as "friction." I think you ought to write up you theory and get it published in an engineering journal; I'm sure they'll be relieved to know they don't need to worry about progressive collapses anymore.

[petgoat]

62. Progressive collapses are not the point.

Obviously four falling floors take out the fifth, five take out the sixth, etc.
The perimeter columns peel off. Nobody disputes that.

What can be disputed is that the first collapsing floor takes out the second,
and apparently NIST doesn't believe it can, because there is not a pancake to
be found in NIST.

What can also be disputed is the notion that a small portion of the mass of the
upper tower can take down the core.

Neither FEMA nor NIST has explained what took down the core. Your attempt to
explain the collapse in terms of the action of the entire top of the building
on the entire lower part of the building obscures this essential point.

[William Seger]

64. Progressive collapses are the topic of the thread

> What can be disputed is that the first collapsing floor takes out the second, and apparently NIST doesn't believe it can, because there is not a pancake to be found in NIST.

WHAT?!? Are you deliberately trying to just double-talk the issue? If you can't find "pancake" in the NIST report, try searching for "global collapse" instead. It's what NIST calls what happened after the first floor collapsed: the structure couldn't absorb the impact.

> What can also be disputed is the notion that a small portion of the mass of the upper tower can take down the core.

Well, go ahead and dispute it, then, and stop merely pretending to. But that would require some actual mathematical analysis based on actual physics, not just tossing out every cockamamie inappropriate analogy that pops into your head.

> Neither FEMA nor NIST has explained what took down the core.

Aw. Well, I suppose they could have included Bazant's analysis -- he is an expert in the strength of structural materials, with a PhD in mechanics and a post-graduate degree in physics, and has written some 480 or so journal papers and authored or co-authored six text books on the subject. Would that have satisfied you? Of course not; you'd just be carping about how that "official" analysis doesn't match your bizarre analogies and imaginary physics. You yammer about no "independent" investigation, but then turn around and dismiss an independent analysis by an expert as being meaningless.

[AZCat]

65. I don't understand...

what you are saying here:

What can also be disputed is the notion that a small portion of the mass of the
upper tower can take down the core.

Please elaborate.

[MervinFerd]

57. I hope you know what you are saying. You've baffled me.

"If you can't dazzle them with brilliance, befuddle them with bullshit."

[rman]

86. You ignore dynamic load, which can be several times static "gravity load".

And any large structure is engineered to take several times the calculated maximum dynamic load, "just to be safe".

[William Seger]

93. No, "gravity load" means ALL the vertical loads due to gravity

... i.e. the dead load of the structure plus the live load of the contents and occupants. It excludes lateral forces due to wind and earthquakes.

[MervinFerd]

100. If all the tenants start jumping up and down....

like at a really big party?

Is that dynamic load?

[AZCat]

102. Like, for example...

at the Hyatt Regency Walkway in Kansas City?

Yeah, I'd say that it would be a dynamic load.

[MervinFerd]

104. Wasn't that caused by support bolts not installed according to plan?

I've just seen this on the Discovery Channel, or such.

There was an outdoor foot bridge somewhere which had a resonance near the natural frequency of human steps. Crowds would unconsciously synchronize their steps with the bridge, resulting in violent oscillation. Discovery Channel, again.

In both cases, a safety factor of, say 10 or 15 would have eliminated all problems.

Speaking solely as a pedestrian and not an engineer.

[AZCat]

105. Not quite, but close.

There was a change to the original plans that went through review by all parties involved (although the P.E. is the only one liable) that weakened an already poorly designed structure. Nobody caught this.




On Edit: fixed tag.

[William Seger]

103. That would be "very live load"

If you classify loads as either "static" or "dynamic" then "dynamic" simply means loads that are transient rather than constant over the life of the building, so that includes floor live loads, wind loads, earthquake vibrations, etc. But floor live loads are still considered as part of the "gravity" load because they are strictly vertical, so being dynamic doesn't really affect how you would design for them. All of the load assumptions would have "safety factors" built into them before calculating the total expected load, and the "factor of safety" would be added to that total at the end of the calculation. So, the live load (with a safety factor) would already be intended as a conservative estimate of maximum per-square-foot usage (and it's usually specified explicitly in the building code, dependent on usage type, e.g. "office building"), while the "factor of safety" is only intended to cover possible flaws in materials and construction or degradation over time. In reality, the "factor of safety" would obviously also give some margin for overloading beyond the load assumptions (such as would probably be the case if densely packed tenants were jumping up and down).

[MervinFerd]

47. The qualifications of a person asserting judgments that a process...

is impossible --are-- legitimate subjects of discussion.

An assertion contrary to -all- qualified expert opinion and not backed up by facts is -not- a legitimate subject of discussion.

Grrrrrrrrrrr.

[rinsd]

90. This is gonna be better than the time Homer was tricked into the power plant building contest!

[William Seger]

97. Except nobody got tricked

Hey, you guys come up with a cash prize for accepting this challenge, and it'll be a horse race to see who can do it fastest. If it's "just try to prove this to me" -- well, that's a bit too challenging, not to mention pointless.

[petgoat]

108. "come up with a cash prize"

Reportedly Jimmy Walter offered a cash challenge. Check reopen911.org

http://www.abc.net.au/news/newsitems/200412/s1266553.htm

http://en.wikipedia.org/wiki/James_W._Walter

[spooked911]

113. Yes, Walter offered a fairly substantial prize

I wonder why nobody has claimed it yet

[William Seger]

117. (Sigh.) reopen911.org appears to be history

SO, how much can you guys come up with?

[MervinFerd]

118. "the Holocaust was a hoax and Hitler deserved the Nobel Peace Prize"

From your Wikipedia site:

Walter's 2005 European 9/11 truth "megatour" -
"A couple of people promoting nonsense were also included in the mix (apart from the fact that Walter's "reopen911" website had highlighted the claim that "nukes blew up the towers"). The worst offender against "truth" on the tour was Christopher Bollyn of the white supremacist American Free Press, whose Barnes Review subsidiary claims the Holocaust was a hoax and Hitler deserved the Nobel Peace Prize. American Free Press works closely (by their own admission) with KKK leader David Duke, who is not known for his accuracy or compassion. A fellow invitee to the tour who raised objections to the inclusion of white supremacy was disinvited from the tour."

Nice progressive figure. NOT.

[MervinFerd]

119. "American Free Press works closely... with KKK leader David Duke"

"Just asking questions."

But, a response to this seems warranted.

[MervinFerd]

122. "invitee ...who raised objections to ... white supremacy was disinvited "

"Just asking questions."

[MervinFerd]

124. .

[MervinFerd]

129. .

[MervinFerd]

131. NOBODY IS GOING TO ADDRESS THIS, ARE THEY? nt

[MervinFerd]

126. Could someone please explain why it is that....

vague and ill-defined "connections" prove vast wicked conspiracies,

but well-documented working and financial relationships between prominent Truthers and Fascist White Supremacist nutcases is not worthy of comment?


"Just asking questions."

[MervinFerd]

133. Please.

Pretty please.

[MervinFerd]

135. Pretty Please.

[AZCat]

125. Please clarify something about Challenge #4.

You call for a 100 mph crosswind - do you mean the model should be able to withstand such a wind or that the model should be able to withstand the equivalent of a 100 mph crosswind for the original structure (obviously this would differ depending on the scale of the model)?

[MervinFerd]

132. A window fan blowing against a chicken-wire cage? :)

I don't think you are getting an answer, so some levity seems appropriate.

I suspect that a structure built out of Jenga blocks, or such, could withstand a scaled wind.

I doubt there is any way to make material blow out from a small structure. There's no way to simulate the violence of a 1000 ft fall. Of course, the -original- claim was that the buildings "fell in their footprints" and that proved CD. Any argument that works.

[AZCat]

136. I don't know if I am going to get one or not.

I am interested to see exactly what kind of "wind" spooked wanted us to simulate.

[MervinFerd]

137. What kind of wind? A "breaking" wind?

[vincent_vega_lives]

134. Still waiting for that retraction (n/t)

[spooked911]

139. I retracted the thing about you altering wikipedia

though as I said, it was weird you didn't cite a source and your source was slightly altered from wikipedia.

but, whatever.

[MervinFerd]

141. Spooked! That was a mean thing to say!

Now, will you address the issue of the "connections" between James Walter and certain unsavory characters?