What's the Non-OTC view on Leslie E. Robertson? The WTC Engineer?

[Kingshakabobo]

I watched the documentary on the collapse - I can't think of the name off-hand - He seemed pretty credible. After all, he designed the building. Why would he not be a good source as to why it collapsed?

This guy:

[FoxOnTheRun]

1. We have Frank DeMartini

on record before 911
http://video.google.com/videoplay?docid=-3281135121622917423&q=demartini&hl=en (44 sec

Frank A. Demartini, on-site construction manager for the World Trade Center, spoke of the resilience of the towers in an interview recorded on January 25, 2001.
The building was designed to have a fully loaded 707 crash into it. That was the largest plane at the time. I believe that the building probably could sustain multiple impacts of jetliners because this structure is like the mosquito netting on your screen door -- this intense grid -- and the jet plane is just a pencil puncturing that screen netting. It really does nothing to the screen netting.

Demartini, who had an office on the 88th floor of the North Tower, has been missing since the 9/11/01 attack, having remained in the North Tower to assist in the evacuation.

Thats what Leslie E. Robertson said about buildings in NYC

According to Robertson, New York City has some of the worst wind loads in the nation, even stronger than Chicago or Los Angeles. This is because of the occasional wind generated off of the Atlantic Ocean during hurricane season.

As a result, buildings in New York City must be designed to be twice as strong as similar buildings designed to withstand an earthquake in Los Angeles.

http://web.archive.org/web/20050220071024/http://nyc24.jrn.columbia.edu/2000/issue08/story01/page2.html

[Kingshakabobo]

2. Does the opinion of the construction manager.....

.....trump the guy who designed the building? What's a "construction manager" anyway and why would he trump the designer of the building?

[FoxOnTheRun]

4. It would be interesting to ask Minoru Yamasaki

the architect, but he died in the 80's


What is a building designer?

Building Designer is the term used in the United States and Australia for people involved in the design of buildings who are not legally registered architects.

In Australia anyone may legally call themselves a building designer, however the term building designer is usually used by persons such as an architectural draftspersons who has been registered as a building designer and persons who have exactly the same or similar qualifications and experience as registered architects; ie, a Bachelor of Architecture degree from an accredited course and many years of experience. The only difference, in many cases, is that they have never bothered to sit the examination required for registration....
Text

http://en.wikipedia.org/wiki/Building_design

Interesting, when I look at the article I posted earlier I assume he has something to do with winds and how to stabilize the building.
He certainly could say something about the impact of the planes.

[Kingshakabobo]

6. By designer, I meant engineer. The guy is an engineer. nt

[DoYouEverWonder]

51. Because it's the people who actually did the work

that really know how the building was designed. They are the ones who had to figure out how to turn what was on paper into reality.

[sgsmith]

3. Screen netting

The obvious problem with the analogy is that window screen netting is under no load, unlike the perimeter or core columns of WTC 1 & 2. Since loads are generally in compression or tension (think of pushing together or pulling apart) what do you thing would happen to a window screen if you hung a large weight from the bottom and then cut the screen with a knife? I bet that the screen would catastrophically fail if it had enough damage.

[DoYouEverWonder]

52. But the rest of the window wouldn't fail.

and neither would anything 60 feet away, like the core columns.

[jberryhill]

78. We also have Siegfried and Roy on record

...about their wonderful relationship with tigers, before Roy was eaten by a tiger.

We also have the designers of the Titanic on record as saying "God Himself cannot sink this ship."

So, yes, we have all sorts of assertions about how the towers were designed to withstand an aircraft impact, based on design assumptions about aircraft impacts, prior to the time aircraft were actually flown into the towers.

A large component of engineering is learning from experience.

[petgoat]

5. Kevin Ryan says the heavy lifting on the design was done by

John Skilling, and Robertson was a junior at the time.

http://www.911truth.org/article.php?story=20060327100957690

I would tend to regard Robertson as an unreliable expert because
in the videos he is obviously distraught about the collapses.

It's easy to imagine the psychology of someone in his position:
He'd dare not consider that anything other than the fires brought
down the towers because he pictures doing so as indulging in
the self-serving lunacy of a sore loser in denial of reality.
Thus he'd bend over backwards to be "fair" and "reasonable" and
"take responsibility" and lose all objectivity completely.

I hope it's not petty and slanderous to speculate that maybe he's
on psychiatric drugs. I know if I were in his position I would be.

I bet you saw the NOVA documentary. It's extremely out of date,
and they've removed the references to the "zipper theory" from the
web pages about it.

[hack89]

7. Yes - it is petty and slanderous. nt

[Kingshakabobo]

8. WOW. I was wondering how the "non-official CTers" handle this aspect.

Just wow.

He was too distraught to tell the truth?

He wasn't, in fact, the engineer of record? the chief engineer?

The guy has credentials out his ass - 50 years worth- and a whole lot more credibility than that guy who penned the article you linked. You think that, if he had any hint of sabotage, he wouldn't speak up?

The psychiatric drugs bit was a nice touch though. Reminiscent of the old Soviets - "You must be crazy to not think the way we do".....nice job :applause:
I guess you need that piece though - to complete a proper smear.

Just wow.

[petgoat]

10. "too distraught to tell the truth?"

Not at all. Too close to the subject to be objective. Just as a doctor is well
advised not to treat his own family members, Mr. Robertson is a poor candidate to
evaluate his own work. 9/11 work is all about nuanced epistemology, King.

Mr. Ryan's source for the claim that Skilling did the design work was
"Structures Can Be Beautiful, World's Tallest Buildings Pose Esthetic and
Structural Challenge to John Skilling," Engineering News-Record, April 2, 1964: 124.

Of course, engineers always have differing opinions on who really did the work.
The originator takes the credit and resents the meddling of later parties; the
guy who comes after often feels he deserves the credit for the design because he
transformed the originator's flaky scheme into something workable.

I thought I was being compassionate about Mr. Robertson's situation, and I'm sorry
that was interpreted as a smear. I've been told that a large proportion of the
9/11 families are zorked on free meds.

I know someone who was mugged by bad psychiatry in a situation that bore some
similiarities to Mr. Robinson's in that it involved adjustment to unfortunate
happenings and the question of whose responsibility they were. She was pretty
much bullied and drugged into accepting responsibility for some stuff that
was in my opinion not her fault, all in the name of transcending victimhood.
The shrink was in no way qualified to evaliuate the facts of the situation.

I could see Mr. Robinson in the same position, being urged to accept that the
fires brought the towers down, even though he knows in his heart that they
couldn't have, and I could see him the medicating away the discord.

So you see, I am not objective enough to analyze Mr. Robertson's situation,
but I do think I can provide some insight.

[mirandapriestly]

15. I've seen speculation that people who were distraught

by the attacks were offered mental health counseling that included psychiatric drugs that would influence their recollections, ie: witnesses, if you know what I mean. Don't know if it's true but thought I'd mention it here. I didn't know what to think of those people in the documentaries that were around since the early days - they must have known.

[dailykoff]

16. I think they had to be in the loop.

There's a thread in here with a quote from a Skilling engineer talking about fires bringing down 7 that was in the NYT the day after 9/11 and he's already spinning like a top.

My guess is that they brought Robertson et al. on board after they botched the 93 attack and realized that taking out a Manhattan highrise requires a little more expertise than blowing up a mosque.

[Kingshakabobo]

19. ''I've seen speculation''

''Don't know if it's true ''

''but thought I'd mention it here''

Do you have ANY links? Why post it if it's speculation and you don't know if it's true? No offense, but how does that help?

[John Q. Citizen]

22. People speculate all the time. It's obvious we aren't going to prove or

disprove LIHOP, MIHOP or incompetence on this forum. We are going to discuss it, but not prove it to the complete satisfaction of anyone/everyone.

I could find you links to decent posters from all points of view who have at one time or another speculated on many aspects of 9/11. but I'd rather not. Speculation isn't a bad thing . miranda states clearly she's repeating speculation. So she need not post a link. Unless she has one and wants to. There is no requirement.

Perhaps someone else who reads her post and has a link will post it. Or maybe not.

[mirandapriestly]

27. It is on a forum that I read

in regards to the "mental health" help people were offered after 9-11. Some random poster thought that it might be because they were giving people psychiatric drugs to help them "forget" what they saw. I really didn't write it for people like you, I don't read your posts unless they are directed to me I don't know why you read mine. I don't care what you think.

[Kingshakabobo]

35. "Some random poster thought "

Oh. OK. I thought DU had a little better standards. Silly me.

"I really didn't write it for people like you, I don't read your posts unless they are directed to me I don't know why you read mine. I don't care what you think."

Um, I started this thread. You don't mind if I post in it, do you?

[John Q. Citizen]

36. I read your OP, I don't mind if you post in it or anywhere for that matter

As to standards, this is from your OP isn't it?

"I watched the documentary on the collapse - I can't think of the name off-hand - He seemed pretty credible. After all, he designed the building. Why would he not be a good source as to why it collapsed?"

Are you meeting your own expectations of the high standards you thought DU requires? I mean, you might have at least provided the name and a link to the documentary you watched....

I don't mind that you didn't. But I'm wondering if you mind that you didn't. Or are your standards only for other posters in your view?

[Kingshakabobo]

37. Nice twist attempt.. You should try out for the republicans with.......

.....THAT talent. Don't even try that shit. I wasn't speculating if there WAS a documentary - I just couldn't remember the name. It's quite clear there IS a documentary.

Nice try. No cigar. Your credibility meter just bottomed out with THAT post.

edit to add:

"I mean, you might have at least provided the name and a link to the documentary you watched...."

Do you comprehend english? What part of "I can't think of the name off-hand" didn't you understand?

[John Q. Citizen]

38. Why are you apparently

upset that another poster offers a speculation that he or she read and clearly states it is a speculation?

What's the big deal? It's not against the rules, anymore than talking about a documentary that you can't remember the name of is a big deal. It's not. Both examples happen all the time.

So please chill out. Thank you.

[Kingshakabobo]

39. First of all.......

.....don't tell me to chill out and I won't tell you to grow up. Second of all, where do you get the idea that I was "upset" at the other poster's lack of proof, links etc.? Third of all, why do you consider it being "upset" to question someone's lack of proof, links, etc.?

"It's not against the rules"

Where did I say it was?

Don't worry. I'm quite "chilled." I just find it pathetic that the best the CTers can come up with is smears against Robertson and his mental health. I guess that proves the point that if you move far enough to the left, you meet the righties.

[petgoat]

40. There's no smear.

The question in the OP was a technical one:

"Why would he not be a good source as to why it collapsed?"

I answered it. He's not objective. You would not let the spouse
of a murder victim serve on the jury of the criminal trial of the case.
You would not let the spouse serve as an expert witness in the case.

From the video, it appears that Mr. Robertson was deeply distressed
about the event.

[Mist]

44. Robertson looks like the guy I saw interviewed on tv very soon after

911. He was saying he couldn't figure out HOW the buildings could have collapsed as they did. 3 or 4 nights later, he was interviewed on a different show--said fire could have brought the buildings down. What I remember is how different he looked in the two interviews: first one, a bit pugnacious and incredulous that the bldgs. collapsed due to fire. Second interview: uptight and nervous-looking.

[dailykoff]

41. Robertson is lying.

We're just trying to figure out why.

[petgoat]

42. I see no reason to be so uncharitable, He's bending over

backwards to be fair. He's trying to avoid being a sore loser.

I did the same thing when bolo (whatever happened to bolo?) presented
that picture he claimed was perimeter column debris in the WTC7
rubble pile. I very quickly conceded the point because I didn't want
to be petty, though I knew there was something wrong with the picture.
It took me a couple of weeks before I thought to measure the picture
and found the proportions were all wrong for perimeter columns.

[dailykoff]

43. I don't doubt that he was upset, goat,

but I also don't doubt that he and every other Skilling engineer knows exactly what brought down those three buildings and have since at least 9/11.

Doesn't it strike you as odd that after five years, Robertson still hasn't figured it out? Or that Skilling, who by your account was of a different persuasion and didn't mind saying so (very good find, by the way) conveniently passed from the scene shortly before 9/11?

[Recursion]

21. That's an odd way to look at it

An engineer takes legal responsibility for the success and failure of his or her work (that, incidentally, is why "software engineer" is a misnomer, and that's my job description...). I would think that if the engineer had any intimation of sabotage he would want it front and center to absolve himself from the failure. Come to think of it, your attack on his credibility could work no matter what he said, because if he did suggest sabotage someone could say, "well of course *he's* going to say that, as the engineer; his credibility is at stake".

[petgoat]

33. "your attack on his credibility could work no matter what he said"

That's just the point. He doesn't dare say there was sabotage, because
it would kill his credibility. Therefore he can't even think there might
have been sabotage. He calls the idea "crazy".

Therefore he can't be objective and for him to offer expert opinions is
not appropriate.

[mp3hound]

23. How would Kevin Ryan know?

Isn't he a young guy who worked in water testing at Underwriter Labs? Is he qualified to opine on Mr. Robertson and Mr. Robertson's role in the WTC project or is he just making stuff up?

And as for writing off Mr. Robertson as an expert because he exhibited emotion, I disagree. He is obviously an expert with multiple degrees, vast knowledge, vast experience, and an impeccable history behind him. I think it is because of his expertise, his commitment to his work, and his genuine belief that the buildings he designs are of benefit to the public that he was emotional about the collapse of the buildings that he designed and the deaths of thousands who were trapped within. I see his emotion as a testament to his humanity, not as a weakness to be exploited by conspiracy theorists.

I think it's sad that he is attacked and slandered by anonymous internet posters on the basis of nothing but unsupported innuendo and an apparent burning desire to build a flimsy house of conspiracy theory cards.

There are better targets. I don't understand why conspiracy theorists are going after Mr. Robertson.

[mirandapriestly]

28. How would you know?

"I think it is because of his expertise, his commitment to his work, and his genuine belief that the buildings he designs are of benefit to the public that he was emotional about the collapse of the buildings that he designed and the deaths of thousands who were trapped within. I see his emotion as a testament to his humanity, not as a weakness to be exploited by conspiracy theorists."

[petgoat]

34. I wasn't attacking Mr. Robertson.

I was offering the opinion that his objectivity was questionable, and
trying to understand his situation by putting myself in his shoes.

I know if I were in his situation, I would be on powerful tranquilizers.
I know from a 9/11 survivor I am not free to identify that the survivors
were offered free counseling and free drugs, and that many of the family
members are dependent on them.

I don't understand why conspiracy theorists are going after Mr. Robertson.

Not going after him. The question in the OP (original post) was:

"Why would he not be a good source as to why it collapsed?"

I answered it. He can't be objective.


Welcome to DU! :hi:

[mp3hound]

46. Thanks for the welcome.

Perhaps now you can address what I said in my post. Let's start with this: You quoted Kevin Ryan as saying that "the heavy lifting on the design was done by John Skilling, and Robertson was a junior at the time."

I asked, "How would Kevin Ryan know? Isn't he a young guy who worked in water testing at Underwriter Labs? Is he qualified to opine on Mr. Robertson and Mr. Robertson's role in the WTC project or is he just making stuff up?"

Your answer did not deal with that at all. So, how about we do this a couple of sentences at a time, starting with those quoted above? I think that would be a more meaningful way of discussing multiple issues raised in singular posts, don't you? There is no purpose served in ignoring the first point and purporting to address subsequent random points. Best to address them all, in order, don't you think?

[petgoat]

47. See post #10

Mr. Ryan's source for the claim that Skilling did the design work was
"Structures Can Be Beautiful, World's Tallest Buildings Pose Esthetic and
Structural Challenge to John Skilling," Engineering News-Record, April 2, 1964: 124.

Of course, engineers always have differing opinions on who really did the work.
The originator takes the credit and resents the meddling of later parties; the
guy who comes after often feels he deserves the credit for the design because he
transformed the originator's flaky scheme into something workable.

[mp3hound]

65. Thanks.

One step at a time, like I said. Here is step 2:

Can you please quote what was written in "Structures Can Be Beautiful, World's Tallest Buildings Pose Esthetic and Structural Challenge to John Skilling," Engineering News-Record, April 2, 1964: 124 that Kevin Ryan was referring to so that it can be assessed here?

Next, "I know if I were in his situation, I would be on powerful tranquilizers."

That is unfortunate for you, and it is of no evidentiary value whatsoever as to whether Mr. Robertson was or was not on any kind of medication, let alone "powerful tranquilizers". I do not doubt that he was adversely affected by the events as were millions of people, but it seems odd to suggest that because your own personal threshold for adversity would require you to be on "powerful tranquilizers", he would react similarly and require "powerful tranquilizers" to deal with the reality of the events.

In other words, unless you have evidence that the man was actually on "powerful tranquilizers", your argument appears weak at best, deliberately malicious at worst.

Next, "I know from a 9/11 survivor I am not free to identify that the survivors were offered free counseling and free drugs, and that many of the family members are dependent on them."

So, you know a single 9/11 survivor and that translates into you "knowing" that "many of the family members" of 9/11 survivors are dependent upon drugs? Sure, okay.

Many people here know 9/11 survivors and, sadly, 9/11 victims. Does this mean that you will accept what they post here as factual since you seem to be suggesting that your post should be accepted as factual? I ask this because I've read these boards for a long time and it appears that you have consistently castigated others for offering personal anecdotes and labelled them unworthy of belief because the posters are anonymous internet posters....... just like you. But now you seem to be suggesting that your personal anecdotes should be taken as factual even though those of many others should not.

[petgoat]

72. Sorry, I don't have time to go to the library this week.

That article is from 1964 so it would have to be read in hard copy.

Your mischaracterization of the situation as one of mere "adversity"
when in fact it is responsibility connected with almost 3000 deaths
shows that you do not appreciate or understand the nature of Mr.
Robertson's problem. You know nothing about my capacity for adversity.

A survivor tells me that other survivors and family members have been
encouraged to medicate away their feelings, and many do. Since this
is standard psychiatric practice in America today, your questioning
of the notion seems peculiar. I do reject personal anecdotes for
factual foundation; I presented this one in explaining how I arrived
at my opinion, not as proof of anything.

Mr. Robertson when interviewed IMHO had the look of someone on powerful
tranquilizers. I've done a lot of social work with drug abusers. That
too is anecdotal and I present it not as proof that Mr. Robertson is
drugged but as part of how I reached my opinion.

This is all beside the point. You just want to play "gotcha." The
point is: the OP asked if there was any reason we should not rely on
Mr. Robertson's opinions on the engineering, and I said he could not
possibly be objective on the situation.

[Carefulplease]

9. Robertson about the aircraft impacts and the design...

Reflections on the World Trade Center

Leslie E. Robertson

The lead structural engineer reflects on the rise and fall of the World Trade Center towers.

http://www.nae.edu/nae/bridgecom.nsf/weblinks/CGOZ-58NLCB?OpenDocument

The buildings survived the impact of the Boeing 767 aircraft, an impact very much greater than had been contemplated in our design (a slow-flying Boeing 707 lost in the fog and seeking a landing field). Therefore, the robustness of the towers was exemplary. At the same time, the fires raging in the inner reaches of the buildings undermined their strength. In time, the unimaginable happened . . . wounded by the impact of the aircraft and bleeding from the fires, both of the towers of the World Trade Center collapsed.

The jets impacting the WTC1 and WTC2 probably had 6 and 10 times more kinetic energy, respectively, than the impact that was contemplated in their design.

[petgoat]

11. Dr. Thomas Eagar characterized the planes' impact as

"like a bullet hitting a tree."

[Carefulplease]

13. That is very poetic Petgoat. Thank you. n/t

[petgoat]

14. Oh Dr. Eagar has his way with images, doesn't he?

It's not just poetic, it's technical. The point is, the impact of the
impact was negligible. The towers were built for a hurricane. They were
built twice as strong as they would have been built in Chicago.

[Kingshakabobo]

17. It appears, though, that he is a OTCer. No? nt

[petgoat]

18. Thomas Eagar, a materials scientist from MIT, was the

originator of the "zipper/pancake theory." I believed it when I read
about it in 2002, and when I saw the pictures on the internet of the
squibs I assumed they were somebody's sick photoshopped hoax. (I'd
probably still believe it if not for the efforts of local Truthists.)

Dr. Eagar's thesis was incorporated in the FEMA/ASCE report. He's
been pretty quiet since NIST rejected his theory. He'd claimed that
weak truss "clips" caused the floors to "unzip," then one floor fell
on a second, two floors fell on a third, and the entire building
pancaked. The problem with this theory is that the core-side clips
must have been strong enough that collapsing floors tore down the
47 14" X 36" core columns.

NIST's theory is that the truss "clips" are so freaking strong
that saggy floors buckled the perimeter columns. I've been amazed
that no one from MIT will defend Eagar's thesis after it was
conventional wisdom for three years.

[Carefulplease]

20. NIST does not have a theory that the clips were "freaking strong"

What you overlook is that the NIST model shows that the perimeter walls bow inward only when the truss floors sag on several (at least three if I remember correctly) consecutive levels.

Also, the finite element model NIST used incorporates actual empirical data concerning the modes of failures and yield stregths of critical structural components such as the truss connections. Finally, the bowing of the walls isn't a theory; it is an empirical datum that you failed to explain away in an earlier discussion.

[petgoat]

30. Your claim of empirical bowing is bogus

What allowances did NIST make for optical distortions due to
heat flowing along the external surface?

Where are the buckled perimeter columns? Why didn't anybody bother
to save any?

NIST's "Bush Science" is about as empirical as the 9/11 Commission Report.

It's plainly been reverse engineered to generate the desired results.

[Carefulplease]

45. We've been over the refraction issue laready...

I've pointed to several objections to this ah hoc hypothesis seemingly tailored to discount inconvenient evidence. Have you thought of something new to address these objections?

http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=125&topic_id=102508&mesg_id=104224

Also, NIST *does* have buckled perimeter column samples. Look it up.

[petgoat]

48. The hypothesized laminar flaw was not inside the towers.

Obviously it's outside the towers--it provides the
optical illusion of bowing.

Are NIST's buckled perimeter columns pulled in by their
truss anchors, or are they artifacts of the collapse?
Have they been identified as particular column trees
pictured in particular photos?

You have clearly read the NIST report very closely.
Frankly I find it very peculiar that anyone from Canada
would take the time if they thought the towers' collapses
were natural.

If you want to defend the NIST report, your credibility
would be much enhanced is you would adopt the position
"I know it's Bush Science, but it's the best we're likely
to get and it's not as bad as you think."

[Carefulplease]

49. This ad hoc hypothesis is both falsified and useless...

Edited for clarification of subordinate clause in second paragraph (addition of a second "if").

I see that I misunderstood your claim about the flow originating outside the tower. Nevertheless the hypothesized "smoothing" issue was addressed. There is no smoothing up of the turbulent flow that is possible for reasons that AZCat spelled out. No smoothing up is observed in the smoky regions anyway.

http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=125&topic_id=102508&mesg_id=104208

However, there is another stronger reason why such a flow could not account for the observed bowing even if the flow were smooth and its optical effect were inconspicuous -- if it produced no detectable turbulent wavering. The magnitude of such an effect could not be nearly large enough to account for the observed bowing. So the hypothesis is useless.

Here are the indexes of refraction of some gases for 589.3 nm light (T=0 degree C; P=101325 Pa)

Air: 1.000292
CO: 1.000338
CO2: 1.000449
N2: 1.000298
O2: 1.000271

Any increase in CO and CO2; or any depletion of oxygen would just offset the effect of increased temperature. So I will discount them. I will also discount the effect of vapour content.

Let us focus on the effect of heat. Refractivity is N = (n - 1) * 1,000,000. This is governed by:

N = 77.6 * P/T

where P is expressed in millibars and T in Kelvin degrees (I discount the small "wet factor" that depends on the partial pressure of H2O)

This indicates that an increase in absolute temperature by some factor results in a reduction of refractivity by the same factor. You can verify this inverse proportionality using some values for T here:

http://emtoolbox.nist.gov/Wavelength/Edlen.asp

Thus, if the temperature or the hot air layer were as high as 1000C when the surrounding temperature is 20C, the refractivity would be reduced by the factor (1000+273)/(20+273) = 4.34. This yelds an index n = 1.000076 for air heated at 1000C.

However hot this layer is, its index would never drop below 1 since the index of refraction expresses the ratio of the seed of ligh in vaccuum to the speed of light in the medium. The latter can never exceed the former. I shall just assume an index of 1 for the hot air layer. This assumption overestimates somewhat the optical effect -- and there is no way it could be magnified further.

Let us assume that the thickness of the hot layer is as large as 20 feet (fully 10% of the WTC Tower's width) and that the zone where the index varies is compressed at the interface with the cold exterior air away from the perimeter wall. This assumption also magnifies the optical effect.

The apparent displacement of a perimeter column can be calculated when the line of sight is displaced 45 degrees to the left or right from the direction normal to the wall. The refractive angular deflection is given by Snell's law n1*sin(theta1)=n2*sin(theta2) and thus:

Theta2 = arcsin((n1/n2)sin(theta1)) = arcsin(1.000292*sin(45degree)) = 45.017 degree.

At this angle the apparent axial bowing displacement matches the apparent lateral deflection. This apparent deflection is

D = H(sin(theta2)-(sin(theta1))

(H is the Hypotenuse of the triangle formed by the line of observation, the cold/warm air interface, and the normal to the wall)

where H = (20feet / sin(theta1)) = 28.3feet

And thus D = 28.3feet*(0.717327-0.717107) = 0.00022*28.3feet = 0.00022*340inches = 0.075 inches.

NIST observed that the perimeter walls bowed as much as three feet with an estimated error of plus or minus 6 inches (if I remember correctly). Very easy back-of-the-envelope calculations show that refraction from hot air would account for an error that is less than a tenth of an inch in the worst imaginable circumstances. They were entitled to dismiss such an effect.

So, what it is that pulled on the columns? And why is it someone from Canada wouldn't take an interest in these matters?

[petgoat]

54. NIST's theory, which you have articulated, is that saggy floors

pulled the perimeter columns inward as they cooled, buckling the
perimeter columns.

[Carefulplease]

58. And what is your explanation of the observed pronounced bowing? n/t

[petgoat]

59. I have stated it many times. Optical refraction due hot air

flowing in a laminar fashion up the external walls of the towers.

[sgsmith]

61. Hoohah

A laminar flow is attached to the surface. It is, by definition, non-turburant. As such, there shouldn't be any optical refraction.


Definition of laminar air flow

1. a flow of air uniformly parallel from ceiling to floor, or wall to wall in a room or workstation, moving with uniform velocity and a minimum of turbulence.

http://www.chemicool.com/definition/laminar_air_flow.html

[petgoat]

62. My understanding of laminar flow comes from hydrodynamics,

so perhaps I'm using the term imprecisely.

I mean pictures clearly show a curtain of hot air moving up the side
of the WTC. Just as a hot road makes the light all wavery in the desert,
this moving hot air will refract the image of the columns behind it.

NIST's assumption that the pictures show bowing is not justified.

[AZCat]

63. There's your problem.

This isn't hydrodynamics. Hydrodynamics is the study of incompressible fluid flows (liquids, in other words) whereas we are dealing with a fluid that is compressible (air and various products of combustion).

The real problem, of course, is that in backing up your argument you are using a concept that does not appear to be well understood by you. Your argument IMO merits at least a caveat from you, rather than being announced as definitive.

[petgoat]

68. "Laminar flow" is not the point

It's just a technical term I am apparently misusing to describe the upward flow
of a layer of hot air up the exterior of the WTC, a phenominon shown in many
pictures of the burning WTC. Air at far lower temperatures has refractive
effects on light, as anyone who spends much time around hot roads knows.

[AZCat]

69. You kinda walked into that.

It's probably not a good idea to appropriate technical terms if you don't fully understand them.

Regarding roads and optical distortions, I think you are comparing two scenarios that differ significantly. When looking down a road, the distortion appears drastic because of the distance between you and the terminus of your vision. This length means that light must pass through a much longer section of hot air before reaching you than in the case of the building exterior of the WTC, where most of the air between the WTC and the viewer was not hot and therefore would not produce any distortion. The amount of refraction is dependent on the length of the medium so the significant difference in lengths between the two scenarios leads me to believe that this would cause a significant difference in the amount of refraction.

[petgoat]

73. I don't fully understand anything.

I looked up the word "laminar" in the dictionary. "Lamina" means a thin
layer. That's exactly what I was talking about, a layer of air moving
up the side of the building. I wasn't talking about an airplane wing.

[Carefulplease]

74. This is what we understood also.

However, the laminar *flow* isn't possible. It is turbulent and its alleged optical effects would be conspicuous. And a turbulent sheet of hot air (and also a sheet with a laminar flow) wouldn't account for the magnitude of the apparent distortion anyway, it seems. See message #49.

[greyl]

66. Why you keep repeating one of your most silly statements

is beyond me. I can only think it's pure desperation.

[Carefulplease]

67. Didn't you read my message #49? The refraction is not enough.

Didn't you read my message #49? There I granted all you assumptions regarding laminar flow. I also assume the refractive index of the warm air to have the smallest possible value for any medium (n = 1) and that the layer of warm air is as much as 20 feet thick. The maximum apparent lateral displacement of a column seen at a 45 degree angle is 0.075 inches. This is nearly three orders of magnitude too small to account for the observed bowing. Where is the mistake in my demonstration? Please read again message #49 and ask some questions if anything is unclear.

[Carefulplease]

50. I haven't heard about this Professor Bush.

Is he still working for NIST? Is he related with the incurious scientifically illiterate president of the U.S.A. who seems so dismissive of serious climatological research and who is so enthusiastic about ineffective methods for combating the spread of AIDS?

[petgoat]

55. Bush is no professor. If you've never heard of him, I guess

you haven't heard of his regime's egregious conduct with the scientists
in NOAA involved in research relevant to global warming.

Bush Science should be a self-eplanatory oxymoron.

[greyl]

57. I think you totally missed the poignant humor. nt

[petgoat]

60. I joked about the collapse early in the afternoon of 9/11,

assuming that everyone had been evacuated. A bystander
who was listening said "Sir, were you there?"

[Carefulplease]

53. Buckled columns...

Are NIST's buckled perimeter columns pulled in by their
truss anchors,

Some might have been.

or are they artifacts of the collapse?

Some might have been. That is not exactly an easy determination to make.

Have they been identified as particular column trees
pictured in particular photos?

Many panels (column trees) have been precisely identified (about 40 of them.) Look it up. Those columns that were known to have been exposed to fires were more likely to have failed through buckling of the inner web. Look it up.

http://wtc.nist.gov/NISTNCSTAR1-3.pdf

You have clearly read the NIST report very closely.
Frankly I find it very peculiar that anyone from Canada
would take the time if they thought the towers' collapses
were natural.

Some people like their beliefs to be grounded, even in Canada.

[petgoat]

56. My belief that the NIST report is a piece of shit is grounded

in my knowledge of Bush Science with respect to global warming issues,
with my recognition that tweaking the parameters until you get the results
you want is just a mite.... unempirical, the recognition that the assumption
that collapse initiation equals total progressive collapse is unjustified,
the recognition that the fire temperature models show a fantastical degree
of specificity, and the recognition that the failure to provide the
visualizations is distressing engineers around the world.

[AZCat]

64. Distressed engineers?

There may be a few, but most that I know realize that visualizations don't mean anything - those are the things you include in a report or presentation when you want to impress laypeople.

[petgoat]

70. Dr. Jones cites a paper in New Civil Engineer,

Parker, Dave (2005). "WTC investigators resist call for collapse visualisation," New Civil Engineer, October 6, 2005.

World Trade Center disaster investigators are refusing to show computer visualizations of the collapse of the Twin Towers despite calls from leading structural and fire engineers, NCE has learned. Visualisations of collapse mechanisms are routinely used to validate the type of finite element analysis model used by the investigators. The collapse mechanism and the role played by the hat truss at the top of the tower has been the focus of debate since the US National Institute of Standards & Technology (NIST) published its findings….

University of Manchester professor of structural engineering Colin Bailey said there was a lot to be gained from visualising the structural response. “NIST should really show the visualisations; otherwise the opportunity to correlate them back to the video evidence and identify any errors in the modeling will be lost,” he said….

A leading US structural engineer said NIST had obviously devoted enormous resources to the development of the impact and fire models. “By comparison the global structural model is not as sophisticated,” he said. “The software used has been pushed to new limits, and there have been a lot of simplifications, extrapolations and judgment calls.” (Parker, 2005; emphasis added.)

http://www.physics.byu.edu/research/energy/htm7.html

[AZCat]

71. Meh...

So some engineers disagree with me. I still think the visuals aren't important, although Bailey makes a good point about comparing the results visually to video evidence. The important stuff IMO is an explanation of the fundamentals of their model - assumptions, simplifications, data - and explication of their method. Without that it's just a bunch of pretty pictures.

[FoxOnTheRun]

12. unimaginable?

The interview was conducted in spring of 2002. During a mass trauma of the western world, thanks to TV.

If he doesn't suspect something, why should he say something?

Planes crashed and the towers collapsed....


The media will certainly look at it in a honest way. And there will be an investigation of the evidence, like the steel...oh I forgot most of it is in China.

[zforce]

24. I was wondering how FEMA got that wrong.

Robertson incorrectly states..

The buildings survived the impact of the Boeing 767 aircraft, an impact very much greater than had been contemplated in our design (a slow-flying Boeing 707 lost in the fog and seeking a landing field). Therefore, the robustness of the towers was exemplary. At the same time, the fires raging in the inner reaches of the buildings undermined their strength. In time, the unimaginable happened . . . wounded by the impact of the aircraft and bleeding from the fires, both of the towers of the World Trade Center collapsed.

"A slow-flying Boeing 707" ?


The official 1964 documents contained within the NIST report state..

http://wtc.nist.gov/NFPA_Presentation_on_WTC.pdf

Available Information on Safety of WTC

Towers in Aircraft Collision (1)

Type of Aircraft: Boeing 707 (largest jet aircraft in the air at that time)DC-8

Speed of Aircraft: 600 mph (Port Authority, February 1964)....



...Location of Impact: 80th floor (Port Authority, March 1964)

Structural design: It appears that the design of the WTC towers considered the impact of 707 aircraft and analysis indicated that such collision would result in only local damage which could not cause collapse or substantial damage to the building

[dailykoff]

25. Proof that Robertson is spinning.

Nice find.

[seatnineb]

26. Excellent find ZForce!..............

I think it is a safe bet that Leslie Robertson is on "their" side:

In the words of Leslie Robertson:
They(theWTC) got run into by an airplane, with the throttle down, laden with fuel,...they took an enormouse physical hit...and then following that a fire, both from...initially from the fuel...and then that fed everything that would burn that was inside the building...and that combination brought down the buildings...

There is no evidence that there was any bomb inside....IN MY VIEW....THAT IS A KIND OF CRAZY THOUGHT(that there could be bombs in the WTC)!

Leslie Robertson(WTC lead engineer)
9/11 Conspiracy Theories
T.V documentary
Channel 4
U.K
(9/9/2004)

[petgoat]

32. Robertson is on "their" side

To be fair, he's probably bending over backwards not to be a sore loser
and not to be a victim.

He can't be expected to be objective on the subject.

[FoxOnTheRun]

29. Has anyone the speed on flight 11 and 175?

I found 470 mph and 590 mph for the planes hitting the WTC.

[petgoat]

31. Designer Confidence

Kevin Ryan says that Skilling was confident about the ability of the towers to withstand
the plane impacts and the fires.

http://www.911truth.org/article.php?story=20060327100957690

"In 1993, five years before his death, Skilling said that he had performed an analysis on jet plane crashes and the ensuing fires and that "the building structure would still be there.""

He cites James Glanz and Eric Lipton, City in the Sky: The Rise and Fall of the World Trade Center (New York: Times Books, 2003), 138.

[jberryhill]

79. Yes - Designer Confidence

"...even God Himself could not sink this ship!"
Bruce Ismay, White Star Line - 1912



Wait, wait, don't tell me. The sinking of the Titanic was an inside job.

You could probably find a Bush family connection. I want royalties on the "Loose Icebergs" video.

[Kingshakabobo]

75. Taking a stroll down memory lane.

:hi:

[freedom fighter jh]

76. What did Robertson say?

I saw Robertson in a video. He was debating someone who believed it was something other than airplanes that hit the buildings. He stated clearly that yes, in his opinion, airplanes could have caused the towers to collapse.

Then someone asked him to explain how the collapses could be so quick. He said he did not know; he had not studied the question.

That is why he would not be a good source as to why it collapsed: There is at least one essential question about it that he has not studied.

[Contrite]

77. Robertson has contradicted himself.

http://www.911blogger.com/node/6040#_ftn9

Analysis:

Robertson has made some glaring contradictions in his statements.

· Robertson claims that the building was designed to only survive plane crashes at speeds of 180 mph. Interestingly he made this claim only a few days before 9/11.<14> A quote by Building Designer Skilling indicates that “A previous analysis, carried out early in 1964, calculated that the towers would handle the impact of a 707 traveling at 600 mph without collapsing”.<15> Robertson must resolve this apparent contradiction. It is a very suspicious statement given the fact that it would be reasonable to consider the maximum speed of a plane flying into the Twin Towers. Is it possible that Robertson was asked to leak this “deliberately misleading information” just before 9/11? However, this is just speculation. Also suspicious is the fact that he said in 1984-5 that there was “little likelihood of a collapse no matter how the building was attacked.”<16>

· Robertson says that the building was not designed to survive jet fuel fires: “To the best of our knowledge, little was known about the effects of a fire”. This claim is suspicious for two reasons: why would they design the towers to survive plane crashes without considering the jet fuel? And more importantly, John Skilling claimed in 1993 that they did consider the jet fuel when they designed the buildings.<17> Given this fact, which statement is more likely to be correct about jet fuel fires being considered?

· NIST is also contradicted when they claim that there was no “evidence to indicate consideration of… thousands of gallons of jet fuel”. This statement is clearly false. See John Skilling’s statement: “Our analysis indicated the biggest problem would be the fact that all the fuel (from the airplane) would dump into the building. There would be a horrendous fire… The building structure would still be there.”<18>

· In an interview with Steven Jones, Robertson claims that he had “never run across anyone who has said that they had in fact seen molten metal.” This statement is extremely suspicious considering the fact that Robertson himself claimed to have seen it in a published news report! This contradicts his own statement about seeing molten metal: “Leslie Robertson, the structural engineer responsible for the design of the WTC, describes fires still burning and molten steel still running 21 days after the attacks.”<19>. As well, substantial eye-witness testimony supports observations of Molten Steel.<20>

· Robertson is also incorrect when he says that “if they had seen performed some kind of an analysis to determine what that metal was. This statement is false. FEMA analyzed samples of the molten steel.<21> However, NIST did not even mention the molten steel and called it “irrelevant to investigation.”<22> This could have simply been a mistake by Robertson.

Is Robertson being pressured to lie and make false statements? Was he asked to leak a false statement just before 9/11 about the speed of the planes having an impact on their destruction? Are these contradictions by accident or mistake?

A news report stated that he wanted to give his opinion to the FBI before making his comments public. This in itself is not overly suspicious—but his contradictions are. No clear answers to these and similar questions can be obtained through speculation alone—Leslie Robertson must account for these himself. If another 9/11 investigation is obtained, it is clear that Leslie Robertson will have to answer these and other relevant questions.