Having complained of people posting off topic, it seems a reasonable solution to give an opportunity for people to discuss the topics I am banning from other threads – of which 9/11 seems the most popular.
I do not believe that the US government, or any of its agencies, were responsible for 9/11. It would just need too many people to be involved. Someone would have objected. There are some strange and dangerous people in America, but not in sufficient concentration for this one. They couldn’t even keep Watergate quiet, and that was a small group. Any group I can think of – even Blackwater – would contain operatives with scruples about blowing up New York. They may be sadly ready to kill people in poor countries, but Americans en masse? Somebody would say it wasn’t a good idea.
I asked a friend in the construction industry what it would take to demolish the twin towers. He replied nine months, 80 men, and 12 miles of cabling. The notion that a small team at night could plant sufficient explosives embedded at key points, is laughable.
The forces of the aircraft impacts must have been amazingly high. I have no difficulty imagining they would bring down the building. As for WTC 7, again the kinetic energy of the collapse of the twin towers must be immense.
I admit to a private speculation about WTC7. Unfortunately in construction it is extremely common for contractors not to fix or install properly all the expensive girders, ties and rebar that are supposed to be enclosed in the concrete. Supervising contractors and municipal inspectors can be corrupt. I recall vividly that in London some years ago a tragedy occurred when a simple gas oven explosion brought down the whole side of a tower block.
The inquiry found that the building contractor had simply omitted the ties that bound the girders at the corners, all encased in concrete. If a gas oven had not blown up, nobody would have found out. Buildings I strongly suspect are very often not as strong as they are supposed to be, with contractors skimping on apparently redundant protection. The sort of sordid thing you might not want too deeply investigated in the event of a national tragedy.
Precisely what happened at the Pentagon I am less sure. There is not the conclusive film and photographic evidence that there is for New York. I am particularly puzzled by the much more skilled feat of flying that would be required to hit a building virtually at ground level, in an urban area, after a lamppost clipping route – very hard to see how a non-professional pilot did that. But I can think of a number of possible scenarios where the official explanation is not quite the whole truth on the Pentagon, but which do not necessitate a belief that the US government or Dick Cheney was behind the attack.
In my view the real scandal of 9/11 was that it was blowback – the product of a malignant terrorist agency whose origins lay in CIA funding and provision. Also blowback in a more general sense that it was spawned in the nasty theocratic dictatorship of Saudi Arabia which is so close to the US and to the Bush dynasty in particular. As with almost all terrorist activity, I do not rule out any point on the whole spectrum of surveillance, penetration and agent provocateur activity by any number of possible actors.
But was 9/11 false flag and controlled demolition? No, I think not.
(Now I have given full opportunity to discuss 9/11 here, any further references on other threads will be instantly deleted).
Tom,
it probably isn’t Glenn or Vronsky either, as they sign their names. Just pull it to bits or whatever.
Tom,
I assume a typo in your 13th para of your 7:09 post; ‘engineer’ should read ‘manager’, right?
To whomever posted Ken Kuttler paper reference:
I answered EXACTLY what Dr. Kuttler got wrong in his paper near the end of this post above:
@ July 31, 2010 2:56 PM
The other mistake that he made (the same as David Chandler, & plasma physicist Crockett Grabbe) is that they work in isolation. Not a structural engineer to be seen…
That is a huge mistake.
tom
Glenn,
“13th paragraph…”
Yeah, I do tend to go on a bit, don’t I…?
___
He was a project manager. Possibly (probably) got an engineering degree. But you are what you do NOW. By this time, he was a manager, not an engineer.
I know his name, but am loathe to repeat it.
I’d wager that that decision destroyed him psychologically, that he left NASA, etc.
I am sure that he thought that he was making a correct decision. I’m sure that nobody has heaped more recrimination on him that he has himself.
It’s a shame all around. And he’s at the top of the list of people that were crushed by this event.
There is only one type of person who never makes a mistake: one who never makes a decision.
And those guys are the first to jump up & down, demanding someone’s head, when someone else makes one.
I’m not excusing him. I am especially not excusing the management at MT. Those guys get paid the big bucks to stand up to pressure.
The engineers did. The management didn’t. They caved.
Oh, BTW, I am not saying that engineers don’t make mistakes, are all perfect, wonderful, honorable, handsome, blah, blah, blah.
We’ve got the same spectrum of competent & incompetent, honest & crooked, etc. etc.
But the business has a SEVERE Darwinian filtering process. Those that make too many mistakes are shuttled out of the field. Many end up in management.
That’s why the older ones are so friggin’ valuable. They’ve survived the war.
If you get caught just one time being dishonest, you’re likely to lose everything.
And the whole concept that any politician could threaten any engineer into signing off on a fraudulent report on any topic, much less one with the visibility of the NIST report, is laughable.
First off, 400 other engineers are going to know about it IMMEDIATELY. They’ve all contributed to the analysis. They all talk to each other about their results, their raw data, the postulates that have been dismissed, those that are still viable, which are the leading contenders, etc.
And every single one of them has read every word of the sections to which they contributed. Imagine what would happen if something that they said was “impossible” ended up as the “probable sequence of events”.
One call to the NYTimes, and the whole jig is up. If they are dumb or timid, they do it anonymously. If the are smart, they give their name, become famous, appear on Oprah & every other talk show, write a book, get it turned into a movie, appear at the opening, join the talk circuit, bloviate about “honesty in engineering” (as tho they invented the concept), quadruple their salary and never have to work a 100 hour work week again.
That’s the reality of “engineers succumbing to political pressure”. PLEASE, some politician, come try to strong arm me into falsifying a significant public document.
I’d like to be able to stop working for a living, too…
tom
Tom,
I really appreciate your posts on WTC7, and also on Challenger. You seem very well informed on both. I have two questions:
1) How come you’re so well informed? You don’t claim to have been involved in these investigations, but you have been involved in others. Is that right?
2) Could you post a link to a decent description of the WTC7 collapse, please? Not too technical, if possible.
I have a further, more frivolous question; where were you going with buckingham-pi?
Tom, please have a bit more patience with the ‘truthers’. As you’ve said yourself, WTC7 flummoxed everyone. I saw the videos of it coming down, and thought “What?”. That doesn’t mean I ‘knew’ it had been demolished, but it just didn’t look ‘normal’, it felt wrong. And I suspect that there are still questions not answered.
There’s still masses of suspicion about, paranoia in some cases. But what can we expect? We KNOW we’re lied to regularly; Iraqi WMDs, extraordinary rendition, Afghani drug barons, etc. Once deception is established, we know that we can’t tell where the boundaries are.
So WTC7 collapsed, and it wasn’t until 2005 that the engineers knew why. In the meantime, the battle lines had been drawn, and suspicion had risen to record levels. Different people, most of whom respect the truth, find themselves on opposite ‘sides’ of the wrong argument.
Tom: What van I say? Wow. Wow! I am truly honoured, that is the most hateful post I have received in quite some time, and you’re up against some pretty stiff competition.
I have to say, it says a lot more about you than anything about me. But you are going to be disappointed, I regret to have to tell you, because I’m not going to take on a role in the “Authoritative Parent Vs Rebellious Child” game that you were clearly hoping for. Know those games, sorry, and I ain’t playing them.
Let me know when you’ve got something of substance to say, and you are willing to take the adult-adult approach, calm down, and we’ll carry on. Hey, you can have your tantrum/bitter moment, I won’t hold it against you, nobody’s perfect. I kindly offer that you stop playing games and attempting to establish roles, and also quit this foolish over-generalising, it really would up your game.
(Another free tip – look at who is posting before you address your reply. You keep replying to the wrong person.)
Re: “I answered EXACTLY what Dr. Kuttler got wrong in his paper near the end of this post above: @ July 31, 2010 2:56 PM”
Kuttler got nothing wrong in calculating the effect of Newton’s law of the conservation of momentum on the rate of collapse of Building 7. Furthermore, his calculation answers the question that prompted reference to it, i.e., the question raised by this comment:
“One might think – should they be entirely untrained and ignorant –
that such a structure would impose a significant restriction when
compared with air.”
As for the claim that “For a brief period of time, the EXTERNAL WALL of the building DID come down at NEAR free fall acceleration”
This is incorrect. It was not merely the external wall of the building, but the roof line as shown in the analysis by David Chandler. This has been acknowledged by NIST. Free fall occurred for 2.25 seconds.
Clark,
Clark: “How come you’re so well informed? ”
Tom: Two reasons. 1. I’m a geek. Thru & thru. (One of the adrenaline-junkie geeks.) 2. Much of this stuff is right down the middle of my profession. It’s relatively effortless to absorb it.
___
Clark: “You don’t claim to have been involved in these investigations,”
Tom: Nope. Nothing at all to do with 9/11 or Challenger.
___
Clark: “but you have been involved in others. Is that right?”
Tom: Yup, several. One of the things that I’m proud of is the range of products that I’ve invented and/or been in charge of. I’ve sent product to the bottom of the Marinanas Trench (70mm camera & strobe system), and to Jupiter (main power transfer switches for the shuttle & the Galileo IUS). And medical devices that I’ve invented (heart catheters & filters) have saved somewhere around 150,000 people lives.
And I’ve had to perform failure analyses, figure out what went wrong, do the analysis, document everything write the report & deliver the analysis to both Boeing/NASA & to the FDA in the US. That’s where I grew up as an engineer.
___
Clark: “Could you post a link to a decent description of the WTC7 collapse, please? Not too technical, if possible.”
Tom: Absolutely. I’ll give you the same advice that I give to everyone. On every subject. “If you really want to learn about something, there is only ONE place to go: the experts”.
Ergo, the best reference by far: http://wtc.nist.gov/NCSTAR1/PDF/NCSTAR%201A.pdf
If you want details on the collapse mechanisms, go to NIST NCSTAR1-9 vol 2.
Both of these are very readable. Sit down with a cup of coffee, a couple of hours and follow along as to how first rate engineers do it.
Learn to use the Executive Summaries. That’s what they are for: a quick, complete summary for people who don’t have time for the details. When you read one of these, you have to decide whether you’re going to accept their conclusions or you’re going to fight them & try to catch them in a mistake.
Kids & amateurs fight them tooth & nail. They approach the whole exercise as a game. I can tell you something for certain: the guys that wrote it do NOT consider it trivial, or a game in any fashion whatsoever.
Every engineer involved knew for absolute certain that this was going to be the single most important report of their career. And that it would be poured over by other experts. And that, if they slipped up in the slightest, they’d look like idiots. It would embarrass the whole project, and humiliate them personally.
With this as a background, I strongly suggest you stop fighting. None of you guys are good enough to catch these guys in a mistake.
___
Clark: “I have a further, more frivolous question; where were you going with buckingham-pi?”
Tom: The Buckingham p theorem is the foundation for one of the most powerful analysis techniques in all of engineering: Dimensional Analysis. With a little bit of knowledge & experience, you can sit down with a pencil & paper & come up with the defining equation for an enormous number of systems, simply by GUESSING at the factors that are involved & keeping track of the units of measure of each. The breadth & power of this technique are truly stunning. (This is most often used in fluid dynamics and aerodynamics, and it demonstrates the incredible usefulness of dimensionless parameters, such as Reynolds numbers, Nussult numbers, Prandl numbers, etc.)
Dimensional Analysis is also at the very core of the engineering science of “scaling”, which is absolutely crucial for doing modeling.
Knowing about scaling & dimensional analysis will tell you immediately why this sort of stuff is utter nonsense:
By the way, if you want to learn something else that is fascinating, I’d highly recommend the following lecture series by Ryan Mackey:
This is the 3rd of 3 videos, but it starts right where Ryan begins talking about modeling.
http://www.youtube.com/watch?v=ZsDn6es7mtk
Mackey is first rate. I’d recommend listening to him carefully. He knows what he is talking about.
___
Clark: “We KNOW we’re lied to regularly; Iraqi WMDs”
Tom: You might find out that some of the folks lying to you are not who you think. In this particular case, I’d recommend that you check out two things:
The al Tuwaitha nuclear facility. No, not the above ground part. The multi-billion dollar facility that was built between 1990 & 2000 that was underground. The one that was never reported to the inspectors. The one that was never inspected. The one that was scorchingly “hot” (radioactively) when US soldiers found it.
The city of Sargat, and what was found there in 2003.
Clearly there was nowhere near what some people thought. It seems pretty clear to me that there was not “nothing” either.
___
Clark: “As you’ve said yourself, WTC7 flummoxed everyone. I saw the videos of it coming down, and thought “What?”. That doesn’t mean I ‘knew’ it had been demolished, but it just didn’t look ‘normal’, it felt wrong. And I suspect that there are still questions not answered.”
Tom: Well, to anyone who knew about the fire fighters’ transit info on the building, the collapse came as no surprise. Once they got into the details, there were some surprises. Once the data & info were picked apart, there is no significant objection or controversy within the structural engineering community.
___
Clark: “Tom, please have a bit more patience with the ‘truthers’.”
Tom: I’ll try.
___
Clark: “So WTC7 collapsed, and it wasn’t until 2005 that the engineers knew why. In the meantime, the battle lines had been drawn, and suspicion had risen to record levels. Different people, most of whom respect the truth, find themselves on opposite ‘sides’ of the wrong argument.”
Tom: The reason I’m in this game is because I care about the young kids who are being exposed to what are clear to me, pernicious, vile & politically motivated lies. Lies about my country, my countrymen, my government, my military, my country’s intelligence establishment, etc. etc. etc.
The kids are not the enemy. They are us. And they are our future. And I think they are worth the effort to try to get them the real facts of the situation.
Tom
“And the whole concept that any politician could threaten any engineer into signing off on a fraudulent report on any topic, much less one with the visibility of the NIST report, is laughable.”
Logically, a single counter-example will do:
“Scientific American condemns restrictions on GM research”
tinyurl.com/2vjpdyf
(snip)
Research on genetically modified seeds is still published, of course. But only studies that the seed companies have approved ever see the light of a peer-reviewed journal. In a number of cases, experiments that had the implicit go-ahead from the seed company were later blocked from publication because the results were not flattering. “It is important to understand that it is not always simply a matter of blanket denial of all research requests, which is bad enough,” wrote Elson J. Shields, an entomologist at Cornell University, in a letter to an official at the Environmental Protection Agency (the body tasked with regulating the environmental consequences of genetically modified crops), “but selective denials and permissions based on industry perceptions of how ‘friendly’ or ‘hostile’ a particular scientist may be toward [seed-enhancement] technology.”
(snip)
@V,
V says:
“And the whole concept that any politician could threaten any engineer into signing off on a fraudulent report on any topic, much less one with the visibility of the NIST report, is laughable.”
Logically, a single counter-example will do:
Followed by: [Story, PUBLISHED in SciAm, about 24 scientists who dropped a dime & have REVEALED what they believe are unethical practices on the part of several agri-corporations…]
Thank you for making my point, V.
Tom
PS. I have little use for lawyers in general. This is what they do: attempt to carve out an absurd, ridiculous, unreasonable concessions for their clients. If you think that these rules stop all research, done without the company’s permission, you’re nuts. It’s one thing to write a EULA. It’s another thing to have it ruled legal & enforceable in court. The software companies (amongst lots of others) have found that out the hard way.
PPS. “… a single counter example will do…” For people who live in childishly simple “black & white” worlds, I guess that’s true.
PPPS. And for people with a adolescent black & white world view, I suppose that “they’re trying to block open research on seeds” is somehow equivalent to “they murdered 3000 innocent people, lied to the nation & started a war”. For EVERY SINGLE ONE of the 2,000 researchers who have contributed to the NIST report. And EVERY SINGLE ONE of the 100,000+ competent engineers & scientists who have read, and understand, the NIST report.
Not one of them has called the NY Times, the Washington Post, the London Times, Le Monde or Der Spiegel and revealed this generations version of “Watergate”. And gone on to collect their Pulitzer Prize, world accolades as champion of truth …
Sure thing. Whatever you say…
Must be nice… having the world so neatly & self-servingly divided into good guys & bad guys…
Tom,
you wrote: “Well, to anyone who knew about the fire fighters’ transit info on the building, the collapse came as no surprise”.
Well, I’m not technically experienced in building collapses. But such a sudden (onset), symmetrical and complete collapse does not seem to be the norm. Some claim it to be unique (unless we include demolition); maybe you know otherwise. In the common (rather than the technical) sense, this *sort* of collapse seems to be surprising.
There is only one more Shuttle mission left, isn’t there? November. I’ve seen the ISS and a Shuttle in the sky at the same time, about two minutes apart. November will be my last chance to see them in close proximity. I watch Shuttle launches on the NASA website. The screens at Mission Control show the Shuttle passing over my location about 20 minutes after launch, I think, but its always been the wrong illumination or too cloudy for me to see it.
Tom, there are lies from ALL sides. It’s not the Great and Good USA vs. a load of lies. Western companies sell distant lands dangerous technology, and Western governments consider this good for Western economies. Up to a point. Then Western companies sell Western governments weapons to go and destroy the same, along with a lot of collateral murder. I’m saying that there is wrong on ALL sides, but we live in (sometimes unresponsive) democracies, so it is our responsibility to restrict the excesses of our OWN nations.
Tom wrote:
“PS. I have little use for lawyers in general”
Strong agreement here. Did someone warn our Larry that Tom would be visiting? I’d much rather chat to Tom than Larry!
Tom,
I don’t suppose you’re planning on becoming a regular here. It’s going to take me some time to read and think about the links you’ve posted, and you may be gone by then. How do I find you later?
anonymous at August 1, 2010 4:12 AM
anon says:
“Kuttler got nothing wrong in calculating the effect of Newton’s law of the conservation of momentum on the rate of collapse of Building 7.”
tomk: The easier question would be “did Dr. (?) Kuttler get anything right?” And the answer is, “Yeah, he solved his equations right.” Unfortunately, this is one giant case of GIGO.
Let’s look at his paper. I’ll quote:
“Could this possibly happen as a result of pancaking floors collapsing from the top down? ”
And he proceeds to calculate for a pancaking, top down collapse…
Pssst, doc. It was NOT a “pancaking, top down collapse.”
A moment’s glance at the video shows what appears to be (but is not) a bottom-up collapse. But going, for the moment, with the bottom up collapse, Kuttler starts calculating conservation of momentum, and its impact on velocity for a top down collapse.
For 12′ fall heights at each story, free fall collapses occur at:
0.86, 1.22, 1.50, 1.73 … seconds. Note that the time interval is getting shorter & shorter as the velocity increases.
The table below shows the drop, the duration, the speed, THE MOVING MASS (in units of “stories”, i.e., the average mass/story), and the momentum of the MOVING MASS according to a top-down collapse.
Drop _____ time __ velocity ___ mass _____ momentum
(stories)__ (sec) __ (ft/sec) __ (stories) __ (stories x velocity)
1 _______ 0.86 _____ 28 _______ 1 ______ 28 x 1
And in his first collision, Dr. Kuttler has 1 floor strike one floor. Which means, in an inelastic collision (which he – reasonably – assumes) means that, in the first collision, the descending mass loses 1/2 of its velocity.
Or as he writes v_k+1 = (k/(k+1)) v_k with k=1 gives v2 = 0.5*v1
In other words, Dr. Kuttler figures the speed of the downward moving mass after the first impact at:
v2 = .5 * 28 ft/sec = 14 ft/sec.
Now, what we know APPEARED to happen (in Dr. Kuttler’s world view) is that the building buckled, somewhere around the 7th floor. And collapsed from the 7th floor up. So, let’s look at the momentum, if Dr. Kuttler had done his analysis at least consistent with it (mistaken) world view…
Note that, assuming the 7th floor buckled, then the first 6 collisions are crush downs of floors 6, 5, 4, … etc. The next 40 collisions are crush ups of the 8th, 9th, 10th, etc. stories.
Drop _____ time __ velocity ___ mass _____ momentum
(stories)__ (sec) __ (ft/sec) __ (stories) __ (stories x velocity)
1 _______ 0.86 _____ 28 _______ 40 ______ 28 x 40
Notice any TEEENSY differences in the momentum calculations at each point?
And as a result of the first collision, the moving block now looses:
v2 = (40 stories)/(41 stories) v1 => v2 = 0.98 v1
A bottom up momentum analysis yields a speed of the downward moving mass after the first collision at:
v2 = 0.98 (28 ft/sec) = 27.3 ft/sec
Notice any teeensy differences in momentum loss from the collisions?
Notice any teeensy difference in the speed after the first collision?
Think that these speed differences might “disturb” Dr. Kuttler’s calculations of the fall time?
Still think he “got nothing wrong”?
___
All of the above is simple nonsense. The fact that he did his calculation for a top-down collapse is just plain sloppy.
The fact of the matter, as I pointed out above, is that these calculations are valid IF AND ONLY IF the floor mass is still there during the collapse. And, in the case of WTC7, the mass of the floors had LONG SINCE collapsed before the external walls ever began to descend. And was therefore irrelevant to the collapse of the outer facade wall.
The reality is that it took WTC7 about 20 seconds to collapse. Which negates his whole “there is something mysterious here” premise.
____
The collapse was not “bottom up”. It was (laughably) not “top down”.
The collapse was a progressive one that started near column 79 (towards the north east corner) and progressed horizontally from that point in all directions, towards the outer walls.
If you bother to read the NIST reports, you’d find that a second collapse wave started (as a result of the collapse damage from WTC1) near the western edge of the building, spreading north, south & east, and the two collapse waves met just west of the center of the building.
Given the reality of the collapse, all of Dr. Kuttler’s momentum calculations are meaningless garbage.
___
anon wrote: “Furthermore, his calculation answers the question that prompted reference to it, i.e., the question raised by this comment:
“One might think – should they be entirely untrained and ignorant –
that such a structure would impose a significant restriction when
compared with air.”
tomk: It did provide “significant (resistance?) compared to air”. If there were no resistance, the building would have collapsed in 6.5 seconds. It took 20 seconds. That’s a “significant resistance”.
___
anon wrote: “As for the claim that “For a brief period of time, the EXTERNAL WALL of the building DID come down at NEAR free fall acceleration”
This is incorrect. It was not merely the external wall of the building, but the roof line as shown in the analysis by David Chandler. This has been acknowledged by NIST. Free fall occurred for 2.25 seconds.”
tomk: You’d do well to read Chandler & NISTs paper before making this sort of silly claim.
Candler did not say one word about the roof of the building. It is not possible to even SEE the roof from the video that Chandler analyzed. He tracked a point on the top external parapet. Not the roof.
But it is possible to see the roof from a different angle. Paradoxically, a lower angle. The “Camera 3” video that NIST analyzed looks up at the building from a low point to the northwest. And it is possible to see, after the east penthouse collapses, through the windows on the upper floors at the east end of the north wall … that the roof is GONE. You can see the sky thru those windows.
Similarly, if you knew the first thing about structures, you’d realize that, in order for the east penthouse, screen wall & west penthouse to disappear like they did (without “accordion” buckling of their short walls), that the roof HAS to be gone behind the parapet.
Nice try with the thoughtless, truther parroting…
Time to do more than pay ironic lip-service to the concept of “think for yourself”.
Tom
Tomk is a fount of incontinent tarradiddle.
But who wants to play silly buggers? Not me.
But it suits Craig Murray’s blog: the tallest buildings in the world at the time and they didn’t bother with bolts or welds. LOL
Tom,
I looked at Kuttler, and couldn’t be bothered with the math after I saw the reference to pancaking. Thanks for the analysis.
One thing bothers me, probably because I haven’t read the NIST report yet:
“If you bother to read the NIST reports, you’d find that a second collapse wave started (as a result of the collapse damage from WTC1) near the western edge of the building, spreading north, south & east, and the two collapse waves met just west of the center of the building”.
That sounds like a huge coincidence, unless, say, one collapse was very slow. Please expound.
Whatever about incontinent, tomk sure takes up a lot of space to make one or two points. His smugness is very irritating and puts me off concentrating on what he says. As if there were no first rate engineers in the UK or Ireland.
“Sit down with a cup of coffee, a couple of hours and follow along as to how first rate engineers do it.”
No thanks, tom. I have one in the family. First rate and well travelled, having worked all over the world. He’s retired now, and not well, but when I get a chance I’ll discuss all this with him. I’ve never asked his opinion before.
I saw the WTC buildings collapse, live. I understood that WTC 1 and 2 were supposed to withstand the impact of a jumbo jet.
If they collapsed as they did, in that short a time, into the footprints they did, and they had no “help”, perhaps it says little for the engineers involved in building them?
Tishman Realty & Construction was it? Do I have the right name?
I had wondered (occasionally) how anyone could set explosives or any “foreign matter” in those towers without being noticed or called to account. But I’ve just read this:
“Of the 110 stories, eight were set aside for technical services in mechanical floors Level B5/B6 (floors 7/8, 41/42, 75/76, and 108/109), which are four two-floor areas evenly spaced up the building.”
Interesting. That was in both 1 and 2 was it?
Do you have any theories, tomk, on why the BBC reporter said live on TV that WTC 7 *had gone down* about 26 minutes before it actually did?
Clark,
Clark: “Well, I’m not technically experienced in building collapses. But such a sudden (onset), symmetrical and complete collapse does not seem to be the norm. Some claim it to be unique (unless we include demolition); maybe you know otherwise. In the common (rather than the technical) sense, this *sort* of collapse seems to be surprising.”
tomk: Not surprising in the least.
I’ll give you theory, and then the experiment that you can (easily) do yourself to produce a sudden, symmetrical & complete collapse. With fall thru a supporting structure that holds up the load, with a factor of safety of about 3. And the collapse will be thru the path of the previously supporting structure, virtually at free fall acceleration, into its own footprint.
And you can do it to impress your friends.
I’ll assume that you’re talking about WTC7 here.
“… sudden …” It wasn’t “sudden”. It was going on for 13 seconds before the outer wall began to fall. The fact that something is out of sight doesn’t mean that nothing is going on there.
What you are claiming as sudden is exactly analogous to some magician, holding up a black cape, and giving his patter to distract the audience, while behind the cape, his assistants remove the tiger from the cage & replace it with the scantily dressed lady…
… and the magician “suddenly” drops his cape, the scantily clad young lady steps out of the cage, and everyone in the audience thinks…
“… Wow, it was so sudden!”
It wasn’t all that sudden. It was just the LAST thing that happened. The facade walls happened to be a black cape between us & all the stuff going on behind them.
But I will concede that …
… after having several hundred tons of girders carve out a 20 story tall x 20′ deep scar down the south face, 7 hours of burning, heating, dislodging of key beams from their end supports, collapse of multiple floors, destabilization of key columns from ground to roof, collapse of the east end of the roof, total progressive collapse of the core of the building that started near the east end (column 79), moved progressively west, destabilization of the western core near the 20 story scar that started a 2nd wave of collapse at the western core, which progressed towards the east just in time to meet the first collapse wave just west of the center of the building, meaning that the entire center of the building had already collapsed (or was in the late stages of collapsing) …
… THEN the last stage, the fall of the north & west facade walls, WAS “sudden”.
Now, how can that be? The wall “buckled”. It buckled somewhere down low (where all the stress is, where all the debris was flying around and (in my opinion, very important) where you had all the “transfer girders” on the 5th – 7th floor. Look at the NIST report, NCSTAR1-9, vol 1. pg 30 (pdf pg 74), Fig 2-24.
See all those cross beams reaching out to the North wall? IMO, a real weak point.
Now, the most important concept of any that I’ve explained:
What characteristic of a building’s support structure is most important to the integrity of the structure?
The strength of the columns? Nope.
The size of the columns? Nope.
What is most important, by far, is the GEOMETRY of the support structure.
Tall, thin columns will carry lots of load ONLY as long as the load is “axial”, directed more or less straight down thru its central axis. Long, thin columns do not like bending moments.
Lose the geometry, lose the building.
So, relatively small, apparently delicate components can play an absolutely crucial role (WAY out of proportion to their apparent size) in maintaining the strength of a structure, if their job is to keep the “strength” members in their proper geometry.
You’ve seen this effect if you’ve ever put together an “do it yourself” bookshelf. You get thick strong side, top & bottom pieces & shelves. But the whole structure will not stand up on its own until you tack on that absurdly thin, pressed cardboard backing plate, with the tiny brads, that keeps the sides & top perpendicular. Without that backing panel, the whole thing forms a parallelogram and fall to the side.
Geometry.
And what you saw in the facade walls of WTC7 was a classic “loss of geometry” failure: a buckling failure.
When a tall think compression column is overloaded, it starts to bow. It’ll resist greater loads while deflecting. However if loaded too much, it reaches a point of instability and suddenly buckles. And when it buckles, its strength goes almost (not quite, but almost) to zero. Now! Right now!
And when the bottom of a tall structure buckles, and its strength goes to “nearly zero”, then the acceleration of the upper portion of the structure will go to “almost g”.
The proof that it was not an explosion, rather that it was a typical, pedestrian buckling of a real piece of the building, lies in the 1.75 seconds “Stage 1”, before the “Stage 2” (“near g” phase), as NIST defines them in NCSTAR1-9.
When a support holding up an object is “blown” with explosives, that is about the most instantaneous way for the support to be removed possible. For such an object, its velocity increases slowly, but it’s acceleration jumps instantly to “g”.
The wall of WTC7 did not act this way. It’s acceleration increased gradually. This is the typical behavior of a mechanical support that is being overloaded, starts to flex to one side, and suddenly buckles.
And here’s a perfect demonstration of this effect. You may have seen it before.
Someone puts their heel on the top of an empty coke or beer can, presses down with about 30 pounds of force. Then, bends over & with both middle fingers, ever so gently taps opposite sides of the can. Be sure to tap it & get your fingers out of the way.
The can INSTANTLY crushes. For all intents, your foot will go into free fall. The sides of the can can support the 30 pounds, with a good safety margin. Try stacking books on top of one. You can build up an impressive stack.
But it can support that weight ONLY as long as the sides stay vertical. Just as soon as the sides get the slightest bit out of vertical, the whole can folds up, & your foot descends, thru the path of most resistance, just as if the supports (which had supported your foot just fine, and would have supported the same weight for 30 years) were suddenly & completely gone.
A “sudden, symmetrical & complete collapse.”
Thru the path of most resistance.
In near free fall.
Into its own footprint.
Just as requested.
Amazing? Well, impressive.
Controlled demolition? Nope.
Inside job? Well, you did do the whole demonstration. So, yeah.
Mysterious? Nope. Ordinary, plain vanilla mechanics.
Tom
Clark,
Clark: One thing bothers me, probably because I haven’t read the NIST report yet:
tom: You’re in for a treat. It’s VERY readable.
___
Clark: “If you bother to read the NIST reports, you’d find that a second collapse wave started (as a result of the collapse damage from WTC1) near the western edge of the building, spreading north, south & east, and the two collapse waves met just west of the center of the building”.
That sounds like a huge coincidence, unless, say, one collapse was very slow. Please expound.
tom: No, not a coincidence at all. Just like the discussion of “progressive collapse” and the Challenger explosion, the two events were not independent of each other.
The first collapse wave CAUSED the second one.
No coincidence at all.
Tom
@ dreoilin,
dreolin: “… His smugness …”
tomk: It ain’t “smugness”. It’s being right. And being sure. That’s what I’m paid to do, and this is my field. What do you expect?
“Well, 1 + 1 MIGHT BE 2… If nobody objects, of course.”
Put on your big-girl panties, and grow a pair. (of ovaries, of course.)
____
dreolin: “As if there were no first rate engineers in the UK or Ireland.”
tomk: Your own drama queen interpretation. Nothing like that came out of anything but your own imagination. (Or hope…)
____
dreolin: “I have one in the family. First rate and well travelled, having worked all over the world. He’s retired now, and not well, but when I get a chance I’ll discuss all this with him. I’ve never asked his opinion before.”
tomk: Wow. Obviously seriously interested in the topic. Apparently a truther. An elder, accomplished engineer in the family. And NINE FRIGGIN’ YEARS without a single discussion…
You truthers sure know how to isolate yourself from expertise…
Why don’t you invite him to come here & post a comment or two. He will find me highly respectful & gracious.
____
dreolin: “I understood that WTC 1 and 2 were supposed to withstand the impact of a jumbo jet.”
tomk: Wrong. Pure urban myth. One that everyone on the project believed, tho. But I’ve got the experience & knowledge to understand that it was mythology. It could not possibly be true.
Ooops, was that “smug”.
Probably. Who gives a rat’s ass. It was also correct.
____
dreolin: “If they collapsed as they did, in that short a time, into the footprints they did, and they had no “help”, perhaps it says little for the engineers involved in building them?”
tomk: Perhaps you should make that comment to your (dad? granddad? uncle?) and get his response.
They designed the tallest building in the world, using slide rules & vellum, built it, on time, on budget, in the middle of downtown Manhattan, using brand new building techniques. And it did its job for 30 years, and that no building in the world (before 2005) is likely to withstand an impact like the ones on 9/11.
[And, yes, I know about the B25 & the ESB. About 1/30th the energy of 9/11, IIRC).
____
dreolin: Tishman Realty & Construction was it? Do I have the right name?
tomk: Minoru Yamasaki designed it. John Skilling was principle engineer. Leslie Robertson was a young engineer who didn’t even have his structural degree when he joined Skilling. Tishman was prime contractor.
____
dreolin: “Of the 110 stories, eight were set aside for technical services in mechanical floors Level B5/B6 (floors 7/8, 41/42, 75/76, and 108/109), which are four two-floor areas evenly spaced up the building.”
tomk: Those were the “mechancal floors”. They are the ones that make up the 3 dark bands around the building when seen from the outside. Buildings need mechanical equipment. Elevators, generators, Air conditioning, etc. These floors were off limits to the public, and used regularly by the buildings’ maintenance staff.
And, no, neither of the buildings collapses initiated at the mechanical floors.
____
dreolin: “Do you have any theories, tomk, on why the BBC reporter said live on TV that WTC 7 *had gone down* about 26 minutes before it actually did?”
tomk: Jane Standley tell all about it herself. If you’re interested, just google her name & learn all about it.
Something around 1/3 of everything you are told on TV is simply wrong. The people on air are reading what other people are telling them. The people getting the info in a crisis get bad info.
Part of the answer is that they knew for HOURS ahead of time that WTC7 was going to come down. If you know much about all of this, you ought to be familiar with how they knew that.
Now I’m going to go enjoy the rest of my weekend.
>”It ain’t “smugness” …Put on your big-girl panties, and grow a pair. (of ovaries, of course.)”
Grow the hell up, tom.
>”Your own drama queen interpretation. Nothing like that came out of anything but your own imagination. (Or hope…)”
Grow the hell up, again, tom. You’ve been pontificating as if you and your mates are the only engineers on the planet. You’re not.
>”Wow. Obviously seriously interested in the topic. Apparently a truther. An elder, accomplished engineer in the family. And NINE FRIGGIN’ YEARS without a single discussion…You truthers sure know how to isolate yourself from expertise…”
I take it you didn’t read what I said to Vronsky July 28, 2010 5:00 PM. I said I was “more of a truther than I was at the start” – the start being the top of this thread. You’re arrogantly jumping to conclusions – again.
>”Why don’t you invite him to come here & post a comment or two. He will find me highly respectful & gracious.”
Like you are to me? I think not. I said he’s not well.
>”Pure urban myth. One that everyone on the project believed, tho.”
Everyone building WTC 1 and 2 thought they were building something due to withstand the impact of a jumbo? So where did they get that idea then?
>”But I’ve got the experience & knowledge to understand that it was mythology. It could not possibly be true.”
So you’re just taking it upon yourself to deny it?
>”Perhaps you should make that comment to your (dad? granddad? uncle?) and get his response.”
My father, grandfather and uncles are dead. Try not to be a smart-arse.
>”They designed the tallest building in the world, using slide rules & vellum, built it, on time, on budget, in the middle of downtown Manhattan, using brand new building techniques.”
Untested building techniques, then?
>”And it did its job for 30 years”
Was it not supposed to last longer than 30 years?
>”and that no building in the world (before 2005) is likely to withstand an impact like the ones on 9/11.”
‘Likely’. You’re beginning to sound less than certain about what you’re saying. Which makes a change …
>”John Skilling was principle engineer. Leslie Robertson was a young engineer who didn’t even have his structural degree when he joined Skilling.”
What has that got to do with it? Or is it more extraneous detail?
>”Those were the “mechancal floors”. They are the ones that make up the 3 dark bands around the building when seen from the outside. Buildings need mechanical equipment. Elevators, generators, Air conditioning, etc. These floors were off limits to the public, and used regularly by the buildings’ maintenance staff.”
That’s precisely why I raised the subject, tom. You’re blathering I’m afraid. Telling me things I just pointed to.
>”And, no, neither of the buildings collapses initiated at the mechanical floors.”
Did I say initiated? How about removing a lot of resistance as the buildings came down? If there had been interference on the mechanical floors?
>”Jane Standley tell all about it herself. If you’re interested, just google her name & learn all about it.”
You’re trying to teach your grandmother how to suck eggs – AGAIN – tom, and it’s annoying. All Jane Standley had to say was that she doesn’t remember exactly what she said or did.
>”Something around 1/3 of everything you are told on TV is simply wrong”.
There you go again … Jesus H Christ … it’s actually quite funny, considering the site you’re on …
>”The people on air are reading what other people are telling them.”
No, tom, she wasn’t reading anyone else’s script. And that’s all you have to say about the fact that everyone could see the building standing there while she was telling us it had just fallen down??
Here’s a quote from the BBC:
“Nobody told us what to say or do on September 11th. We didn’t get told in advance that buildings were going to fall down. We didn’t receive press releases or scripts in advance of events happening.”
(and then, of course, they lost their tapes of the incident. Sad.)
>”Part of the answer is that they knew for HOURS ahead of time that WTC7 was going to come down. If you know much about all of this, you ought to be familiar with how they knew that.”
Except the BBC said that they didn’t. See above. You’re starting to give very sloppy answers, tomk …
Tomk, do you have any connections with Tishman Realty & Construction? Or did you at any time?
dr,
Welcome to ignore.
Pointless.
Tomk: A lot has been written this weekend! I’m trying to wade through it to find something I’m supposed to be addressing, but if you’re trying to teach “us lot” anything, maybe you could do a better job. If you want to put the backs up of anyone who’s not already 100% behind your views, dismiss you and not take you seriously, then you are doing a fine job already so just keep it up.
I’m hoping you can overcome the urge to edge conversations with anyone not immediately agreeing with you into ‘parent Vs rebellious child’ game-role nonsense, but maybe you can’t help it, and this is just your way whenever there’s disagreement.
Anyway, let’s wade back up to your 30/7 01:18 post, if we may.
Let me make something clear – unlike yourself, I’m genuinely looking for the truth instead of presuming myself to be in full possession of it. Bombastic assertions and belittling anyone questioning them is not a winning strategy if you really want to persuade a moderately intelligent fence-sitter who is very rightly suspicious, not to say cynical, of Official Truths.
*
I daresay there have been sweeping assertions incorrectly made on various “truther” sites. I’ve not read them, and am certainly not answerable for them. You keep bringing them up, and saying “you guys” this and that, as if we were one and the same. You’ve argued against positions nobody has taken here, then claimed this is because it’s a popular claim of “truthers”.
Well that’s fine, but largely irrelevant in present company.
Maybe it’s battle fatigue, and one starts to grossly overgeneralise. That’s why I advised you against it – half the people here (the blog host included) do not support the ‘controlled demolition’ supposition. But one of the problems with people like you is you assume your claimed superiority in one specialised field extends to a general superiority, carrying over to a ‘how the world works’ knowledge far exceeding that of your correspondents. That is arrogance, and does you no credit.
*
Why do you keep saying Veronsky and myself were “unaware of the ability of a free end of a ruler to fall faster than the washers on top” – why persist in saying this? Either you are grossly mistaken, failed to read properly the numerous occasions when I illustrated that I was not, or you are dissembling.
If you persist with what I know full well to be an untruth when it comes to such obvious matters that recently happened, with the evidence right here in this thread, how do you expect me to accept your word and authority when it comes to less clear matters?
*
Is it worth spending the time having a discussion with you, Tom? Or are you going to do the lofty/irritated dismissal, play role games and make yourself ineffective as someone who potentially has a very worthwhile argument here.
I’d like to talk about your 31/7, 02:25 post to Clark, but don’t want to waste my time if all I’m calling to get is name-calling in return.
Over to you Tom, let me know how you’d like to play this. You’ll find I’m not one to hold grudges long, not even to someone who thinks personally insulting me is a good way to resolve disputes in your specialised field.
You should notice that I have not personally insulted you even once, while you’ve done it to me dozens of times now.
dreolin: “I understood that WTC 1 and 2 were supposed to withstand the impact of a jumbo jet.”
tomk: Wrong. Pure urban myth. One that everyone on the project believed, tho. But I’ve got the experience & knowledge to understand that it was mythology. It could not possibly be true.
Just a little calm correction here >
Seattle Times interview 1993.
“We looked at every possible thing we could think of that could happen to the buildings, even to the extent of an airplane hitting the side,” said John Skilling, head structural engineer. “However, back in those days people didn’t think about terrorists very much.”
cached@
http://911research.wtc7.net/cache/wtc
/analysis/seattletimes_withstandjet.html
And,
Medserv Article “Towers collapse shocks engineers”, posted just after the event –
Lee Robertson, the project’s structural engineer, addressed the problem of terrorism on high-rises at a conference in Frankfurt, Germany, last week, Chicago engineer Joseph Burns told the Chicago Tribune.
Burns said Robertson told the conference, “I designed it for a (Boeing) 707 to hit it.”
cached@
http://911research.wtc7.net/cache/wtc/
analysis/medserv_collapseshocks.html
—
“I am nobody. He who talks too much says nothing.”
Timothy Test… Testing, testing, 1… 2… 3…
Noam Chomsky on 9/11 conspiracy theories
http://video.google.com/videoplay?docid=-9216919997676165205
Thanks for opening it Clark.
Craig. I don’t think there’s much chance of you coming in here, but I’d appreciate a comment from you on what you said about whistleblowers over on http://www.craigmurray.org.uk/archives/2012/10/the-extraordinary-rarity-of-whistleblowing/
Previously you have said (wtto) one reason why you don’t subscribe to 911 bing some kind of inside job or whatever, is because someone would have blown the whistle about it already. Given the powerful post you wrote, URL above, October 19, 2012 12:12 pm, don’t you think your view on the matter should be re-evaluated? You said peoples career protectionism mindset prevents them from speaking out. It’s not hard to assume that if 911 was some kind of conspiracy or inside job (etc), then these people would also face a loss of career – a permanent one! brought about by the ‘loss’ of life.
You have also stated (I think in Catholic Orangemen – or on the blog?) that you believed an attempt on your life was made. I think you would probably agree with me that the matter of what you were whistleblowing about is very small with regards that of a 911 whistleblower would face.
Yours with little hope of your reply…
lwtc247.
lwtc24/7 and David, thanks for observing the moderation policy. My comment, reposted from the “Whistleblowers” thread is below.
lwtc247, I think you’re probably at crossed-purposes with Craig. As a former diplomat, Craig thinks of “false flag” as a secret action by the state apparatus itself. Here’s a quote that you may have forgotten from Craig’s original 9/11 Post:
…which basically only rules out actual US policy. I don’t think you disagree with Craig as much as you think.