Forum Index Register Members List Events Search Today's Posts Mark Forums Read Help

 International Skeptics Forum Moderated: Steel structures cannot globally collapse due to gravity alone

 Welcome to the International Skeptics Forum, where we discuss skepticism, critical thinking, the paranormal and science in a friendly but lively way. You are currently viewing the forum as a guest, which means you are missing out on discussing matters that are of interest to you. Please consider registering so you can gain full use of the forum features and interact with other Members. Registration is simple, fast and free! Click here to register today.
 18th February 2009, 05:12 AM #521 Gravy Downsitting Citizen     Join Date: Mar 2006 Posts: 17,078 Originally Posted by 3bodyproblem ...Yah, no. Progressive collapse was well defined in building code well before 9/11 for a reason. This was true in the UK (after the Ronan Point collapse), and in some other countries, but not in the US, where codes requiring "structural integrity" were in place, but progressive collapse wasn't specifically addressed. The principle, of course, was well known and studied by engineers around the world. There's a section with papers about engineering to resist progressive collapse at my website. __________________ "Please, keep your chops cool and don’t overblow.” –Freddie Hubbard
 18th February 2009, 05:22 AM #522 Christopher7 Philosopher     Join Date: Aug 2006 Posts: 6,538 Originally Posted by C7 The previous section was: Velocity of Air Ejected from the Tower and the following section is: Energy Dissipated by Comminution (or Fragmentation and Pulverization) Originally Posted by Dave Rogers This seems to be another example of your adjacent=identical fallacy. These are different sections. That's what I said. I was just pointing out that: Originally Posted by C7 They do not offer another mechanism for the "large steel pieces". Originally Posted by Dave Rogers Nor do they claim that the large steel sections were ejected by air pressure. Yes they do. Is English your first language? Resisting Forces Due to Ejecting Air and Solids The air mass within the confines of one story, which is . . . , gets accelerated from 0 to velocity va as it exits the tower perimeter. The kinetic energy acquired by the escaping air of one story just outside the tower perimeter is . . . . where . . . = initial volume of air within the story. The energy dissipated by viscosity of flowing air and by boundary friction is estimated to be negligible. Therefore, virtually all of the kinetic energy of escaping air must be supplied by gravity, . . . The average over-pressure of air within the tower is . . . . The pressure peaks near the end of squeezing of a story are doubtless much higher, as already mentioned, and thus must contribute to the break up of many floor slabs (theoretically, the pressure in a thin layer of viscous gas between two colliding parallel flat slabs approaches infinity at the end). The mass that is shed from the tower, characterized by k-out, exits at various velocities ranging from nearly 0 to almost either the air ejection velocity, for fine dust, or to roughly z˙, for large steel pieces. They are discussing the role of air pressure. They do not offer another mechanism for the ejection of the "large steel pieces". Find one or stop saying one exists. Where do they allow for the energy necessary to hurl numerous 4 ton framing sections up to 600 feet?
 18th February 2009, 05:30 AM #523 Christopher7 Philosopher     Join Date: Aug 2006 Posts: 6,538 Originally Posted by Gravy Chris, I took the time to assemble a website that answers exactly these kinds of questions. Is there any reason that you haven't availed yourself of the wealth of information there? On page 1 of the engineering section: Why didn't the towers, or the upper portions of them, topple over? Why didn't the upper part pivot about it's base? See Bazant & Zhou (2001) Appendix II Eduardo Kausel (MIT): Why the Towers didn't fall like trees Frank Greening: An analysis of the tipping of the upper section of WTC 2 (PDF) A simple graphic explanation of why the top of the south tower didn't fall to the side. Physicist Dave Rogers on tipping of tower tops. Structural engineer "Newton's Bit" on "tipping" I have read some of your diatribes, debunked Greening's garbage and debated with Newtons Bit and Dave Rogers enough to know that they are not what they say they are. Don't try to send me on a wild goose chase. If you have something relevant to say, say it.
 18th February 2009, 05:36 AM #524 Gravy Downsitting Citizen     Join Date: Mar 2006 Posts: 17,078 Originally Posted by Christopher7 Don't try to send me on a wild goose chase. If you have something relevant to say, say it. You refuse to read the explanations of why toppling didn't occur? You are a Basking Shark in a sea of ignorance. Back on ignore you go, and good riddance. __________________ "Please, keep your chops cool and don’t overblow.” –Freddie Hubbard Last edited by Gravy; 18th February 2009 at 05:37 AM.
 18th February 2009, 05:53 AM #525 Architect Chief Punkah Wallah     Join Date: Aug 2006 Location: UK Posts: 9,763 Originally Posted by Gravy This was true in the UK (after the Ronan Point collapse), and in some other countries, but not in the US, where codes requiring "structural integrity" were in place, but progressive collapse wasn't specifically addressed. The principle, of course, was well known and studied by engineers around the world. There's a section with papers about engineering to resist progressive collapse at my website. The Eurocode has been updated to require greater resistance to dispropportionate progressive failure in light of post-911 research. Which means, of course, that lots of learned engineers have pored over the drafting and are content with the underlying issues. Something the Truther Movement always seem to overlook. __________________ When the men elected to make laws are but a small part of a foreign parliament, that is when all healthy national feeling dies. James Keir Hardie (1856 - 1915): Politician, Founder of Scottish Labour Party
 18th February 2009, 05:54 AM #526 Architect Chief Punkah Wallah     Join Date: Aug 2006 Location: UK Posts: 9,763 Originally Posted by Christopher7 I have read some of your diatribes, debunked Greening's garbage and debated with Newtons Bit and Dave Rogers enough to know that they are not what they say they are. Really? I can't say that I arrived at the same conclusion. What exactly in their expertise do you feel them to be misrepresenting? __________________ When the men elected to make laws are but a small part of a foreign parliament, that is when all healthy national feeling dies. James Keir Hardie (1856 - 1915): Politician, Founder of Scottish Labour Party
 18th February 2009, 06:13 AM #527 Christopher7 Philosopher     Join Date: Aug 2006 Posts: 6,538 Originally Posted by Gravy You refuse to read the explanations of why toppling didn't occur? You are a Basking Shark in a sea of ignorance. Back on ignore you go, and good riddance. Bazant wrote that 9-13-01 and updated on 9-22-01 This is not science. This is pure conjecture. He doesn't have any data. Appeal to authority denied. Speak for your self. Don't glibly pass the buck. * * * * * Do you have a response to this: Newton's first law says an object in motion will remain in motion unless acted on by an external unbalanced force. The top section was in motion to the side and down. Both motions continued as the collapse progressed. The side motion would continue and the top section would fall off the side of the building unless some external balancing force were applied. * * * * * or are you just a blow hard that blows by now and then to make a sarcastic comment and leave without contributing anything specific like a particular relevant quote from one of the sources you claim makes your point.
 18th February 2009, 06:20 AM #528 peteweaver Graduate Poster     Join Date: Mar 2007 Posts: 1,006 If downward force is greater than tilt, and the structure below cannot arrest the collapse, there is insufficient resistance and the load above the structural failiure will cause progressive collapse. Why can't the troofers realise that ?
 18th February 2009, 06:38 AM #529 Dave Rogers Bandaged ice that stampedes inexpensively through a scribbled morning waving necessary ankles     Join Date: Jan 2007 Location: Cair Paravel, according to XKCD Posts: 33,343 Originally Posted by Christopher7 I have read some of your diatribes, debunked Greening's garbage and debated with Newtons Bit and Dave Rogers enough to know that they are not what they say they are. The final clincher, for me, that a conspiracy theorist is delusional, is when he or she makes personal statements about me that I know to be false. So, Chris, so that I can finally dismiss everything you have ever said as the product of a malfunctioning mind, would you please state what it is that I say I am and you know me not to be? Dave __________________ There is truth and there are lies. - President Joseph R. Biden, January 20th, 2021
 18th February 2009, 06:45 AM #530 Heiwa Banned   Join Date: Jul 2007 Posts: 3,148 I look fwd to a reply to #515 to finish the discussion.
 18th February 2009, 06:52 AM #531 GStan Graduate Poster     Join Date: Nov 2007 Posts: 1,350 Originally Posted by Christopher7 Bazant wrote that 9-13-01 and updated on 9-22-01 This is not science. This is pure conjecture. He doesn't have any data. Appeal to authority denied. Speak for your self. Don't glibly pass the buck. * * * * * Do you have a response to this: Newton's first law says an object in motion will remain in motion unless acted on by an external unbalanced force. The top section was in motion to the side and down. Both motions continued as the collapse progressed. The side motion would continue and the top section would fall off the side of the building unless some external balancing force were applied. * * * * * or are you just a blow hard that blows by now and then to make a sarcastic comment and leave without contributing anything specific like a particular relevant quote from one of the sources you claim makes your point. Gravity pulling straight down is the only force, the whole time. The tilt to the side is created by a hinge (the imbalance between damaged and intact support columns in the impact zone). Even though its moving to the side, gravity is still the force applied. When the hinge breaks (the intact columns can't sustain the additional weight), the mass is all falling more or less, straight down, by force of gravity. And the sporadic lateral ejections are the results of collisions between pieces of the falling, breaking mass (not explosives), which would be expected in a collapse that released the amount of energy it did. I don't know what the exact amount is but I'm sure you've seen Beachnut post it several hundred times in various threads here. Its alot. Do you really not know this basic stuff or are you just pretending not to know it? __________________ On why one would debate truthers at JREF..."Kind of like holidaying with a cult, without the inconvenience of having to give away the deed to your house." - Confuseling Last edited by GStan; 18th February 2009 at 06:53 AM.
 18th February 2009, 06:56 AM #532 tfk Illuminator   Join Date: Oct 2006 Posts: 3,454 Originally Posted by Heiwa No, pls read my article at http://heiwaco.tripod.com/nist3.htm to find the answer. Topic is steel structures + gravity, etc. But yes, no collapse occurs ever of lower object. It may be crushed down from top down. But that is not a collapse. Collapse is something else. And again, topic is what happens to the upper object. According NIST, Bazant, etc, it should remain intact. It is however impossible, if it attempts to crush down the lower object just assisted by gravity. And that's why the NIST/Bazant theory is nonsense. I think it is time to lock this thread, moderator. Heiwa, "Crush down" is different than "collapse"...? Ahhh, you might have defined your terms sooner. Why don't you give your definition now. If it "collapses", floor by floor by floor, from the contact interface between the lower & upper segment to the ground, just like the WTC towers did, you do not consider this a collapse?? Seems to me to be a pretty arbitrary definition. You say the lower segment will NEVER collapse. I disagree. Suppose that you have a weak point on the ground floor. This weak point was strong enough to support the structure above statically. But, due to the combination of the static load and dynamic load, this point may well have a very high STRESS (the factor that determines failure, not force) level that exceeds its strength. Then, by what I am presuming to be your definition of "collapse", this structure could indeed collapse from this weak point, even if a progressive crush down does not start from the top most floor. There is no mechanical theory that says that a smaller segment can never cause a collapse in a larger lower structure. It all comes down to local stresses. tk
 18th February 2009, 06:59 AM #533 Dave Rogers Bandaged ice that stampedes inexpensively through a scribbled morning waving necessary ankles     Join Date: Jan 2007 Location: Cair Paravel, according to XKCD Posts: 33,343 Originally Posted by Christopher7 Yes they do. Is English your first language? Why do you keep posting quotes that don't support your argument, and claiming that you do? Everyone can see it except you. Nowhere in this passage is it asserted that large sections of steel are ejected by air pressure. If you want clarification, ask the people who wrote it. I've told you where to find them. Dave __________________ There is truth and there are lies. - President Joseph R. Biden, January 20th, 2021
 18th February 2009, 07:08 AM #534 Christopher7 Philosopher     Join Date: Aug 2006 Posts: 6,538 Originally Posted by Dave Rogers The final clincher, for me, that a conspiracy theorist is delusional, is when he or she makes personal statements about me that I know to be false. So, Chris, so that I can finally dismiss everything you have ever said as the product of a malfunctioning mind, would you please state what it is that I say I am and you know me not to be? Dave You guys constantly call me delusional, liar, coward etc. but then you get all indignant when I say what I think about you. Put it in a sock. You claim to be a physicist. do you have one of these? Seriously folks, Show your credentials or stop claiming to be anything other than an anonymous smartass.
 18th February 2009, 07:11 AM #535 e^n Muse   Join Date: Mar 2007 Posts: 810 Originally Posted by Heiwa I look fwd to a reply to #515 to finish the discussion. I look forward to your response to #484 Christopher7. You are resorting to some pretty silly tactics in this argument. No matter how much you bold certain sections, your interpretation is not supported by this paper. I pointed out how these are handled in the same post I have linked above, but now you have resorted to trying to poison the well by claiming Newtons Bit, Dave Rogers etc are lying about their credentials I see no point in continuing. I doubt you can point out errors in their work, if you apply the same technique as you do to the passage you quote then I think it is likely you have formed an interpretation of their work, and resist changing this even if informed you are incorrect. I don't mean to slander you, and I am not accusing you of anything directly. I just want to point out that you are unable to see that you are wrong in this immediate case, and this may be a sufficient explanation as to why you disagree so vehemently with people who have demonstrated their expertise. edit: Originally Posted by Christopher7 Show your credentials or stop claiming to be anything other than an anonymous smartass. Please state your exact criteria for what credentials you will accept. I would not be happy posting my credentials (if i had any that were relevant) until I was assured that no goalposts could be moved. __________________ Conspiracy Theorist Correspondent, Panic Watch! Last edited by e^n; 18th February 2009 at 07:14 AM.
 18th February 2009, 07:14 AM #536 Bananaman Banned   Join Date: Feb 2008 Posts: 299 Chris7 Quote: Put it in a sock. I think the phrase you're looking for is 'put a sock in it'. Only 5 words and you get 4 of them in the wrong order. Sort of a metaphor for everything you post. OK, carry on crucifying him, guys. Bananaman.
 18th February 2009, 07:14 AM #537 GStan Graduate Poster     Join Date: Nov 2007 Posts: 1,350 Originally Posted by Christopher7 You guys constantly call me delusional, liar, coward etc. but then you get all indignant when I say what I think about you. Put it in a sock. You claim to be a physicist. do you have one of these? http://img6.imageshack.us/img6/967/a...eorg800zc2.jpg Seriously folks, Show your credentials or stop claiming to be anything other than an anonymous smartass. Ok, so you are credentialed and qualified to talk about Air Force Mishaps. Have you posted in any threads here about Air Force Mishaps in which your expertise or credentials were questioned? __________________ On why one would debate truthers at JREF..."Kind of like holidaying with a cult, without the inconvenience of having to give away the deed to your house." - Confuseling
 18th February 2009, 07:17 AM #538 e^n Muse   Join Date: Mar 2007 Posts: 810 Originally Posted by GStan Ok, so you are credentialed and qualified to talk about Air Force Mishaps. Have you posted in any threads here about Air Force Mishaps in which your expertise or credentials were questioned? I believe that is Beachnut's certificate __________________ Conspiracy Theorist Correspondent, Panic Watch!
 18th February 2009, 07:17 AM #539 GStan Graduate Poster     Join Date: Nov 2007 Posts: 1,350 Originally Posted by Bananaman Chris7 I think the phrase you're looking for is 'put a sock in it'. Only 5 words and you get 4 of them in the wrong order. Sort of a metaphor for everything you post. OK, carry on crucifying him, guys. Bananaman. __________________ On why one would debate truthers at JREF..."Kind of like holidaying with a cult, without the inconvenience of having to give away the deed to your house." - Confuseling
 18th February 2009, 07:18 AM #540 Christopher7 Philosopher     Join Date: Aug 2006 Posts: 6,538 Originally Posted by Dave Rogers Why do you keep posting quotes that don't support your argument, and claiming that you do? Everyone can see it except you. Nowhere in this passage is it asserted that large sections of steel are ejected by air pressure. If you want clarification, ask the people who wrote it. I've told you where to find them. Dave I found and read their papers. There is nothing there about the ejected debris other that the section about air pressure. No clarification needed. Can you find where Bazant or Greening account for the ejected debris? Post the part where either one addresses this issue or stop claiming that they do.
 18th February 2009, 07:18 AM #541 Grizzly Bear このマスクによっ     Join Date: May 2008 Posts: 7,866 Originally Posted by GStan Ok, so you are credentialed and qualified to talk about Air Force Mishaps. Have you posted in any threads here about Air Force Mishaps in which your expertise or credentials were questioned? That's a certificate which beachnut posted a few times around the forum in a few of the CT threads.... Not C7's credentials. I don't believe he's (C7) claiming it as his own, just using it to make his point... __________________ Current Set:http://i.imgur.com/IoqiUdK.jpg
 18th February 2009, 07:27 AM #542 ElMondoHummus 0.25 short of being half-witted     Join Date: Oct 2006 Location: Somewhere north of the South Pole Posts: 12,279 Look, folks, I realize that this is a hairsplit of a distinction, but: Chris didn't actually say that certificate was his. And sure, Chris, in spite of my observation, the context you put that in really, really suggests that you're trying to claim it as your own. In doing so, you're really testing the boundary of tolerance. It's best that you clarify whether you were claiming that as your own, or whether you were just making a general appeal to the forum to demonstrate their bona-fides. Everyone else: Let's keep in mind that he just acknowledged Beachnut's expertise in the area of air accident investigation. If he's making an argument about the strength of authority to judge matters, then his post by his own argument validates all of Beech's criticisms. That's probably an unintended consequence of his post, but hey, people do that sometimes. __________________ "AND ZEPPELINS!!! We haven't even begun to talk about Zeppelins yet! Marauding inflatable Teutonic johnsons waggling their way across the sky! Indecent and flammable all at once." Last edited by ElMondoHummus; 18th February 2009 at 07:45 AM. Reason: better phrasing
 18th February 2009, 07:28 AM #543 Bell Penultimate Amazing   Join Date: Sep 2006 Posts: 21,050 Originally Posted by Christopher7 You guys constantly call me delusional, liar, coward etc. but then you get all indignant when I say what I think about you. Put it in a sock. You claim to be a physicist. do you have one of these? http://img6.imageshack.us/img6/967/a...eorg800zc2.jpg Seriously folks, Show your credentials or stop claiming to be anything other than an anonymous smartass. What you did above, is very close to lying. You could have stated - to avoid deliberate confusion - that the certificate you posted is from BEACHNUT
 18th February 2009, 07:31 AM #544 GStan Graduate Poster     Join Date: Nov 2007 Posts: 1,350 Originally Posted by Grizzly Bear That's a certificate which beachnut posted a few times around the forum in a few of the CT threads.... Not C7's credentials. I don't believe he's (C7) claiming it as his own, just using it to make his point... Alright, ignore post 537. I understand what he was going for now. __________________ On why one would debate truthers at JREF..."Kind of like holidaying with a cult, without the inconvenience of having to give away the deed to your house." - Confuseling
 18th February 2009, 07:33 AM #545 Dave Rogers Bandaged ice that stampedes inexpensively through a scribbled morning waving necessary ankles     Join Date: Jan 2007 Location: Cair Paravel, according to XKCD Posts: 33,343 Originally Posted by Christopher7 You guys constantly call me delusional, liar, coward etc. but then you get all indignant when I say what I think about you. Put it in a sock. But you didn't say you thought I wasn't what I say I am, you said you knew I wasn't what I say I am. What do you claim to know, and how do you claim to know it? Originally Posted by Christopher7 You claim to be a physicist. do you have one of these? No, for some reason an aircraft mishap investigation course certificate from the University of Southern California tends not to get issued free along with a physics doctorate. Originally Posted by Christopher7 Seriously folks, Show your credentials or stop claiming to be anything other than an anonymous smartass. If I ever chose to commit the fallacy of appealing to my own authority, I might have some reason to post my degree certificate. Since I don't do so, and I freely admit that my qualifications are irrelevant to the value of the content of my posts, I shall continue to choose not to do so. Live with it. Now, please post the evidence you claim to have that I am not a physicist (as you claimed in post #523), or admit that you were lying when you said "I have read some of your diatribes, debunked Greening's garbage and debated with Newtons Bit and Dave Rogers enough to know that they are not what they say they are." Dave __________________ There is truth and there are lies. - President Joseph R. Biden, January 20th, 2021
 18th February 2009, 07:40 AM #546 Christopher7 Philosopher     Join Date: Aug 2006 Posts: 6,538 Originally Posted by e^n Christopher7. You are resorting to some pretty silly tactics in this argument. "The mass that is shed from the tower, characterized by k-out, exits at various velocities ranging from nearly 0 to almost either the air ejection velocity, for fine dust, or to roughly z˙, for large steel pieces." How do you interpret that section and where does Bazant say what ejected the large steel pieces if not air pressure? Quote: Please state your exact criteria for what credentials you will accept. I would not be happy posting my credentials (if i had any that were relevant) until I was assured that no goalposts could be moved. Post a verifiable degree and proof that you are that person. Also a license if you have one.
 18th February 2009, 07:52 AM #547 Dave Rogers Bandaged ice that stampedes inexpensively through a scribbled morning waving necessary ankles     Join Date: Jan 2007 Location: Cair Paravel, according to XKCD Posts: 33,343 Originally Posted by Christopher7 Post a verifiable degree and proof that you are that person. Also a license if you have one. Chris, you are a liar. Post your proof that I'm not a physicist and I'll retract that accusation. Dave __________________ There is truth and there are lies. - President Joseph R. Biden, January 20th, 2021
 18th February 2009, 08:04 AM #548 GStan Graduate Poster     Join Date: Nov 2007 Posts: 1,350 Originally Posted by Christopher7 "The mass that is shed from the tower, characterized by k-out, exits at various velocities ranging from nearly 0 to almost either the air ejection velocity, for fine dust, or to roughly z˙, for large steel pieces." How do you interpret that section and where does Bazant say what ejected the large steel pieces if not air pressure? What point are you making here? You noted just a few posts ago that the paper to which you are referring was written less than two weeks after the attacks. Is it unreasonable to expect that it is not comprehensive? I didn't read the first 8 or 9 pages of this thread; are there posters claiming that air pressure alone ejected the steel columns outward, and furthermore, basing that claim on nothing more than the absence of a specification of any other mechanism by Bazant? __________________ On why one would debate truthers at JREF..."Kind of like holidaying with a cult, without the inconvenience of having to give away the deed to your house." - Confuseling
 18th February 2009, 08:04 AM #549 Mince Master Poster     Join Date: Sep 2006 Posts: 2,009 Originally Posted by Christopher7 You guys constantly call me delusional, liar, coward etc. but then you get all indignant when I say what I think about you. Put it in a sock. You claim to be a physicist. do you have one of these? http://img6.imageshack.us/img6/967/a...eorg800zc2.jpg Seriously folks, Show your credentials or stop claiming to be anything other than an anonymous smartass. Look at me: I'm a doctor: a lawyer: and a pilot: And you know, merely because i've posted them, these documents are legitimate and mine. ETA: Oh, yeah. I forgot, I'm also an engineer: and I know CPR: Last edited by Mince; 18th February 2009 at 08:10 AM.
 18th February 2009, 08:06 AM #550 Christopher7 Philosopher     Join Date: Aug 2006 Posts: 6,538 Originally Posted by Dave Rogers But you didn't say you thought I wasn't what I say I am, you said you knew I wasn't what I say I am. What do you claim to know, and how do you claim to know it? I know that you know that I know that you don't know what you say you know because it's clear that you don't know what you are talking about. Quote: If I ever chose to commit the fallacy of appealing to my own authority, I might have some reason to post my degree certificate. Since I don't do so, and I freely admit that my qualifications are irrelevant to the value of the content of my posts, I shall continue to choose not to do so. Live with it. No worries mate. Quote: Now, please post the evidence you claim to have that I am not a physicist (as you claimed in post #523), You want I should prove a negative? Let's get back on topic. I have been through the Greening and Bazant papers and neither one accounts for the ejected framework sections and other heavy debris. [except for the air pressure section] They do not account for the weight of the ejected debris or how much energy it took to eject that material or where that energy came from. Without this critical information their theories are incomplete and they don't work.
 18th February 2009, 08:16 AM #551 Bananaman Banned   Join Date: Feb 2008 Posts: 299 Chris7 Quote: You want I should prove a negative? Actually it's not that much of a negative because you say you know that he isn't a physicist; it implies you have proof. Show us your proof. Seems fairly simple. Just saying he writes stuff that you disagree with (or more accurately could be said not to understand) is, by no stretch of the imagination, proof. Chris7 Quote: Let's get back on topic. Or in other words, let's change the subject as fast as possible because I've backed myself into a corner I can't wheedle my way out of. Bananaman Last edited by Bananaman; 18th February 2009 at 08:37 AM.
 18th February 2009, 08:17 AM #552 Mince Master Poster     Join Date: Sep 2006 Posts: 2,009 Originally Posted by GStan Ok, so you are credentialed and qualified to talk about Air Force Mishaps. Have you posted in any threads here about Air Force Mishaps in which your expertise or credentials were questioned? I was in the U.S. Navy for 11 years and an Aviation Electronics Technician for four years. I always found it interesting how many (most?) technical service members would overappreciate, overestimate and overstate their education and certification. In my experience, a lot pf service members would, after receiving their "brake rider" certification, believe they are now a pilot, with extensive knowledge of aerodynamics and aircraft operation. C7 is demonstrating this behavior. Aircraft Mishap Investigation Course? LMFAO!
 18th February 2009, 08:23 AM #553 Christopher7 Philosopher     Join Date: Aug 2006 Posts: 6,538 Originally Posted by GStan What point are you making here? You noted just a few posts ago that the paper to which you are referring was written less than two weeks after the attacks. Is it unreasonable to expect that it is not comprehensive? I didn't read the first 8 or 9 pages of this thread; are there posters claiming that air pressure alone ejected the steel columns outward, and furthermore, basing that claim on nothing more than the absence of a specification of any other mechanism by Bazant? The ejection of large steel pieces is referred to in a sentence about air pressure. There is no mention of ejection of large steel pieces anywhere else in the document. If you don't want to put 2 and 2 together then Bazant did not account for the the energy necessary to eject the large steel pieces nor the mechanism to hurl them up to 600 feet. His theory is therefore incomplete and is not an explanation for the collapse of the towers. Last edited by Christopher7; 18th February 2009 at 08:28 AM.
 18th February 2009, 08:31 AM #554 e^n Muse   Join Date: Mar 2007 Posts: 810 Originally Posted by Christopher7 "The mass that is shed from the tower, characterized by k-out, exits at various velocities ranging from nearly 0 to almost either the air ejection velocity, for fine dust, or to roughly z˙, for large steel pieces." How do you interpret that section and where does Bazant say what ejected the large steel pieces if not air pressure? I interpret that section this way: Mass ejected from the towers and therefore no longer contributing to collapse exits at various velocitiesAir exits at an increasingly velocity tied to the collapse time of a floor Dust closely matches this velocity, due to the relatively low mass increase and similar mechanism Steel exits at roughly $\.{z}$ There is no mention of mechanism of any kinda, and I have absolutely no idea where you would get the idea that the air ejection is responsible for the steel ejection. They are both energy sinks, that is actions which take energy away from the upper block to be used in crushing the next floor. The mechanism of ejection is somewhat irrelevant if the quantity of energy lost is available. Please note that $\.{z}$ is the derivation of the upper block's coordinate, and the first derivation of position is velocity. So therefore steel exits at roughly the velocity of the descending block. Can you see the mechanism which is implied? Originally Posted by Christopher7 Post a verifiable degree and proof that you are that person. Also a license if you have one. These require more definition. What is a "verifiable degree"? Is it a degree you can confirm is offered by the school who produced it? Is it a degree with a serial number you can look up? Is it a degree you can hold in your hand etc? Without these, I certainly would not be willing to produce anything, as there would be nothing stopping you from simply moving the goalposts and saying "Well that degree isn't good enough, i want more proof" forever. Something some truthers are well acquainted with. edit: Man those $z$s are ugly. Perhaps my latex is a little too rusty. edit2: Originally Posted by Christopher7 If you don't want to put 2 and 2 together then Bazant did not account for the the energy necessary to eject the large steel pieces nor the mechanism to hurl them up to 600 feet. His theory is therefore incomplete and is not an explanation for the collapse of the towers. What complete rubbish. The force required to accelerate large steel pieces associated with the fraction of mass shed per floor is very clearly calculated at the bottom of the paragraph you are quoting. This is a very dishonest thing to say. $F_e = \frac{1}{2} K_e K_{out} \mu (z) \.{z}^2$ PS. My Latex was very rusty. edit3: Damnit those zs are pretty, but the others are not, maybe it's because I can't include packages but I am blaming international communism for this. __________________ Conspiracy Theorist Correspondent, Panic Watch! Last edited by e^n; 18th February 2009 at 08:44 AM.
 18th February 2009, 08:32 AM #555 Dave Rogers Bandaged ice that stampedes inexpensively through a scribbled morning waving necessary ankles     Join Date: Jan 2007 Location: Cair Paravel, according to XKCD Posts: 33,343 Originally Posted by Christopher7 You want I should prove a negative? Yes, liar, because you claimed one. Dave __________________ There is truth and there are lies. - President Joseph R. Biden, January 20th, 2021
 18th February 2009, 08:32 AM #556 Christopher7 Philosopher     Join Date: Aug 2006 Posts: 6,538 Originally Posted by Mince Aircraft Mishap Investigation Course? LMFAO! That was a joke. I'm glad you enjoyed it. beachnut posted that when I asked him for his credentials.
 18th February 2009, 08:36 AM #557 RevDisturba Muse     Join Date: Feb 2009 Posts: 647 I used to think that something was going on in the world trade center building collapses but now after reviewing the data and vids etc I think that the heat destroyed the structural ability of the steel I beams etc. I have no credentials (I am pastor and have a MA in comparative religion). I did work putting myself through school as a structural and a reinforcing iron worker. I just don’t see anything but the jets hitting the buildings (I worked on over a span of ten years) and the heat taking the temper out of the steel. Heck we couldn't even use a torch on many of the steel elements in the most of the building because even that bit of heat would make the steel brittle. Think what a few tons of high grade jet fuel would do. ; {> __________________ Proverbs 26:4–5 ‘Do not answer a fool according to his folly, lest you also be like him. Answer a fool according to his folly, Lest he be wise in his own eyes.’ Job 18:14 'His confidence shall be rooted out of his tabernacle, and it shall bring him to the king of terrors'. Last edited by RevDisturba; 18th February 2009 at 08:38 AM.
 18th February 2009, 08:57 AM #558 ElMondoHummus 0.25 short of being half-witted     Join Date: Oct 2006 Location: Somewhere north of the South Pole Posts: 12,279 Just for the sake of accuracy, Rev: The jet fuel burnt out rather quickly; estimates are as low as 4 and as high as 14-some minutes. The source of heat that's responsible for the thermal expansions and sagging has been demonstrated to be the office contents and flammable building components (drywall, etc.) burning. But yes, I do see your point. It's ridiculous to propose some external element like thermite being present where there were already myriad other fuels available. __________________ "AND ZEPPELINS!!! We haven't even begun to talk about Zeppelins yet! Marauding inflatable Teutonic johnsons waggling their way across the sky! Indecent and flammable all at once." Last edited by ElMondoHummus; 18th February 2009 at 08:59 AM.
 18th February 2009, 09:03 AM #559 Dave Rogers Bandaged ice that stampedes inexpensively through a scribbled morning waving necessary ankles     Join Date: Jan 2007 Location: Cair Paravel, according to XKCD Posts: 33,343 Originally Posted by ElMondoHummus It's ridiculous to propose some external element like thermite being present where there were already myriad other fuels available. You're claiming a JREF moderator planted the incendiaries? Dave __________________ There is truth and there are lies. - President Joseph R. Biden, January 20th, 2021
 18th February 2009, 09:03 AM #560 Christopher7 Philosopher     Join Date: Aug 2006 Posts: 6,538 Originally Posted by e^n I interpret that section this way: Mass ejected from the towers and therefore no longer contributing to collapse exits at various velocitiesAir exits at an increasingly velocity tied to the collapse time of a floor Dust closely matches this velocity, due to the relatively low mass increase and similar mechanism Steel exits at roughly  There is no mention of mechanism of any kind, "The mass that is shed from the tower, characterized by k-out, exits at various velocities." They are talking about the mass which includes large steel pieces. "ranging from nearly 0 to almost either the air ejection velocity, for fine dust, or to roughly z˙, for large steel pieces." They are talking about ejection velocities. What accounts for the ejection velocity of the large steel pieces if not air pressure? Quote: The mechanism of ejection is somewhat irrelevant if the quantity of energy lost is available. No,no! The energy necessary to hurl a great many large steel pieces up to 600 feet in all directions is very significant and must be accounted for. Furthermore, the mechanism that transferred all that energy to the 4 ton frame work pieces and ejected them up to 600 feet laterally must be explained for any analysis to be considered complete. This is why I doubt your credentials. That statement is glibly dismissive of two critical factors in the collapse. Quote: Please note that  is the derivation of the upper block's coordinate, and the first derivation of position is velocity. So therefore steel exits at roughly the velocity of the descending block. Can you see the mechanism which is implied? Double talk. What makes it go sideways instead of down?

International Skeptics Forum