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 JREF Forum Merged: Why WTC7 should not have collapsed

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 27th August 2008, 07:05 PM #81 Newtons Bit Philosopher     Join Date: Apr 2007 Posts: 6,890 Originally Posted by Homeland Insurgency So then post some and their personal opinions. It shouldn't be hard with 99.999% of them. The other 10 engineers in my office all concur with the NIST report. Most of them think that designing buildings for burn-out, as recommended by NIST, is absurd. __________________ "Structural Engineering is the art of molding materials we do not wholly understand into shapes we cannot precisely analyze so as to understand forces we cannot really assess in such a way that the community at large has no reason to suspect the extent of our own ignorance." James E Amrhein My website.
 27th August 2008, 07:06 PM #82 X Slide Rulez 4 Life     Join Date: Oct 2007 Location: Launching the army, waiting for Hok to commit her forces (then the moles strike...) Posts: 4,082 Originally Posted by Grizzly Bear Regardless of what goal posts you shift the analogy is invalid. In building structures there's a concept called the square-cube effect. Say for example we have an umbrella shaped shelter that is 10 ft & 10 ft deep with a flat concrete roof 1 ft thick and a single center column having an area of 1ft2. Concrete is roughly 150 Lbs/ft3, the total load on the column is about 15 kips, and the compressive stress is 15 kips/ft2 Note: 1 kip = 1,000 lbs Take the same structure and increase the size 3 fold, overall size increases to 30 ft in each dimension; The roof slab would increase in thickness to by 3 fold as well resulting in a slab with about 2700 ft3, and a weight of 405 kips. The area of the center column would increase to 9 ft2. The column stress would be 45 kips, which is three times that of the original smaller structure. In order to effect the same compressive stress , the column area would have to triple to 27 ft2 with column dimension increasing to 5.2 ft on each side. In other words even using the same materials in you "analogy" would result in drastically different results. The problem is compounded just by using different materials... A 1 ft3 volume of concrete can be loaded with many times it's own weight, however a slab of concrete the size of a building may only support double it's own weight. Which is exactly why I've been trying to get Heiwa to provide calculations for his scale experiments. I thank you for putting more clearly than I managed to. __________________ It is sad that this is necessary: Argumentum Ad Hominem: "You are wrong because you are ugly." Not Ad-Hom: "You are wrong and you are ugly." [X's posts are] ...as good as having 24 hours of Justin Bieber piped into your ears! - kmortis
 27th August 2008, 07:07 PM #83 Homeland Insurgency Banned   Join Date: Jun 2008 Posts: 1,705 Originally Posted by Newtons Bit The other 10 engineers in my office all concur with the NIST report. Most of them think that designing buildings for burn-out, as recommended by NIST, is absurd. They concur with NIST but they think it's absurd?
 27th August 2008, 07:12 PM #84 Jontg The Bear Skeptic     Join Date: Oct 2004 Location: A world of kindling. Posts: 926 They agree with NIST's account of events, but not with their recommendations. __________________ All that is sacred must burn.
 27th August 2008, 07:14 PM #85 X Slide Rulez 4 Life     Join Date: Oct 2007 Location: Launching the army, waiting for Hok to commit her forces (then the moles strike...) Posts: 4,082 Originally Posted by Homeland Insurgency They concur with NIST but they think it's absurd? I'd hazard that Newton's Bit means that his colleagues agree with NISTs findings on the collapse, but think the recommendations in building design change are absurd. __________________ It is sad that this is necessary: Argumentum Ad Hominem: "You are wrong because you are ugly." Not Ad-Hom: "You are wrong and you are ugly." [X's posts are] ...as good as having 24 hours of Justin Bieber piped into your ears! - kmortis
 27th August 2008, 07:38 PM #86 Newtons Bit Philosopher     Join Date: Apr 2007 Posts: 6,890 Originally Posted by Homeland Insurgency They concur with NIST but they think it's absurd? Try reading. __________________ "Structural Engineering is the art of molding materials we do not wholly understand into shapes we cannot precisely analyze so as to understand forces we cannot really assess in such a way that the community at large has no reason to suspect the extent of our own ignorance." James E Amrhein My website.
 27th August 2008, 07:40 PM #87 Grizzly Bear このマスクによっ     Join Date: May 2008 Posts: 5,690 Originally Posted by [X] Which is exactly why I've been trying to get Heiwa to provide calculations for his scale experiments. I thank you for putting more clearly than I managed to. I remembered that this stuff is discussed in one of my older text books, If I get the chance maybe I'll post the pages that cover it. What's just as important to understand is that the strength of a column is dependent on its cross sectional area of structural members the weight is determined by volume more or less, and then you add the live and dead loads after wards. In general as the structure is scaled up the volume (and gravity load) increases at the rate of the cube of the scale, while its members strengths increases at a slower rate of the square of the scale. Neither Heiwa, HI, or for that matter any other irrational CT member understands that and yet they persist in using weak analogies in some vain effort that they'll somehow equate to each other. Richard Gage takes it to the extra leap by trying to equate card board boxes to the towers, and he wonders why he's being ridiculed.... This same effect is present in the ratio of weight that a beatle can carry compared to that of a human, as well as to the varying skeletal features on any animal really... __________________ Graduation on 8/13/2011 8D Last edited by Grizzly Bear; 27th August 2008 at 07:42 PM.
 27th August 2008, 09:01 PM #88 Mince Master Poster     Join Date: Sep 2006 Posts: 2,019 You might want to show this thread to NIST. I don't think they're aware of your findings.
 27th August 2008, 11:57 PM #89 Travis Misanthrope of the Mountains     Join Date: Mar 2007 Location: Tuolumne City, CA Posts: 17,941 It looks like we're back to the old Indestructible Skyscraper Canard. If column 79 didn't fail after losing lateral support why did the penthouses bend downward right where column 79 interfaced with the roof? __________________ "Because WE ARE IGNORANT OF 911 FACTS, WE DEMAND PROOF" -- Douglas Herman on Rense.com Zingiber Officinale
 28th August 2008, 01:10 AM #90 Corsair 115 Philosopher     Join Date: Apr 2007 Location: Tranquility Base Posts: 8,564 This thread needs more Newtons Bit and Architect. Though I have a hard time following along, I do like it when they break out the mathematics to validate their positions. Something conspiracists seem particularly incapable of doing. __________________ "We choose to go to the moon in this decade and do the other things not because they are easy, but because they are hard. Because that goal will serve to organize and measure the best of our abilities and skills, because that challenge is one we are willing to accept, one we are unwilling to postpone, and one which we intend to win."
 28th August 2008, 01:32 AM #91 Heiwa Banned   Join Date: Jul 2007 Posts: 3,149 Originally Posted by leftysergeant The table analogy is absurd. You are not talking about the same materials or forces. Your arresting mechanism assumes only one action, thje collapse of the floors. You disregard the other floor slabs pushing against the vertical columns after the slabs on the other side have fallen. You have a lot of forces pushing unevenly in several directions. That was what Sunder repeated several times in the report, when he emphasized the asymetricality of the floors. No forces are pushing! After column 79 fails the floor (and roof) beams attached to it are assumed to be disconnected (column 79 drops down and is out of the action). At this instance the beams are still hanging on their other end connections to other columns and hinges down. No pushing in several directions. Just pulling down. And that's it. Only thing that can happen is that some beams shear off the remaining end connection and drops down. The secondary beams cannot damage other primary structure columns. REPEAT. A beams is first connected at both ends to columns. Then one end connection is locally damaged, when that column (no. 79) fails and, yes - an asymetrical state develops - and the beam is only connected at its other end. So the beam hinges down around that connection and the load on the beam slips off. End of failures unless the other end connection fails, and the beam drops down. That adjacent column will not fail at it is still supported by many other beams in all directions. It is called redundancy. The table analogy is not absurd. Remove one leg ... and there is no global collapse. You can stack a number of tables on top of one another and remove any leg anywhere. No collapse. Sunder & Co suggest otherwise but cannot show any calculations for their absurd allegations. Sunder & Co actually suggest that all steel towers in the USA are wrongly designed and built and removing one primary part collapse follows as shown in some Hollywood pictures. Primary and secondary structural parts flying in all directions. It is insane. It is NWO.
 28th August 2008, 01:35 AM #92 Heiwa Banned   Join Date: Jul 2007 Posts: 3,149 Originally Posted by Travis It looks like we're back to the old Indestructible Skyscraper Canard. If column 79 didn't fail after losing lateral support why did the penthouses bend downward right where column 79 interfaced with the roof? Column 79 is assumed to fail first due to a local fire. Read the report. But the penthouse was also supported by other columns and they could not fail due to failure of columnn 79 (unless assisted of course).
 28th August 2008, 01:40 AM #93 Dave Rogers Bandaged ice that stampedes inexpensively through a scribbled morning waving necessary ankles     Join Date: Jan 2007 Location: In a world lit only by fire. Posts: 17,894 Originally Posted by Galileo non-responsive. This is a forum for the scientific. It's not non-responsive at all. Heiwa starts with no assumptions about the weight, composition or strength of the structure, none about the temperature, extent or duration of the fires, none about the thermal properties of the materials involved, and makes no calculations; he simply advances a line of reasoning which he claims leads to the conclusion that progressive collapse cannot occur. In the absence of any data or calculations, this can only be assumed to be a perfectly general result. Since progressive collapse does occur, it is also a completely wrong result. Having thus summarised Heiwa's arguments, I can conclude that they are not worthy of further consideration. This is called attacking the argument. In effect, Heiwa is saying, not that WTC7 should not have collapsed, but that nothing can ever collapse. It's a perfectly reasonable response to say that this conclusion is insane. Dave __________________ "We will punish the murderer together. Our punishment will be more generosity, more tolerance and more democracy." - Fabian Stang, Mayor of Oslo SSKCAS, covert member
 28th August 2008, 02:24 AM #94 JihadJane Penultimate Satisfaction     Join Date: Jul 2008 Posts: 42,721 I don't understand why anyone is taking this latest NIST joke report seriously. How can such a study claim to be authoritative when it's not even based on physical evidence but on infinitely malleable computer models and guesswork? I'm quite sure that NIST "scientists" would be able to demonstrate, mathematically, that the moon is made of cheese and bricks are made of wood and their cultish ideological soulmates would be on here enthusiastically "proving" them right.
 28th August 2008, 02:30 AM #95 boloboffin Guest   Join Date: Aug 2006 Location: Dallas, TX Posts: 5,001 Originally Posted by Heiwa Column 79 is assumed to fail first due to a local fire. Read the report. This is like saying George Washington became the first President of the United States because of his leadership in the French and Indian War. There are a few steps in between. Read the report yourself.
 28th August 2008, 02:31 AM #96 Dave Rogers Bandaged ice that stampedes inexpensively through a scribbled morning waving necessary ankles     Join Date: Jan 2007 Location: In a world lit only by fire. Posts: 17,894 Originally Posted by JihadJane I don't understand why anyone is taking this latest NIST joke report seriously. How can such a study claim to be authoritative when it's not even based on physical evidence but on infinitely malleable computer models and guesswork? You need to re-assess your definition of the term "physical evidence". It includes, but is not limited to, "steel samples from collapsed buildings". You also need to re-assess your definition of "infinitely malleable" to exclude requirements to comply with physical laws and observed phenomena. Finally, you might consider that, in the light of your repeated claims of minimal understanding of engineering issues, your admittedly uninformed opinions on these issues might not be seen as compelling evidence. Dave __________________ "We will punish the murderer together. Our punishment will be more generosity, more tolerance and more democracy." - Fabian Stang, Mayor of Oslo SSKCAS, covert member
 28th August 2008, 02:50 AM #97 Hokulele Official Nemesis     Join Date: Feb 2007 Location: Trying to decide whether to set defenses against an army, or against mole rats. Posts: 27,268 Originally Posted by JihadJane I don't understand why anyone is taking this latest NIST joke report seriously. How can such a study claim to be authoritative when it's not even based on physical evidence but on infinitely malleable computer models and guesswork? Heh, by that standard, the entire field of astrophysics is invalid. __________________ Yvette: "Blasty! Blasty! Blasty!" Some person: "Why did you shoot that?" Yvette: "Blasty! Blasty! Blasty!" - Tragic Monkey
 28th August 2008, 03:45 AM #98 JihadJane Penultimate Satisfaction     Join Date: Jul 2008 Posts: 42,721 Originally Posted by Dave Rogers You need to re-assess your definition of the term "physical evidence". It includes, but is not limited to, "steel samples from collapsed buildings". What else does "physical evidence" include? Quote: You also need to re-assess your definition of "infinitely malleable" to exclude requirements to comply with physical laws and observed phenomena. Good point. Infinite was a bit of an exaggeration! Quote: Finally, you might consider that, in the light of your repeated claims of minimal understanding of engineering issues, your admittedly uninformed opinions on these issues might not be seen as compelling evidence. Dave It requires absolutely no knowledge of engineering issues to know the removing and destroying all the physical evidence from a crime scene fatally compromises any investigation. This is why criminals do their best to destroy all physical evidence of their crimes. It makes it far more likely that they will get away with their crimes.
 28th August 2008, 03:49 AM #99 JihadJane Penultimate Satisfaction     Join Date: Jul 2008 Posts: 42,721 Originally Posted by Hokulele Heh, by that standard, the entire field of astrophysics is invalid. No astrophysicist is arrogant enough to claim that they cannot be wrong.
 28th August 2008, 04:31 AM #100 Grizzly Bear このマスクによっ     Join Date: May 2008 Posts: 5,690 Originally Posted by Heiwa Only thing that can happen is that some beams shear off the remaining end connection and drops down. The secondary beams cannot damage other primary structure columns. REPEAT. A beams is first connected at both ends to columns. Then one end connection is locally damaged, when that column (no. 79) fails and, yes - an asymetrical state develops - and the beam is only connected at its other end. So the beam hinges down around that connection and the load on the beam slips off. End of failures unless the other end connection fails, and the beam drops down. That adjacent column will not fail at it is still supported by many other beams in all directions. It is called redundancy. I'll repeat my question yet again: Again on what grounds? Does this take into account secondary effects from structural damage on one side? Does this take into consideration plastic creep of some portions of the structure and/or connections? Does it consider shear forces applied by thermal expansion and contraction cause by structural members being heated by the fires? Does this consider WTC 7's own design for the structural frame? You apply a generic standard as if the structure will behave the same regardless of construction methods? If you expect to have the slightest chance of convincing me you will need to explain why the same behavior will be expected in different designs. What considerations have you made? And do any include the above I mentioned? Originally Posted by Heiwa The table analogy is not absurd. Remove one leg ... and there is no global collapse. You can stack a number of tables on top of one another and remove any leg anywhere. No collapse. No Heiwa, it is ridiculous to assume a table comes anywhere near comparison to a building. I explained why already, get off the subject and reread my post regarding it: LINK Stop using that silly weak analogy, it really isn't working Heiwa __________________ Graduation on 8/13/2011 8D Last edited by Grizzly Bear; 28th August 2008 at 04:39 AM.
 28th August 2008, 04:35 AM #101 leftysergeant Penultimate Amazing     Join Date: Jul 2007 Location: Spanaway WA Posts: 18,613 Originally Posted by JihadJane It requires absolutely no knowledge of engineering issues to know the removing and destroying all the physical evidence from a crime scene fatally compromises any investigation. Leaving the steel where in situ during the investigation was not an option that anyone with a room-temp or higher IQ would entertain. Stop bringing it up. The steel was examined at Fresh Kills. Did you hear Astineh-Asl complaining that there should have been more than he saw?
 28th August 2008, 04:47 AM #102 Mobyseven President of Covert-Ops     Join Date: Nov 2006 Location: Not the Rat. Posts: 5,672 Originally Posted by Homeland Insurgency I think it's you who doesn't understand if you think that is a reasonable comparison. 200 ft and 3 feet are the difference. The match car would be damaged at 200 feet and the car not very from 3 feet. *facepalm* If I dropped a car, an actual size car, 3', then that car is not going to be a happy bunny. Indeed, dropping a car from three feet up is going to send you in for quite a few repairs. But if you really think that a car won't be very damaged from three feet, scale, take it up a bit further. I can throw (yes, throw) a matchbox car out of a third story window and it won't get too damaged (perhaps a few scratches). What would happen to a car dropped from the same height? __________________ "[Mobyseven is] a fantastically friendly, open, curious, happy, charming, sweet and adorable young man! And those are his bad points." - HistoryGal on Mobyseven "Damn, you're good." - Ichneumonwasp on Mobyseven
 28th August 2008, 04:52 AM #103 Heiwa Banned   Join Date: Jul 2007 Posts: 3,149 Originally Posted by Dave Rogers It's not non-responsive at all. Heiwa starts with no assumptions about the weight, composition or strength of the structure, none about the temperature, extent or duration of the fires, none about the thermal properties of the materials involved, and makes no calculations; he simply advances a line of reasoning which he claims leads to the conclusion that progressive collapse cannot occur. In the absence of any data or calculations, this can only be assumed to be a perfectly general result. Since progressive collapse does occur, it is also a completely wrong result. Having thus summarised Heiwa's arguments, I can conclude that they are not worthy of further consideration. This is called attacking the argument. In effect, Heiwa is saying, not that WTC7 should not have collapsed, but that nothing can ever collapse. It's a perfectly reasonable response to say that this conclusion is insane. Dave Hm, do I say nothing can collapse? Where? No, I just say when a local failure occurs for any reason, you have to analyse the consequences of this local failure. Other parts may get damaged. What happens then? Just do the analysis step by step and record the results in a simple manner. NIST is not doing that in its WTC7 reports and it is the same people that wrote the WTC1/2 reports that are now back in action. Same method - plenty of words, little logic. Typical when you do not know what you are talking about.
 28th August 2008, 04:58 AM #104 Grizzly Bear このマスクによっ     Join Date: May 2008 Posts: 5,690 Originally Posted by Heiwa Same method - plenty of words, little logic. Typical when you do not know what you are talking about. Dare I say you're having an irony moment? __________________ Graduation on 8/13/2011 8D
 28th August 2008, 05:13 AM #105 JihadJane Penultimate Satisfaction     Join Date: Jul 2008 Posts: 42,721 Originally Posted by leftysergeant Leaving the steel where in situ during the investigation was not an option that anyone with a room-temp or higher IQ would entertain. Stop bringing it up. Please give reasons why the WTC 7 debris pile could not have been forensically dismantled. Who, BTW, said it should have left in situ during the investigation? Quote: The steel was examined at Fresh Kills. Did you hear Astineh-Asl complaining that there should have been more than he saw? Correct me if I'm wrong but I think the steel was taken to scrap yards not Fresh Kills. Only a small portion of it was "examined".
 28th August 2008, 05:14 AM #106 boloboffin Guest   Join Date: Aug 2006 Location: Dallas, TX Posts: 5,001 Originally Posted by JihadJane No astrophysicist is arrogant enough to claim that they cannot be wrong. Well, the reason they might be wrong isn't because it's all a dark velvet cloth with holes poked through it.
 28th August 2008, 05:15 AM #107 Travis Misanthrope of the Mountains     Join Date: Mar 2007 Location: Tuolumne City, CA Posts: 17,941 Originally Posted by Heiwa Column 79 is assumed to fail first due to a local fire. Read the report. So you are saying you don't feel that the loss of lateral support when the girder connecting column 79 and 44 failed had anything to do with column 79's collapse? Quote: But the penthouse was also supported by other columns and they could not fail due to failure of columnn 79 (unless assisted of course). So what do you think caused the bent in the penthouses right above column 79 that preceded the collapse of the east penthouse? __________________ "Because WE ARE IGNORANT OF 911 FACTS, WE DEMAND PROOF" -- Douglas Herman on Rense.com Zingiber Officinale
 28th August 2008, 06:17 AM #108 Cuddles Decoy Moderator     Join Date: Jul 2006 Location: A magical land full of pink fluffy sheeps and bunnies Posts: 16,581 Originally Posted by Galileo there's no evidence that column # 79 failed. So the new construction on the WTC site has been slow because the columns from the old WTC are still standing? Don't you think it's just a little bit stupid to claim that a column didn't fail when it's rather obvious that the entire building, columns included, is no longer there? Originally Posted by Quad4_72 Explain to me the similarities of a high rise building and a table. "And that, my liege, is how we know the Earth to be banana-shaped." Sorry, seemed appropriate for some reason. __________________ I am not a little teapot.
 28th August 2008, 06:25 AM #109 Stellafane Village Idiot.     Join Date: Apr 2006 Location: Green Mountains Posts: 6,272 Originally Posted by JihadJane No astrophysicist is arrogant enough to claim that they cannot be wrong. Heh, then you're not familiar with Norman Lockyear or Allan Sandage. In any case, there's a huge difference between "I might be wrong" and "this is all based on infinite malleability and guesswork." __________________ Another Shameless Googlebomb Plug for www.stopsylvia.com
 28th August 2008, 10:21 AM #110 Hokulele Official Nemesis     Join Date: Feb 2007 Location: Trying to decide whether to set defenses against an army, or against mole rats. Posts: 27,268 Originally Posted by JihadJane No astrophysicist is arrogant enough to claim that they cannot be wrong. You haven't met very many astrophysicists, have you? (Grrr, Stellafane beat me to it.) __________________ Yvette: "Blasty! Blasty! Blasty!" Some person: "Why did you shoot that?" Yvette: "Blasty! Blasty! Blasty!" - Tragic Monkey
 28th August 2008, 10:53 AM #111 JihadJane Penultimate Satisfaction     Join Date: Jul 2008 Posts: 42,721 Originally Posted by Cuddles So the new construction on the WTC site has been slow because the columns from the old WTC are still standing? Don't you think it's just a little bit stupid to claim that a column didn't fail when it's rather obvious that the entire building, columns included, is no longer there? What kind of logic is this?
 28th August 2008, 11:24 AM #112 leftysergeant Penultimate Amazing     Join Date: Jul 2007 Location: Spanaway WA Posts: 18,613 Originally Posted by JihadJane Please give reasons why the WTC 7 debris pile could not have been forensically dismantled. Who, BTW, said it should have left in situ during the investigation? And where are you proposing that this examination should have taken place and when? In the immediate area of the collapse? I think not. Investigators knew where the steel was taken. There is no evidence that i have seen that anything was recycled without the investigators having a chance to look at it, aside from a small percentage that was stolen.
 28th August 2008, 11:28 AM #113 WildCat NWO Master Conspirator     Join Date: Mar 2003 Location: Albany Park, Chicago Posts: 49,019 Originally Posted by Mobyseven *facepalm* If I dropped a car, an actual size car, 3', then that car is not going to be a happy bunny. Indeed, dropping a car from three feet up is going to send you in for quite a few repairs. But the General Lee was always fine in the Dukes of Hazzard!
 28th August 2008, 12:14 PM #114 leftysergeant Penultimate Amazing     Join Date: Jul 2007 Location: Spanaway WA Posts: 18,613 Originally Posted by Heiwa Hm, do I say nothing can collapse? Where? No, I just say when a local failure occurs for any reason, you have to analyse the consequences of this local failure. You are looking at this with too narrow a view. When one floor slab fails due to expansion, it does stop pushing against the column due to expansion, there is still another floor slab pushing against it with no resistance. That is one of the problems with twoofers. They look at what they see and do not think about what they do not see.
 28th August 2008, 01:04 PM #115 cmcaulif Critical Thinker     Join Date: Jul 2007 Posts: 405 Originally Posted by Heiwa 3D-beam structures with say 60 vertical columns as primary parts carrying the loads to the base and with horizontal beams as secondary parts with loads on them connected to the columns at regular intervals do not collapse, if you remove one column. Try it yourself with a table with say 10 legs. Remove one leg and the table does not collapse. Try it with a table with only three legs and remove one leg. Nothing happens if you have secured the legs to the ground! Or try my famous model test at http://heiwaco.tripod.com/nist.htm (and scroll down a little). It is just 4 legs and all are supposed to fail, due to heat. But nothing happens. May we see your dimensional analysis which proves that your model is representative of the actual tower? Scale models of fires is difficult enough Dr. Quintiere actually advanced this field while at NIST, but scaling of structural strength is even more difficult. I'm interested in seeing how you manage it. Furthermore, to asses the progressive collapse potential of a structure, engineers do not rip a leg off the nearest table and declare their structure fit. One analytical method is the so called push down analysis, a dynamic energy based method in which a critical column is removed suddenly, resulting in a net acceleration. Elastic and plastic strain energy will then have to dissipate the resulting kinetic energy to prevent damage from propagating to other parts of the structure. If you are interested in more detail, I can provide a good reference. NIST chose to take a numerical approach, and since many truthers seem to have some unreasonable disdain for finite element, I'll just remind you that FEA is just an approximate method for solving differential equations. In the case of LS-DYNA, a program for dynamic analysis with explicit time integration, its solving DE's using a central difference scheme. Bottom line, NIST has provided an approximate, although accurate solution to an extremely complex physical problem. Pulling legs off tables without any thought of scale or physics won't do.
 28th August 2008, 02:53 PM #116 DGM #4     Join Date: May 2007 Location: West of Northshore MA Posts: 14,324 Originally Posted by Newtons Bit Try reading. People that argue that we can build buildings that can withstand anything that nature (or anything else) could throw at it have no clue as to the economics of building it in the first place. I agree with you that NIST's recommendations (the newest) are good on paper but who will pay the price? Have you written a response (forgive me if I missed it)? PM me a link if you have. Thanks. __________________ Join the team, Show us what your machine can do (or just contribute to a good cause)Join the JREF Folders ! Team 13232 "Remember that the goal of conspiracy rhetoric is to bog down the discussion, not to make progress toward a solution" Jay Windley
 28th August 2008, 03:25 PM #117 dudalb Penultimate Amazing     Join Date: Aug 2007 Posts: 22,814 Jihad Jane pretty much showed where she is coming from with this little statement in another thread: Quote: In my opinion political literacy is far more important to understanding 911 than scientific literacy. My jaw just fell open at that foolishness. Just a fancy way of saying "My Mind Is Made Up, Don't Confuse Me With Facts". Last edited by dudalb; 28th August 2008 at 03:26 PM.
 28th August 2008, 04:38 PM #118 Stellafane Village Idiot.     Join Date: Apr 2006 Location: Green Mountains Posts: 6,272 Originally Posted by dudalb Jihad Jane pretty much showed where she is coming from with this little statement in another thread: Quote: In my opinion political literacy is far more important to understanding 911 than scientific literacy. My jaw just fell open at that foolishness. Just a fancy way of saying "My Mind Is Made Up, Don't Confuse Me With Facts". "In my opinion political literacy is far more important to understanding 911 than scientific literacy." That quote could serve perfectly as the rallying cry of the Truther Movement -- and ultimately, its epitaph as well. __________________ Another Shameless Googlebomb Plug for www.stopsylvia.com
 28th August 2008, 10:57 PM #119 Heiwa Banned   Join Date: Jul 2007 Posts: 3,149 Originally Posted by cmcaulif May we see your dimensional analysis which proves that your model is representative of the actual tower? Scale models of fires is difficult enough Dr. Quintiere actually advanced this field while at NIST, but scaling of structural strength is even more difficult. I'm interested in seeing how you manage it. Furthermore, to asses the progressive collapse potential of a structure, engineers do not rip a leg off the nearest table and declare their structure fit. One analytical method is the so called push down analysis, a dynamic energy based method in which a critical column is removed suddenly, resulting in a net acceleration. Elastic and plastic strain energy will then have to dissipate the resulting kinetic energy to prevent damage from propagating to other parts of the structure. If you are interested in more detail, I can provide a good reference. NIST chose to take a numerical approach, and since many truthers seem to have some unreasonable disdain for finite element, I'll just remind you that FEA is just an approximate method for solving differential equations. In the case of LS-DYNA, a program for dynamic analysis with explicit time integration, its solving DE's using a central difference scheme. Bottom line, NIST has provided an approximate, although accurate solution to an extremely complex physical problem. Pulling legs off tables without any thought of scale or physics won't do. FEA or simple 3-D beam analysis is an excellent tool when designing and analysing structures. What is lacking in the NIST report is an analysis of the intact structure before any failures and the static and dynamic design loads used in the design. Then we would know the forces, moments and stresses in all primary (columns) and secondary (beams) parts and thus get a feeling of the whole structure (and the weakest links/parts). I assume the FoS were >3, i.e. the static (+ dynamic) stresses were less than 1/3 of the permissible stresses in all parts and connections. The beauty with such a model is that it is simple to simulate failures and to see what happens, i.e. to find out the redundancy, e.g. to remove (complete failure) one complete column and disconnect the attached beams and allow the attached beams just to be attached at their other ends. The (remaining) load on the beam is then only transmitted to the intact, adjacent column. A complete new situation/structure has developed. What happens then? You will then find - by analysing this model - that adjacent intact columns will not be overloaded and collapse. It is basic. Evidently you remove one supporting beam of an adjacent column but as there are still three other beams at each level, there is enough support, the stress in the adjacent column will increase a little but due to initial FoS the stress is still below permissible values (redundancy). Or simply - each column (primary structure) is quite independent of adjacent columns and the failure of one column and removal of beams attached to it cannot produce a progressive, global collapse. NIST has made big noise about thermal expansion as a contributing factor but it is all nonsense. It is easy to check thermal expansion with an intact model, e.g. just allow the sun to shine (heat) on one side with the other in the shade. Evidently the structure will deform like a banana but the stresses remain the same. You can do the same with internal parts at various floors to simulate a fire.
 28th August 2008, 11:13 PM #120 Heiwa Banned   Join Date: Jul 2007 Posts: 3,149 Originally Posted by leftysergeant You are looking at this with too narrow a view. When one floor slab fails due to expansion, it does stop pushing against the column due to expansion, there is still another floor slab pushing against it with no resistance. That is one of the problems with twoofers. They look at what they see and do not think about what they do not see. You don't know anything about structural analysis, do you? A horizontal beam (secondary structure) is not pushing against a column (primary structure). The load on the beam is simply transmitted as shear to the column via the connection beam/column and produces compression of the column. Remove the beam and no load at all is transmitted to the column. Thermal expansion do not cause progressive collapse of complete structures! If that were the case, the easiest way to demolish a steel structure would be to arrange fires around some primary parts (columns) and then just wait for thermal expansion to do the job. However, it does not work! Try my simple model test at http://heiwaco.tripod.com/nist.htm . I find it interesting to note how the American public ignores basic facts of structures, fires, redundancy, etc, or just does not want to hear about it and accepts the crude propaganda of NIST & Co that the WTC demolitions were natural consequences of fires, etc.

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