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Post by twinstead on Aug 1, 2007 8:04:11 GMT -4
From what I have read, there was no way a building that tall, built like the WTC, could have collapsed in any way other than symmetrical, no matter if the damage and fires were symmetrical or not.
I'm no expert but I've had experts explain to me why the buildings didn't 'topple over' and it sounds quite reasonable. Perhaps it's not, as you are fond of saying for things that are certainly possible and if true would contradict your theory, 'proven', but it certainly made sense to me.
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Post by gillianren on Aug 1, 2007 14:04:57 GMT -4
Has anyone ever heard of a symmetrical fire?
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Post by nomuse on Aug 1, 2007 16:44:12 GMT -4
Basic square-cube stuff, really. A small enough building can fall over. When you get into the skyscraper range, though, the individual strength of structural members or even a whole (single) floor is so much smaller in relation to the total potential load. The aggregate strength is still sufficient to hold up the building under normal conditions, but under abnormal conditions the presence or lack of any single structural member is simply inconsequential to the shape of the final collapse.
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Post by turbonium on Aug 2, 2007 3:25:46 GMT -4
Basic square-cube stuff, really. A small enough building can fall over. When you get into the skyscraper range, though, the individual strength of structural members or even a whole (single) floor is so much smaller in relation to the total potential load. The aggregate strength is still sufficient to hold up the building under normal conditions, but under abnormal conditions the presence or lack of any single structural member is simply inconsequential to the shape of the final collapse. That's an interesting theory you've got there. The smaller the structure, the greater its likelihood of toppling over. Toddlers are first fooled, by playing with building blocks. Even moreso as they grow up, when they have Legos, Lincoln Logs, and Meccano sets. They eventually come to believe that the higher they build something, the more likely it will topple! I must admit, I believed that to be true. Thanks for the reality check!
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Post by nomuse on Aug 2, 2007 4:27:14 GMT -4
Exactly so. The smaller the structure, the better the ratio between strength (aka the square of the supporting members) and the mass (the cube of the dimensions; aka the volume). Which is why a toddler can crawl away from a fall that would severely injure a 200 lb man. Or as was once poetically put; "for a fall of the same given distance a cat breaks a leg, a man dies, and a cow splatters."
Pick up one of those wooden blocks by the corner. That's easy. Now pick up a wood-framed house by the corner.
Better example (lets use solid forms here); pick up a pencil and hold it horizontally, holding near one end. Notice how it does not bend. Now pick up a California redwood and hold it the same way. Oops! Poor redwood bent then snapped.
Children's blocks and toddlers can be quite informative if you know how to look at them.
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Post by gwiz on Aug 2, 2007 5:07:31 GMT -4
Okay, so why did the buildings collapse the way they did? In a nutshell, a 767 hit each WTC 1 and 2 at about 500 mph. The shock loading knocks off the cladding of the steel supports. You've left out a big factor: the impact causes major damage to the steel structure. According to the Purdue University simulation, about a quarter of the core columns would have been cut in the impact.
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Post by turbonium on Aug 3, 2007 2:18:07 GMT -4
You've left out a big factor: the impact causes major damage to the steel structure. According to the Purdue University simulation, about a quarter of the core columns would have been cut in the impact. The results of a project funded by the government (NSF) which..believe it or not.... supports the government's official claim for what caused the collapses!! What a shocker that is! Here's their diagram of the 95th floor of WTC 1... "Core columns estimated to be heavily damaged or destroyed in numerical simulation"19 core columns heavily damaged or destroyed!! Oh, sure. That's perfectly reasonable! Apparently, not only can two 767 engines cut straight through 6 steel core columns each, but so can a thin-shelled aluminum fuselage!! That's after having first impacted the perimeter steel columns, then burrowing about 60 feet through at least two floors - each one with a 4" thick concrete slab and 1.5" thick corrugated steel decking - before it reached the core columns. Santiago Pujol, an assistant professor of civil engineering, worked with the researchers to develop experimental data to test the accuracy of the simulation by using an "impact simulator" to shoot 8-ounce beverage cans at high velocity at steel and concrete targets at Purdue's Bowen Laboratory. These data enabled the researchers to fine tune and validate the theoretical model for the simulation.
"We created a mathematical model of the beverage can and its fluid contents the same way we modeled the airplane, and then we tested our assumptions used to formulate the model by comparing the output from the model with that from the experiment," Sozen said.www.purdue.edu/UNS/html4ever/2006/060911.Sozen.WTC.htmlThey tested the accuracy of the simulations by hurling cans of Coke at steel and concrete targets! Now, why nobody else came up with a "pop-can" validation test before this, is beyond me. Pure genius! It really helps explain how they got their results.
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Post by nomuse on Aug 3, 2007 2:58:51 GMT -4
At least you are consistent. You misread what that coke can was doing in exactly the same way you misread what the sampled temperatures was doing. Have you ever done a mathematical model of anything? Have you ever tested the output of that model or the assumptions of that model? Heck...have you ever measured the same thing twice with different methods? I'm beginning to think you don't even touch the tips of an ohmeter together before you check suspect components for continuity.
The weakness is not in "testing" the model with a coke can, the weakness would be if the model was inadequately scaleable. Or it might be more precise to say, if the scaleability of the applicable factors was properly accounted for when testing the predictive power of the model with a coke can.
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Post by turbonium on Aug 3, 2007 4:24:49 GMT -4
At least you are consistent. You misread what that coke can was doing in exactly the same way you misread what the sampled temperatures was doing. Have you ever done a mathematical model of anything? Have you ever tested the output of that model or the assumptions of that model? Heck...have you ever measured the same thing twice with different methods? I'm beginning to think you don't even touch the tips of an ohmeter together before you check suspect components for continuity. Take a deep breath and relax. Emotions can often block rational thinking, as exhibited in the above paragraph. The weakness is not in "testing" the model with a coke can, the weakness would be if the model was inadequately scaleable. Or it might be more precise to say, if the scaleability of the applicable factors was properly accounted for when testing the predictive power of the model with a coke can. What they said was... ..develop experimental data to test the accuracy of the simulation by using an "impact simulator" to shoot 8-ounce beverage cans at high velocity at steel and concrete targets at Purdue's Bowen Laboratory. These data enabled the researchers to fine tune and validate the theoretical model for the simulation.The "impact simulator" - hurling cans of Coke at steel and concrete targets. They developed data using the "impact simulator". That is, they developed data by hurling Coke cans at steel and concrete targets. This data was used to test the accuracy - that is, to validate - the WTC 1 simulation model. Now, I simply said this... "They tested the accuracy of the simulations by hurling cans of Coke at steel and concrete targets!" Makes sense now? There are several problems with using the "impact simulator" data Determining whether or not it's scaleable to the WTC model is one issue, but it's hardly the only issue. Now, do I really have to list all the other problems in using a Coke can to represent a 767?
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Post by nomuse on Aug 3, 2007 4:53:11 GMT -4
Perhaps I am speaking too quickly. I am not sure how I can speak slowly enough to make this point, however. What I assume is implied by the phrase "the simulation" is a robust mathematical model that is complex enough to allow simulation of more than one specific kind of incident. Which is to say, it is a method that should give a set of numbers. Flying a plane into a building was not an economical test to see if those numbers came close to observed reality. Apparently a coke can could fall within the limits of what the simulation could calculate.
Would you be less aghast if they checked the predictive ability of the model against real-world observation of something much less like the WTC impacts? Perhaps, testing to see if the model accurately predicts what happens if you drop a claw-foot bathtub four stories onto the roof of a late-model Pinto?
The map is not the territory here. The coke can is NOT a model of the WTC. It is something that can be modeled within the same set of mathematical abstractions (or at least, so they are claiming with this test). It's accuracy at validation is limited by how many factors it shares in common, and by any errors (scaleability and other) that may be masked by the level of accuracy possible within the coke can experiment.
But I suppose you will continue to characterize this as assuming that there is no physics-based mathematical model at all, and the entire behavior of the model is just multiplying quantities as appropriate off of the measured performance of a coke can.
All I can say is, if I built and tested the things I do this way, I'd have a lot more failures to deal with. So if I can do it right, why can't they?
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Post by gwiz on Aug 3, 2007 9:05:32 GMT -4
Apparently, not only can two 767 engines cut straight through 6 steel core columns each, but so can a thin-shelled aluminum fuselage!! And why is that unreasonable? You appear to be saying that in a collision between two objects of unequal density, the denser object would come out unscathed. Two counter examples: after every tornado, there are pictures of flimsy things like straws that have pierced solid wood; the blast wave from a bomb is just air, very low density, so you are saying that bombs are harmless.
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Post by wharris on Aug 3, 2007 9:11:18 GMT -4
Apparently, not only can two 767 engines cut straight through 6 steel core columns each, but so can a thin-shelled aluminum fuselage!! Sure, when the "thin-shelled aluminum fuselage" is moving at 500+ mph. Remember, about fout years ago some people were saying it was ridiculous to think that a chunk of foam could damage a space shuttle wing.
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Post by phunk on Aug 3, 2007 10:37:56 GMT -4
The plane doesn't need to cut through those thick columns anyway. Those columns are made of shorter sections attatched end to end, it mearly had to break the connections and push the columns out of alignment to effectively cut them.
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Post by nomuse on Aug 3, 2007 16:32:30 GMT -4
Surprised no-one has mentioned the I-35 bridge failed symmetrically and fell into its footprint. Funny how all the supports went simultaneously, isn't it? What? Isn't that required for a total and "symmetrical" (whatever that means) collapse?
Of course the CT crowd is already going on about demolitions. Apparently I-35 was demolished by the union to create a new construction contract....
Demolitions were also mentioned with the recent overpass collapse in my area, too. I've heard the conspiracy believers go as far as to claim it was demolished in order to prop up the WTC fantasy that fires can weaken steel (funniest post on that collapse; "A fighter plane disguised as a freeway overpass attacked the tanker....")
But then, what can we expect with Pacific Gas and Electric mining the entire area? Or hadn't anyone noticed that when a conductive silty coating left by light rains on top of an unusual amount of dust led to several transformers shorting, that the eyewitness report was invariably "It sounded like a bomb!"
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Post by PhantomWolf on Aug 5, 2007 21:11:11 GMT -4
I'm probably nuts, but I'm going to directly address Turbonuim because I am sure that he isn't as stupid as he is determinely trying to appear.
Turbonuim. If I create a program that is designed to predict the actions of a storm waves on costal erosion using formulas based on methods such as fluid mechanics and particle cohesion. Is running a test based on a wave washing over a sand castle a good validation experiment for the program? Why, or why not?
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