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Dave W.
Info Junkie
USA
26020 Posts |
 Posted - 10/02/2006 : 10:40:44 [Permalink]
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quote:
Originally posted by ergo123
...(that's "scientist talk" for weight)...
How snotty can you get?quote:
Also (for Valiant Dancer), the report I referenced did NOT ignore the weight of the floors above the crash zone. The whole point of the article was to show that the mass (that's "scientist talk" for weight) of the floors in the upper block above the crash zone did not posess enough kinetic energy, even if free-falling, to create a sustained collapse of the towers.
And the report that Val linked to says that Ross' analysis is totally inappropriate for the design of the WTC. Eagar and Musso describe a failure mode which doesn't depend upon the buckling of supporting beams, only the failure of the floor joists attachments. With the ability to support 1,300 t, more than 70% of the mass of each tower would have to be in the structure itself if gently placing the mass of one floor onto another would not collapse it. For instance, if 80% of the mass of the building were in its structure, then each floor would mass approximately 909 t, requiring two floors' worth of mass to be gently placed (not crashing from a height of 3.7 meters) on a third floor to cause its joists to fail. No kinetic energy calculations need be discussed for the further collapse, since if two floors can cause the failure of a third without the two falling, then three floors falling from 3.7 meters will definitely cause a fourth to fall, etc. And all that needs to occur to get the ball rolling is the deformation of the outside beams by enough to make the joist clips fail. No beams need to actually buckle to start this snowball effect.quote:
Further your comment about no one suspecting anyone would deliberately crash planes into the buildings is probably TECHNICALLY correct, but it is contrary to the fact that the building were designed to withstand several direct impacts from commercial airliners--although the designers probably figured it would happen by accident.
"Several?" Where does that word come from? Last I heard, they'd been designed to survive the crash of a single 727, each. |
- Dave W. (Private Msg, EMail)
Evidently, I rock!
Why not question something for a change?
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chaloobi
SFN Regular
1620 Posts |
Posted - 10/02/2006 : 11:35:33 [Permalink]
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On a tangential note.... I give no stock to conspiracy theories about 9/11. But when I saw those buildings collapse, I thought the deaths would be in the 10s of thousands. Yet, less than 3k died, total, in the entire event. Is the number of dead unusually low, or is it right on? Some factors:
A. The time of day -- assuming people start work at 9:00am, only the work-aholics were in their offices.... was the tourist deck not yet open..?
B. Evacuation of the second tower.... I read somewhere that the evacuation order for the second (south) tower was recinded and people were told it was OK to go back to their desks. Not so good. 600 people were caught above the second impact who might have been saved. But that's half the number above the impact in the North tower. On a side note, who the heck would stay at work in the South Tower with the North burning like that?!?!?! I'd have been LONG gone!
C. The height at which it hit. Upper stories less populated? Pay more rent for the view, etc.... Not sure. Wiki didn't say what floors the planes hit on but from the pics, it looks pretty high for the North tower, less so for the South.
Anyway - not sure what the point is, here. LOL. I don't believe there was a conspiracy involved. I AM surprised so few died in NY. But I'm completely ignorant as to how many resided in those offices... so whatever.
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-Chaloobi
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| Edited by - chaloobi on 10/02/2006 11:36:52 |
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Valiant Dancer
Forum Goalie
USA
4826 Posts |
Posted - 10/02/2006 : 11:59:09 [Permalink]
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quote:
Originally posted by ergo123
Also (for Valiant Dancer), the report I referenced did NOT ignore the weight of the floors above the crash zone. The whole point of the article was to show that the mass (that's "scientist talk" for weight) of the floors in the upper block above the crash zone did not posess enough kinetic energy, even if free-falling, to create a sustained collapse of the towers.
Further your comment about no one suspecting anyone would deliberately crash planes into the buildings is probably TECHNICALLY correct, but it is contrary to the fact that the building were designed to withstand several direct impacts from commercial airliners--although the designers probably figured it would happen by accident. But keep in mind that the dynamics of an accidental crash and a deliberate crash follow the same laws of physics.
And if WTC 7 fell due to fire, why have no other steel & concrete building ever before or since fell due to fire--even ones that burned much hotter for much longer?
Well, because the other steel buildings probably referenced by your sources (in somewhat bigbrainish style) were largely empty, did not have a structure compromised by debris strikes, and had fire departments actively trying to extinguish the blaze. WTC 7 had none of these advantages.
Again, the impacts were significant because they
1) severed firefighting apparatus
2) weakened the structure somewhat
3) started a raging fire
Had it been one airplane by accident it may have survived. Multiple strikes, that's a little suspicious. No building is designed to take multiple heavy aircraft strikes. As Dave mentioned, one 727 strike each. And, indeed, the towers withstood the strikes. |
Cthulhu/Asmodeus when you're tired of voting for the lesser of two evils
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ergo123
BANNED
USA
810 Posts |
Posted - 10/02/2006 : 12:28:47 [Permalink]
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DaveW: Of course, before they start falling, the upper floors have no kenetic energy (by definition). They have only potential energy. The potential energy converts to kenitic energy once the mass begins to move due to gravity--and increases due to the force of gravity through its supposed free-fall into the first impacted floor. What pre-movement kinetic energy are you talking about?
And what coupon are you talking about? Is it the "You get to disregard the laws of physics for 3 10 second periods on 9/11/01" coupon?
Regarding the dust: If the dust is not acting as downward-acting mass, and all the contents of the floors and everything on the floors was essentially pulverized to dust (as reported by clean-up workers) what mass was left to hit floors bemeath the dust? In other words, if all the energy in the system goes into pulverizing the concrete and other materials, what is left to knock the next floor downward? You can only "spend" energy once. And what Ross shows is that EVEN IF YOU SPEND ZERO ENERGY PULVERIZING MATERIALS, the mass of the moving block of floors above the crash zone DOES NOT HAVE ENOUGH ENERGY TO COLLAPSE THE FIRST IMPACTED FLOOR. What part of that do you not understand?
First of all, the plane was on the first impacted floor--not in the block of floors ABOVE the crash zone. So, if anything, the plane would act as an energy absorber. Ross does not take this into account, but this omission helps the energy audit in favor of collapse. Also, since fire generally burns what is above sooner than what is below (again, physics at work), the mass of the upper floors would be reduced. Ross ignores this as well--again favoring the condition of collapse. And yet, with all these collapse-favoring elements being ignored, the block of upper floors STILL does not have enough energy to collapse the first impacted floor. It's looking more and more like you can't even afford the hamburger bun!
And it's the dust itself that is shot upwards. And that uses up energy. Ross' comment on the concrete is an aside, Dave. He figures 0% pulverized in his calculations--which favors the collapse scenario. SO he shows that without accounting for ANY concrete being pulverized, which would give a collapse it best shot at happening, there STILL isn't enough energy to collapse the first impacted floor. And if ANY of the concrete WAS pulverized, (which of couse it was) then there would be even LESS energy available to collapse that first floor. And A < B, and D is >=0, then A - D < B. Or, if you don't have enough money for a burger, and you spend some of it, you still don't have enough for a burger.
And you support my point by mentioning that we never see steel and concrete buildings pancake. The only way we see steel and concrete building fall as they did on 9/11/01 is when we see a controlled demolition.
I've read Ross' paper several times. But if you ignored what it said, no wonder you are confused.
Dave, you really need to re-read Rosses paper. All the things you list that Ross ignores he states as such. He ignores all those things because if while ignoring them he can show the upper block has too little energy to collapse the first impacted floor below the crash zone, then he doesn't have to worry about calculating the energy expenditures on those ignored elements--as they will only lessen the available energy being imparted on the first impacted floor. Er, you do realize we are talking about the first floor impacted by the upper block of floors and NOT the first floor impacted by the plane, right?!
Dr. Mabuse: Yes and no. The elasticity of the concrete is NOT taken into account, but the elasticity of the steel support beams is. And that is exactly Ross' point. Ross shows that the steel supports absorb enough of the kenitic energy as to halt the collapse--given the mass of the floors above. And he accounts for only the elacticity of the bottom floors--but acknowledges that there would be elacticity in the upper floors as well since they would no longer be responding to the upward force of the beams below the crash zone.
Of course, concrete DOES have elasticity, too. But ignoring it only works in favor of the collapse condition. Many scientists point out that there would not be enough energy to both pulverize AND collapse the towers. Pulverization takes a lot of energy and converts the mass of what is pulverized into a form that no longer falls at "free-fall" speed in our atmosphere (i.e., it tends to take longer to fall than the surrounding big chunks (due to a reduced ratio of mass-to-surface area). It's like taking a Newton's Cradle and putting a band-aid on one of the balls so that the pad is between two of the balls. Doing so keeps the cradle from working so well. |
No witty quotes. I think for myself. |
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Dave W.
Info Junkie
USA
26020 Posts |
Posted - 10/02/2006 : 12:31:54 [Permalink]
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quote:
Originally posted by ergo123
Interesting how the 9/11 commission report doesn't even mention building 7...
Page 284:The OEM's headquarters was located at 7 WTC. Page 293:By 8:48, officials in OEM headquarters on the 23rd floor of 7 WTC-just to the north of the North Tower-began to activate the Emergency Operations Center by calling such agencies as the FDNY, NYPD, Department of Health, and the Greater Hospital Association and instructing them to send their designated representatives to the OEM. Page 302:At about 9:57, an EMS paramedic approached the FDNY Chief of Department and advised that an engineer in front of 7 WTC had just remarked that the Twin Towers in fact were in imminent danger of a total collapse. Page 305:After the South Tower was hit, OEM senior leadership decided to remain in its "bunker" and continue conducting operations, even though all civilians had been evacuated from 7 WTC. At approximately 9:30, a senior OEM official ordered the evacuation of the facility, after a Secret Service agent in 7 WTC advised him that additional commercial planes were not accounted for. Actually, I don't see any discussion of the physics of the collapse of any WTC building in the 9/11 Commission Report, perhaps because the Commission's mandate didn't actually include reporting on the physics of the destruction. So when you chided Dude,quote:
"Dude," did you even read the pop mech article? It doesn't discuss momentum transfer or any laws of physics. It just parrots the administration's explanation. It basically says that what the 9/11 Commission Report says is true because they read it in the 9/11 Commission Report!
So I fail to see how the Popular Mechanics could possibly be saying "that what the 9/11 Commission Report says is true because they read it in the 9/11 Commission Report!" Now, had you said that they were parroting "a major study... by the National Institute of Standards and Technology (NIST)," then yeah, they say they got their info from a NIST spokesman.
And wow, I'd never seen this photo before, which clearly shows gouts of dust bursting from the building a few floors below the zone of failure for the outside structural steel itself. What better way to see that Ross' analysis is simply wrong? |
- Dave W. (Private Msg, EMail)
Evidently, I rock!
Why not question something for a change?
Visit Dave's Psoriasis Info, too. |
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ergo123
BANNED
USA
810 Posts |
Posted - 10/02/2006 : 12:53:58 [Permalink]
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DaveW: Explain to me how the upper block of floors managed to shrink so as to fit within the footprint of the first impacted floor--and don't forget that each floor was like a square donought held up by joist attachments along the outer ring of 240 supports and along the "hole" with an additional 47 attachments. I'll wait... As for mentions of WTC 7--I had meant there were no mentions of it COLLAPSING. And that picture is awesome--and proves Ross' point. I think you just don't understand Ross' point. In a nutshell, Ross is saying that there was not enough energy in the upper floors to cause a sustained collapse of the WTC buildings. GIVEN THAT THEY DID INDEED COLLAPSE, additional energy MUST HAVE BEEN ADDED to the system. The only additional enery delivery system (barring god pushing it down with his thumb) that accounts for the observable physical evidence is that of a controlled demolition.
Chaloobi: Even the government says it was a conspiricy. Do you think it was all just an accident?
Valiant Dancer: What about WTC 3, 4, 5 & 6? There were all struck by debris and had fires. So did buildings across the street from WTC 1 & 2. The only buildings that collapsed were ones owned by Silverstein (WTC 1, 2 & 7). And why would it have mattered (in your mind) whether the plane hit by accident or on purpose?!
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No witty quotes. I think for myself. |
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Dave W.
Info Junkie
USA
26020 Posts |
Posted - 10/02/2006 : 12:57:21 [Permalink]
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quote:
Originally posted by ergo123
Regarding the dust: If the dust is not acting as downward-acting mass, and all the contents of the floors and everything on the floors was essentially pulverized to dust (as reported by clean-up workers) what mass was left to hit floors bemeath the dust? In other words, if all the energy in the system goes into pulverizing the concrete and other materials, what is left to knock the next floor downward?
You are implying that all of the concrete in the buildings was completely pulverized, in which case I've got to ask you what you think the clean-up crews spent a lot of time landfilling? I find your reliance on the idea that 100% of the concrete was pulverized to be ludicrous.quote:
You can only "spend" energy once. And what Ross shows is that EVEN IF YOU SPEND ZERO ENERGY PULVERIZING MATERIALS, the mass of the moving block of floors above the crash zone DOES NOT HAVE ENOUGH ENERGY TO COLLAPSE THE FIRST IMPACTED FLOOR. What part of that do you not understand?
The part where he counts the same energy twice, and the part where he assumes that buckling columns would be required for a floor to collapse.quote:
And it's the dust itself that is shot upwards.
Where? Where can I see dust being "shot upwards?"quote:
He figures 0% pulverized in his calculations...
Then why did he include 304 MJ for pulverizing concrete on both the impacting and impacted floors? What report are you reading?quote:
And you support my point by mentioning that we never see steel and concrete buildings pancake.
I never mentioned any such thing. Now you're just making stuff up!quote:
Dave, you really need to re-read Rosses paper.
I think you need to read something other than Ross' paper, like maybe something about how the buildings were actually put together. Ross assumes that floor collapse will only occur if the supporting columns buckle. That isn't a valid assumption. |
- Dave W. (Private Msg, EMail)
Evidently, I rock!
Why not question something for a change?
Visit Dave's Psoriasis Info, too. |
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chaloobi
SFN Regular
1620 Posts |
Posted - 10/02/2006 : 13:15:53 [Permalink]
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quote:
Originally posted by ergo123
<snip>
Chaloobi: Even the government says it was a conspiricy. Do you think it was all just an accident?
<snip>
Cute. You know exactly what I meant. |
-Chaloobi
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chaloobi
SFN Regular
1620 Posts |
Posted - 10/02/2006 : 13:19:14 [Permalink]
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quote:
Originally posted by Dave W.
<snip>And wow, I'd never seen this photo before, <snip>
Wow is right. Took a lot of balls to get that pic. I wonder if the photographer made it.... |
-Chaloobi
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Dave W.
Info Junkie
USA
26020 Posts |
Posted - 10/02/2006 : 13:29:44 [Permalink]
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quote:
Originally posted by ergo123
DaveW: Explain to me how the upper block of floors managed to shrink so as to fit within the footprint of the first impacted floor...
Why in the world would you think that it did? In other words, why should I explain something that didn't happen?quote:
As for mentions of WTC 7--I had meant there were no mentions of it COLLAPSING.
The 9/11 Commission Report was about terrorism and the emergency response to it. The report mentions that 7 WTC was evacuated. It mentions the collapse of the twin towers because they were not completely evacuated, and why.quote:
And that picture is awesome--and proves Ross' point.
I don't see how it can do so when the internal structure of the building is invisible, and Ross' point depends on the columns supporting each and every floor to individually buckle.quote:
I think you just don't understand Ross' point. In a nutshell, Ross is saying that there was not enough energy in the upper floors to cause a sustained collapse of the WTC buildings.
Ross' conclusion is based upon the mistaken idea that the outer columns have to buckle between each floor prior to floor collapse.quote:
GIVEN THAT THEY DID INDEED COLLAPSE, additional energy MUST HAVE BEEN ADDED to the system.
Only if you ignore how the building was built.quote:
The only additional enery delivery system (barring god pushing it down with his thumb) that accounts for the observable physical evidence is that of a controlled demolition.
Or a building in which the floors are hung from the supporting columns, rather than being pushed up by them.quote:
Valiant Dancer: What about WTC 3, 4, 5 & 6? There were all struck by debris and had fires. So did buildings across the street from WTC 1 & 2. The only buildings that collapsed were ones owned by Silverstein (WTC 1, 2 & 7).
Because 1, 2 and 7 were the largest of the bunch? 3 WTC was a 22-story hotel which the South Tower partially fell on; 4 WTC was a 9-story building; 5 WTC was another 9-story building which suffered a partial collapse; 6 WTC was only 7 stories. |
- Dave W. (Private Msg, EMail)
Evidently, I rock!
Why not question something for a change?
Visit Dave's Psoriasis Info, too. |
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ergo123
BANNED
USA
810 Posts |
Posted - 10/02/2006 : 13:49:57 [Permalink]
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DaveW: What % of the concrete and other materials were pulverized? And Ross doesn't count any energy twice. He doesn't even account for the buckling of the beams--which again works in favor of collapse; yet his calculations show that even ignoring this energy absorber, the first impacted floor would not collapse. FOr a photo of dust being shot upwards, look at the photo link you added to one of your posts. He only adds in the energy to pulverize concrete that Greening adds. It is Greening that assumes (although he doesn't state the basis for this assumption) that only 10% of the concrete was pulverised on the impacting and the impacted floor. You see, Greenings paper shows that the buildings will collapse--but Greening assumes floors floating in mid air. Ross uses all of Greenings assumptions except the part about the floors floating in mid air, and adds in the porpagation of force into the equation (which Greening does not include as his floating assumption has no mechanism through which to propagate force) and shows that the buildings would not collapse. And I'm still waiting to hear how the upper floors shrink to fit within the donought-shaped footprint to cause a failure of only the joist attachments... Oh, and while you are at it, explain to me how once the upper section had shrunk and impacted only the floor joist attachments it managed to snap each of the 287 steel box columns into 30-foot sections at the same time... In the end Dave, it doesn't matter how the towers were built. You just can't have ALL the physical evidence you had after the collapse as the result of a gravity-only collapse.
Chaloobi: But even what you meant made little, if any sense. I think it is easier to believe the US government pulled this off than it is to believe 19 guys who were on several intelligence agency watch lists, who we have no evidence were even on the planes pulled it off. But I guess it it is too frightening to think that the US government did it, it is more calming to think the impossible happened. The mind has been known to play bigger tricks... |
No witty quotes. I think for myself. |
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chaloobi
SFN Regular
1620 Posts |
Posted - 10/02/2006 : 14:07:54 [Permalink]
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quote:
Originally posted by ergo123
<snip>Chaloobi: But even what you meant made little, if any sense. I think it is easier to believe the US government pulled this off than it is to believe 19 guys who were on several intelligence agency watch lists, who we have no evidence were even on the planes pulled it off. But I guess it it is too frightening to think that the US government did it, it is more calming to think the impossible happened. The mind has been known to play bigger tricks...
Perhaps you failed to read my posts fully. All I said is that I didn't believe there was a [US Government] conspiracy to blow up the WTC. And then I wrote a bunch about how I initially thought it was odd so few died. So in the context of your fantasy, what is it that makes no sense? My simple statement of belief?
So, believing the US government somehow secretly planned and staged the entire 9/11 terrorist attack, willfully murdering 3k of it's own citizens, making it look like Mideast terrorists did it, and being able to keep the truth entirely secret throughout the planning and execution, outside of a few complaints by supposed demolition experts, does make sense?  |
-Chaloobi
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trogdor
Skeptic Friend
198 Posts |
Posted - 10/02/2006 : 14:19:49 [Permalink]
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Wow. Time for a confession.
I started all of this. I had been debating Ergo for a week or so, but the whole "being a senior in high school" thing caught up with me. So I sent him here. He, like all of us, uses stronger language to strangers than to people he knows, so I did not expect anything like the "that's scientist talk for weight" comment. Then again, you guys handled HYBRED, so I trust you can take Egro.
Only one thing, Ergo, you have mentioned this a couple times without actually pointing out the source. Look at that carefully. Figure out how much explosives would have been needed to demolish those buildings using Hoffman's calculations. And when you realize that it would have taken nearly 30 Hiroshima's of explosives, you might see that his calculations may be a little off. And you may see why I always asked for the sources for your claims.
Your friend,
Trogdor
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all eyes were on Ford Prefect. some of them were on stalks.
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| Edited by - trogdor on 10/02/2006 14:22:18 |
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ergo123
BANNED
USA
810 Posts |
Posted - 10/02/2006 : 14:21:50 [Permalink]
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Okay Dave... If it didn't happen, then how can it account for the collapse of the building?!? Your contention is that the first impacted floor was knocked off of its floor joist attachments (as suggested by VD's linked article). Well the floor joist attachments were on the inside of the outer walls of the building and the outside of the inner walls. To impact only the floor joist attachments, you would have to shrink the perimiter of the outer walls of the building while increasing the perimiter of "hole" in the center of the building. Otherwise, the top floors just sit on the supports of the building (which is why it didn't collapse while they were building it!). An example: Let's say you have a pipe that is 2" in exterior diameter with a 1/2" wall (that makes for a 1" hole down the axis of the pipe. The pipe is clogged with gum. How do get the gum out if the only thing you are allowed to use is another piece of pipe that is 2" in exterior diameter with a 1/2" wall? The answer--you can't. To get out the gum you need a tool that is less than 1" in exterior diameter, or you won't be able to get it INSIDE the tube to hit the gum.
And why do you think the commission was not allowed to examine WHY the buildings fell?
Ross points out that the supports WOULD have to buckle--but he does not include that in his energy audit. His energy audit shows the first impacted floor would not collapse EVEN WHEN IGNORING THE FACT THAT THE SUPPORTS WOULD HAVE TO BUCKLE AND THAT THAT WOULD ABSORB EVEN MORE ENERGY FURTHER PREVENTING A COLLAPSE.
And Ross does not ignore how the building was built. He ignores things like floating floors and shrinking blocks which just can't occur.
As for "Or a building in which the floors are hung from the supporting columns, rather than being pushed up by them," if the joist attachments were ATTACHED to the support columns, they were being pushed up by them.
Do you have any background in physics? |
No witty quotes. I think for myself. |
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Dude
SFN Die Hard
USA
6891 Posts |
Posted - 10/02/2006 : 14:42:30 [Permalink]
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quote:
If the dust is not acting as downward-acting mass, and all the contents of the floors and everything on the floors was essentially pulverized to dust (as reported by clean-up workers)
Your continued assertion that "everything on the floors was essentially pulverized to dust" is entirely unevidenced.
Feel free to google up some pictures of the massive piles of rubble.
Your assertion that proper placement of demolition explosives can be overcome by just increasing the ammount of explosive used is equally unevidenced. Sure, with enough tnt you can blow up anything. But your claim is one of a controlled demolition. You cannot accomplish such a thing without precision placement of your explosives.
Controlled demo uses shaped charges to sever the support beams. In a building the size of the twin towers, those support beams are significant. The ammount of explosive you would need if you were not using shaped charged placed in specific points would also be obvious, and even more obvious when detonated.
As for how I know what it takes to demo a building that size? I carried out an email exchange with the lead demolitions manager of one of the largest demolition companies in the US on the subject.
The bottom line is simple. In order to carry out controlled demolition, even if you didn't care if anyone died, you would need to expose the support beams in hundreds of places, carry in a few tons of explosives, and route the control wires to every individual charge you placed. It also would require a crew of hundreds of people to accomplish.
So please, I'd like to hear your explanation of how this could have been done without any of the 10K people in each building noticing it and without any of the hundreds of people who set it up talking about it.
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Ignorance is preferable to error; and he is less remote from the truth who believes nothing, than he who believes what is wrong.
-- Thomas Jefferson
"god :: the last refuge of a man with no answers and no argument." - G. Carlin
Hope, n.
The handmaiden of desperation; the opiate of despair; the illegible signpost on the road to perdition. ~~ da filth |
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The physics behind the collapses
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