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NIST Releases Report On WTC 7 Collapse
photonic writes "After three years of study, the National Institute of Standards and Technology (NIST) finally released its report on the collapse of World Trade Center building 7. The main conclusion is that the building came down due to fire, not due to debris damage or some conspiracy demolition team. The fire started pretty small after the collapse of WTC 1, but was left to burn several floors out completely. The important finding is that the collapse was triggered by thermal expansion of beams, which could detach asymmetrically loaded girders from the main columns. Some limited pancaking of floors then caused a lack of lateral support and buckling of a single column. This triggered the failure of the entire core of the building, which finally fell down as a single piece. Crackpot theories can be discussed elsewhere; please limit the discussion to the science here. All documents can be found at NIST's WTC page, which read like a porn magazine for finite element junkies. Simulation movies are also available. And yes, they used Beowulf clusters to do the simulations, some of which lasted for several months."
It didn't. The hundreds of tons of flaming debris ignited by hundreds of gallons of aviation fuel did.
The principles of demolitions are pretty similar - you destroy the supports of the building causing it to collapse down on top of itself. The WTC towers suffered a similar failure only the primary cause was a combination of damage, stress and weight of material from above that caused the supports to fail, rather than controlled explosions.
Not long after this shit, there was a building in Europe, where the fire was so intense, it burned everything off. The steel structure was still standing [...]
I'm pretty sure you're talking about the Windsor building in Madrid.
I've got news for you, buddy: It actually works against you.
First, the Windsor building had a concrete core and two concrete technical floors. A very different design from that of the Twin Towers.
Second, the steel portions of the building exposed to the fire did in fact get all melty and collapsey. The only reason the building is still standing is because of the features I mentioned above.
http://www.911myths.com/html/madrid_windsor_tower.html
http://www.debunking911.com/madrid.htm
People will pass up steak once a week, for crap every day.
Let's see...hmm...full tanks of aviation grade fuel.
The 767-200ER, the UA plane which went into one of the towers, has a fuel capacity of 23,980. The flight was a few hundred miles from it origin at Logan International Airport in Boston.
Let's assume that the plan had only 15,000 gallons onboard.
The flash point of jet fuel is 100.4 ÂF (38 ÂC). Many surfaces - including the engines of the plane - would be well above this point.
In addition, there were numerous electrical connections which could have sparked causing the fuel to ignite.
Jet fuel has between 127,000 and 135,000 BTUs per gallon.
Therefore, at the point of impact we had between 1,905,000,000 and 2,025,000,000 BTUs of energy being released in a highly concentrated area (3-5 floors).
Even without the energy generated by the burning of other materials, this is sufficient to inflame the entire area and to cause the required heat damage to the tower.
Jordan
About 23,000 gal. of diesel fuel was stored in the bldg, mainly on the bottom floors but some as high as the 7th. "Several months after the WTC 7 collapse, a contractor recovered" the fuel from the tanks and, "unaccounted fuel totaled... somewhere between 0 and 2,000 gallons..." And "The worst-case scenarios associated with fires being fed by ruptured fuel lines-or from fuel stored in day tanks on the lower floors-could not have been sustained long enough, could not have generated sufficient heat to weaken critical interior columns, and/or would have produced large amounts of visible smoke from the lower floors, which were not observed."
http://www.nist.gov/public_affairs/factsheet/wtc_qa_082108.html
Anyway, steel bends in fires, that's why it has to be insulated and why steel bldg's must have sprinkler systems. I doubt the fire dept. was able to respond effectively in time.
The fire in the North Tower was still burning and spreading when the tower collapsed. While it was obscured somewhat by dust and smoke during the fall, flaming debris did spread out over considerable distances, some of it striking WTC7, breaking through the windows and setting aflame material in the lower floors, which spread rapidly as the collapse of the Twin Towers had done considerable damage to the water systems in the area, and water pressure for the firefighting systems was very low.
The immediate evacuation of WTC7 (among others) as soon as the evacuation of the main towers was ordered saved a great many lives.
You can never go home again... but I guess you can shop there.
This is pretty simple math; the weight increases with the cube of the scaling factor as you scale up a model, yet the strength of the materials used only increases with the square of the scaling factor since it depends on the area of the cross section of the member.
That still doesn't explain why the owner of the building himself said that they blew it up. Or why the BBC reported its fall 20 minutes before it actually fell.
It's in how the government knew exactly who was responsible, the minute it happened, and flew them the hell out of the country. WE KNOW THIS. Why doesn't anyone focus on it??
Total nonsense. The rest of bin Laden family had absolutely nothing to do with the attacks.
Also, the hijackers weren't using assumed names, they appeared on the flight manifests, and they were known. It doesn't take very long to add 2 and 2...
Also, bin Laden's relatives were allowed to leave the country after the national ground stop was lifted and not without being questioned. http://911myths.com/html/family_flights.html
People will pass up steak once a week, for crap every day.
I saw the video link, it might be helpful to you to be accurate and precise with what the owner said when you report. The owner said the firefighters had come to him and said they couldn't sustain the effort needed to control the fire and that they should pull "it". The "it" referred to the effort to control the fire, not pull the building down. The firefighters were admitting what they were doing was ineffective and they couldn't sustain the effort. They concluded there was nothing they could do so they told the owner they'd pull out the effort spent on the building.
The abutment of that clip with the building collapsing is misleading as is the whole clip. It is just someone's effort for 15 minutes of fame and nimrods like you help him...pathetic...
Gerry
If the WTC 7 did come down because of a government conspiracy (and I'm not saying that it did or didn't!) then it would stand to reason that a federal agency like NIST would draw a conclusion of structural failure rather than deliberate demolition. No big surprises here.
That's called affirming the consequent. It's not insightful, informative, or valuable in any way; it's a fallacy.
People will pass up steak once a week, for crap every day.
Um, fires can pretty much bring down every building without some sort of suppression.
The sole exception is concrete, which can leave a hollow shell. Of course, no one on earth can build a 47 story concrete building.
Any building with steel as part of the support, on fire long enough, is eventually going to see that steel buckle, which will bring down the building. You can't just let tall buildings burn and then walk in the next day with new paint and furniture.
When they build steel buildings, they spray insulation on the steel to keep it intact during fires. For the WTC7, that was something called 'Monokote', which is rated for three hours for steel columns. (There is an entirely different 'Monokote' which is just a kind of plastic shrink wrap. Don't get confused.)
This would have been more than enough if the fire-suppression systems had been working, but they were not. It is also why the firefighters pulled out when they did...enough of the steel had started to buckle that the building was listing to the side.
If corporations are people, aren't stockholders guilty of slavery?
So, the implication is that a big conspiracy set up charges to bring down the towers and that this conspiracy is good enough to never be uncovered, but not good enough to make it look unlike a professional demolition?
Also, I was watching it. The only thing that made it look like a professional demo is that the building fell downward. Professional demos have a bunch of blasts in a visible pattern to take out the major supports; the Twin Towers didn't have any of that, it merely fell in the direction of gravity, which doesn't much surprise me.
Do you have ANY idea just how much effort is involved in demolition? Sure, it seems easy from the outside, if you know what you are doing, you can bring a house down with a sledgehammer, but it will be noticed. The same with controlled explosives, this is not a case of slapping a bit of TNT to a wall and walking out, if you do that, the explosion just goes outside and the building keeps standing. No, you got drill a hole into the structure. If it is still beam you got to apply a chaped charge that cuts it through. Buildings are constructed to be able to withstand the loss of a couple of support beams, so you need to cut them all. How the hell would you do that without anyone noticing? It would require truck loads of explosives and days of demolition to setup. No, the conspiracy theories fail NOT because it is impossible to consider the idea that someone might want to fake this but because the logisitics just don't work. I read one theory, that the cia was controlling the planes, the idea being that they were refuel planes because the planes had no windows. Right. Because the CIA, a organisation KNOWN to operate civilian aircraft finds it easier to aquire military planes of which there are only a few instead of buying just one of the countless 2nd hand civilian airliners. Look at the way that red department store in china collapsed, that is know to be an accident and it collapses just the way a controlled demolotion building collapses. You seem to have the idea that because you saw some demo docu's you now think that if a building collapses like that, it must have been done like that. It is as another poster said almost impossible to even start to explain how stupid your logic is.
MMO Quests are like orgasms:
You may solo them, I prefer them in a group.
Yeah, we've been so lucky to find Mohammed Atta's passport in pristine condition several blocks from Ground Zero one day after that hell-like firestorm brought down 1.2 million ton of material.
This... survived this...
People will pass up steak once a week, for crap every day.
What evidence?
The BBC made a mistake, probably because of the huge amounts of confusion that was abound. As for your other claim about a 'NY radio station', that's not something I've heard before, and your lack of detail leads me to believe that you've just made it up.
There is nothing interesting going on at my blog
Fire doesn't melt steel. If you did metallurgy in college, you would know that above a certain temperature the most stable crystalline structure of steel becomes one which is a lot weaker. If you really care, you can google to find phase diagrams of steel like this one that tell you exactly how steel behaves when you heat it up.
If you didn't do metallurgy in college, then you have no idea what you're talking about.
There is nothing interesting going on at my blog
The only video I see is one where someone repeatedly asserts the 'pulled' means 'demolished'.
There are plenty of manuals on controlled demolitions, and they don't get quoted. You know why? Because they do 'pull' buildings. That means to pull over a building using cables hooked to the supports.
You couldn't do that to WTC 7, and it wouldn't have gone down like.
The fun thing about the 9/11 Truthers is that their conspiracies make no sense. They have holographic missiles flying around, explosives in advance, news media with a scripted story that sometimes jump ahead.
Do you want to know how the US government would have actually done 9/11?
They would have installed non-overriddable autopilots on the airplane, either some sort of sleeping gas, or cellphone/radio jammers to keep the people from contacting anyone.
They would have tapped the phones of some of the passengers booked on United 93, recorded some of their voices, and forged phone calls from them. Hard to do in real time, but they were in a hostage situation on a plane, so if anyone you're talking to asks a question you can't answer, well, the call would get 'dropped' or the hijackers would take the phone away or something.
Then they would have flown the actual airplanes into the actual buildings and let whatever happened.
They would have not contacted any media in advance. They would not have replaced any airplanes. They would not have rigged the twin towers buildings to fall. They would not have used this opportunity to take down an unrelated building. They would not have put the planes they stole back into service under a different number. They would not use actual terrorists who can be found alive later. (They wouldn't have made them all Saudis instead of Iraqis.)
If corporations are people, aren't stockholders guilty of slavery?
How can anyone on this web site stand there and demand to limit to science as if the fact that the only steel buildings in existence to ever fall from fire all did so on 9/11 (which includes WTC Building 7).
This is absolutely false. There are many examples of other steel buildings that collapsed due to fire before 9/11. One example off the top of my head would be the Sight and Sound Theater fire of 1997. http://www.firefightersonline.com/opsandtactics/tr-097/ Just google around for a few minutes if you want many more examples.
The way 9/11 conspiracy theorists mindlessly repeat these lies (like the lie that no other steel buildings have collapsed due to fire) without bothering to spend even five minutes googling around with terms like "steel building fire collapse" is a testimony to their extreme gullibility and intellectual laziness. It's not different than the oft-repeated claim that the fire wasn't hot enough to melt steel, which ignores the fact that steel loses much of its strength well before it actually melts.
Ugh, ok, I'm tired of this, so let me explain to you exactly how the building collapsed from my perspective, watching it across the Hudson a few miles away, and then seeing it up close on the news:
Pancaking, a term which you completely misunderstand, is the event which occurs when you cause the upper floors of a building to collapse suddenly. You question how the fire in the upper floors weakened the lower floors. The answer is that it didn't have to. When the upper floors gave way, they impacted the floors directly beneath them. The kinetic energy that is gained by those floors basically free falling 1 story down is immense, and this cause the floor beneath, also weakened by the fire, to collapse, and so on this process went until it reached low enough that the floor beneath the collapsing floors was undamaged by the impact or fire.
The problem though is two-fold: first of all, those collapsing upper floors sent a huge shockwave of compressing air down the elevator shafts and stairwells, blowing out the windows on the floors below and causing some very minor structural damage. No big deal, but it's what makes people think the lower floors were "blown out". The big thing is that by this point, the upper floors have gained such an incredible amount of momentum from their falling, which is only increasing with their mass, that the lower floors have no hope of "catching" them. I say "catching" because they're not supporting them, they have to stop them from a freefall, and stopping an object in motion, especially an object composed of tons of concrete and steel falling directly downward, requires more structural integrity than any skyscraper has.
This is why the Windsor building is a poor example. This event did not occur. It was the WTC's own height working against it, giving the collapsing segments more and more mass until it was enough energy to break through the structurally sound floors.
People who claim there should have been a core, or or more left of it are people who try to compare this to other events, and often lack an understanding of physics and engineering. ALL of the steel in the WTC towers did not have to melt or be weakened. Only a small portion, in a small area, had to be structurally weakened enough to give way. The rest is simply F=ma
You can say "FACT" all you want, but you still havn't said which radio station you're talking about, or acknowledged the possibility that the BBC made a simple mistake.
You're the government, you want to covertly bring down a building. Now, do you get ready press statements saying that the buildings have fallen over, or do you just blow them up and hope that someone notices? There is no universe in which the "BBC got a press release 20 minutes early" makes any kind of sense.
There is nothing interesting going on at my blog
Presuming, of course, that such efforts existed.
"Uncontrolled" collapses of very large buildings are exceedingly rare events, so nobody would really know a priori how the WTC collapses "ought" to have looked. After the fact, the way the floors pancaked doesn't seem at all improbable. As the force of the collapse propagates downward, it meets elements designed to spread a fraction of a single floor's weight onto vertical supports. Since the force of the collapse would be orders of magnitude greater than what these elements were designed to support, it seems probable that they would impede the progress of the collapse to about the same degree that a cloud of smoke would impede a lazily swung sledgehammer.
Of course, this is just after the fact rationalization, but the engineering analysis confirms it the intuition that no special measures would need to be taken in order for the collapse to proceed in a way that superficially resembles a controlled implosion.
This conspiracy theory has the usual problems of conspiracy theories, such as providing what mystery writers call "motive, means and opportunity". Motive is a particularly vexing issue, given that seven buildings were destroyed past recovery and numerous other ones damaged, it's hard to connect the end result to the purported motive. Another commonsense question would be whether a government that could not keep Abu Ghraib, Guantanamo, Echelon, or warrantless surveillance under wraps could have engaged in what must have been a substantial engineering effort on three busy Manhattan buildings without anybody noticing.
The real appeal of any conspiracy theory is this:it provides an illusion of control. Limited control, that is certain, but the seat of the pants risk evaluation is actually quite astute: if it were some cabal of government officials, you'd actually be less exposed than if twenty men, each armed with a tool costing $1, could kill nearly three thousand people and bring the country to a virtual standstill for weeks.
Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
God I get sick of this. Same arguments again and again, 7 years now, 7 years and we are still faced with the same psuedo-scientific babble.
I'm afraid I'm going to have to summarise here. Steel does not need to be 'melted' to be weakened well beyond safety margins, and beyond its required design strength. At moderately high temperatures it is weakened significantly. Go look up a materials handbook or two. The buildings collapsed in an entirely ordinary and predictable manner, they did not 'free fall'. Structures such as that are designed to collapse pancake style, like a concertina, they do not ever topple over. Can you imagine the extreme dangers that a toppling building of say 110 stories would pose to say, half of the surrounding CBD? The bomber in the 40s was not a jumbo jet, not even remotely close, there weren't even planes that big built back then. Neither did the planes that existed in those days have the same high strength materials embedded in them as in this case. I believe the NIST report suggests that elements such as the titanium axles used in the engines caused significant structural damage to the building core in certain places.
You *are* peddling a conspiracy theory. Multiple investigations and simulations have drawn the conclusion that the buildings fell down as a result of the observed evidence: Two fucking giant jumbo jets flew into them. Occams razor my friend. And you are here jabbering on repeating the same debunked theories of a small group of complete crackpots in the face of it.
...since at the Pentagon they cannot find:
The wings Any of the seats The tail ...
Who says? Your idiot tr00fer friends? Planes don't make a cartoon like plane-shaped hole when they hit a reinforced concrete building. Delicate structures like the wings and tail planes practically disintegrate. Hell, most of an aircraft is aluminum, and betrwwen fire and impact, not much remains intact. You wanna see the wreckage of AA flt 77? See here. It's right there, in the pentagon, in small, torn up, fire damaged pieces.
Idiot.
If a job's not worth doing, it's not worth doing right.
"If you say so..."
The building you're showing has about 10 floors. WTC 1 and 2 had 10 times that and weighed exponentially more, in spite of being made with substantially similar materials. What would be strong enough to act as a pivot point for a 10 story building would buckle like a house of cards under a 100 story building, long before leaning over enough to "topple over" properly.
Exactly - it's the same principle which allows a martial-artist to smash through 10 stacked concrete slabs. If you stacked the slabs directly on top of each other he'd smash his fist into goo before doing any damage to them, but if you leave a gap - even just a quarter of an inch - it creates enough space for the slabs to break individually instead of as a combined mass.
The only way any large building can collapse in such a short amount of time, is if it's ENTIRE support structures is instantaneously removed.
And the only way to have the entire support structure vanish instantaneously is to have hundreds of professionals working on placing explosives along the entire support structure. These explosives are set of using utterly standard wiring, in the case of something as large as the WTC, hundreds of miles worth of wiring. Finally, the explosives would have to be placed with extreme accuracy all around the building by drilling holes in the support infrastructure.
Now, what do you think is more likely, either the government has access to:
or, they have access to the MIB Neuralizer and they have bee able to Neuralize all the witnesses
Here's idea: The premise for you conspiracy theory is incorrect. The building never dropped as if all it's support structure was instantaneously removed.
You can scale the dimensions and strengths of your model to account for the differing stiffness -to- weight-per-unit-length and weight-per-unit-area of the models materials. That would allow you to model loadings like (for example) if the top of the two towers were linked by a cable, and the cable tensioned, how much would the towers pull together (not that that could ever have happened (by the way, the film is very good, if you like talking with people with the "thousand yard stare")).
Unfortunately, for modelling the fires, and the spread of fire, you have a number of additional things which you've got to scale correctly and simultaneously - the thermal responses of the materials, the heat-release-per-unit-volume-per-unit-time, and probably most difficultly, the changes in viscosity and density of the air with temperature.
A broadly comparable disaster that I'm familiar with used physical 1:4 modelling to understand the destruction of the gas compression module on the Piper Alpha. But they didn't try modelling the spread of the fire similarly, nor the step-wise collapse by heat-buckling of the platform structure. Which is probably because the experiment would have been very expensive and wouldn't have yielded much new information ("Don't set fire to oil rigs with hundreds or thousands of tonnes of hydrocarbons on board" was a well known lesson before 1998-07-06.). It's a lot faster (particularly when you take into account construction time) to do a stimulation than to build a model. And you can always burn your simulation down again tomorrow. And again. And again.
Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
It's like this: It's steel and concrete. Each floor is 200 feet square. That's about one acre. Picture a poured concrete pad of one acre suspended by a (really strong) rope. Cut the rope, it goes straight down. Now try to push it sideways. The inertia of the mass of the concrete resists that force. Gravity wants to pull it straight down. So it wants (cause this is smart concrete and has a choice)to go down. (Insert your own lewd thought here) A pancaking building is doing just that. The weakened steel joints cannot bear the force of the weight above it and snaps. Once you set that mass in motion, and the momentum builds up, it is inevitable that it come straight down. Remember, the building was 110 stories of an acre of concrete each. Such an enormous mass needs an enormous force to do anything but come straight down.