Slashdot Mirror
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."
Crackpot theories can be discussed elsewhere; please limit the discussion to the science here.
What site is this, and what has it done with Slashdot
-- This and all my posts are in the public domain. I am a lawyer. I am not your lawyer, and this is not legal advice.
And your point is? It's a common misconception that random events don't or can't look very neat and tidy. One of the common mistakes people make when faking random data is to make it look too random. Meaning they don't have enough places in the data which appear to be non-random.
The way that a skyscraper is designed and built favors it falling more or less straight down rather to one side or the other. The reason being that if it were to topple, as remote a possibility as that is, the building shouldn't be allowed to hit other buildings. Nobody wants a set of dominoes that large.
Let's just get this out of the way first. BULLSHIT!
The rest of the world knows something suspicious went on, but America has their head in the sand.
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 but oxidizing flame was enough to melt or buckle steel in the trade center? The sheer ignorance of the American populace astounds me.
Interesting. Then I am curious as to what temperature would be required to melt and/or buckle the structure of your aluminum foil hat?
"Yes, But did they run linux?" No, XP/Vista - that's whay it took 3 years to do the graphics.
Do they mean to say that a fire can cause a building to collapse? Next they'll be telling us damage to structures following earthquakes isn't manmade.
Let's just get this out of the way first. BULLSHIT!
The rest of the world knows something suspicious went on, but America has their head in the sand. 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 but oxidizing flame was enough to melt or buckle steel in the trade center? The sheer ignorance of the American populace astounds me.
How about if we get this out of the way:
A statement that one building somewhere at sometime didn't collapse under certain conditions is no grounds (in fact it's a logical fallacy) for saying a building couldn't collapse under the same conditions... and worse, it's also no grounds to subsequently stereotype an entire group of people and flame them.
Thank you and have a nice day.
Well, back to rejecting software patent applications.
but you can still publish goatse links here.
Their they're doing there hair.
Both are afected by gravity, which exerts a downward force.
Another big reason large buildings tend to fall straight down is that is the direction gravity is pulling them. Anything much bigger than three or four stories is going to come apart very soon after leaving vertical, and the pieces come straight down.
Anarchists never rule
If someone left a crackpot burning, couldn't that have started the fire in the first place?
Ipso diabolico facto nonsensicalico.
These guys have resources. It could be quite damaging to be caught with a smoldering crackpot.
Ergo, they crash a plane into the building to cover it all up.
Sheeple, the answers are RIGHT IN FRONT OF YOU, just light them up and breathe deeply.
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.
It needn't be as subtle as seeing patterns where there are none, although we know that happens all the time.
In simple terms, things tend to fall down. Surely, if it were easier to get a building to topple over sideways, a team of terrorists isn't going to go through the trouble of averting what would surely be a larger and more spectacular catastrophe.
People whose experience with construction is limited to building models tend to imagine buildings are much lighter relative to the strength of materials in them then they are.
Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
Let's leave McCain out of this one.
Nerd rage is the funniest rage.
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.
Asking Slashdot readers to stick to science, refrain from discussing conspiracies, AND taking the fun out of a beowulf cluster reference?
This submitter is a black belt troll and you all know it!
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.
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
Actually, "gravity" is ~9.8 m/s^2. That's an acceleration, not a flat rate, meaning that air resistance notwithstanding, the average rate at which something will accelerate when falling is 9.8 meters a second per second. It absolutely should have taken fewer than 23 seconds to fall.
You may wish to learn a little bit more about gravity here: http://en.wikipedia.org/wiki/Standard_gravity .
Yes, you're right, holocaust deniers, intelligent design proponents, and 9/11 conspiracy theorists all feel like they've been denied the right to debate their theories.
The thing is, they're lying to themselves. They have lots of debates. I've heard 9/11 conspiracy theories deconstructed and made out to be bullshit lots and lots of times. Holocaust deniers do have conventions (like the one in Iran last year). Intelligent design, which should be laughed out of any adult conversation, has managed to actually be taught in schools and considered in courts of law. All of these people already get way, way, way, way, way more attention than their theories deserve.
These people say the opposite of the truth, not only when spouting their absurd theories, but when explaining why other people won't listen to them. "Oh, they're just sheep, led astray by a huge conspiracy." No, actually, you're a petty fool with a reality deficit. We don't ignore you because we are dummies, we ignore you because we have better judgment than you do and can see thru what you say.
First, I need to say a few things to inoculate myself from being labeled one way or the other:
1. The concept of a "conspiracy theory" is flawed, and is simply a cop out. There is no such thing as a conspiracy theory. There are just good and bad theories. Labeling an idea a "conspiracy theory" is just a form of jingoism and does nothing to increase the flow of ideas. Labeling something a conspiracy theory is a brilliant tactic to bury an idea as it takes advantage of herd mentality. Judge an idea by its merit and not by its label. Here on Slashdot extremely brilliant and extremely stupid ideas are posited all the time, so why now are we disallowed to discus a certain set of ideas? I thought there was a strong freedom/libertarian mindset here...
2. If you examine history, conspiracies are actually the norm and not an aberration. Look at Rome, or the times of Shakespeare, or Nazi Germany, or the French revolution, etc etc. Look at the behavior of the current administration of the United States and say there haven't been conspiratory behaviors with a straight face. All a conspiracy means is that more than one person plans together to do something secretly. That happens ALL THE TIME, whether criminally or not.
3. As Slashdot readers many of you consider yourselves to be scientifically minded and aware of logical fallacies. Why does this mindset breakdown when it comes to politically charged events? You are labeling people nut cases and tinfoil hat wearers and conspiracy theorists the same way people were labeled communists during the McCarthy era. The ad hominem attacks are relentless.
4. In light of the awareness that several agencies in the US with billions of dollars in funding and specific programs for controlling the flow of information DO exist, wouldn't you think that Slashdot, a hub of meme flow on the internet, would be a specific target of operations? Opinions are manipulated on the net regularly. You only have to look at China with their "wangyou" (internet friends) that are paid 50 cents chinese for each message they post that supports a certain agenda. The manipulation in the US is much more subtle. Teams of PhDs and psychologists know what buttons to press to get a certain response out of a self-admittedly obsessive compulsive crowd of nerds.
5. Building 7 was never hit by an airplane. The owner of the building admitted to it being demolished, then reneged his statement. There are videos of reporters describing building 7's fall while it is still standing in the background. It took SEVEN years for investigators to come up with a reason for the building to fall the way it did. Is it possible that the SEVEN years were spent honing a story plausible enough to convince even the most skeptical people of it's truth?
6. Unless you've visited the site of the building and done your own scientific measurements, everything you know comes from suspect media sources. This relates to point 3 above. I freely admit I don't know the truth of what happened due to this single fact.
In summary: Don't buy into either side of the story. There are plausible explanations for it being due to fire, but there are equally plausible explanations to it being due to malicious intent. Don't follow the herd - a certain subset of humans are purely pragmatic and will do whatever it takes to gain money or power.
PLEASE PLEASE refer to the last 5000 years of history and don't make the mistake of thinking that somehow right now things are different and innocent.
LS
There is a fine line between being a cultivated citizen and being someone else's crop. - A. J. Patrick Liszkie
This is WTC 7 that we are talking about, not towers 1 or 2. It wasn't struck by a plane and didn't have hundreds of gallons of aviation fuel in it. As colfer pointed out, it had some diesel fuel tanks in the basement, but these were found to have not contributed largely to the fire (which was on the upper stories).
The conclusion of the board is that a normal building/office fire starting by falling debris from WTC 1 is what brought the building down. If we are going to be building dense cities with skyscrapers then it is important that a normal fire merely gut the building, not compromise it's structural support. The building techniques used in WTC 7 were not sufficient, and shouldn't be used in the future.
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
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.
"Another big reason large buildings tend to fall straight down is that is the direction gravity is pulling them."
Bullshit - Gravity is just a theory, just like Evolution.
"As God is my witness, I thought turkeys could fly." A. Carlson
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.
If you Buy Fraggle Rock, Season 2 on DVD and watch episode 36, titled "The Doozer Contest," you will find, about 3 and a half minutes in, Flange saying "Look the Fraggles are Destroying the North Tower" and then all of the Doozers Cheer. If you don't believe that this is proof positive that Jim Henson was behind the events of September 11th, then you are a disinformation agent and a muppet of the shadow government.
Knock-knock
Who's there?
Nine-eleven.
Nine-eleven who?
YOU SAID YOU WOULD NEVER FORGET!