Leaked FEMA/ASCE Draft Report On WTC Collapse 562
securitas writes "The New York Times obtained a copy of the World Trade Center draft report by the Federal Emergency Management Agency and the American Society of Civil Engineers about the engineering failures that caused the towers to collapse. Among the findings: 'Fireproofing, sprinkler systems and the water supply for hoses were all disabled and the fires generated heat equivalent to the energy output of a nuclear power plant' reports the NYT (Yahoo link). Amazingly, if it wasn't for the fire (or another secondary catastrophic force), the towers would have remained standing."
Wasn't this recently on the TV (Score:4, Informative)
IIRC the person that designed it has an office that overlooks Ground Zero...
discovery channel special (Score:4, Informative)
They explained that most of the WTC towers' strenth was in the outer steel "shell" and the brackets connecting the floor to that were found in the wreckage badly warped. They think the floors collapsed and there was nothing to keep the 4 outer walls from buckling without the floors.
The most amazing part was in the beginning when they were lifting a huge piece of steel off of a tractor trailer truck. It was as long as the trailer, 4 feet wide, and a foot thick. A bit grabber backhoe thing couldn't even lift it, it sort of slid it off the truck. They made the point that this piece of metal falling just a foot to the ground, shook the ground and the camera 30 feet away. Then they said there was 5,000,000 or some large tonnage falling to the ground at 120mph at the time of the collapse. quite amazing
Not the cost of being competitive (Score:4, Informative)
Pity that:
Asbestos (Score:4, Informative)
The jet fuel burned at an excess of 2000 degrees,
so it's likely the towers still would have collapsed, but some extra time would have allowed further evacuation efforts.
putting out fires (Score:4, Informative)
The report seems not to say anything about the fact that the WTC was a steel construction and thus rather unprotected against fire as opposed to ferroconcrete which is safer but would have needed the buildings to be smaller. This is the cause why there are not similar high buildings in Europe where regulations demand ferroconcrete.
Re:Fuzzy thinking... (Score:3, Informative)
Yes, obviously the Hydrogen burned... but that was not what did it in.
It was the coating on the outer shell, made chiefly of the yet-undiscovered ingredients for dry rocket fuel.
Re:Asbestos (Score:5, Informative)
Face it, no building could have survived a planeload of burning jet fuel that was busy eating its way through the building, with dozens of floors above adding weight to the weakening structure. And for all those people bemoaning the lack of a rooftop water supply for the sprinklers: consider the fact that the fire trucks at airports are not loaded with water, but with foam. You need foam, not water, to effectively put out burning jet fuel. Otherwise, the water would evaporate into steam before it had a chance to extinguish the flames.
Really, it's amazing that they stood as long as they did. Of course, knowing the limitless bounds of greed, people are still going to try to find someone to sue. "I want a bazillion dollars because the contractor didn't design the building to resist the destructive impact of a 767 and a plane-load of burning fuel!" Sheesh.
:Peter
Re:Wasn't this recently on the TV (Score:3, Informative)
So, it wasn't the designer. The original poster didn't *remember correctly*... hardly an example of 'spreading disinformation', IMHO. (BTW- IMHO means In My Humble Opinion) (PS- BTW means By The Way) (PS means... oh forget it, I just realized I'm trying to enlighten an AC).
Re:Amazingly (Score:5, Informative)
The looked at factors like the blast having blown the fire protective coating off the steel and the way the building was designed with the majority of the load being carried by the steel skeleton on the perimeter of the buildings, as opposed to columns within. The achilles heel was reported to be the steel trusses running under the floors connecting the outer steel to the core.
The heat from the fire caused these trusses to weaken and fail, leaving the outer steel frame without the stabilizing and load-transfering benefit. By the time the first floor had begun to collapse, there was so much inertia in the falling portion of the structure that it was inevitable that the each floor below would fail under the crushing pressure.
They interviewed the cheif structural engineer and he said that they had designed the structure to withstand an impact from the largest airliner of the day, the 707... flying at low speed and lost in the fog. They didn't anticipate a modern widebody, loaded with enough fuel for a coast-to-coast flight crashing into the buildings at full speed.
He said that even if they took all that into account, he doesn't think there could have been any way to design the buildings to withstand that. The fact that the structures stood as long as they did is actually a testament to the good overall design (so the program said, anyway).
Re:putting out fires (Score:2, Informative)
True, however a sprinkler system would have reduced the temperatures reached inside the building, quite possibly enough to have saved more people. Also a sprinkler system would've reduced the number and intensity of secondary fires; office furniture and the like.
Smaller buildings using 'feroconcrete' may well be safer, but this is irrelevant to the WTC terrorist attack, the towers weren't smaller or built using this concrete.
Working sprinklers would've made a difference. Your comment on halon is well received; probably halon would be more effective, assuming the delivery system was operating.
Overall I see this report as optimistic, better protected fire escapes, better fireproofing and more redundancy in the fire fighting capability may have saved, not only more people, but the buildings themselves. Applying the knowledge gained, will result in even studier building.
Empire State Building (Score:5, Informative)
The following excerpt is from "Empire: A Tale of Obsession, Betrayal, and the Battle for an American Icon", copyright © 2001, available from John Wiley & Sons. It describes the impact of the B25 that hit the Empire State Building in 1945.
"Army Lieutenant Colonel William Smith Jr., a 27-year-old veteran of 34 bombing missions over Germany, had been flying a twin-engine B-25 bomber from Bedford, Massachusetts, to New York's LaGuardia Airport, and had secured permission to continue to Newark, New Jersey.
The fog was blinding. When he dropped down out of the clouds, he found himself approaching a forest of skyscrapers. In a panic, he banked away from the Grand Central Building, then from another tower on Fifth Avenue, only to find himself bearing down on the biggest one of all.
In desperation, he pulled up hard, twisting. The 10-ton (9-tonne) bomber plowed into the office of War Relief Services of the National Catholic Welfare Conference on the 78th and 79th floors, 913 feet (278 meters) off the street, tearing a gaping hole in the Empire State Building's north side."
The full article describing the impact in 1945 can be found here: Empire State Building Collision [architectureweek.com].
Not so amazing, really (Score:4, Informative)
In fact, it probably wouldn't have mattered what fire suppression system the building used...jet fuel is basically kerosene and it is much lighter than water. You can't effectively extinguish a kerosene fire with water. That's why you see aviation firefighers using something called aqueous film-forming foam. It floats on the kerosene.
Maybe to the layman the fact that the buildings survived the impact was amazing, but in fact it was simply a matter of good, purposeful design. Unfortunately, it's asking an awful lot to expect structural steel to survive the kind of intense temperature that is generated by an aviation fuel fire, particularly when the fuel supply is effectively limitless.
-h-
Asbestos revisited (Score:1, Informative)
Fact is had more asbestos been used in WTC, towers would have taken longer to collapse, more people would have gotten out. Asbestos was used extensively for fireproofing, but not for duration of construction due to EPA/tree huggers. Also, when the scares on asbestos first started in the 70's/80's, and corporations said get it all out (now they manage it in place and only remove when area is going to be disturbed), a contractor was hired to remove large amounts of spray on asbestos in the WTC. Most asbestos abatement contractors also are in the fireproofing business, same industry, one puts it on, one takes it off. When a company performs asbestos abatement in NYS, by law, the fireproofing/insulation must be replaced. If the abatement contractor also reinsulates, they bid the reinsulation, or they sub it. Or in some cases a reinsulation company is brought in separately. But it must be done at the conclusion of the abatement. So the contract did not specify that the NEW spray on insulation must be asbestos free. Since the abatement contractor was in the spray on insulation business, and they had just banned the MANUFACTURE of asbestos in the US, guess what type of spray on insulation the contractor had in his establishment? And guess what he sprayed back on after he removed the old asbestos? You got it. Asbestos. They couldn't do anything to him, as the contract did not specify asbestos free for the replacement. But they learned there lesson. Since then, and up until last year, there has been continued asbestos removal.
Asbestos was in not just spray on insulation, but also plaster, floor tile, gypsum wallboard, joint compound, mastic (glue), caulking, drop ceiling panels, paint, and hundreds of other building materials. Anytime any renovation went on in the WTC, either testing was done, or previous test results were used to identify asbestos containing material (ACM), and asbestos abatement workers were used, under a long term contract, to remove the asbestos. Tons and tons of asbestos were removed over a period that continued up till last year.
But if more spray on asbestos had been used, and more had not been removed, the steel would not have lost its strength as fast, giving everyone more time to get out. Asbestos has a melting point far in excess of 1000 degrees. Substitutes for asbestos have lower melting points. Therefore, the fire rating for buildings with asbestos is higher than for buildings without asbestos. Period.
The terrorists killed my friend Mike, fireman, my friend's wife, my aunt's maid of honor, some moving men from my old union local Teamsters 814, and they almost got my cousin, but he made it out. Asbestos may kill my uncle, who has asbestosis, and may shorten my life later on, but it possibly would have saved my friends, had they more time to get out.
.
Re:Asbestos (Score:5, Informative)
Except that if you consider that the first tower to come down was the second hit, and that it was hit below the 70th floor, it becomes quite clear that the asbestos that was there did little to help.
I don't think you can make a rational statement one way or the other, since we are dealing with two different crashes which probably cut different beams and spilled fuel in different patterns. Also, the beams on the 70th floor were bearing a lot more weight. So, they required less heat before they lost their cohesion.
As for all the people slinging accusations of greed, I agree that's bollox.
The WTC was designed to withstand an 8.0 earthquake. It handled the impact of the planes just fine. This hardly seems like the work of companies that were cutting corners. That the slurry wall holding back the Hudson river held is simply amazing considering it contained the epicenter of a minor earthquake. If that had broken, we would be looking at a huge lake there today. No recovery efforts would have been possible until a new slurry wall was built, and that would have taken months.
That said, I do have to question the use of "trusses". On the Discovery Channel they quoted a fireman who said that they always say "don't trust the truss" because they have a tendancy to melt quickly. Perhaps there should be a review of what types of trusses can be used in all new construction. Would it have been possible to build the WTC's wide-open design with heavier cross beams instead of trusses?
As bad as all this is, I'm sure we can learn from it. What will buildings of the future use for fire suppression? How about active cooling systems for structural components? Perhaps insulation can be coated with a material that is resistant to blast waves so that the material will be retained. From now on, architects will be thinking more about explosions and huge incendiary bombs. Perhaps they will improve design, thus resulting in safer buildings for everyone.
Re:Not so amazing, really (Score:3, Informative)
Personally, I think the engineers and architects who built those buildings should be awarded and applauded. The buildings were made on budget and schedule. Only 3000-4000 people died, when they could easily hold close to 100,000 between the two of them. Neither building fell over and crashed other buildings, they pretty much imploded, which is remarkable. And despite the huge trauma, they stood for nearly an hour. It's amazing if you ask me.
This security second guessing crap is what's going to cause the next recession and put a minor stop to modern engineering. Money and time are really the difference between academia and engineering. Do you have any idea what it will cost to start engineering all of our buildings to withstand the worst? The WTC was over engineered as it was and we're talking about making it able to withstand twice what it was speced to. If it's possible and there are steel makers that don't think it is, I'm guessing we're talking about a 10x hit to the costs. That's crazy. The same thing can be said about all the security checks everywhere else. It'll work for a year or two and then the bills will start adding up and people will be astounded.
Re:Wasn't this recently on the TV (Score:3, Informative)
Architects draw a pretty picture and then ask the engineer, "will this fall over?"
Re:putting out fires (Score:3, Informative)
Hell yeah. (Score:3, Informative)
They detected WTC 270 miles away!
http://www.volcanolive.com/wtc.html
Both planes hitting, and again, both collapses.
Re:putting out fires (Score:2, Informative)
Water alone will NOT put out a kerosene fire. EVER. I've been through Navy boot camp... I've also been on a fire team on an aircraft carrier for the last five years. Jet fuel is put out using foam, period. You never, ever, EVER put straight water on a jet fuel fire, as the only thing you will succeed in doing is spreading the fire all over the ship and probably killing yourself and a whole bunch of other people in the process. Also, the LAST thing you want to do in a kerosene fire is put water on it and generate steam. Many more people die from steam burns than from the actual fire -- 212 degrees on enough of your body will kill you so quickly you won't have time to wonder how badly you F/d up...
Re:UK Horizon program (Score:3, Informative)
However, I find interesting the fact that the lack of asbestos coating for the structural steel above the, what was it, 60th floor is being ignored. That was the insulation that was supposed to reduce the heat impact on the structural elements in just such a fire for ~8-10 hours. And application of which was stopped midway through construction, after NYC passed their "no asbestos" laws.
Re:Not so amazing, really (Score:2, Informative)
Well, according to Boeing's site, a 707's max takeoff weight is 336,000 lbs, and a 767's max takeoff weight is 450,000 lbs. So holding speed constant a 767 would hit something with 76% more force than a 707. (Right, square of the differences if I remember my physics correctly).
Add in the fact that at least one of the places was reported to be going around 500 MPH when it hit, which is almost full throttle for one of those as opposed to the low speed collision that they looked at when designing the buildings, and they easily withstood a collision with 3 to 4 times the force they were designed to withstand.
Re:Not So Amazingly (Score:3, Informative)
The solution to the "fire problem" (Score:2, Informative)
Therefore, to solve the problems with the fire we need a fuel that will either burn very very slow when NOT under pressure, or not burn at all unless it's under pressre, ala + 350-450psi.
Slam a jet into the building and you'll have a fire that burns very slowly or no fire at all. And as I said, if someone can make this happen then I'll be happy for you. You'll save some lives.
Without the fuel a fire doesn't start that fast. (Score:3, Informative)
The existence of the jet fuel, in the few seconds for which it existed in the fire, assured that the fire would be unstoppable and most definately not of the ordinary nature that one could expect a firefighting system to be able to stop.
It's not "Fuel fire -> ordinary fire -> collapse, as you claim. It's "Fuel fire-> really huge gigantic fire in an instant with every flammable material available in flame all at once, which would not normally happen in a normal fire -> collapse.
Re:Amazingly (Score:3, Informative)