Posted on 09/15/2001 5:39:27 PM PDT by imberedux
"It sounds harsh - this had never happened in the world, so you can hardly criticise them. But I would have given the order to get out. You would have thought someone with technical expertise would have been advising them." But he acknowledged that the sheer scale of the tragedy probably overwhelmed the operation commanders. "I think everyone was not thinking. It was like a horror film and I think people's rationale had gone," he said.
The building's design was standard in the 1960s, when construction began on what was then the world's tallest building. At the heart of the structure was a vertical steel and concrete core, housing lift shafts and stairwells. Steel beams radiate outwards and connect with steel uprights, forming the building's outer wall. All the steel was covered in concrete to guarantee firefighters a minimum period of one or two hours in which they could operate - although aviation fuel would have driven the fire to higher-than-normal temperatures. The floors were also concrete. The building had to be tough enough to withstand not just the impact of a plane - and the previous bomb attack in 1993 - but also of the enormous structural pressures created by strong winds.
Newer skyscrapers are constructed using cheaper methods. But this building was magnificent, say experts, in the face of utterly unpredictable disaster.
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Trade Center architect discusses buildings Taken from CNN http://www.cnn.com/2001/US/09/12/wtc.architect.cnna/index.html
(CNN) -- When they were completed in the early 1970s, the Twin Towers of New York's World Trade Center were the tallest buildings in the world. That designation didn't last long -- Chicago's Sears Tower took the title in 1974, a year after Two World Trade Center was finished -- but the buildings' standing as a New York City landmark, anchors amid the office-tower canyons of Manhattan's financial district, remained unchallenged.
Tuesday, the buildings -- daytime home of more than 50,000 workers -- were destroyed when two hijacked passenger jets were flown into the structures.
CNN's Leon Harris spoke with Aaron Swirsky, part of the architectural team led by World Trade Center chief architect Minoru Yamasaki, on the way the building was designed.
LEON HARRIS, CNN ANCHOR: So many of us had thought for so long that the Twin Towers were invincible. We had heard for so many times over the years that the buildings have been built to withstand an impact from the crash of a plane.
Let's talk right now on the telephone with Aaron Swirsky. He's in Jerusalem. He was one of the original architects of the complex, as I understand it.
Is that the case, Mr. Swirsky?
AARON SWIRSKY, ARCHITECT: I was working with Minoru Yamasaki, who is the architect of the building. But I was one of the workers with him. We were a team of 14 architects, and I was one of the members of the team.
HARRIS: As a member of the team, and having such insight to how this building was constructed, could you believe that a plane could bring these buildings down?
SWIRSKY: No, as a matter of fact, one of the rationales of the structure of the building was that it would be built as a pipe. And that proved itself to work during the explosion of 1993, when a hole was brought into the building, and it survived. But somehow, nobody could foresee anything like (Tuesday's incident).
Also, at that time, the planes were not like these types of planes that we have now. I think the biggest plane was a 100-passenger plane, something like that, and the fuel capacity of those planes was not like they are today.
The criterion was that if a plane hits, it would go right through it. And nobody could foresee something like that. The tower was protected in such a way that the damage would be limited to one story, but it wouldn't travel to the other stories.
HARRIS: The planes that crashed yesterday were much bigger than that. They were 757s.
SWIRSKY: And also the fuel capacity is much more tremendous.
HARRIS: Exactly. That's what I want to ask you about. Which was it that made the biggest difference? Was it the impact felt from the larger plane, or was it the heat generated by the burning and that much fuel.
SWIRSKY: I imagine, when I saw the pictures of the implosion of the building, it looks like the fuel must have leaked right to the core of the building, and from there it was the massive explosion that caused the building to collapse. So it was something completely unforeseen, so far as the design criteria was (concerned).
HARRIS: Let me ask one final question, if I may. Considering what you know about the building -- you say it was constructed like a pipe, these two buildings -- and the manner in which we saw them collapse, does that give you any hope at all that the way it collapsed, there will be more packets inside, at the bottom, where survivors could be found?
SWIRSKY: Well, I sure hope so. We pray that there will be survivors and that this won't happen again. It's a terrible, terrible, incredible tragedy.
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Page last edited by: TJW
It appears that you called it exactly right, _Jim. It's too bad that on the thread where you explained this you were pooped on by a bunch of anarchist, conspiracy-sniffing loons.
What is this guy talking about? The 747 was flying in 1969.
Very true. It is getting to the point that no Jew was ever killed by the Nazis either, according to them.
It's too bad that on the thread where you explained this you were pooped on by a bunch of anarchist, conspiracy-sniffing loons.I allow two types of living beings to 'poop' on me on account of *who* they are -- one group is the 1) anarchy-bound, conspiracy-sniffing loons and the other is 2) a member of the Cockatiel (bird) family.
Both groups possess about the same intelligence level, one group, however, *is* working at maximum intellectual capacity ...
I came across this pice while debating this subject with another group:
From:http://lava.ds.arch.tue.nl/lava/people/rob/slany/
TUBULAR SYSTEMS
@@@ A recent development in structural design is the concept of tubular behaviour introduced by Fazlur Khan of S.O.M. At present, four of the world's five tallest buildings are tubular systems. They are the Hancock Building, the Sears Building, and the Standard Oil Building in Chicago, and the World Trade Center in New York.
Tubular systems are so efficient that in most cases the amount of structural material used per square foot of floor space is comparable to that used in conventionally framed buildings half the size.
Tubular design assumes that the facade structure responds to lateral loads as a closed hollow box beam cantilevering out of the ground. Since the exterior walls resist all or most of the wind load, costly interior diagonal bracing or shear walls are eliminated.
The tube's walls consist of closely spaced columns around the perimeter of the building tied together by deep spandrel beams. This facade structure looks like a perforated wall. The stiffness of the facade wall may be further increased by adding diagonal braces, causing trusslike action. The rigidity of the tube is so high that it responds to lateral loading similar to a cantilever beam.
As we see later, the exterior tube alone can resist all lateral loads entirely, or it can be further stiffened by adding interior bracing of some kind. The earliest application of the tubular concept, was first used in the 43-story Dewitt Chestnut Apartment Building in Chicago (S.O.M., 1961).
In this Vierendeel tube system the exterior walls of the building, consisting of a closely spaced rectangular grid of beams and columns rigidly connected together, resist lateral loads through cantilever tube action without using interior bracing.
The interior columns are assumed to carry gravity loads only and do not contribute to the exterior tube's stiffness. The stiff floors act as diaphragms with respect to distributing the lateral forces to the perimeter walls.
Other examples of hollow framed tube buildings are the 83-story Standard Oil Building in Chicago and the 110-story World Trade Center in New York.
Although these buildings have interior cores, they act as hollow tubes because the cores are not designed to resist lateral loads.
They bugged me too. On the night of 9/11 and on 9/12 I posted some responses to some other goofy speculations, in which I discussed the possible failure mechanism, with the principal culprit being the fire, but not to the level of technical detail as you have collected here. I repeat, you have done us all a great service. Thank you very much.
It's an interesting figure I plucked from a quick read that the building had an extimated mass of 1,000,000 tons. If contents were 70 tons per floor and we have 220 floors between the two towers, that brings the debris to 1,154,000 tons. If building 7 and the hotel and others are thrown in that is approximately 1,500,000 tons.
As of today they have said they have moved 20,000 tons of debris which means that they are only 1.33 Percent through the pile.
Damn!
This occured to me too. The fact that it fell straight down(almost like a planned demolition) saved untold thousands of lives.
I know they are supposed to withstand tremendous stresses and some have withstood the test of time, but it still seems to me that A Pyramid shape would be much more sturdy. I particularly like the Ziggurat style where there are tiers.
Of course it would require a little more real estate but I am certain that a pyramid shape would withstand much more stress. I even like the BankAmerica pyramid although it does not have a large enough base.
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