As soon as the first plane hit Tower 1 my colleagues and I gave a 1 hour timeframe for the bldg to collapse altogether. It is common knowledge to many of us in NYC that the steel in these skyscrapers melts after about an hour of incineration.
DOD your comment about toppling one could topple the other was the theory that the terrorists had in '93. They had hoped that the explosion would knock the one building into the other. I thought what one radio anouncer said was interesting it was that the empty space when ever you look at the new york sky line will always serve as a monument to the events that took place today. They also commented on how vonerable the Empire State Building looked standing there all by its self has the highest building in NY City
Well, I'm certainly not a Grizzlies fan anymore, so I guess I should do something about the handle. ;-) Good observation. I agree with you on this for the first building, but the second was hit much higher up and the building seemed to pancake when it failed. The failure seemed to be "progressive collapse" which DoDs info said it was supposed to be able to withstand. I'll be talking to some structural guys tomorrow, so I'll ask and pass on what they tell me.
I think that not only the obvious stresses placed on the building by the weight of the airplane debris and the weakening of the structure by the impact and the intensely hot fire that was burning due to all the jet fuel caused its collapse. But also the inevitable fire sprinklers that must have gone off on every floor...and the possibly severed mains that would transport those large volumes of water to the top of a 110 story building...after all water is very dense and heavy as we all know...so the extra weight of all that water being pumped up there might have contributed to the collapse as well. This combination of structural damage and stress could not be planned for adequately.
Many buildings actualy have a water supply on the roof for the sprinkler system. On a building this big, I don't know if that's the case.
For you guys that are interested, they talked to the designers of the WTC on television I believe. Their response as I understand it was that the buildings could have withstood those hits (simply amazing in and of itself). However, what really probably brought them down was the intense heat caused by the jet fuel igniting. I believe temperatures of around 3000 degrees or more were created by the burning of that fuel. This in turn probably melted the steel near the point of impact causing floor after floor to collapse downwards. I really also have to feel bad for those guys that worked their tails off in building these 2 wonders of constructions. To see what you toiled and labored over come crashing down like that and take possibly thousands of people with it has got to be the sickest feeling in the world.
A lot of what you guys are saying (about the fire) makes sense. I hadn't taken into account the tremendous temperatures reached with the jet fuel fire. I don't think the weight of the plane nor the impact were the main cause for structural failure. But, then again, I'm no structural engineer. I heard one account that a guy ran back into the lobby when he saw one of the planes hit (1st one?) and as he entered he was met with a fireball, which suppposedly came down the elevator shafts. I hadn't really thought about how fast a fire like this would spread due to the fuel and explosion which furthered the spread. I just never thought a "fire" could bring down a 110-story building.
I was watching an American broadcast of the attacks, and they were talking to an architect. He said that the plans of the WTC are online, and that the terrorists new where to hit the towers to create the most damage. He also said that it was 'lucky' that the towers fell straight down, rather than get knocked over sideways onto other buildings. They also said something about the hijackers being pilots, because at one stage, the second plane did a very quick 270degree turn, which is extremely hard to do in a plane that size.
Does anybody know if they were built so that in the event of a collapse it would fall on its self as apossed to on other buildings.
Mayor Rudy has said that the World Trade Center buildings will be built again and they will be as great as their formers. I believe the building of the buildings will far exceed the $400 million price tag when they were built in the 70's though.
I agree with you 100%. Remember when or hearing about the B-52 bomber that flew into the Empire State Building? It happened and the Empire State Building still stood afterwards and it still stands today.
It was in 1945. And it was a B25, not a B52 (big difference). The planes that hit the WTC were significantly larger, significantly heavier and had a whole lot more fuel and were likely going faster when they hit the structures. Here's a link: http://www.elevator-world.com/magazine/archive01/9603-002.htm
I just heard on CBS radio this evening that the WTC towers had innovative design that posited their strength in the outer shell and that that is why the buildings so definitely collapsed inward rather than toppling. Guess it's true.
The fire caused the building to collapse. Typically there is some sort of fire protection, but with the amount of fuel on board it must have burned away the protective coating. Gravity alone caused it to collapse straight down.
