Interesting lecture on WTC 7
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Joined: Apr 2005
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RE: Interesting lecture on WTC 7
The letter you posted says that people claimed the steel softened. Every engineer knows that is not what the report claimed.
Buckling is not a product of softening. It is a product of pressure. Steel expands huge amounts with heat. .00065 is the coefficient of linear expansion. So say they are 40' spans increased ~1900 degrees fahrenheit. That is .4 feet of expansion. And the design of the building used a pin system designed for resisting forces from the building. Expansion pulled/ broke the pins (which should have been bolts) off the columns and the outside colapsed. The calcs are so simple, like sophmore engineering.
Ultimately, if you want to claim something was wrong, attack the engineer who built all the buildings with the idea that he could do it most cheaply. And the fact that cheap engineering still happens today. Heck this is Audi Forums, you want to know why you ignition switches burn up, because it is cheaper to have a few million burn up before warranty that to recall all of them. The building, it was cheaper to not fireproof properly, go with incorrect fireproofing on the stairwell to save weight because the building was not designed originally with proper safety factors, use pins instead of bolts. Light weight design killed the building. It was the race to be the tallest building. And the surrounding buildings were built poorly with it.
Buckling is not a product of softening. It is a product of pressure. Steel expands huge amounts with heat. .00065 is the coefficient of linear expansion. So say they are 40' spans increased ~1900 degrees fahrenheit. That is .4 feet of expansion. And the design of the building used a pin system designed for resisting forces from the building. Expansion pulled/ broke the pins (which should have been bolts) off the columns and the outside colapsed. The calcs are so simple, like sophmore engineering.
Ultimately, if you want to claim something was wrong, attack the engineer who built all the buildings with the idea that he could do it most cheaply. And the fact that cheap engineering still happens today. Heck this is Audi Forums, you want to know why you ignition switches burn up, because it is cheaper to have a few million burn up before warranty that to recall all of them. The building, it was cheaper to not fireproof properly, go with incorrect fireproofing on the stairwell to save weight because the building was not designed originally with proper safety factors, use pins instead of bolts. Light weight design killed the building. It was the race to be the tallest building. And the surrounding buildings were built poorly with it.
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Joined: Apr 2005
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RE: Interesting lecture on WTC 7
It was not built like other buildings. It was an inner and outer column set with spandrels connected by pins.
The pins failed in the buckling, that is what the report claimed. The spandrels compressed the columns and the pins sheared. Then the spandrels were able to move, and bucled out of position.
The pins failed in the buckling, that is what the report claimed. The spandrels compressed the columns and the pins sheared. Then the spandrels were able to move, and bucled out of position.
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3rd Gear
Joined: Apr 2005
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RE: Interesting lecture on WTC 7
ORIGINAL: dan908
The letter you posted says that people claimed the steel softened. Every engineer knows that is not what the report claimed.
Buckling is not a product of softening. It is a product of pressure. Steel expands huge amounts with heat. .00065 is the coefficient of linear expansion. So say they are 40' spans increased ~1900 degrees fahrenheit. That is .4 feet of expansion. And the design of the building used a pin system designed for resisting forces from the building. Expansion pulled/ broke the pins (which should have been bolts) off the columns and the outside colapsed. The calcs are so simple, like sophmore engineering.
Ultimately, if you want to claim something was wrong, attack the engineer who built all the buildings with the idea that he could do it most cheaply. And the fact that cheap engineering still happens today. Heck this is Audi Forums, you want to know why you ignition switches burn up, because it is cheaper to have a few million burn up before warranty that to recall all of them. The building, it was cheaper to not fireproof properly, go with incorrect fireproofing on the stairwell to save weight because the building was not designed originally with proper safety factors, use pins instead of bolts. Light weight design killed the building. It was the race to be the tallest building. And the surrounding buildings were built poorly with it.
The letter you posted says that people claimed the steel softened. Every engineer knows that is not what the report claimed.
Buckling is not a product of softening. It is a product of pressure. Steel expands huge amounts with heat. .00065 is the coefficient of linear expansion. So say they are 40' spans increased ~1900 degrees fahrenheit. That is .4 feet of expansion. And the design of the building used a pin system designed for resisting forces from the building. Expansion pulled/ broke the pins (which should have been bolts) off the columns and the outside colapsed. The calcs are so simple, like sophmore engineering.
Ultimately, if you want to claim something was wrong, attack the engineer who built all the buildings with the idea that he could do it most cheaply. And the fact that cheap engineering still happens today. Heck this is Audi Forums, you want to know why you ignition switches burn up, because it is cheaper to have a few million burn up before warranty that to recall all of them. The building, it was cheaper to not fireproof properly, go with incorrect fireproofing on the stairwell to save weight because the building was not designed originally with proper safety factors, use pins instead of bolts. Light weight design killed the building. It was the race to be the tallest building. And the surrounding buildings were built poorly with it.
(Not that WTC 1 and 2 has anything to do with this thread, as it is about WTC 7, go figure)
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Joined: Apr 2005
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RE: Interesting lecture on WTC 7
It is too bad this is not available downladable (that I can find) it explains the design of the buildings and you would see why the failure occured.
http://store.aetv.com/html/subject/i...tml?id=wwf1033
http://store.aetv.com/html/subject/i...tml?id=wwf1033
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3rd Gear
Joined: Apr 2005
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RE: Interesting lecture on WTC 7
Answer me this Dan, as this is the 'burning' question. Why did it come down the way it did if it was due to expansion??? Why not topple to one side, or one weaker side collapse first? Why the whole lot, and at the rate of gravity, with no impedence from the building under it? It takes weeks to prepare a building to collapse in it's own footprint. If we could do it by setting a few fires then demolition companies will be way out of pocket!
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3rd Gear
Joined: Apr 2005
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RE: Interesting lecture on WTC 7
Want to see a good program? Check out
http://video.google.com/videoplay?do...87809452836609
http://video.google.com/videoplay?do...08674021515498
http://video.google.com/videoplay?do...+of+nightmares
Not quack jobs, but done by the BBC about the whole war on terror, and the lead up to the whole al quaeda thing. Good program.
http://video.google.com/videoplay?do...87809452836609
http://video.google.com/videoplay?do...08674021515498
http://video.google.com/videoplay?do...+of+nightmares
Not quack jobs, but done by the BBC about the whole war on terror, and the lead up to the whole al quaeda thing. Good program.
2nd Gear
Joined: Apr 2005
Posts: 505
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RE: Interesting lecture on WTC 7
In the footage they show of the first collapse, there is an obvious inner stairwell that remains. I cannot say on building 7, but the theory that is proposed about the failure does follow engineering principles.
Jones theories do not pencil, and he does not pencil them so people can see what he is claiming. It is all emotional. Fema and Katrina, poor examples, Bush's war on terror, etc. it is to appeal to the normal person with no engineering judgement to say "yeah" "yeah" "that jerk" Bush did it". I can't say I like or voted for bush but I am not going to listen to his emotional crap.
Jones theories do not pencil, and he does not pencil them so people can see what he is claiming. It is all emotional. Fema and Katrina, poor examples, Bush's war on terror, etc. it is to appeal to the normal person with no engineering judgement to say "yeah" "yeah" "that jerk" Bush did it". I can't say I like or voted for bush but I am not going to listen to his emotional crap.
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3rd Gear
Joined: Apr 2005
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RE: Interesting lecture on WTC 7
You cannot say on Building 7.. Oh great.. well any chance you could join the thread. Which bits do not parry with engineering principles? It's fine to say they don't but any chance you could point us in the direction of the stuff that disputes his stuff? Again, WTC 7 collapsed into its own footprint, after some fires 'raged' on the 47 th floor. For whatever reason the building dropped in a symmetrical fashion. Why would that happen if the structure fails? For it to happen, EVERY support structure would have to fail, at exactly the same time, and fire, especially random one, would not create this scenario.