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Originally posted by Jack Tripper
Thanks for your input Flyer but nobody is asserting it was a "solid" concrete core.
Oldtimer 2
I'm sure it had a concrete foundation,and possibly light concrete floors,if it were constructed of concrete it would be rigid therefore could snap and break apart
Originally posted by Oldtimer2
On a high rise it would have to be built of steel,being that close to the ocean the building would have to have some flex to it,I'm sure it had a concrete foundation,and possibly light concrete floors,if it were constructed of concrete it would be rigid therefore could snap and break apart
Originally posted by Clever Name
Ok so how does this change what happend on Sept. 11? The first thought I had after I saw them burning is that those towers were gona fall. Explosives? Mini-Nukes? are you joking? The collapse clearly starts where the planes hit. As to the statement that no other tower has fallen due to a fire. Show me one that had an airliner with thousands of pounds of jet fuel crash into it. I believe what I saw with my own eyes.
[edit on 22-5-2006 by Clever Name]
Originally posted by Leto
Nicely done Christophera and bsbray11.
Originally posted by JIMC5499
Unless they changed them after 1984 the fire stairs of the WTC were made of poured concrete. This might help explain the presence of the rebar shown in the pictures. My ship was in New York for the July 4th celebration that year and we went to the observation deck on top of one of the towers. There was such a crowd for the elevators that they were letting people use the fire stairs to go down to the main elevator lobby. I definitly remember them being concrete, my feet still hurt from thinking about it.
Originally posted by Clever Name
Ok so how does this change what happend on Sept. 11? The first thought I had after I saw them burning is that those towers were gona fall. Explosives? Mini-Nukes? are you joking? The collapse clearly starts where the planes hit. As to the statement that no other tower has fallen due to a fire. Show me one that had an airliner with thousands of pounds of jet fuel crash into it. I believe what I saw with my own eyes.
[edit on 22-5-2006 by Clever Name]
Originally posted by TxSecret
Oldtimer 2
I'm sure it had a concrete foundation,and possibly light concrete floors,if it were constructed of concrete it would be rigid therefore could snap and break apart
So far as I understand it the concrete that was poured around the center box collumns WTC 1 and 2 was done in sections so what you say does not apply. No one here is trying to say that the "core" was "solid" concrete. It was not.. There was a section of box collumns with a "curtain of concrete" around them.
Originally posted by Christophera
Originally posted by Oldtimer2
On a high rise it would have to be built of steel,being that close to the ocean the building would have to have some flex to it,I'm sure it had a concrete foundation,and possibly light concrete floors,if it were constructed of concrete it would be rigid therefore could snap and break apart
The flex was a serious problem and was exactly the reason the concrete core was used. Flex from wind and sway as well as torsion could deform the tower betond it's calculated load bearing capacity and cause failures. Foundations are always concrete at least. It did have lightweight concrete floors. There is a post earlier in the thread that actually has the architects concrete schedule.
Originally posted by Christophera
Steel reinforced cast treads made from lightweight concrete are standard. The treads are welded into the stairways structure.
How long did it take to get to the bottom?
Originally posted by Christophera
Originally posted by Clever Name
Ok so how does this change what happend on Sept. 11? The first thought I had after I saw them burning is that those towers were gona fall. Explosives? Mini-Nukes? are you joking? The collapse clearly starts where the planes hit. As to the statement that no other tower has fallen due to a fire. Show me one that had an airliner with thousands of pounds of jet fuel crash into it. I believe what I saw with my own eyes.
[edit on 22-5-2006 by Clever Name]
This image shows something that absolutely cannot be a collapse.
Originally posted by JIMC5499
Unless they changed them after 1984 the fire stairs of the WTC were made of poured concrete. This might help explain the presence of the rebar shown in the pictures. My ship was in New York for the July 4th celebration that year and we went to the observation deck on top of one of the towers. There was such a crowd for the elevators that they were letting people use the fire stairs to go down to the main elevator lobby. I definitly remember them being concrete, my feet still hurt from thinking about it.
Originally posted by Christophera
The flex was a serious problem and was exactly the reason the concrete core was used. Flex from wind and sway as well as torsion could deform the tower betond it's calculated load bearing capacity and cause failures.
Robertson and the Port Authority made another choice that proved fateful decades later. They chose not to use thick masonry or cement to encase the three escape stairways in each tower but rather light sheets of gypsum. Although the gypsum was extremely resistant to fire, and less likely than masonry to crack when the building swayed in the wind, it would work only if it remained intact -- and it was much more susceptible to being shaken loose or damaged by an explosion or any other kind of unexpected impact.
He had been kicking around the idea of building shock absorbers into a building, and now he went ahead and developed the idea, eventually patenting it. Called viscoelastic dampers, they were flat metal pieces, two and a half feet long, held together with a tough, rubbery glue developed by 3M. One plate would connect to an exterior column, and two others would be fixed to the underside of a steel truss. When the building swayed in the wind, the plates would slide against one another and damp the motion a little -- a shock absorber. Put 11,000 of them into each tower, as Robertson did, and they became a very good shock absorber.
The second part of Robertson's solution to the motion-sickness problem was a huge support structure called a hat truss, which would sit atop each building and tie its core to its exterior. Robertson realized that the hat truss could add stiffness to the entire building, from top to bottom, by acting as a rigid cap. He also widened the exterior columns slightly, adding further stiffness to the structure.
Originally posted by JIMC5499
Originally posted by Christophera
Steel reinforced cast treads made from lightweight concrete are standard. The treads are welded into the stairways structure.
How long did it take to get to the bottom?
This wasn't cast treads. These were poured sections. Some fairly heavy sections of concrete.
We didn't go all the way to the bottom. Only went about 40 floors. There were more elevators there.
Originally posted by Tha Troubleshoota
Also, the pictures of the sun against the back of the WTC's does nothing but show me where the elevators were. Those small, weak looking columns are very minor structures compared to the building as a whole. They even seem to be conduits for the antennas located at the top of both buildings! WEAK.