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NIST conducted an extremely thorough three-year investigation into what caused the WTC towers to collapse, as explained in NIST’s dedicated Web site, wtc.nist.gov....
NIST’s findings do not support the “pancake theory” of collapse, which is premised on a progressive failure of the floor systems in the WTC towers (the composite floor system—that connected the core columns and the perimeter columns—consisted of a grid of steel “trusses” integrated with a concrete slab; see diagram below). Instead, the NIST investigation showed conclusively that the failure of the inwardly bowed perimeter columns initiated collapse and that the occurrence of this inward bowing required the sagging floors to remain connected to the columns and pull the columns inwards. Thus, the floors did not fail progressively to cause a pancaking phenomenon.
The collapse of the WTC towers was not caused either by a conventional building fire or even solely by the concurrent multi-floor fires that day. Instead, NIST concluded that the WTC towers collapsed because: (1) the impact of the planes severed and damaged support columns, dislodged fireproofing insulation coating the steel floor trusses and steel columns, and widely dispersed jet fuel over multiple floors; and (2) the subsequent unusually large, jet-fuel ignited multi-floor fires weakened the now susceptible structural steel. No building in the United States has ever been subjected to the massive structural damage and concurrent multi-floor fires that the towers experienced on Sept. 11, 2001
Furthermore, a very large quantity of thermite (a mixture of powdered or granular aluminum metal and powdered iron oxide that burns at extremely high temperatures when ignited) or another incendiary compound would have had to be placed on at least the number of columns damaged by the aircraft impact and weakened by the subsequent fires to bring down a tower.
This is awesome. It is an answer to all of your questions and you treat it as if it means nothing.
Originally posted by esdad71
it will be ignored. Sad....
The damage from the impact of a Boeing 767 aircraft (which is about 20 percent bigger than a Boeing 707) into each tower is well documented in NCSTAR 1-2. The massive damage was caused by the large mass of the aircraft, their high speed and momentum...
Pure liquid aluminum would be expected to appear silvery. However, the molten metal was very likely mixed with large amounts of hot, partially burned, solid organic materials (e.g., furniture, carpets, partitions and computers) which can display an orange glow, much like logs burning in a fireplace. The apparent color also would have been affected by slag formation on the surface.
Thermite burns slowly relative to explosive materials and can require several minutes in contact with a massive steel section to heat it to a temperature that would result in substantial weakening.
Many such liquid flows were observed from near this location in the seven minutes leading up to the collapse of this tower.
floors sagged and pulled inward on the perimeter columns. This led to the inward bowing of the perimeter columns and failure of the south face of WTC 1 and the east face of WTC 2, initiating the collapse of each of the towers
NIST’s findings do not support the “pancake theory” of collapse, which is premised on a progressive failure of the floor systems in the WTC towers
NIST’s findings also do not support the “controlled demolition” theory since there is conclusive evidence that:
* the collapse was initiated in the impact and fire floors of the WTC towers and nowhere else, and;
* the time it took for the collapse to initiate (56 minutes for WTC 2 and 102 minutes for WTC 1) was dictated by (1) the extent of damage caused by the aircraft impact, and (2) the time it took for the fires to reach critical locations and weaken the structure to the point that the towers could not resist the tremendous energy released by the downward movement of the massive top section of the building at and above the fire and impact floors.
clearly show that the collapse initiated at the fire and impact floors and that the collapse progressed from the initiating floors downward until the dust clouds obscured the view.
Knocked off fire proofing
massive structural damage
Originally posted by bsbray11
Pure liquid aluminum would be expected to appear silvery. However, the molten metal was very likely mixed with large amounts of hot, partially burned, solid organic materials (e.g., furniture, carpets, partitions and computers) which can display an orange glow, much like logs burning in a fireplace. The apparent color also would have been affected by slag formation on the surface.
Did I miss the silvery molten aluminum coming out of the corner of WTC2, or do the rest of you realize that it just wasn't there, too? All I saw was bright yellow-orange running out.
Thermite burns slowly relative to explosive materials and can require several minutes in contact with a massive steel section to heat it to a temperature that would result in substantial weakening.
as a reason there wouldn't have been thermite, even right after stating that the molten material could be seen coming from WTC2 for several minutes before its collapse.
Many such liquid flows were observed from near this location in the seven minutes leading up to the collapse of this tower.
So... any critical thinking going on over there at all?
Therefore, while a thermite reaction can cut through large steel columns, many thousands of pounds of thermite would need to have been placed inconspicuously ahead of time, remotely ignited, and somehow held in direct contact with the surface of hundreds of massive structural components to weaken the building. This makes it an unlikely substance for achieving a controlled demolition.
But like I said, the majority of it seems to me to be similar to the counter-arguments commonly made here on ATS.
Originally posted by Slapnuts
The NIST is PURPOSELY misleading in their statement here saying a 767 is LARGER but ignoring that it would have hit with far les force and far less momentum than a 707.
The capability to conduct rigorous simulations of the aircraft impact, the growth and spread of the ensuing fires, and the effects of fires on the structure is a recent development. Since the approach to structural modeling was developed for the NIST WTC investigation, the technical capability available to the PANYNJ and its consultants and contactors to perform such analyses in the 1960s would have been quite limited in comparison to the capabilities brought to bear in the NIST investigation.
Originally posted by esdad71
There is also proof that there was buckling of the floor trusses in the fire that occured in 1975.
Originally posted by LeftBehind
Therefore, while a thermite reaction can cut through large steel columns, many thousands of pounds of thermite would need to have been placed inconspicuously ahead of time, remotely ignited, and somehow held in direct contact with the surface of hundreds of massive structural components to weaken the building. This makes it an unlikely substance for achieving a controlled demolition.
Imagine that, using facts to build an argument.
Originally posted by Griff
Why couldn't it be planes and fire with the help of a few hundred pounds of thermite?
I just can't believe how people can think that plane damage and fire can cause the buildings to fail, but they would need thousands of pounds of explosives/thermite when in both scenerios you have the plane impacts and subsequent fires. It's a red herring/smoke screen if you ask me.
Originally posted by Slap Nuts
Originally posted by esdad71
There is also proof that there was buckling of the floor trusses in the fire that occured in 1975.
Yet, the building didn't collapse!!!
Not even a single chunk of concrete fell!!
You are off topic... take it somewhere else.
Originally posted by tuccy
Originally posted by Slap Nuts
Originally posted by esdad71
There is also proof that there was buckling of the floor trusses in the fire that occured in 1975.
Yet, the building didn't collapse!!!
Not even a single chunk of concrete fell!!
You are off topic... take it somewhere else.
Maybe because the fire was only on a part of only one floor and there was no 767 to slam into the building?