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Originally posted by LeftBehind
Yes it is amazing that it took this long to realize that I was right all along.
But seriously, it was a good debate, even if the topic turned out to be nothing so special anyhow.
I guess this is just another example of anything 9-11 related being blown out of proportion. And this wasnt even related to 9-11.
Originally posted by Valhall
BY THE WAY, if you play the audio on slow speed, Bush sounds drunk! LMAO...it's funnier than all get out.
Originally posted by GradyPhilpott
Two 400,000 pound aircraft with full loads of fuel crashed into the World Trade Center towers and people cannot believe that that was sufficient to cause massive structural failure.
"There are none so blind as those who will not see."
Originally posted by GradyPhilpott
Two 400,000 pound aircraft with full loads of fuel crashed into the World Trade Center towers and people cannot believe that that was sufficient to cause massive structural failure.
Originally posted by bsbray11
Even NIST and FEMA will tell you the impacts were insignificant, lol. You should stick with the military recruiting.
Too bad those buildings were so redundant, or people like Grady would be able to make such simplistic statements and be somewhat accurate.
Why did NIST not consider a “controlled demolition” hypothesis with matching computer modeling and explanation as it did for the “pancake theory” hypothesis?
A key critique of NIST’s work lies in the complete lack of analysis supporting a “progressive collapse” after the point of collapse initiation and the lack of consideration given to a controlled demolition hypothesis.
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.... This included consideration of a number of hypotheses for the collapses of the towers.
Some 200 technical experts—including about 85 career NIST experts and 125 leading experts from the private sector and academia—reviewed tens of thousands of documents, interviewed more than 1,000 people, reviewed 7,000 segments of video footage and 7,000 photographs, analyzed 236 pieces of steel from the wreckage, performed laboratory tests and sophisticated computer simulations of the sequence of events that occurred from the moment the aircraft struck the towers until they began to collapse.
Based on this comprehensive investigation, 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 (which reached temperatures as high as 1,000 degrees Celsius) significantly weakened the floors and columns with dislodged fireproofing to the point where 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. Both photographic and video evidence—as well as accounts from the New York Police Department aviation unit during a half-hour period prior to collapse—support this sequence for each tower.
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.
Diagram of Composite WTC Floor System
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.
Video evidence also showed unambiguously that the collapse progressed from the top to the bottom, and there was no evidence (collected by NIST, or by the New York Police Department, the Port Authority Police Department or the Fire Department of New York) of any blast or explosions in the region below the impact and fire floors as the top building sections (including and above the 98th floor in WTC 1 and the 82nd floor in WTC 2) began their downward movement upon collapse initiation.
In summary, NIST found no corroborating evidence for alternative hypotheses suggesting that the WTC towers were brought down by controlled demolition using explosives planted prior to Sept. 11, 2001. NIST also did not find any evidence that missiles were fired at or hit the towers. Instead, photographs and videos from several angles 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. [emphasis mine]
wtc.nist.gov...
14. Why is the NIST investigation of the collapse of WTC 7 (the 47-story office building that collapsed on Sept. 11, 2001, hours after the towers) taking so long to complete? Is a controlled demolition hypothesis being considered to explain the collapse?
When NIST initiated the WTC investigation, it made a decision not to hire new staff to support the investigation. After the June 2004 progress report on the WTC investigation was issued, the NIST investigation team stopped working on WTC 7 and was assigned full-time through the fall of 2005 to complete the investigation of the WTC towers. With the release and dissemination of the report on the WTC towers in October 2005, the investigation of the WTC 7 collapse resumed. Considerable progress has been made since that time, including the review of nearly 80 boxes of new documents related to WTC 7, the development of detailed technical approaches for modeling and analyzing various collapse hypotheses, and the selection of a contractor to assist NIST staff in carrying out the analyses. It is anticipated that a draft report will be released by early 2007.
The current NIST working collapse hypothesis for WTC 7 is described in the June 2004 Progress Report on the Federal Building and Fire Safety Investigation of the World Trade Center Disaster (Volume 1, page 17, as well as Appendix L), as follows:
An initial local failure occurred at the lower floors (below floor 13) of the building due to fire and/or debris-induced structural damage of a critical column (the initiating event) which supported a large-span floor bay with an area of about 2,000 square feet;
Vertical progression of the initial local failure occurred up to the east penthouse, and as the large floor bays became unable to redistribute the loads, it brought down the interior structure below the east penthouse; and
Triggered by damage due to the vertical failure, horizontal progression of the failure across the lower floors (in the region of floors 5 and 7 that were much thicker and more heavily reinforced than the rest of the floors) resulted in a disproportionate collapse of the entire structure.
This hypothesis may be supported or modified, or new hypotheses may be developed, through the course of the continuing investigation. NIST also is considering whether hypothetical blast events could have played a role in initiating the collapse. While NIST has found no evidence of a blast or controlled demolition event, NIST would like to determine the magnitude of hypothetical blast scenarios that could have led to the structural failure of one or more critical elements.
[emphasis mine]
wtc.nist.gov...
Originally posted by bsbray11
Grady, I don't think anyone is questioning your abilities to copy and paste.
Originally posted by GradyPhilpott
It's called providing substantiation for my previous post
Originally posted by bsbray11
Your previous post asserted that the impacts caused "massive structural failure". Unless you consider >13% of the perimeter columns severe in structures designed several times redundant (from NIST figures!), please show me where NIST has substantiated this claim.
Originally posted by GradyPhilpott
Based on this comprehensive investigation, 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 (which reached temperatures as high as 1,000 degrees Celsius) significantly weakened the floors and columns with dislodged fireproofing to the point where 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. Both photographic and video evidence—as well as accounts from the New York Police Department aviation unit during a half-hour period prior to collapse—support this sequence for each tower.
wtc.nist.gov...