mikwut wrote:If you think the contrary hypothesis is crazy then start on page 8 and tell me what is so nuts about the truthers table?
mikwut
Let's start with its title.
Table 1: The Features of a Controlled Demolition versus Fire-induced Failure.There are two columns in this table, but neither reflects what is claimed occurred at WTC1 and 2. They aren't attempting to compare the known facts regarding the collapse of the twin towers with the claims of the investigation but instead include two columns reflecting the towers either fell due to a fire-induced collapse alone, or one has to accept they fell due to a controlled demolition event. They don't include the option that the report claims: structural damage caused by a plane followed by high-intensity fire. They are trying to bias the reader into seeing a preference for one of those two columns intended to match the rows of the table.
So, out of the gate one should be skeptical of the table's value. Anyway.
The NIST website faqs covers each row so let's quote them in order.
Row one: Controlled demo results in total collapse, fire does not.NIST: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 number of jet-fuel ignited multi-floor fires (which reached temperatures as high as 1,000 degrees Celsius, or 1,800 degrees Fahrenheit) 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.
In other words, what happened at WTC 1 and 2 are not consistent with either column in the table but require a third condition - what happens when a building is hit by a large plane and set on fire with jet fuel.
Row 2: Controlled demo involves sudden collapse, fire includes collapse after many minutes or hoursNIST: 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.
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NIST estimated the elapsed times for the first exterior panels to strike the ground after the collapse initiated in each of the towers to be approximately 11 seconds for WTC 1 and approximately 9 seconds for WTC 2. These elapsed times were based on: (1) precise timing of the initiation of collapse from video evidence, and (2) ground motion (seismic) signals recorded at Palisades, N.Y., that also were precisely time-calibrated for wave transmission times from lower Manhattan (see NIST NCSTAR 1-5A).
As documented in Section 6.14.4 of NIST NCSTAR 1, these collapse times show that:
"The structure below the level of collapse initiation offered minimal resistance to the falling building mass at and above the impact zone. The potential energy released by the downward movement of the large building mass far exceeded the capacity of the intact structure below to absorb that energy through energy of deformation.
Since the stories below the level of collapse initiation provided little resistance to the tremendous energy released by the falling building mass, the building section above came down essentially in free fall, as seen in videos. As the stories below sequentially failed, the falling mass increased, further increasing the demand on the floors below, which were unable to arrest the moving mass."
In other words, the momentum (which equals mass times velocity) of the 12 to 28 stories (WTC 1 and WTC 2, respectively) falling on the supporting structure below (which was designed to support only the static weight of the floors above and not any dynamic effects due to the downward momentum) so greatly exceeded the strength capacity of the structure below that it (the structure below) was unable to stop or even to slow the falling mass. The downward momentum felt by each successive lower floor was even larger due to the increasing mass.
From video evidence, significant portions of the cores of both buildings (roughly 60 stories of WTC 1 and 40 stories of WTC 2) are known to have stood 15 to 25 seconds after collapse initiation before they, too, began to collapse. Neither the duration of the seismic records nor video evidence (due to obstruction of view caused by debris clouds) are reliable indicators of the total time it took for each building to collapse completely.
Row 3: The collapse lasts a matter of seconds in a controlled demolition while it takes place over a longer duration in a fire.NIST: See row 2.
Again, the attempt to shoehorn what happened on 9/11 is creating a false sense that one of the two scenarios in the table fits better when the facts don't fit either column because the cause of the collapse isn't accurately represented in the table.
Row 4: In a demolition, the collapse starts at the base while in a fire the collapse initiates around the fire event.NIST: 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 City 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.
Row 5: Descent in a controlled demolition is symmetrical, asymmetrical in a fire-caused collapseNIST: "The structure below the level of collapse initiation offered minimal resistance to the falling building mass at and above the impact zone. The potential energy released by the downward movement of the large building mass far exceeded the capacity of the intact structure below to absorb that energy through energy of deformation.
Since the stories below the level of collapse initiation provided little resistance to the tremendous energy released by the falling building mass, the building section above came down essentially in free fall, as seen in videos. As the stories below sequentially failed, the falling mass increased, further increasing the demand on the floors below, which were unable to arrest the moving mass."
Row 6: Free fall speeds in controlled demolition, slowed by lower floors in fire-caused collapses.NIST: See quotes used in Rows 3 - 6. Again, the issue is what happened is based on a building being damaged by a plane, suffering critical structural damage and internal jet-fueled fires within the damaged sections of the building for a long period of time which led to it's collapse. Neither column in the table uniquely covers that event exclusively. Neither column accurately describes what actually happened which should tell you they aren't the right comparisons. The table is a misdirection that you fell for, mikwut.
Row 7: Smaller explosions are visible outside of the building in controlled demolitions, only happen at the fire location if at all in fire-caused collapses.NIST: As stated in Section 6.14.4 of NIST NCSTAR 1, the falling mass of the building compressed the air ahead of it—much like the action of a piston—forcing smoke and debris out the windows as the stories below failed sequentially.
These puffs were observed at many locations as the towers collapsed. In all cases, they had the appearance of jets of gas being pushed from the building through windows or between columns on the mechanical floors. Such jets are expected since the air inside the building is compressed as the tower falls and must flow somewhere as the pressure builds. It is significant that similar "puffs" were observed numerous times on the fire floors in both towers prior to their collapses, perhaps due to falling walls or portions of a floor. Puffs from WTC 1 were even observed when WTC 2 was struck by the aircraft. These observations confirm that even minor overpressures were transmitted through the towers and forced smoke and debris from the building.
Row 8: Concrete sometimes gets pulverized in controlled demolitions, not in fire-caused collapses where most of the building is left intactNIST: See above responses. The table is trying to account for the pulverizing of concrete and debris fines that scattered out from the collapsing towers and affected large areas using two conditions that don't fit. This is another example of the table trying to artificially create an either-or condition and ask the reader to pick one when the claims regarding what happened aren't actually represented in the table.
Row 9: Same as 8, but with steel.These are bad arguments you're putting forward.
