Steve Watson | Wednesday, June 20, 2007
A new study into the collapse of the World Trade Center towers has been released that correlates with the findings of the 2005 National Institute of Standards and Technology (NIST) report and supports the theory that intense fires weakened the structure and initiated “global collapse”. Much like the NIST report however, it is fatally flawed.
A computer simulation of the 2001 World Trade Center attacks supports a federal agency’s findings that the initial impact from the hijacked airplanes stripped away crucial fireproofing material and that the weakened towers collapsed under their own weight.
In reality the new study by structural engineers at Purdue University does not provide any scientific evidence to explain the collapses, it merely confirms the NIST fireproofing claim in its animation and then jumps to the same conclusions as NIST, conclusions that fly in the face of the laws of physics.
“The aircraft moved through the building as if it were a hot and fast lava flow,” Mete Sozen, a professor of structural engineering and a lead investigator says. “Consequently, much of the fireproofing insulation was ripped off the structure. Even if all of the columns and girders had survived the impact – an unlikely event – the structure would fail as the result of a buckling of the columns. The heat from an ordinary office fire would suffice to soften and weaken the unprotected steel. Evaluation of the effects of the fire on the core column structure, with the insulation removed by the impact, showed that collapse would follow whatever the number of columns cut at the time of the impact.”
There are a number of problems with these claims. Lets take them one by one:
1. Even if the fireproofing had been removed the idea that a regular office fire could weaken steel and cause buckling requires a leap of faith to say the least.
Statements made by Kevin Ryan of Underwriters Laboratories, the company that certified the steel components used in the construction of the World Trade Center towers confirm that the claim is ridiculous. In a 2004 letter to NIST Ryan wrote:
We know that the steel components were certified to ASTM E119. The time temperature curves for this standard require the samples to be exposed to temperatures around 2000F for several hours. And as we all agree, the steel applied met those specifications. Additionally, I think we can all agree that even un-fireproofed steel will not melt until reaching red-hot temperatures of nearly 3000F.
Now I’m no physicist but given that Jet fuel doesn’t even burn to those temperatures (No fuel, not even jet fuel, which is really just refined kerosene, will burn hotter than 1500 degrees Fahrenheit) the idea that “ordinary office fires” would is patently farcical.
2. Intense fires lasted only minutes
The NIST report states that: “The initial jet fuel fires themselves lasted at most a few minutes and office material fires would burn out within about 20 minutes in a given location.” (NIST, 2005; p. 179.)
This is further corroborated by the fact that intense dark choking smoke was being emitted from the towers before they collapsed indicating the fires were oxygen starved and burning at low temperatures.
In addition NIST stated that of the more than 170 areas examined on 16 perimeter column panels, only three columns had evidence that the steel reached temperatures above 250ºC… Only two core column specimens had sufficient paint remaining to make such an analysis, and their temperatures did not reach 250 ºC. … Using metallographic analysis, NIST determined that there was no evidence that any of the samples had reached temperatures above 600 ºC. (NIST, 2005, pp. 176-177)
At any given location, the duration of [air, not steel] temperatures near 1,000oC was about 15 min to 20 min. The rest of the time, the calculated temperatures were near 500oC or below.” (NIST, 2005, p. 127, emphasis added.)
In addition the firefighter tapes released to the New York Times clearly indicate that right before the towers collapsed the fires were minimal and under control.
So even if you believe unprotected steel can be melted by office material fires, the official NIST report states those fires would not last more than 20 minutes and also states that beams recovered show that they were not exposed to high enough temperatures to be significantly weakened.
3. The study contradicts multiple statements made by the structural engineers who designed the buildings:
Ayhan Irfanoglu, a Purdue professor of civil engineering, said half of the building’s weight-bearing columns were concentrated at the cores of the towers.
“When that part is wiped out, the structure comes down,” Irfanoglu said. “We design structures with some extra capacity to cover some uncertainties, but we never anticipate such heavy demand coming from an aircraft impact. If the columns were distributed, maybe, the fire could not take them out so easily.”
This is directly contradicted by the following statements from the designers of the buildings:
“A previous analysis [by WTC building designers], carried out early in 1964, calculated that the towers would handle the impact of a 707 traveling at 600 mph without collapsing”
(Between Early 1984 and October 1985):
“However, O’Sullivan consults ‘one of the trade center’s original structural engineers, Les Robertson, on whether the towers would collapse because of a bomb or a collision with a slow-moving airplane.’ He is told there is ‘little likelihood of a collapse no matter how the building was attacked.’”
“[Building designer] John Skilling recounts his people having carried out an analysis which found the twin towers could withstand the impact of a Boeing 707. Our analysis indicated the biggest problem would be the fact that all the fuel (from the airplane) would dump into the building. There would be a horrendous fire. A lot of people would be killed.” But, he says, “The building structure would still be there.”
“The analysis Skilling is referring to is likely one done in early 1964, during the design phase of the towers. A three-page white paper, dated February 3, 1964, described its findings: “The buildings have been investigated and found to be safe in an assumed collision with a large jet airliner (Boeing 707—DC 8) traveling at 600 miles per hour. Analysis indicates that such collision would result in only local damage which could not cause collapse or substantial damage to the building and would not endanger the lives and safety of occupants not in the immediate area of impact.” However, besides this paper, no documents are known detailing how this analysis was made.”
“Leslie Robertson, one of the two original structural engineers for the World Trade Center, is asked at a conference in Frankfurt, Germany what he had done to protect the twin towers from terrorist attacks. He replies, ‘I designed it for a 707 to smash into it,’ though does not elaborate further.”
[Leslie Robertson:] “The twin towers were in fact the first structures outside the military and nuclear industries designed to resist the impact of a jet airplane.”
[Frank A. Demartini:] “The building was designed to have a fully loaded 707 crash into it. That was the largest plane at the time. I believe that the building probably could sustain multiple impacts of jetliners because this structure is like the mosquito netting on your screen door — this intense grid — and the jet plane is just a pencil puncturing that screen netting. It really does nothing to the screen netting.” Frank A. Demartini, on-site construction manager for the World Trade Center, spoke of the resilience of the towers in an interview recorded on January 25, 2001.
Sept 3-7, 2001—just before 9/11
“The Boeing 707 was the largest in use when the towers were designed. [Leslie] Robertson conducted a study in late 1964, to calculate the effect of a 707 weighing 263,000 pounds and traveling at 180 mph crashing into one of the towers. [Robertson] concluded that the tower would remain standing. However, no official report of his study has ever surfaced publicly.”
4. The study, like NIST’s, only focuses on a portion of the building:
“To estimate the serious damage to the World Trade Center core columns, we assembled a detailed numerical model of the impacting aircraft as well as a detailed numerical model of the top 20 stories of the building,” Sozen says. “We then used weeks of supercomputer time over a number of years to simulate the event in many credible angles of impact of the aircraft.”
So they only focused on 20 stories of the building.
In a similar fashion NIST admitted that it didn’t even attempt to model the undamaged portions of the buildings and only modeled a portion of each tower in any detail — its “global floor model” which consisted of “several stories below the impact area to the top of the structure.” Thus the structurally intact floors 1-91 of WTC 1 and floors 1-77 of WTC 2 were excluded from the so called “global” models of the towers. NIST provides no evidence that its model even predicted “collapse initiation”.
Neither the NIST report nor the new Purdue report nor any other report has ever explained how all of the critical columns can suffer buckling at the same time to precipitate the complete and nearly symmetrical collapse observed.
Physics Professor Steven Jones points out that the total annihilation of the building, core columns and all, defies the laws of physics unless it was artificially exploded:
“Where is the delay that must be expected due to conservation of momentum – one of the foundational Laws of Physics? That is, as upper-falling floors strike lower floors – and intact steel support columns – the fall must be significantly impeded by the impacted mass. If the central support columns remained standing, then the effective resistive mass would be less, but this is not the case – somehow the enormous support columns failed/disintegrated along with the falling floor pans.”
More unexplainable mysteries:
The study does not explain how the concrete in the buildings was completely pulverized.
The study does not explain the presence of molten metal at the base of the buildings after their collapse, which was confirmed by multiple sources as well as eyewitnesses.
The study does not even take into account building 7 which was not hit by a plane and collapsed in 6.5 seconds into its own footprint at 5.30pm. The fireproofing in that building was certainly not dislodged yet all its core columns collapsed at exactly the same time despite fire (caused by falling debris from the towers) being restricted to just a few floors.
In addition there are literally hundreds of eyewitnesses, including reporters, firefighters and rescue workers, who stated that they heard explosions prior to the collapses. There were so many that CNN’s news feed even displayed the words “Third Explosion collapses World Trade Center” and the FBI announced that they believed secondary devices were involved.
Yesterday we revealed details of another high level official who is on record stating that he witnessed explosions in building 7 before either tower collapsed.
In conclusion the new study, like NIST’s before it, is yet another case of a body attempting to prove a pre-determined hypothesis. It does not discount any of the points we have continually raised and does not make the case for an independent investigation any less imperative.