Just some food for thought. The maximum at which jet fuel can burn is 980degC and this requires a controlled burn where the fuel air mixture is prime. An open air burn which produces yellow/orange flame and lots of smoke will burn lower than this.

At best you would get 60% giving you a temperature of 588degC. The melting point of the steel is ~1500degC. The jet fuel would have been the hottest burning substance found in the building and it would have burned up within seconds. In fact with the second crash (the one that oddly brought a building down first) 90% of the fuel burned up outside the adjacent wall. The plane only caught the corner of the building.

The main support columns were shielded by concrete and so was always separate from the fire and never in it. Now it is true that the temperature inside an inferno can reach 2000degC this is again under ideal circumstances and your looking at less than this. Now you may be thinking that 2000degC is more than enough to melt the steel, keep in mind that this temperature is recorded in the heart of the inferno. This temperature quickly comes down to anywhere between 600 - 1000degC. Add the distance (and heat absorption value) of the concrete filled with connecting rhubarb (that would have acted like a heat sink) and the temperature reaching the main supports would be even less.

Now you may be thinking that the columns were designed to support tons of weight and the heat could have been enough to weaken the steel allowing for a collapse from the top down. Keep in mind that these planes hit near the top for one (the second which oddly fell first) and above center for the other. The steel columns that support the building are identical at the bottom as they are at the top. The beams and surrounding concrete goes straight up without a taper. So the steel at the floors affected that were supporting ~15% of the towers total weight for one (the second one hit that fell first) and ~35% of the towers total weight for the other were strong enough to support the towers complete (100%) weight plus max personal cap plus high winds. Also called gross max weight under windy conditions. So there is no way the steel would have weakened the 85% for the first tower to fall with 90% of the jet fuel burning up outside the building in one huge fireball.

Also in both situations the heat would have originated from an isolated location then spread. This means the beams closest to the fire would heat up first then the ones farther away. This would have led to an uneven weakening of the main support column. The result would be collapse at one side then the other. Also called a topple. Once the top portion toppled over far enough then the stress placed upon the remaining columns would cause them to shear off. The tops (section above impact) of the building would have toppled over off of the bottoms (section below impact).

Instead the buildings came straight down in ~10 seconds. This is consistent with a near free fall state which can only be achieved with a demolition.

Also the building that was hit second and received the least damage closer to the top was first to begin its collapse without warning in just under an hour.

The columns that were exposed after collapse showed angled cuts with almost no warping and had slag indicating the column was cut and the charge used (expected to be thermite) creates molten metal materials which will solidify as slag under the cut.

There is no way the planes brought the towers down. It was an illusion or slight of hand. Bush (who is business associates with Bin Laden in the oil industry) got Bin Laden to create a diversion (in the form of a terrorist act) so that he could get away with demolishing the buildings. What was there to gain?

The buildings were old and filled with out dated (toxic) building material such as asbestos (a superb, fire retardant insulator) which was coating the steel beams and insulating the walls. The cost of repair was beyond the value of the buildings but the cost of deconstruction would have been too. Cost of clean up after a terrorist attack was not.

Invest in the right things and you can walk away quite rich since the value of some stocks went up from their destruction. Certain people who have close ties to the bush family including the new owner of the trade center benefited from this.

The massive insurance policy specific against terrorist attack that had a larger than normal pay out if both towers were to be targeted as opposed to just one.

The realization that the defense of the US was lacking and they were becoming vulnerable. So a staged assault like this was enough to turn the tables and security was increased to the liking of those who were really responsible. This included a defense budget increase. Remember that this money has to come from somewhere and there needs to be a valid reason to increase the budget.

So there was much to gain.

Now where are those weapons of mass destruction that Saddam supposedly had? Why is it that they found, trialled, and hung Saddam so quickly but Bin Laden is still roaming free somewhere?

This was an excuse to start Gulf War no.2 and was nothing more than an oil grab for a predicted (now existing) oil shortage. Hidden behind the public title "war against terrorism" is the true title "war so we can get the oil".

The columns had the same overall dimensions, but the gauge of the steel decreased from being very thick at the bottom to quite thin at the top. (if memory serves)

There were no "angled cuts", except those made by the clean up crew.

Your politicizing and otherwise creative writing tells us all we need to know about your true ability to debunk the "official story" on scientific grounds. If you could, there'd be no need for all those additional fairy tales.

You're using them as a crutch, which is evident to all, and without which you'd fall.

reasonwhy



Here you are, DA.

NIST NCSTAR throughout this document refers to one of the 43 volumes that comprise NIST’s final report on the WTC Towers issued in October 2005. All sections of the report listed in this document are available at http://wtc.nist.gov.)

1. If the World Trade Center (WTC) towers were designed to withstand multiple impacts by Boeing 707 aircraft, why did the impact of individual 767s cause so much damage?

As stated in Section 5.3.2 of NIST NCSTAR 1, a document from the Port Authority of New York and New Jersey (PANYNJ) indicated that the impact of a [single, not multiple] Boeing 707 aircraft was analyzed during the design stage of the WTC towers. However, NIST investigators were unable to locate any documentation of the criteria and method used in the impact analysis and, therefore, were unable to verify the assertion that “… such collision would result in only local damage which could not cause collapse or substantial damage to the building.…”

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.

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, which severed the relatively light steel of the exterior columns on the impact floors. The results of the NIST impact analyses matched well with observations (from photos and videos and analysis of recovered WTC steel) of exterior damage and of the amount and location of debris exiting from the buildings. This agreement supports the premise that the structural damage to the towers was due to the aircraft impact and not to any alternative forces.

2. 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, http://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 composit wtc floor system

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.

http://wtc.nist.gov/pubs/factsheets/faqs_8_2006.htm

Grumpy