A few points:
1. The melting point of steel is 2,500-2,750 degrees Fahrenheit. For steel to to become malleable requires exposure to temperatures approaching 2,000 degrees Fahrenheit. Yet, only 3 out of 170 perimeter and core columns retrieved from the site had been exposed to temperatures above 482 degrees Fahrenheit. We're expected to believe that the towers collapsed after the columns from the core and perimeter became too malleable at temperatures over 1,500 degrees LOWER than their malleability point. I don't buy it and neither should you.
2. FEMA's metallurgical analysis of those 3 samples revealed that a "liquid euctectic mixture containing primarily iron, oxygen, and sulfur" began severely corroding the steel at approximately 1,800 degrees Fahrenheit. In some cases, eating large holes into it. The source of the large quantities of sulfur have yet to be identified, FEMA was not permitted to retrieve anymore samples for testing, and it's requested investigation into the source of the mixture and, specifically, the sulfur was and continues to be ignored. Even if that mixture alone didn't cause the collapse, it certainly accelerated it.
3. Witnesses, including office workers and firemen that were inside the towers, reported hearing and/or seeing primary and secondary explosions. Specifically, in the basement, lobby, and lower floors. Video footage in the lobby confirms that an explosion did take place at least there and most of these have been attributed to jet fuel. William Rodriguez, Phillip Morelli, Mike Pecoraro, Felipe David, Salvatore Giambanco, and Jose Sanchez, all of whom worked in the basement of the WTC, reported hearing, feeling, and seeing the effects of a large explosion in the basement BEFORE Flight 11 struck the North Tower. No investigation into the cause of these explosions has ever been conducted nor were they mentioned or considered as factors in the collapse of the buildings despite the testimony of Mr. Rodriguez to the 9/11 Commission.
4. Nearly every simulation compiled by those supporting the conclusions of the government required that the planes remain largely intact, that they collided with the core, and that the core and perimeter columns be exposed to extreme heat in excess of what they were actually exposed to. This despite the fact that the whole world saw the planes blow apart almost immediately upon impact on national and international television and even though chunks of the planes were scattered all over lower Manhattan! Much of the damage to the core was attributed to the "intact steel engines". Tell me, how did the "intact steel engines" make it unscathed all the way to the core then end up three blocks away in the opposite direction on the corner of Church and Murray Street before the collapse?