Let's examine one of the first scientific papers released suggesting that fire was responsible for the collapse of the World Trade Center buildings. This paper was submitted to ASCE on October 13, 2001 and an update in March 2002. You may read the March 2002 paper here.

Whilst the author is specific that this analysis is a "simplified approximate" of the collapse, meaning an educated guess, it is often used as absolute proof when presented to the public. If it is not presented as absolute proof, then it is often implied that the physical evidence supports the conclusion.

As before, my comments will appear in black text and the paper will be in blue italics.

Let's begin...

Abstract: This paper presents a simplified approximate analysis of the overall collapse of the towers of World Trade Center in New York on September 11, 2001. The analysis shows that if prolonged heating caused the majority of columns of a single floor to lose their load carrying capacity, the whole tower was doomed.

So far, the principle is not exactly rocket science. Actually, its more like a lesson in how to state the obvious using a scenic route through the English language. I mean, if a building of any substantial height should lose the majority of its columns, on a mid-level floor, it only stands to reason that the top section of the building is going to fall down.

It can hardly float in mid-air.

I do respect that he goes on to describe how one floor basically punches through the next, causing the outer facade to collapse, but, it is still only basic common sense. Within the abstract we are introduced to the key element that this entire principle hinges on:

if prolonged heating caused the majority of columns of a single floor to lose their load carrying capacity

Let's now locate what he describes as "prolonged heating".

the conflagration, caused by the aircraft fuel spilled into the structure, causes the steel of the columns to be exposed to sustained temperatures apparently exceeding 800°C.

We can end this analysis right here. The samples of steel provided to NIST show temperature ranges of 250-600C. There is, nor ever was, any physical evidence to support this analysis.

Thus, this analysis is irrelevent to a factual discussion on the collapse of the WTC.

In addition, there is very little combustable material in the central core and as we note in the paper the authors rely on jet fuel as their primary source of this heat. According to NIST:

"The jet fuel, which ignited the fires, was mostly consumed within the first few minutes after impact. The fires that burned for almost the entire time that the buildings remained standing were due mainly to burning building contents and, to a lesser extent, aircraft contents, not jet fuel."
Key Findings of NIST’s June 2004 Progress Report on the Federal Building and Fire Safety Investigation of the World Trade Center Disaster

Is a "few minutes" worth of burning jet fuel going to resulted in "sustained temperatures apparently exceeding 800°C"?

Not likely.