Dr. Frank Legge and Mechanical Engineer Tony Szamboti team together on a paper published today in the Journal of 9/11 Studies, entitled:
"9/11 and the Twin Towers: Sudden Collapse Initiation was Impossible"
This paper is the 100th paper to be published in the Journal of 9/11 studies in its nineteen months of existence, or about five scholarly, peer-reviewed papers per month on average (including full articles and letters). A great place to get solid facts and analyses!

This paper should be read for its cogent, pithy arguments regarding the sudden initiation of the destruction of the Towers. Quoting brief extracts:

"Numerous arguments have been presented that the Twin Towers at the World Trade Centre could not have collapsed in the observed manner due to the cause asserted in the NIST report, namely damage from plane impact and fire. 1 The bases of these arguments include the rapidity and symmetry of collapse, 2 the adequacy of the steel supports, 3 and the finding of incendiary residues in the dust. 4 It has also been argued that the initiating event in the official explanation, the sudden collapse of one storey, 1 could not have occurred because the steel was not hot enough. 5 This argument is based on data set out in the NIST report itself. There is another argument, as will be described here, that is based simply on the behaviour of hot steel under load...."

Conclusion: "It is clear therefore that the upper section should only have moved down slowly and only continued to do so if additional heat was supplied. A slow, protracted, and sagging collapse was not observed however with either tower. As observed in videos of both tower collapses, the upper sections suddenly start to fall and disintegrate.10 In the case of the south tower, initially a lean of the upper section developed but within the first second this turned into a rapid collapse with upper section disintegration, just as was observed with the north tower.

"It appears therefore that the official concept of a free fall collapse of the upper portion through the initiation storey, due to heat effects from fire, is a fantasy. If the temperature did become high enough for collapse to occur it could not have happened in the observed manner. 9 In particular it could not have been sudden and thus could not have produced the velocity, and hence the momentum and kinetic energy, upon which the official story depends for the second stage of collapse. In contrast, all observations are in accord with the use of explosives in a timed sequence."

The paper is concise and packs a punch in just 3 pages. You may wish to read the rest of the paper here: http://journalof911studies.com/volume/200703/Sudden_collapse_initiation_impossible.pdf