Originally Bazant, using his pile-driver theory of collapse of the Twin Towers, glibly asserted that the top block would remain rigid and act as a hammer, destroying the lower unheated, undamaged portion of the tower, storey by storey. When that was finished the top block would destroy itself. He called the first phase “crush down” and the second phase “crush up”.
As already stated, this explanation must be false as it flies in the face of the observed disintegration of the top section before the lower section started to move. It also fails to take into account Newton’s third law, which states that the forces between two contacting objects will be equal and opposite. We can deduce from this that if the impact is sufficient to destroy the upper storey of the lower section it will also destroy the lower storey of the upper section. Apparently Bazant became troubled by criticism of his earlier work and in 2008 brought out a paper which made a number of adjustments to his original explanation.
Firstly he backed away from his earlier assertion that a temperature of 800 degrees C occurred. Instead he made claims that viscoplastic creep could cause failure when substantial loads were applied for long periods at moderate temperatures. He was hoping this would would get him past the obvious lack of evidence for 800 C to initiate the collapse. This is clearly far-fetched as we have a photo showing a woman leaning against a column shortly before the building collapsed. The steel could not have been more than comfortably warm. Even if the core, out of sight, had been red hot at that time, and there is evidence indicating otherwise, the outer columns, with a design safety factor of 5, would have held the building up by themselves.
Secondly Bazant allows that at the first impact there will be some effect on the upper block but asserts that it will be negligible and that only the lower portion of the building will be damaged in the crush down phase. He is thus still denying that Newton’s third law will be operating.
Following further criticism of his work Bazant brought out another paper in 2010 which again asserted that the damage above the impact interface would be small. We will look into this more closely. Imagine for a moment the scene which Bazant sets for the north tower: the columns separating two floors have buckled and the upper section is falling. At its bottom is floor number 98. At the top of the lower section is floor 97. When these two floor contact, the force due to deceleration will be applied downward against the columns below and upward against the columns above. These forces will be almost equal as the force due to the mass of the contacting floors will be negligible compared with the deceleration force. Also the columns above will have been heated more by the fires than the columns below and may also be thinner. We can expect both the columns above and below the interface to buckle equally, if they buckle at all. Let us imagine that they do buckle and that the top, now with one less storey, continues to descend.
As the second impact is approached the situation is different. We now have the columns of two storeys buckling. When these columns start to buckle, the two floors, 97 and 98, together with the remnants of the columns previously holding them apart, will form a mass of material which Bazant likes to call “zone B.” This material will be half way between the next two floors, 96 and 99. It is important to note that these two sets of buckling columns will be involved in progressive collapse, “everything will not be instantaneous,” (to borrow a phrase from Shyam Sunder, NIST’s team leader). During this collapse the force required to continue the collapse will be approximately equal above and below zone B. What this implies is that zone B will remain half way between floors 96 and 99 throughout this stage of the collapse.
Here is where Bazant applies a conjuring trick. He asserts that zone B will fall in contact with the remainder of the top section and will provide a cushion, thus protecting it from further impact damage. This sounds reasonable until one recalls that zone B was not in contact with the top section but half way between the sections. Its cushioning effect will thus be felt equally by both sections. Newton’s third law will of course apply at this impact, as it did at the first. The columns above and below zone B will again collapse equally. At each subsequent impact exactly the same thing will happen and the falling top block will be shortened by one storey with each impact. As there were only 12 storeys in the top section to begin with, the collapse must soon come to an end, due to its weight diminishing and the cushioning effect of zone B increasing.
Dissatisfaction with Bazant’s explanations has been widespread. Numerous writers have pointed out their failings, as can be seen in the Journal of 9/11 Studies and elsewhere. The most recent is a paper by Tony Szamboti and Richard Johns, submitted to the Journal of Engineering Mechanics in May, 2011. Without touching on the mechanistic impossibility of the Bazant pile-driver concept, they dispute his paper by showing that it contains several incorrectly calculated inputs and thus cannot produce a correct result.
Here we find something rather surprising, interesting and, if it continues much longer, highly unsatisfactory: the paper has still not been published. Could it be that Bazant is finding it impossible to refute the work of Szamboti and Johns? Could the JEM be deliberately stalling to protect Bazant?
This particular journal has certainly been shown to be biased against fair treatment of 9/11 arguments in the past. James Gourley provides a thorough discussion of his experience at 911Blogger.