I published a detailed discussion criticizing several points of their paper supporting the official view that the buildings of the WTC collapsed from fire from the planes on 9/11. The 1st item of their reply to my discussion is an incredible ignoring of what I said & a flagrant disagreement with the facts. I brought up an issue on the ST that I have presented at physics conferences and which nobody else has discussed before. As I said in the discussion, just after the white squibs start streaming out the side of the South Tower & the gray starts profusing out its side just above that "A measurement of how fast the top of the top segment started coming down yields about 24 m (+-1 m) in the initial 1.0 s." Bazant & Le respond that "The claim is supported by ... no measurements, & the conlict with various evidence is ignored. In contrast, Bazant et al (2008) analyzed in detail the video record of the collapse & showed the collapse to be, for the ST, (after the lapse of 2 s) 10.5% slower than the free-fall velocity..."
The last statement is false & uses a subterfuge to back it up. Notice the "after a lapse of 2s". The very fast drop of the top of the ST tskes place within the initial 2s, & notice I stated "in the initial 1.0 s". If anybody is skeptical about my claims of very fast acceleration of the top down, see 3 photos in my book National Swindle of the World Trade Center (containing 37 photos) which I initially published online in 2011 (the 2nd Edition now available as an E-book in Amazon's Kindle at amazon.com/dp/B00D5ZHWBW .)
Figure 5, 6, & 7 of Chapter 2 of that book show 3/4 of a second of the collapse of the ST roughly 1 second after the collapse initiates, with timing of 1/2 sec between Fig 5 & 6, & 1/4 sec between Fig 6 & 7. Note that in that time the top of the top of the ST drops 70 feet or more (for reference, the Towers are 209 feet wide)! The fall is accelerating, with that acceleration averaging over 4X the acceleration of gravity for the 1st second (see Fig 3 & 5 below), & over 2X gravity's acceleration for the period (3/4 sec) in Figs 5-7 (see below). The proves that gravity is NOT the main force causing the top segment to collapse (notice the bottom segment has not moved -- the Tower has been broken in 2 by the forces on it!).
The top segment is being pulled down much faster apparently by the force of a gradient in the pressure of an internal explosion. Fires could not have produced it. Bazant & Le use a subterfuged denial to try to counter the facts.
Figure 3 of Chap 2. South Tower collapse near initiation, in which the squibs are over 30 feet outside of their ejection region. Note that the leaning of the top tower. Note also that the gray dust coming out just above the squib level near that corner have remarkable characteristic imprints of a sound wave in it, suggesting there may be a loud sound nearby. The top of the Tower is still up in the smoke.
Figure 5 of Chap 2. South Tower collapse 1 second after Figure 3, in which gray clouds coming from the lower part of the top segment have quickly grown to a large size, at the same time at which the top segment has moved down in height 70 feet in that second, indicating an average acceleration rate in that second over 4X as large as gravitational acceleration. The top segment is clearly disintegrating at its bottom.
Figure 6. Collapse 0.5 second later, in which a new set of squibs has ejected out on 2 different floors. With those squibs the lower part of the top tower makes a major turn to the right, indicating it acquires significant momentum in that direction. The top of the top segment has moved down more than 45 feet, totalling at least 115 feet drop from Figure 3, or an average acceleration of over 3X as large as gravitational acceleration for the the initial 1.5 seconds. This collapse is caused by further disintegration at the bottom of the top segment, and the gray clouds are fed by this disintegration of the top segment.
Figure 7. Collapse 0.25 seconds later, in which both the white squib clouds and the gray clouds have expanded. The top has dropped another 25 feet.
 The collapse sequences of the South Tower for the photos in Figures 3, 5, 6 and 7 was filmed by NBC.