The collapse mechanics discussed above are only a frac-
tion of the available evidence indicating that the airplane
impacts and ensuing fires did not cause the collapse of
the Twin Towers. Videos show that the upper section of
each tower disintegrated within the first four seconds of
collapse. After that point, not a single video shows the up-
per sections that purportedly descended all the way to the
ground before being crushed. Videos and photographs
also show numerous high-velocity bursts of debris being
ejected from point-like sources (see Fig. 5). NIST refers
to these as “puffs of smoke” but fails to properly analyze
them [6]. NIST also provides no explanation for the midair
pulverization of most of the towers’ concrete, the near-total
dismemberment of their steel frames, or the ejection of
those materials up to 150 meters in all directions.
NIST sidesteps the well-documented presence of
molten metal throughout the debris field and asserts that
the orange molten metal seen pouring out of WTC 2 for
the seven minutes before its collapse was aluminum from
the aircraft combined with organic materials (see Fig. 6)
[6]. Yet experiments have shown that molten aluminum,
even when mixed with organic materials, has a silvery ap-
pearance—thus suggesting that the orange molten metal
was instead emanating from a thermite reaction being
used to weaken the structure [12]. Meanwhile, unreacted
nano-thermitic material has since been discovered in
multiple independent WTC dust samples [13].
sections—which NIST acknowledges “came down essen-
tially in free fall” [5-6]—nor does it explain the various
other phenomena observed during the collapses. When a
group of petitioners filed a formal Request for Correction
asking NIST to perform such analysis, NIST replied that
it was “unable to provide a full explanation of the total
collapse” because “the computer models [were] not able
to converge on a solution.”
However, NIST did do one thing in an attempt to sub-
stantiate its assertion that the lower floors would not be
able to arrest or slow the descent of the upper sections in
a gravity-driven collapse. On page 323 of NCSTAR 1-6,
NIST cited a paper by civil engineering professor Zdeněk
Bažant and his graduate student, Yong Zhou, that was
published in January 2002 [7] which, according to NIST,
“addressed the question of why a total collapse occurred”
(as if that question were naturally outside the scope of
its own investigation). In their paper, Bažant and Zhou
claimed there would have been a powerful jolt when the
falling upper section impacted the lower section, causing
an amplified load sufficient to initiate buckling in the
columns. They also claimed that the gravitational energy
would have been 8.4 times the energy dissipation capacity
of the columns during buckling.
In the years since, researchers have measured the de-
scent of WTC 1’s upper section and found that it never
decelerated—i.e., there was no powerful jolt [8-9]. Re-
searchers have also criticized Bažant’s use of free-fall ac-
celeration through the first story of the collapse, when
measurements show it was actually roughly half of gravita-
tional acceleration [2]. After falling for one story, the meas-
urements show a 6.1 m/s velocity instead of the 8.5 m/s
velocity that would be the result of free fall. This difference
in velocity effectively doubles the kinetic energy, because
it is a function of the square of the velocity. In addition,
researchers have demonstrated that the 58 × 106
kg mass
Bažant used for the upper section’s mass was the maxi-
mum design load—not the actual 33 × 106
kg service load
[10]. Together, these two errors embellished the kinetic
energy of the falling mass by 3.4 times. In addition, it has
been shown that the column energy dissipation capacity
used by Bažant was at least 3 times too low [2].
In January 2011 [11] Bažant and another graduate
student of his, Jia-Liang Le, attempted to dismiss the
lack-of-deceleration criticism by claiming there would
be a velocity loss of only about 3%, which would be
too small to be observed by the camera resolution. Le
and Bažant also claimed conservation-of-momentum
velocity loss would be only 1.1%. However, it appears
that Le and Bažant erroneously used an upper section
mass of 54.18 × 106
kg and an impacted floor mass of
just 0.627 × 106
kg, which contradicted the floor mass
of 3.87 × 106
kg Bažant had used in earlier papers. The
former floor mass is representative of the concrete floor
slab only, whereas the latter floor mass includes all the