Instead, NIST’s final report provides an elaborate scenario involving an unprecedented failure mechanism: the
thermal expansion of floor beams pushing an adjoining
girder off its seat. The alleged walk-off of this girder
then supposedly caused an eight-floor cascade of floor
failures, which, combined with the failure of two other
girder connections—also due to thermal expansion—left
a key column unsupported over nine stories, causing it to
buckle. This single column failure allegedly precipitated
the collapse of the entire interior structure, leaving the
exterior unsupported as a hollow shell. The exterior columns
then allegedly buckled over a two-second period
and the entire exterior fell simultaneously as a unit [3].
NIST was able to arrive at this scenario only by omitting
or misrepresenting critical structural features in its
computer modelling.[4] Correcting just one of these
errors renders NIST’s collapse initiation indisputably
impossible. Yet even with errors that were favorable to
its predetermined conclusion, NIST’s computer model
(see Fig. 3) fails to replicate the observed collapse, instead
showing large deformations to the exterior that are not
observed in the videos and showing no period of free
fall. Also, the model terminates, without explanation,
less than two seconds into the seven-second collapse.
Unfortunately, NIST’s computer modelling cannot be
independently verified because NIST has refused to release
a large portion of its modelling data on the basis
that doing so “might jeopardize public safety.”
