The final report of the University of Alaska Fairbanks analyzing the collapse of World Trade Center 7, a 47-storey building which fell into its own footprint on Sept. 11, 2001, was published March 25th, 2020. An excellent video explicating the differences between the NIST study done of this collapse in 2008, and the UAF study, is here. Roland Angle, P.E., walks the viewer through both studies explaining the differences in terms a layperson can understand. In a nutshell, NIST insists there was a “progressive collapse” of the building caused by office fires alone, which burned primarily on the 7th through 13th floors (and provides no viable explanation for the cause of such fires). “Progressive collapse” means that the failure of girders, beams, and columns was sequential, one failure causing the next on the way down. It implies bump-bump-bump of the floors, as well as twisting of the façade, which is inconsistent with what is seen in videos. Physics teacher David Chandler established, several years ago, that the first 2.5 seconds were at free-fall acceleration, meaning: there was no resistance whatsoever. UAF has confirmed that finding and disproven other conclusions of the NIST study.
Importantly, NIST omitted from its model information about critical structural elements which would completely change its result. This information is available from building blueprints. As discovered by 9/11 researcher David Cole from examination of the plans there were stiffeners supporting the end of one northeast girder which NIST omitted mention of in its modeling. NIST said the failure of this girder, A-2001 on the 13th floor, initiated the collapse: that thermal expansion of five beams connected to A-2001 pushed it off its seat at column C-79, causing it to fall and progressively impact the girders for seven floors on the way down. When the stiffeners are included in the model girder A-2001 cannot get pushed off the column.
NIST also omitted sideplates on the girders, which would have impeded their movement, and lateral supports on the beams, which would have made them unable to buckle when heated, more examples of it removing structural elements from its model to get the desired result. NIST’s calculation of the force necessary for A-2001 to break the girder underneath, on the 12th floor—632,000 lbs—is also more than ten times the force UAF calculated would be caused by its impact, so that even if the initiating event occurred the subsequent failure of the girders below would not have. There are other serious problems with NIST’s model. Another video explicating the importance of the stiffener plates, and the breach of professional standards by NIST, is here, by Scots researcher Gerry Burns.
The UAF researchers—Prof. J. Leroy Hulsey, Prof. Feng Jiao, and Dr. Zhili Quan (now of the South Carolina Dept. of Transportation)--have thus proven what any lay observer immediately concludes on seeing the video: WTC 7 came down as the result of controlled demolition. According to NIST, fire had never caused the collapse of any steel-framed office tower prior to WTC 7. Fire did not cause the collapse of WTC 7, either.
by Alison Maynard