Teschler on Topic
Leland Teschler • Executive Editor
On Twitter @ DW_LeeTeschler
Looking for something to do while sheltering in place during the COVID-19 pandemic? Try dissecting the latest results from an outfit called Architects & Engineers for 9/11 Truth which looks at the collapse of WTC building 7 on 9-11-01. AE911Truth promotes the idea that the World Trade Center buildings were destroyed in a controlled demolition, despite conclusions to the contrary in the the 9/11 Commission Report as well as FEMA’s WTC Building Performance Study.
WTC building 7 collapsed on 9-11 even though it wasn’t directly hit by an airliner. Flaming debris from the collapse of WTC 1 and 2 impacted the southern face of WTC 7. Unfortunately, both the primary and back-up water supplies for the building sprinkler system failed, and a fire ensued. NIST scientists and engineers analyzed the sequence of events and produced the 9/11 Commission Report. In it they concluded fire and the impact of the debris initiated the eventual collapse of the building. (One good thing: No one perished in WTC 7.)
Unsurprisingly, the latest AE911Truth report completely disagrees with this conclusion. It says the collapse of WTC 7 was “a global failure involving the near simultaneous failure of all columns in the building and not a progressive collapse involving the sequential failure of columns throughout the building.” Without saying so outright, the “simultaneous failure of all columns in the building” would seem to be a scenario consistent with AE911Truth’s controlled-demolition claims.
The AE911Truth report uses a lot of finite element analysis and engineering mechanics to make this case. But even those who lack a background in these subjects may have reason to take issue with its claims: They just don’t stack up against the mountain of work pointing to causes other than controlled demolition.
Consider that the NIST WTC investigation report lists 12 investigators, 77 technical contributors, five expert consultants, and about 120 technical contractors. The FEMA report on the collapse lists 27 team members. Other outside investigators have examined WTC building 7 events as well. As part of a lawsuit in 2010, a structural engineering firm analyzed the collapse for the plaintiff and claimed fire, lateral bracing code violations, and “structural vulnerabilities” caused the building’s demise. Another engineering firm working for the building owner (the defendant) said fire, not construction practices, constituted the main cause. And over the years, researchers examining aspects of the WTC collapse have published several articles in the American Society of Civil Engineers Journal of Engineering Mechanics. None of these works mentioned evidence of the simultaneous failure scenario posited by AE911Truth.
In contrast, the recent WTC building 7 report from AE911Truth was authored by three researchers who, in essence, are saying the small army of engineers and scientists who previously examined the evidence are completely wrong. Interestingly, in 2011 NIST, perhaps exasperated with the various conspiracy theories about WTC events, put out an FAQ addressing these ideas.
The latest AE911Truth report may make interesting reading for FEA nerds, but on this one I’ll just go with Occam’s razor: When presented with competing hypotheses, go with the one with the fewest assumptions. In this case, you might amend this advice to say, going with the one that doesn’t involve ignoring years of careful analysis by multiple experts. DW
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Filed Under: Commentaries • insights • Technical thinking