I have been reading some stuff on the WTC collapse that asks some interesting engineering questions about the NIST reports of the events in the World Trade Center on 9/11 from the time of the plane hits until the buildings went down.
Hoffman's critique points out that NIST's Report, while avoiding even claiming to model the collapses, implies but does not show that it modeled the onsets of the collapses. The Report's section entitled Results of Global Analysis" describes the tops of the Towers first tilting and then moving downward as intact blocks, but there are no images in the Report of its computer models showing this behavior. The New Civil Engineer (NCE), an engineering trade journal based in the United Kingdom, published an article highlighting NIST's failure to publish visualizations of its alleged analysis of "collapse initiation."More from the UK:
University of Manchester (UK) professor of structural engineering Colin Bailey said there was a lot to be gained from visualising the structural response. "NIST should really show the visualisations, otherwise the opportunity to correlate them back to the video evidence and identify any errors in the modelling will be lost," he said.Interesting. Right after 9/11 I began hearing a lot of "demolition theory" stuff and dismissed it. Now I'm not so sure.
University of Sheffield professor Roger Plank added that visualisations of the collapses of the towers "would be a very powerful tool to promote the design code changes recommended by NIST."
Of course a lot in any simulation depends on initial conditions - which would be hard to know in detail with most of the evidence gone - but we could Monte Carlo it and see what the range of results might be.
Some interesting photos of the building collapse and these bullet points here:
# The buildings collapsed straight down, and at virtually free-fall speed, as in controlled demolitions, and then the rubble smoldered for months.The difference between a gravity collapse and explosive demolition with respect to the WTC.
# Many people in the buildings said that they heard or felt explosions.
# Virtually all the concrete of these enormous structures was pulverized into very fine dust.
# Much of this dust, along with pieces of steel and aluminum, was blown out horizontally several hundred feet.
# Most of the steel beams and columns came down in sections about 30 feet long, conveniently ready to be loaded on trucks.
This link got me started: James Fetzer where I got the recent studies of the JFK Zapruder film. (through a slightly different link).