SamRebel35
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Just dropping these links in here regarding WTC7:
WTC7
http://ine.uaf.edu/media/92216/wtc7-structural-reevaluation_progress-report_2017-9-7.pdf
Brief quote: "At the macro-level, progressive collapse, i.e., the structural systems response to local failures, is being studied using SAP2000 with wire elements, as well as with ABAQUS, and it is near completion. The findings thus far are that fire did not bring down this building. Building failure simulations show that, to match observation, the entire inner core of this building failed nearly simultaneously."
Study conducted by engineers, but funded by "truthers", so I'm sure it will be criticized for all of the usual reasons.
On a more general note, it's difficult not to notice in this thread, and at other places where the topic is discussed, that people frequently rely on models, simulations, experts, superior experts, consensus among experts, etc. That goes for sources on both sides of the aisle, including the ones I've posted above. Over the years, I've developed a serious distrust of anyone who relies too heavily on such things. Any time a computer model or expert is trotted out in support of something, I immediately start with the premise that I'm being misled (at best) or outright lied to. Chaos theory suggests that, to successfully model anything that happens in reality would require an exact replica of the entire universe. An even basic understanding of that concept should put to rest any reliance on computer modeling to prove anything. And where to even begin with "experts" and any so-called consensus among such experts? It's laughable.
NIST assumed floor load of 88 psf? Seems very light. Live load alone by ASCE 7-10 would be 80 psf for corridors (not including any dead load or self weight). Granted, the codes used during design were 70's or 80's codes but I would expect them to be reasonably close to current code.