The Great Thermite Debate...

[William Seger]

92. Again: the temperature of the columns did not affect the floor sagging

Some things don't require the FEA to understand. After the sagging floors pulled the perimeter columns inward until they buckled, the core was doomed, regardless of any heat weakening assumed in the model. That's because that buckling caused the top to tilt, which made the core the fulcrum of a lever: Load immediately started shifting off the opposite perimeter wall and onto the core columns. As the tilting continued, more and more of the entire weight of the upper building was shifted onto just the core columns and a few perimeter columns nearest to the buckled wall. Without any heat weakening at all, those columns would have been overwhelmed at some point by that much load -- heat weakening would just make it sooner rather than later. When those columns began to buckle, the load was immediately dumped onto adjacent columns which also failed, on across the building -- a "progressive" collapse.

> I think the models are highly suspect, especially the higher temperatures that NIST boosted up without justification other than to get the result they wanted.

Absolute nonsense. The justification was to get the same results for "key observables" as those that were actually observed in the actual collapse. Why are you having such difficulty understanding that that's about the only rational justification for thinking one of these models is more accurate than another? If you have some better justification for any other set of inputs, let's hear it.