NIST's WTC7 collapse models: some observations
A few days ago I posted a graphic from NIST's latest WTC7 report that depicts the exterior buckling after global collapse initiation. In no way does it resemble how the structure actually looks when it imploded. I had not noticed that this was the model for the scenario without debris impact damage. You see, NIST actually has models for the scenario without debris impact damage and for the scenario with their best estimated impact damage (the damage to the south side). They conclude that the building would also have collapsed without any impact damage.
So I checked the report for their modeling of the exterior buckling with the best estimated impact damage; the model of what actually happened. It's there but there is something missing: the top 23 floors are not shown and the north side is not shown; the side that can actually be seen in the videos and photographs of the collapse.
It would be hard to imagine that the scenario with the asymmetrical damage to the south side would leave the top 23 floors (which are not shown) looking any better than the scenario without damage.Videos show that WTC7's walls remained straight during most of its collapse. Their model is simply not showing what actually happened, and it looks like they are trying to hide it by not showing the top 23 floors and the north side.
There are no models of the core collapse of the top of the building in the scenario with the best estimated damage. They give 12 models of the complete core collapse in the scenario without damage. Apart from a single graphic of the penthouse sinking in the roof, there are no models of the top of the building during the collapse in the scenario with impact damage.
Let's put their model of the core collapse in the no impact damage scenario next to a video of WTC7 imploding.
Clearly this scenario is way too slow. So we look to their model of the scenario with the best estimated impact damage but floors 18 and above are not shown and the last image is of all the core columns buckling at 6,5 seconds. What happens next is a mystery, they do not show a model of the actual visible collapse. Makes you wonder why they would stop at 6,5 seconds, while showing us 15 seconds of the no damage scenario.
NIST's models of the collapse are obviously no good. You only have to look at their model of the exterior buckling to see that.They are also trying to hide it by not showing any modeling of the upper floors collapsing (the floors that can be seen in the video's.) The actual exterior collapse is not shown at all.
Everything discussed can be found in chapter 12 of the new NIST report