Long span trusses only connected the core to the perimeter, so that point can only be used to imply that the region outside the core was weak. The core columns were robust and according to NIST they had no debris damage and no significant weakening due to heat. Yet we are supposed to believe that the core collapsed before the damaged exterior.
The core columns hold up the south end of those long span trusses at , iirc the eighth floor, which support 2/3rds of the NW part of the building. Lose the first core column to the west of column 79 and the building still stands, lose another one and the building still stands. As the core columns fail the draw down will propagate to the roof top. That's what we see as the western roof structures begin to fall in. That propagation to the roof takes time though so by the time we see it at the roof the progression of core failure has moved further to the west. So where is the greatest stress on that raised foundation? Along the perimeter where loads are being transferred. As the core failure progresses west though there is also a lateral pull in. At some point the perimeter can no longer hold up and fails first at one point which increases pull in and the rest of the perimeter fails.
Note that the first perimeter failure is along the line of the 'kink' and then the rest of the perimeter fails.
Steel framed high rises are essentially built like modules Chris. This is the purpose of having so many columns; load from damaged columns can be spread to all the others, and this makes partial collapses more likely than total collapses.
In typical post and beam construction yes. In long span construction the partial failure area is so large it quickly propagates to include ever larger areas.
This is why the jets could poke out huge holes in the big Towers without them collapsing. The designer of the Towers said they could withstand hurricane winds even if one whole side collapsed.
Really? That's not how I recall it. Citation?
This is why demolition of these structures is so tricky, and why those professionals have to very carefully rig the core columns AND make sure they go out at pretty much the same instant. If the core collapse is asymmetric the buildings fall to the side, you can see plenty of videos of that.
There have been no demolitions of anything approaching the height of even WTC 7. If you have an example of demolition of a long span steel structure I'd be interested in seeing it.
- NISTs computer simulation shows the same thing, the exterior collapses asymmetrically as the interior collapses asymmetrically.
Is that WTC 7?
Not really, unless you refer to the fact that the initial failure took place 1/3 of the distance along the north wall(from the east). The eastern third had an entirely different and stronger core area below the eighth floor than did the western 2/3rds. Its understandable that the eastern portion stood until much of the western 2/3rds core had failed. The NIST sim shows the perimeter failing
differently in the east as opposed to the west but they fail at essentially the same time.
Yes, the major revelation here is that over-g is not compatible with NIST´s story of how the building collapsed, natural collapse, or your previous "third force" storyline.
Its entirely consistent with NIST and so called 'natural collapse'.
You don´t really have to worry about explaining over-g because it has not been proven yet.
Then neither do you, yet you do strive to explain it don't you.
Tony has said controlled demolition could explain over-g and if memory serves this would involve the core creating tension on the girders connecting it to the exterior, and them releasing this built up energy sort of like a compressed spring and pull on the exterior with a force for a brief moment. Tony is the man to explain this in detail.
Yep, and this is exactly what many debunkers have been saying occurred in the 'natural collapse for a few years now. Glad Tony is catching up. No reason why these forces would be exclusive to demolition. With added forces such as these then, the peak value of acceleration can tell us NOTHING specific about the cause of collapse. Chandler, under bus......
There is no evidence to suggest that the penthouses fell more than a floor or two.
Other than the formation of the kink at about the very line where the penthouse material would be falling. Tell me again what causes that kink to form before global collapse?
The purpose of that may have been to get the top sections of the exterior to start folding invard, to make sure the exterior would fold inward as the rest of the core was dropped.
If the penthouse fell only a couple of floors it would NOT cause that inward folding along THE ENTIRE height of the structure from roof to below line of sight(the kink)
There may be other reasons as Tony has explained. The main portion of the core would have to have been dropped symmetrically to pull down the exterior symmetrically.
Nope, only has to have progressive core fail until forces build up to cause an initial perimeter failure, then the whole thing fails quickly. Have you seen the videos of a person standing on a pop can then taping ONE small point of the can with a golf club? At that point the entire can loses structural integrity. It isn't required to compress a ring around the can.