Nobody used an 11" seat anywhere in this connection. Have you actually looked into this issue at all?
OK, 12 inch seat, and the girder moved such that, let's say 40% of the girder bottom flange was not on the seat.
The whole thing, seat, flange, girder, column, stiffener plates, is hot, several hundred degrees C.
Yet this is supposedly absolutely safe and enough to keep the floor from failing.
Except,,,, its hasn't been shown that this situation would in fact disallow girder roll off. That is a bare assumption, conjecture , on AE911T's part.
You want an fea that reflects every aspect of the real situation? OK go for it. Include forces on column 79 due to expansion of the beam between 76 and 79, include heat effects on the seat, on the bottom flange, on the stiffener plates.
Include the entire ceiling, and floor of that level as well as the one above and below.
Include a model of transfer of stresses from the destruction of the south face, I.e. the loss of the entire SW corner.
Then there are the unknowns, for instance, what caused an elevator car to be ejected from its shaft at the fifth floor? Could that indicate core column twisting above the fifth floor?
In short, the NIST fea that shows significant movement of the girder is entirely consistent with that the theory that this girder failed at its seat to col 79.
A column 79 failure is the most likely explanation of the first visible roof top event, the in falling of the EPH. A loss of the girder at col 79 is consistent with the theory that this resulted in a failure of the hot col 79.
If AE911T has another theory to put forth that is as consistent with observables then perhaps they should bring it forth. Up to now its been now its been nothing but "NIST is wrong!", and absolute handwaving about explosive or incendiary demolitions.