So basically the only evidence that the building collapsed due to fire is based on computer simulations which are never accurate anyway.
You just established that you do not understand what an FEA is for.
In the case of WTC7, you have a structure that did not have permanent identifiers on the structural steel elements.
That would make positive identification of the original location of steel from the rubble not possible.
Much of the rubble underwent heating in the rubble fires.
That would make it impossible to determine the heating effect on samples caused by the fires during which the building was still standing.
OTOH we do have the recorded observable collapse sequence.
This definitely indicates that col 79 failed low down in the structure, followed by a progressive east to west failure along the line of the core of the building.
The FEA predicts that a progression to east - west core failure is consistent following a column 79 failure and that a failure of the core would lead to global collapse.
To further check on the validity of this sequence NIST also ran the FEA as a fully whole structure, without the south side structural damage. Again the simulation predicted that ba column 79 failure would progress through and east west core failure to global collapse. The major difference between starting with or without south side damage is the amount of twisting the structure would undergo at the global collapse phase.
The only thing that recovery and identification of steel could do for the above investigation, is confirm that column 79 failed and that specific of the collapse sequence is quite well bolstered by the observations of the collapse. Having physical evidence of a column 79 failure would not aid investigators in determining what progressed from that failure and in fact having a great deal more of the steel would not be able to illustrate what sequence they failed in any better than, ( if it could do so at all) than the FEA.
This also demonstrates that there is most certainly no requirement to invoke unobserved explosive demolitions of a large number of columns.
Secondary to all of that is the cause of column 79 failure. To that end one looks for an input that would drive such an event, and the only observable mechanism for that is fires in the building, specifically those occurring in the vicinity of column 79.
Research determined that heating of column 79 could not directly lead to column 79 failure. For instance it was not enough to cause column creep under axial load. It was enough however, to cause horizontal members to expand and deliver lateral forces and indeed calculations show that the girder between column 79 and 44 would be moved very close to being fully past its seat on column 79. A failure would see this girder fall and cause floor failure over several levels along col 79, the very same column that had been established as having failed.
Interestingly the report shows that calculations of the expansion of the beam between column 79 and 76 would exert enough force to shift column 79 half an inch east. This shows that saying that expansion shoving the girder between 79/44 is not the whole story and that the small amount of difference between calculated lateral "walk" and the width of the seat would be easily accounted for by the complexity of the real life situation.
IMHO, AE911T would be much further ahead if they simply said that column 79 was demo's. Instead, they chose to disregard all research done into the collapse, all observed sequence before the final six seconds of collapse, and declare a comical fantasy demolition for which there is no evidence at all other than bald assertions and made up contentions about demolitions.
