Good point. But even at an average temperature of a little over 200 °C, the A2001 girder would be pushed up against the face of column 79 and could not get by the side plate.@Christopher 7, in the calculations you've presented re the expansion of A2001 at 400°C, is it your assumption that the entire beam was continuously heated to a single, uniform temperature?
center line of A2001 girder to face of column 79 - 1-3/4 inches
girder flange 11-1/2 inches wide divided by 2 = 5-3/4 inches
east end of girder flange 5-3/4 inches from girder center line
angle is 7/8:12 or 7/16 in 6 inches so:
1-3/4 – 7/16 = 1-5/16
east end of girder flange just over 1-5/16 inches from column face
A2001 girder 45 feet
K3004 floor beam 53.57 feet – expands 2.325 inches at 300 °C
45 divided by 53.75 = .837
45 is 83.7% of 53.75
2.325 x .837 = 1.946 or 1-15/16 inches
Net expansion of K3004 at 600°C is 5.392 x .837 = 4.51
Net expansion of K3004 at 500°C is 4.348 x .837 = 3.64
Net expansion of K3004 at 400°C is 3.307 x .837 = 2.77
Net expansion of K3004 at 300°C is 2.325 x .837 = 1.95
Net expansion of A2001 at 200°C average temperature would be a little over 1 inch.
Another good point.(Note that I am leaving aside the other points you raised, such as the ridiculous claim that the concrete decks and steel framing members would in all temperature conditions act in unison
Everything would expand together until connections started to fail.
The concrete decks and columns would act in unison unless the concrete deck was crushed in compression. But that did not happen in the NE corner of floor 13.