More From Steve Jones

There seems to be something missing from the above diagram.

There seems to be a lot missing from this representation. Where are the transverse trusses and the intermediate support angles? How has their variable effect upon the floor trusses accounted?
What about the floor trusses which were not connected to the core? How did they react and how did that reaction differ from the core attached trusses?
Does it strike you as odd that the maximum force due to expansion pushing outwards on the perimeter columns, equivalent to some 115 kN, had no discernible effect, yet the inward pulling force upon the perimeter columns due to sagging and amounting to some 60kN was sufficient to initiate global collapse?

Gordon.