I don't believe they used little 1/4" fillet welds on the strongest buildings in the world.<quoted text>
And what's the tensile strength of 60xx welding rod?
Trick question but relevant.
And how much stress and in which directions can a 1/4" fillet 1-2" long take before it breaks along the heat affected zone?
And how much force were the welds exposed too?
And geometry of the structure no doubt was important but the reality is any structure can fail given the right conditions given that the materials used to construct it had limits of force they could withstand before plastic deformation made them next to useless as load bearing members.
It was not a pancake collapse, it was initiated by pancaking but the collapse was progressive with the joints between the hat trusses and the perimeter columns failing and causing the structure to globally collapse.
You always want to indicate the architects who designed it are all a bunch of dumb bastards, well I cannot believe that either.