13-08-2013, 03:38 AM
Lauren Johnson Wrote:Jeffrey, As I understand your sketch entitled Top Drop Cartoon, the load supported by the compromised core columns was slowly transferred to the perimeter columns via the hat trusses. As the perimeter column exceeded their designed load capacity, they began to buckle and slip pulling the core columns down. The core detaches from the hat trusses. After that I am a little vague. But somehow this leads to a cascading collapse which Major Tom calls ROOSD, which stands for Runaway Open Office Space Destruction. Am I correct in interpreting your cartoon?
Basically you are getting the gist of the diagram. It's meant to show what happens as the core columns are weakened. When the lose capacity the 12 floors of the core ... and there were only 2 elevator chafts in the core at that height... were hanging from the hat truss. And this include part of the weight of the floors outside the core as the 24 perimeter core columns support about 45% of the outside the core floor loads. When the core lost capacity all of the loads were moved over to the facade columns which buckled and in so doing there was lateral translation and the facades slipped past each other 2 side passed outside and 2 inside. But surely the facade wasn't able to carry the floor loads alone including those inside the core up there. This mass.. became the ROOSD mass driving through the inside of the tower down to the ground.