10-08-2013, 11:39 AM
Jeffrey Orling Wrote:I call them cartoons... but I could call them sketches. That hardly matters. Like all drawings they are abstract graphics representations. I deal with drawings all the time and they are not reality.... nor are formulas reality... just another form of abstraction. as the core was destroyed column by column, or it was losing strength and lost its load carrying capacity that had to be picked up by the facade columns... the load was not disappearing. The loads were redistributed through the horizontal members including the hat truss. That is to say if you severed the columns several stories below the HT those still attached above the severed columns who have the part of the floor loads and their own weight and this load would then be hanging from the HT ... the columns would switch from compression members to tension ones. If he column splices held then the weight would add a series of concentrated loads to the bottom chord of the HT and these would add load the bearing points of the HT or the truss itself would fail and collapse. My hunch is that there would have been a very rapid increase in load and it would result in some buckling of the facade at some of the bearing locations of the HT.
As we can't see how the damage / weakening progressed we can't know precisely how loads were redistributed.. and I don't believe all the core columns of this region have been recovered and analyzed. That would show if there were explosive devices or if the core columns failed from heat, distortion, warping and connection failures. The pre release movements suggests a failure PROCESS over time not an instantaneous one... but the moment of release was when aggregate capacity dropped below the aggregate service load... and the failure raced through all remaining load bearing columns.
It seems that you allow yourself much more freedom in your explanation than science would allow. Hence, your your convoluted explanation ..... is inappropriate, as that did not happen in real life.
The horizontal propagation was extraordinarily rapid across the 98th floor (about 0.7 seconds), where no core columns had been affected by the aircraft and no more than two perimeter columns, as only the very end of the wing hit that floor. Doesn't that give you pause in your arbitrary assignment of severe column load capacity degradation?