A review of the bearing measurement data indicates a large and erratic discrepancy between the measured and theoretical bearing movements for temperature changes. It appears that each bearing behaves in its own way in terms of overcoming the friction for longitudinal movement. ... There is enough frictional resistance due to corrosion and debris to keep the bearing from moving until there is enough thermal force built up in the system to cause a drastic and quick movement of the bearing to relieve the force.
My feeling is that just such a "drastic and quick movement" was the trigger of the collapse, and I'm even inclined to believe that a bearing on the South pier may have actually failed due to such a movement. This would neatly explain everything.
From my understanding, common practice is to build bridges with a fixed support point, and with movable bearings at other support points. Would it be practical to replace the fixed point with another movable bearing that was attached to a motor that would move it every day or so? I would think that would help prevent the other bearings from seizing up, detect if one of them sizes up anyway (assuming instrumentation at the motor point), and provide an alternate relief point until such time as the seized bearing is repaired. I'd think that would be an all-around win.
This looks like an even more interesting report than the inspection report. I will study it further.
The first page or so says that there were a total of 52 members in the bridge that would bring down the entire birdge if any one of them failed. That is a LOT of places for disaster to strike. Your theory is certainly possible.