Again we have the concrete pier in the foreground that seems to mark the point of collapse. From all the pictures I've seen, it appears that the rocker plate/pin sitting on top of this pier is completely gone. The truss structure supporting the left side of the bridge must have crumbled like an accordian, and what's left of it is burried underneath the concrete roadway, completely out of sight.
Great comments. Can you speculate as to what could have been the initiating event that could cause that rocker plate to fail like that?
The first thing I noticed in the video that was first presented of the collapse, is that you can see the shock wave from whatever it was that failed, travel the length of the bridge as the collapse begins. Something significant let go first, and something had to be the trigger...