I've noticed that at the beginning of the extreme load traffic in the early Emergency Spillway repairs that they did not have steel plates at the "critical" spalling locations on the bridge. The locations are the two ends (where the bridge end slabs are sliding "concrete-on-concrete" in the bearing area of the left and right bridge end abutment support columns). The third location is in the center of the FCO between gates 4 & 5. This is a "contraction joint" seam where the monoliths of gates 1-4 abut the counterpart monolith of gates 5-8.
The chipping/spalling is the worst at the ends of the bridge.
Sometime later, during this extreme load traffic, the steel plates were emplaced. This is a likely indicator that someone noticed something, possibly more spalling at the abutment support bearing areas.
DWR has known for nearly 20 years that there were no "sliding" bearing pads to protect the concrete from chipping away at these expansion support joints. Yet they simply apply more red paint to watch the obvious chip away.
The steel plates help mitigate an immediate "localized" radius flexure (directly at the abutment load bearing surface edge), but the stressing of the 16 ft diagonal crack is not alleviated (i.e. still remains an issue until fully understood).
Here are a few of the before and after pics (plates):
The plates are helpful (spreading the load, reducing the shift from one platform to another, as trucks roll over the seam), but the real issue needs to be dealt with. Based on your earlier images, they really need to minimize the use of heavy loads across that spillway bridge IMHO. If I were running the project (and it would be better that I’m not), I’d require that heavy loads go around and across the bottom if at all possible.