I just checked the dam cam - cement trucks are still passing over the spillway roadway bridge as of 1 PM or so today. That’s a lot of weight.
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):