I never built a Lake/Dam this size in my career. As I focused on buildings, storm water structures were the incidental size. That being said, aprons, large “lay-down” areas, road beds, all were often built with the main slab segments not having reinforcing in the main body or the segment, but instead having dowels and reinforcing bars at the joints acting as “load transfer bars. These bars in the body of the slab were often smooth and set to slip for movement and then along the perimeter joints deformed bars to lock the segments together.
Building footings, walls, grade beams and structural members all have reinforcing steel throughout. Slabs on grade have temperature mesh except in heavy load bearing instances.
Caltrans has been rebuilding Interstate 80 over the Sierras for more that a decade now. The technique they are using is a rebar cage at either end of a slab section with dowel pins between. Seem to be pretty durable. That said I haven’t seen any sign of steel in the main spillway at Oroville Dam. Good news is that no steel will make the demolition of the spillway faster when they start.