Viaducts, and trestles, can be built on a curve, but bridges have a tendency to always be straight sections. A "bridge" that carries a curve, may be something like a double track bridge with a single track curve through it, and relatively short. To carry a long curve over a wide valley, or river, many short bridges are strung together, each on supported by a pier, or a bent. In many cases, a trestle is used for the bridge approaches, with just a short span between that is bridged over.
Atlas has a "pier girder" that will carry curved track from bridge pier to bridge pier, but these are straight sections.
For 22" radius, you could use "two track" bridges, to go from pier to pier.
Kalmbach has a book on bridges and trestles that may be helpful.
