Other than using a railway bridge and converting it to a hiway bridge. Or inverting a deck bridge , painting it a "Jade" colour. Then theres a wooden dowel painted concrete or cast in plaster.
But i'm trying to design, then make 1950's hiway bridges found on 4 lane devided hiways. The deck is simple, and supports maybe dowels? Or styrene ? Or cast hydrocal? But what about the guard rails and side railings? The bridge shoes i can make as well. And expantion metal joints are seemingly easy with styrene , i would think.