A bridge assembly is made up of stackable components that are arranged together to span substantially any size and type of geological formation. The bridge assembly is made up of one or more support columns having respective saddle members at their upper ends. Each saddle member has a lower bearing surface that engages the support column and permits variations in their relative positioning. Each saddle member further has an upper bearing surface for receiving at least one cross beam having a lower bearing surface, which bearing surfaces permit movement between a given saddle member and the cross beams it supports. The bridge components can be pre-formed out of concrete, and are typically assembled by stacking the various components.