US Patent 7600283 Prefabricated, prestressed bridge system and method of making same

The prefabricated, prestressed bridge system comprises one or more prefabricated, prestressed bridge modules. Each module includes one or more steel beams arranged in a first direction on three or more supporting formwork elements that are arranged in a second direction generally perpendicular to the first direction. Rebar runs through the steel beams in a direction perpendicular to the steel beams and above at least two of the supporting formwork elements. Concrete material is poured to form concrete diaphragms on top of and around the rebar at locations above the supporting formwork elements. After the diaphragms are poured, one or more of the supporting formwork elements are adjusted to stress the steel beams. A concrete deck is fabricated over the surface atop the diaphragms and the steel beams such that the resulting compression stress of the concrete deck secures in place the stresses imparted to the steel beams.