Philadelphia’s U.S. Route 13/Frankford Avenue Bridge, the nation’s oldest active vehicular structure, is set to undergo rehabilitation work that will keep it in service for several decades. According to PennDOT, the 73-ft-long, three-span stone masonry and concrete closed spandrel arch structure was built in 1697 and reconstructed in 1893 to accommodate streetcars. As part of a $7.2-million bridge improvement program that includes six other area structures, Loftus Construction of Cinnaminson, N.J., will remove and rebuild the bridge’s north spandrel wall, excavate and replace arch backfill with lightweight concrete, repoint stone masonry along the arch barrel and reconstruct damaged stone masonry parapet walls.