THE PROJECT The original reinforced-concrete closed-spandrel arch bridge carrying PA Route 75 over Norfolk Southern's Pittsburgh Line in Port Royal (SR 0075/A03) was constructed in 1910 and was a contributing element to the Pennsylvania Railroad Main Line Historic District. The structure is the westernmost in a series of end-to-end bridges crossing the railroad, a local roadway, and the Juniata River. The agency selected Erdman Anthony to provide preliminary engineering, final design, and construction consultation for the bridge replacement.
FEATURES/SOLUTIONS The replacement structure is a 75-foot-long steel-plate girder bridge with an additional 26-foot-long reinforced-concrete slab span. The steel span is metalized for corrosion protection and long-term serviceability. Based on a seismic tomography investigation of the existing foundations, portions of the abutments were able to be improved to support the new bridge. This alleviated the need for extensive temporary support during construction of the adjacent ramp bridge to First Street that shares an abutment with the PA 75 bridge.
The project also required extensive coordination with Norfolk Southern to minimize disturbance to the rail lines, which carry nearly 80 trains each day.
IMPACTS To mitigate the loss of the historic resource of the original bridge, the southwest quadrant of the project area includes a parklet with bench seating, interpretive panels with historical photographs and text, and greenspace overlooking the rail lines.