South Salem Street Bridge Over NJ Transit

The South Salem Street Bridge Replacement Project was designed to address both the structural and functional deficiencies of the existing bridge crossing over New Jersey Transit’s Morristown Line in Dover, NJ. The original bridge was constructed in 1934 and was in poor condition with a weight limit posting of 22 tons. The bridge thru-girders were located at the edge of the traveled way presenting a hazard to motorists, the horizontal roadway alignment on the south approach had a substandard reverse curve, and the railroad clearance envelope was inadequate to meet New Jersey Transit’s needs. To address these deficiencies, Arora was selected by the NJDOT to prepare the final project scoping and final design services. In addition to the bridge replacement, roadway widening, realignment and reconstruction, Arora prepared the design of traffic signals, highway lighting, drainage, and utility relocations. Arora performed an alternatives analysis that considered single-span prestressed concrete and welded steel plate girders on an alignment shifted slightly east to simplify the construction staging, correct the substandard reverse curve, and eliminate the need for a traffic detour. Arora recommended replacement of the bridge with a new 112-foot long single-span, 58-foot-wide steel multi-girder structure at a 47-degree skew to the railroad below. The bridge was designed to improve railroad clearances and accommodate an additional track planned by New Jersey Transit. The superstructure was designed on full height cantilever abutments with spread footings. The north abutment foundation was designed to incorporate a New Jersey Transit duct bank avoiding the need for a costly relocation. The bridge carries one 12-foot lane, a 10-foot shoulder, and a 6-foot sidewalk in each direction. Staged construction minimized impacts to local traffic and allowed one lane to be maintained in each direction during construction. Prior to Stage 1, two self-supported stand-alone catenary structures were constructed on each side of the proposed bridge. To carry dead-end loads, one structure was designed as an A-Frame while the other was a portal frame. The portal structure was supported on drilled shafts, and the A-Frame structure was founded on spread footings with one side on rock and the other side on dense glacial till. The catenary system was detached from the bridge and the catenary, communication, traction, and signal wires were reprofiled. In Stage 1, the easterly half of the bridge, roadway and retaining walls were constructed while traffic was maintained over the existing bridge. In Stage 2, traffic was shifted to the newly constructed. The project also addressed the community’s needs by providing a sustainable bridge that satisfied future transportation demands, fit into this unique historic area and minimized the environmental footprint. To minimize the adverse effect of the project, several aesthetic treatments were incorporated. The bridge parapets were detailed to match the original construction and the retaining walls and abutments were faced with a colored ashlar stone pattern. Decorative highway lighting was added to be compatible with the Town of Dover Historic District.