GSP Improvements

Interchange 38 connects the Garden State Parkway Northbound and Southbound to the Atlantic City Expressway. Operational improvements in this segment were needed in order to reduce vehicular traffic queues on the mainline. Under this $8.5 million design contract, the Garden State Parkway was widened with a third continuous mainline lane and full shoulders on both the Northbound and Southbound roadways between Interchanges 30 and 80. SJH provided engineering design and the development of contract drawings, specifications, cost estimates, and construction support services for two bridges, costing $12M. This work involved geometric enhancements, shoulder reconstruction, highway lighting, coordination of utility relocations, and drainage improvements.

The team designed the upgrades to widen the existing GSP over Penn Reading Seashore Line Bridge, at MP. 36.3. The existing structure, carrying the Parkway mainline, is a single span simply supported prestressed concrete I-beam bridge with a span length of 39 feet and overall width of 94 feet. In order to maintain the 23 foot minimum railroad vertical clearance for the 150 foot wide structure, superstructure replacement with twenty painted W24X68 rolled steel beams supporting a HPC single course deck was selected. To accommodate the raised mainline profile, semi-integral abutment design was utilized, resulting in reduced earth pressure to allow the existing full height abutment on spread footings to be retained, and a jointless superstructure with a longer service life. The widened portion of substructure features full height reinforced concrete abutments and wing walls founded on steel. The design accommodates an additional 12 foot lane, a 12 foot auxiliary lane and full width shoulders in both the Northbound and Southbound roadways. Seismic analysis was performed in accordance with the NJTA Design Manual.

SJH also designed a new 154 foot long ramp bridge, located north of the existing bridge over the GSP mainline. The design incorporates reinforced concrete integral abutments on a row of piles, with wrap around MSE walls, which was a more economical option. The highway design complies with the latest AASHTO Policy on Geometric Design of Highways and Streets / National MUTCD, and structure design complies with the latest AASHTO LRFD Bridge Design Specifications.