Project Type: Structural and Seismic Design
D&R Canal Pedestrian Bridge Over Route US 1
Mercer County the Delaware and Raritan Canal State Park
On behalf of the Delaware and Raritan Canal Commission (DRCC), Arora and Associates, P.C. was retained by the New Jersey Department of Transportation (NJDOT) to design a signature bridge to reconnect the Delaware and Raritan Canal’s towpath across US Route 1 in Lawrence Township, Mercer County, New Jersey. The D&R Canal is on the National Register of Historic Places and is New Jersey’s largest state park and natural resource. It is also a key link in the East Coast Greenway between Maine and Florida. The project eliminated the pedestrian and bicyclist practice of using the shoulders of the heavily traveled Route 1 corridor until a crossing could be made at a signalized intersection. The challenge to Arora was to design a pedestrian overpass that would enhance the 66 mile long historic linear state park while providing the necessary safety and operational improvements.
As the prime consultant, Arora provided engineering design services, including: survey, site development, geotechnical recommendations, structural design, maintenance and protection of traffic, and environmental permitting. During the concept development stage, Arora’s structural engineers worked closely with NJDOT, the DRCC, the Historic Preservation Office of the New Jersey Department of Environmental Protection, and local community groups to develop the preferred alternative.
The choice of a Pratt truss with a curved top chord for the main span was inspired by railroad bridges constructed during the period in which the D&R canal was in operation. The design evokes the history of the commercial growth of the region brought on by construction of the D&R Canal and railroads. To further complement the park and the truss main span, steel thru-trusses were selected for the approach ramps and the substructures were detailed with coursed-rubble, sandstone masonry. The trusses, picket fencing and enclosure fencing were painted black to firmly ground the structural architecture with the past. Additional site improvements included park signage, landscaping, drainage, and parking facilities.
The 7-span bridge consists of a 131-foot steel truss main span over US Route 1 with three 66-foot steel truss ramp spans and graded ramps on each approach. Bolted connections were used to mimic traditional riveted connections and to facilitate fabrication and erection. The main structural components of the truss were fabricated and fit-up in the shop in Ohio using the first industry application of automatic-feed magnetic-base high speed drills. The truss was then shipped to the site in pieces and reassembled in the southbound shoulder of US Route 1. In October 2003, a detour was implemented for a 4-hour nighttime closure of US Route 1, and the preassembled 45-ton truss main span was lifted into place in a single operation, minimizing impacts to traffic.
The resulting structure has been cited by NJDOT, the East Coast Greenway Alliance, and environmentalists as an exceptional example of community partnering and Context Sensitive Design. Although the bridge looks as if it predates the highway, Arora’s use of state-of-the-art engineering and materials met the project objective of providing a new, durable, low-maintenance, ADA compatible crossing. The bridge was opened to the public in March 2004. The project has since received the 2004 Project of the Year Award from the Professional Engineers Society of Mercer County, NJ. It was also nominated by NJDOT for New Jersey’s 2004 Historic Preservation Awards Program and FHWA’s 2004 Excellence in Highway Design.