Route 175 over Amtrak

Bridge No. 04326 (Lt. James T. Hall Memorial Bridge) was constructed in 1980. The structure carries Route 175 over Amtrak rail lines in Newington. The existing bridge consisted of a single-span prestressed concrete adjacent box beam structure. Continuing leakage at the underside of the box beams resulted in significant deterioration over time, necessitating the need to replace the superstructure. Benesch provided bridge and highway design and administration and design services during construction for the project under its Task Order Contract with the Connecticut Department of Transportation (CTDOT).

The original bridge carried approximately 32,600 vehicles per day across four lanes of traffic. The substantial traffic volumes and corresponding lane restrictions required the use of Accelerated Bridge Construction (ABC) techniques to minimize potential user delays. Steel Prefabricated Bridge Units (PBUs) were selected to accelerate construction. The PBUs were substantially deeper than the existing adjacent box beam superstructure, so the vertical profile of the roadway was increased by over one foot to accommodate them.

The replacement was completed in two major stages, each taking place within 56-hour weekend work windows. Benesch maintained a high level of communication with the Contractor to keep the project on schedule. The complex design also incorporated specialized post-tensioning details required to maintain traffic on the remaining precast box beams after partial removal.

Benesch also responded to Newington’s request to provide additional roadway width on the bridge to accommodate a future turning lane for a potential development. Abutments were widened adjacent to the railroad right-of-way prior to construction. Significant coordination with Amtrak was required throughout the duration of the project to schedule closures and ensure the protection of the rail lines.