Central Street Bridge Superstructure Improvement

Central Street is a heavily used corridor, connecting residential neighborhoods, local businesses and regional transportation routes. Where Central Street crossed the North Shore Channel, an existing three-span bridge had reached the end of its service life. Inspections identified significant deterioration of the pier columns, reduced load-carrying capacity and a bridge deck that required patching over more than 40% of its surface area. Based on these findings, rehabilitation was determined to be impractical and full replacement was recommended.  

During the Phase I study, Stanley Consultants evaluated bridge alternatives, construction methods, traffic staging requirements and stakeholder priorities to identify the preferred replacement solution. Extensive public involvement included stakeholder, advisory group and community meetings that helped shape project decisions and bridge aesthetics. The study advanced a replacement bridge concept that addressed the corridor's operational, environmental and community needs while supporting long-term performance. 

Several constraints influenced the final design. The project extended through an active commercial area with a very flat roadway profile that required careful coordination of pavement design and drainage. Construction staging needed to maintain two-way traffic at all times while preserving access to businesses, side streets and 24-hour emergency access to a nearby fire station. Environmental considerations were equally important, as the North Shore Channel supports sensitive aquatic habitat, including the endangered banded killifish. To protect the species during spawning season, in-stream construction was prohibited from May 1 through July 15, requiring careful sequencing of construction activities. 

Following Phase I, Stanley advanced the project through final design and construction. The final design replaced the deteriorated three-span bridge with a more than 170-foot single-span structure that eliminated permanent substructures within the North Shore Channel. The bridge and roadway improvements addressed structural deficiencies, variable subgrade conditions and corridor mobility needs. 

The completed project provides a safer, more reliable transportation link for the community while reducing long-term maintenance needs. Delivered nearly $750,000 under budget, the project improved connectivity along a critical corridor while balancing community access, environmental stewardship and long-term infrastructure performance.