Sebago Technics was a key member of the Figg/Hardesty Hanover CMGC Team performing the roadway and intersection design, traffic engineering, and railroad design in support of this $160M two-state construction project between Maine and New Hampshire.
The scope of this Project entailed the replacement of the existing vertical lift (middle) bridge over the Piscataqua River between Kittery, ME and Portsmouth, NH. The new design called for a two-level structure to carry automobiles and rail over the river just upstream of the existing bridge. The vertical alignment of the new bridge provides added clearance for ship traffic to reduce the number of openings by as much as 65%. The Portsmouth approach remains largely the same as it was with the old bridge, with the Project limit being located at the intersection of the Market Street Connector. The Kittery approach, though, provides a new signalized intersection to replace the existing grade separated interchange with Bridge Street. A comparative evaluation was made between a roundabout and a signalized intersection and the signalized intersection was found to be less costly. Sebago was responsible for the overall alignment development, as well as the two approach designs – road and rail. In addition, the firm prepared necessary ROW mapping and conducted much of the utility coordination with assistance from MaineDOT.
Roads & Bridges Magazine ranked this bridge #2 of its Top Ten for 2018.
The Project was completed and opened to traffic in 2018 and ACEC National ranked it a Grand Award winner in its annual Engineering Excellence competition for 2019.
Project DetailsSarah Mildred Long Bridge
- Client: Figg, Hardesty-Hanover
- Location: Kittery, ME and Portsmouth, NH Date Completed: Spring 2018
- Services: Transportation
- Tags: Construction Phase Services, Horizontal and Vertical Alignment Development, Railroad Design, and Service Utilities