Client: Maine & New Hampshire Departments of Transportation
Construction Cost: $159M
Key Facts:
- Construction Manager/General Contractor (CM/GC)
- Three bridges in one: fixed level vehicular, fixed level railroad, and a moveable lift span
- Total bridge length is 2,800’ for vehicles and an additional 1,795’ for railroads
- Approach spans over the river are in a stacked configuration with vehicle spans above and railroad span underneath
The innovative Sarah Mildred Long Bridge is a vertical lift bridge that serves two modes of transport (rail and roadway) which reach it from double-decker approach spans. The bridge connects Kittery, ME and Portsmouth, NH, carrying US Route 1 Bypass and heavy rail. Its vertical lift span is 300’ long and 50’ wide with railroad track running down its center and roadways on both sides. The span “rests” in the roadway position, lowers 50’ to carry rail, and raises 135’ for tall maritime vessels.
The design centered around the community’s theme of “Local Simplicity of the Working Waterway.” Long open span lengths of 320’ for the vehicle bridge were built in balanced cantilever construction. The heavy rail spans of 160’ tie with the columns of the vehicle bridge and have interim foundations. These spans were also built using the balanced cantilever method. The lift span towers are made of precast concrete segments with hollow sections that are elegantly shaped to accommodate the lift span counterweight and maintenance access stairs. The new bridge creates an aesthetically pleasing solution using segmental technology
GM2's Complex Bridge staff partnered with Hardesty & Hanover for this Design JV.