Bismarck Rail Bridge: A modern bridge for the next century
Travel back in time to the ’80s. The 1880s, that is. The Second Industrial Revolution is underway, ushering in the Gilded Age. Railroads are the engine driving the economy and settlement in the Dakota Territory. The new railroad bridge whisks freight and passengers over the Missouri River to points farther west.
Today, rail continues to support the regional and national economies. The bridge, however, has reached the end of its useful life. The truss spans were replaced in 1905, but the original granite pier supports remain.
Ames Construction began a project to replace the bridge in mid-2023. The new rail bridge is under construction just north of the existing bridge.
2024 milestones
The 1,554-foot-long bridge will feature four main structural steel spans with precast concrete girder approach spans on each end. Crews will build approximately 150,000 cubic yards of track embankment, 60 feet high, in stages to meet compaction requirements and ensure stability. The substructure construction requires cofferdams, H-pile foundation, and concrete piers.
One of the biggest challenges of the project is building the substructure under a portion of the existing bridge, with limited overhead room to install cofferdams and construct the new piers. By the end of the 2024 construction season, Ames will have completed three of the project’s five cofferdam river piers.
Embankment construction has wrapped up for the 2024 season, and the east dock wall construction access will be complete by the end of the year. This will open up access for construction of the final two cofferdam river piers in 2025. Girder erection will also begin in the spring of 2025.
Taller, wider, faster
Like its predecessor, the new bridge will serve the railway for 100 years or more, but with the ability to carry taller and wider commodities in heavier rail cars. Trains will be able to maintain their speed as they travel across the bridge rather than slowing down, and the new bridge will be safer for rail employees to inspect.
Finally, under a grant program set up for the project, granite blocks that can be successfully removed from the site are destined to become part of a new welcome sign for the city of Mandan.
Learn more about this critical railway bridge project.
