Transportation
Skanska Tapped for $450M Bridge Replacement on North Carolina Coast
The existing swing-span bridge over Alligator River in North Carolina was constructed in 1960, and will be replaced by a fixed-span bridge set for completion in 2029.
Photo courtesy NCDOT
Skanska will construct a bridge on North Carolina’s coast, between Tyrrell and Dare counties, to replace the aging Lindsay C. Warren Bridge on U.S. 64 over the Alligator River. The $450-million contract was awarded to Skanska USA Jan. 8 by the North Carolina Board of Transportation—funded in part by $110 million from the Federal Highway Administration under the Infrastructure Investment and Jobs Act.
Also referred to as the Alligator River Bridge, the 65-year-old bridge is “structurally deficient,” says the North Carolina Dept. of Transportation, which adds that it is not unsafe. The swing-span bridge is reaching the end of its lifecycle and must be better monitored, inspected and maintained.
“The work to maintain the current bridge negatively impacts its ability to provide a reliable connection between Columbia, Manns Harbor, Manteo and the Outer Banks,” says the state agency.
Replacing the aging swing-span structure just to its north in a new location will be a 3.2-mile, fixed-span, high-rise bridge that will include two 12-ft travel lanes with 8-ft shoulders with bicycle access.
Work is expected to start early this year, and plans call for the bridge to open to traffic in fall of 2029, with the existing swing span bridge to be demolished in the spring of 2030.
The route serves as a critical hurricane evacuation route and is the main route to access the state's Outer Banks from the west, says the DOT. Mechanical failures of the swing span, which the agency says the bridge is prone to, force motorists to take a 99-mile detour. The design is also expected to improve river traffic, as more than 4,000 boats pass through the swing span each year.
The bridge and waterway were each closed nine times in 2018, according to the state DOT’s funding application to the Federal Highway Administration. Between 2017 and 2021, the bridge was closed to traffic an average of five times per year, and the waterway an average of 5.6 times—with average closure time about 2 hours, although some lasting up to 36 hours have occurred in that time, says the application.
Environmental planning and preliminary design phases began in early 2021 and finished in late 2022, and final designs were completed in winter 2023. In July 2024, 11 test piles for the bridge were driven into the riverbed at various depths to learn more about soil layers, depths and consistency at the site of the new bridge, which state DOT Transportation Resident Engineer Pablo Hernandez said at the time would help the department determine the final bridge design.
The proposed bridge will be grade-separated and feature redundant precast, prestressed concrete girders with precast deck panels with composite concrete deck, says the funding application. The fixed-height span will measure 65 ft and provide 140-ft of horizontal clearance in one channel.
