📋 Tender Overview
Scope : To Construct Pedestrian Bridge in Charleston, South Carolina, United States
Superior Construction will start work next year on a cable-stayed, horizontal hydraulic swing pedestrian bridge over the Ashley River in Charleston—a $72.6-million project that will be the first of its kind in the U.S.
Working with design partner Johnson, Mirmiran & Thompson, Superior will kick off design in November and break ground with at-grade tie-ins to existing infrastructure on each end of the project in the second quarter of 2024. Work on the bridge itself will start later in 2024.
Expected to complete in 2027, the bridge will traverse the Ashley River, connecting downtown Charleston to the city's West Ashley area with a 4,100-ft pedestrian-only bridge featuring a 225-ft cable-stayed movable center span that will be constructed in the open position to minimize impacts to marine traffic. It's the first bridge with a cable-stayed movable span to be built in the United States
The design was developed with engineering firm TranSystems, and its subcontractor COWI, helping the team secure the contract from the city.
The city’s initial cost projections of about $42 million were found to be insufficient as firms began to submit proposals, local media reported in September, with city leaders citing inflation and construction costs for the increase.
The design-build project will be funded by Charleston, Charleston County, the South Carolina Dept. of Transportation and the Federal Highway Administration. The bridge will be constructed with large-diameter drilled shaft foundations of 8-9 ft.
Five spans will traverse the river itself, including the cable-stayed movable span, and four others constructed of traditional girders with poured deck spans. On other parts of the bridge, 34-ft spans will cross the marshy areas with a precast, prestressed concrete box slab design stacked transversely to create the riding and walking surface, Kirkland says—an approach that’s expected to speed design, fabrication and construction.
More than 63,000 cars cross the Ashely River every day on two parallel bridges with narrow sidewalks, which has resulted in more than 100 pedestrian-related crashes in the five-year period between 2014-19. A key feature of the bridge will be a V-shaped pylon, while the bridge’s outward-leaning stay cable plane will reduce risk of ice on cables falling onto the pedestrian path.
Most of the bridge will be 15 ft wide, with tapering portions to expand to 24 ft for the five spans crossing the river. The scope of work also includes new movable bridge operations with CCTV monitors, a touchscreen display and discrete pushbuttons for the gates, as well as s trailhead with benches, water stations and bike repair stations.
