U.S. Highway 601 Bridge Replacements over Congaree River and Swamp

U.S. Highway 601

U.S. Highway 601 Bridge Replacements over Congaree River and Swamp

Aging infrastructure continues to be a growing problem throughout America. The U.S. Highway 601 bridge over the Congaree River and swamp, originally built in 1948, had parts of its underside falling off. The bridge would shut down if it was not replaced. South Carolina Department of Transportation (SCDOT) chose HDR | ICA to design a replacement for the 1,740-foot, two-lane bridge.

Our engineers designed an offset alignment, allowing traffic to be maintained on the existing roadway during new-bridge construction.

The project is located in an environmentally-sensitive area called the Congaree River floodplain, located downstream of the state’s only national park, Congaree National Park. It is widely known for towering trees that grow in the floodplain.

Extensive coordination with natural resource agencies was required to avoid, minimise and mitigate impacts to the ecologically important floodplain. During preparation of the environmental assessment and permitting process, environmental agencies proposed a change in the design. They recommended one long bridge instead of multiple sections of bridge divided by land. This would have drastically increased the project’s price tag from $37 million to $75 million. 

With our help, SCDOT reached a compromise by adding an additional bridge length to the design to better accommodate flooding and wildlife. 

In addition, our team developed remediation plans for the existing embankment of the old bridge to allow for wetlands to be restored.

U.S. Highway 601
South Carolina Department of Transportation

Richland and Calhoun Counties, SC
United States

4,110 feet