“Getting the bridges open was a big deal to the public,” says Ginny Jones, Spokesperson for the South Carolina Department of Transportation (SCDOT). “We got positive feedback.”
The bridges have an impact on local folks and needed to finish early before adding lanes to the interstate. Many drivers on the mainline are not local to the area. More than 52,000 vehicles drive on the interstate in this area daily.
The project entails widening the highway from MM 85 in Little Mountain to MM 101 in Irmo, before exit 101; rebuilding three interchanges; building a new drive-through weigh station; straightening the road to improve sightlines; and adding 306,000 square feet of noise barriers.
“This is a congestion mitigation project and is part of SCDOT’s 10-year plan,” says Brad S. Reynolds, Project Manager for SCDOT. “It’s adding capacity, but as an added benefit, we are getting safety improvements, bringing everything up to current standards in the corridor.”
“Design-build allowed us to get to construction quicker and evaluate alternative concepts,” Reynolds says. It also provided opportunities for innovation. The design-build team made suggestions about phasing, moving an interchange, and building the two-span bridges with concrete girders and similar construction types.
Infrastructure Consulting & Engineering of Columbia, South Carolina, serves as the engineer of record, and HDR of Omaha, Nebraska, is handling construction engineering and inspection.
Most of the teams are comprised of Archer Western and United employees. The two companies have more than 160 employees working on this project.
“I’m proud of all of our craft tradesmen,” says Michael Kann, Project Manager for Archer Western. The Archer-United employees “work hard, nights and weekends, to make sure we keep with the schedule and put a good product out, one that will last for many years.”
Archer Western is self-performing the concrete paving. The project requires 1.3 million square yards of concrete for the highway travel lanes, shoulders, and entrance and off ramps. The concrete is produced at two batch plants built on site at exits 91 and 97. Archer-United is using silt fences to control erosion and sediment from entering the streams.
“It’s a significant undertaking to make sure we are not allowing any sediment or erosion to get off of the site,” Reynolds says.
The department divided the 16-mile-long project into three segments, starting closest to Columbia on the eastern end of the work zone. The contractors are maintaining two lanes of traffic in each direction, with traffic shifting to one side, completing that work and when finished, moving vehicles to the new roadway. The department website and message boards help to educate drivers about the changes.
“The phasing has been a big challenge,” Kann says. “We worked with the DOT to get the best maintenance of traffic possible for the traveling public.”
Seven overpass bridges have been completed with the project limits.
Segment 1 is furthest along, with the two inside lanes and shoulder widened. The 4 miles closest to Columbia will expand from two lanes in each direction to four lanes in each direction. The two inside lanes and shoulder are finished, paved with concrete and have opened to traffic. Archer-United is working on the two outside lanes and shoulder and expects to finish in the upcoming months.
The eastbound lanes of Segment 3 – widening the western most miles from two lanes in each direction to three lanes in each direction – is complete and paved with concrete.
The modifications to the exit 85 interchange are finished, with new on- and off-ramps. It has opened to traffic.
Crews are moving exit 91 about a half-mile west of the existing interchange to eliminate traffic next to existing restaurants and other businesses. Archer-United poured the bridge deck in May 2023 and expects it will open by July 2023.
“Ultimately, this was the best product, and I think they will be happy with it,” Kann says.
Work is progressing on Segment 3. Crews are griding and sealing the joints. Kann expects the concrete paving will finish by the end of this year.
Some bridge work is under way on the shift of interchange 97 to a diverging diamond configuration, requiring new additional on and off ramps. The interchange allows left and right turning vehicles to flow freely, but building it necessitates constructing more ramps.
“It moves a lot of vehicles through the interchange,” Reynolds says. “There were some capacity issues, and the diverging diamond allows us to address the congestion.” Archer-United expects it to open 2024.
The project entails creating a new weigh station for the Department of Public Safety, with new ramps, pavement and a building. It will feature a drive-through system.
Both SCDOT and Archer-United praised teamwork with contributing to the success of the project.
“This is one of the largest projects the SCDOT has completed,” Reynolds says. “So far, the contractor is on schedule. We are looking forward to it being complete in 2024 and addressing a big need in the capital city.”