“It’s a unique bridge,” says John Burns, at the South Carolina Department of Transportation (SCDOT). “This bridge has a technical aspect to it, because it is on a large radius and super elevated.”
The existing 460-foot, box-girder bridge was built in the early 1970s and had structural deficiencies. The bridge required significant maintenance, and the department decided to replace it with a steel-girder bridge. The shorter southbound bridge already was a steel-girder bridge.
In 2017, the DOT worked with the legislature to come up with a 10-year plan with four major programs, including bridge replacements and interstate improvement projects. The plan resulted in the first gas tax hike with a sustained revenue increase for the first time in 30 years.
“It allowed us to streamline a bunch of projects,” Burns says. “That included the design-build SC 277/I-77 interchange. We’re pleased our legislature passed a bill that allows us to build this project. It’s been fun.”
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The department uses design-build for larger projects, and this project fell into that category. “Design-build is a fast procurement and faster turnaround on the projects,” Burns said.
About 38,000 vehicles travel on the SC 277/I-77 interchange daily. The bridge crosses over six interstate travel lanes and an acceleration ramp. SCDOT recently completed widening I-77 under this bridge.
“The project had a set completion date, which forced the design team to get together to come up with a package quickly and partner with the DOT,” Burns says. “We did not waste any time reviewing the plans and moved to construction as fast as we could. It’s a great partnership. We work day and night.”
The same team at the SCDOT and Archer Western had worked together from 2016 to 2019 on the I-77 project and had built strong relationships.
“The same team just picked up where we left off,” Burns reports. “We have an open-door policy between the two of us. We call each other with questions and ideas. We’re both open to communication, which is great and very rare.”
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Rick Brissey, Senior Project Manager for Archer Western, agreed about the good collaboration on this project. “We like to be transparent, open and honest and to work through issues,” Brissey says. “We find the job gets along a lot better if the owner and contractor are on the same side. Both sides have done a good job with that.”
The department and design-build team worked together to mobilize quickly and stay ahead of the deadline. “Everyone is working long hours,” Burns says. “Everyone needs to have this open and done. We need to finish this corridor and release resources, manpower, and equipment to other jobs in the area.”
“The difficulties came in when the contractor had to lift the 260-foot-long steel beams,” Burns says. Those steel-plate beams are curved, 10-foot-tall and weigh as much as 160,000 pounds each. In total, they weigh 1.6 million pounds. Crews used two large cranes for the lifts: a Manitowoc 300-ton and a Kobelco 2750 275-ton Crawler Crane. “There was a lot of planning up front to get it worked out,” says Josh Daniels, Assistant Project Manager for Archer Western.
During the lifts, Archer Western worked at night and on weekends when traffic was at a minimum, then two of the three lanes would be closed by pacing state highway patrol officers to keep the traffic from under the bridge during the steel erection.
“We have two to three highway patrol cars sitting about a mile back and block traffic and keep them for 20 to 30 minutes,” Brissey explains. “That gives us enough time to get the girders up and set in place safely. When the girder is secured, they let traffic through.”
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The contractor completed the steel lifts within five weeks. The beams were spliced together with hundreds of bolts. The torqueing procedure for the bolts and DTI washers also presented challenges. Archer Western used Tone guns to tighten the bolts. “The bolts have to be torqued to specific values,” Brissey says.
Archer Western brought together everyone involved with the bolt operation, including the manufacturers of the nuts and bolts, to orchestrate the operation. It was called “Boltapalooza.” “We got everyone on board up front, and it has worked out great,” Daniels says.
The bridge curves and has a horizontal and vertical slope, similar to a NASCAR racetrack. “It’s going to be a challenge to place the concrete,” Burns says.
Brissey agrees that the curve makes it trickier for pouring the concrete. “With it being curved, it takes away from gauging by line of site,” Brissey says. “We are heavily dependent on survey.” The company is using a Bidwell 4800 Paver to finish the bridge deck.
Once the new bridge is ready for traffic, Archer Western will detour for a weekend and then take down the existing bridge. The demolition subcontractor, United Demolition of Charleston, South Carolina, will use large excavators with hydraulic jaws and hammers to knock the bridge down.
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The project has been safe. Archer Western has a strong culture of safety. This year, the regional office received recognition for its safety record. On this project, the company has involved crafts in the safety effort.
“A team of craft members walk around the project with a staff member to tour the job,” Daniels says. “It’s an opportunity to see the work through their eyes and see what can be improved as far as safety. We have seen the benefits of getting input from the crafts.”
The project is on track for an on-budget, on-time September 2020 completion.
“The process of design-build is working on this job,” Burns concludes. “There have been no delays. Every submittal is on track, and every construction operation worked out together. … The teamwork is going well.”
