Crews have completed the cofferdam at the Kentucky Lock Addition Project, a milestone in preparing for downstream excavation work that will include construction of the remaining portion of the new lock chamber.
Johnson Brothers Construction, the contractor on the $68 million downstream cofferdam, is working on punch-list items now but has already turned over the completed cofferdam, said Jeremiah Manning, resident engineer with the Nashville Engineer District.
“We had a great big challenging project,” Manning said, referring to difficult river conditions in 2018 and 2019 that resulted in delays to construction progress and about one year of schedule growth. “Hopefully the tide is turning on this project, and we’re isolating ourselves from our biggest risk factor, which is the tailwater at Kentucky Dam.”
Jody Robinson, contract administration team lead at the Western Kentucky Area Office, said the cofferdam is the most important spot on the job site because its specific purpose is to hold back the tailwater from construction activities. “This cofferdam is critical to the entire rest of the project,” Robinson said.
At one point during the height of the construction and installation of the concrete shells, Johnson Brothers had about 150 people on the job site, including subcontractors, which made for a very busy construction zone.
Jamie Willcutt, construction manager for Johnson Brothers Construction, said his crews have done an incredible job under difficult conditions, and the team has been working around the clock over the past year to complete the cofferdam.
“Everything has come together fairly nicely,” he said. “We’ve had some adversity but overcome it. This is a highly technical and highly engineered project … so to be where we are at is amazing. I probably won’t build another one of these in my lifetime, so to just be a part of it and to work with the Corps has been great. It’s been an amazing journey.”
Heeter Geotechnical Construction, contractor for the $58 million downstream excavation contract, is already installing a grout curtain into the cofferdam. Once the grouting is completed, water behind the cofferdam can be pumped out, making it possible to excavate in dry conditions.
Robinson said Heeter has already been busy excavating in areas more upstream near the completed portion of the upstream lock chamber but can now excavate across the entire construction footprint.
Manning said the Nashville District is working on design and acquisition for the next phase of the project and plans to bid the downstream lock monoliths contract this year. The contract will structurally finish the new chamber and place all the remaining concrete for the new lock.
Lee Roberts, public affairs specialist for the Nashville Engineer District, contributed to this report.
Caption for photo: A Johnson Brothers Construction crew performs spot welds March 22, 2021, on a steel sheet pile on the completed cofferdam at the Kentucky Lock Addition Project on the Tennessee River in Grand Rivers, Ky. The Nashville Engineer District is constructing a new 110- by 1,200-foot navigation lock at the Tennessee Valley Authority project. (Photo by Lee Roberts/Nashville Engineer District)