Crews working on the U.S. Army Corps of Engineers Nashville District’s $1.56-billion Kentucky Lock Addition on the Tennessee River reached a milestone with the recent completion of the first downstream monolith.
The project will add a 1,200-ft-long, 110-ft-wide lock chamber to alleviate the heavy traffic delays that are occurring with the existing 600-by-110-ft lock. The lock at the Kentucky Dam is the lowest on the Tennessee River, located at mile 22.4 in Grand Rivers, Ky., near where the Tennessee meets the Ohio River.
The first completed monolith, called L31, is at the lowest elevation of 50 monoliths to be built under the Corps’ contract with Thalle Construction Co. Thus far, 35 are under construction. Each is being built with sequential 5-ft concrete lifts, and L31 required 17 lifts.
Graphic U.S. Army Corps of Engineers Nashville District“We still have many monoliths to complete, but this first top-out is a major milestone that gives us confidence moving forward,” said Capt. Rachel Nelson, Kentucky Lock Addition project manager, in a statement.
The Corps awarded a $167-million base contract to Thalle for the work in 2021, and later exercised eight contract options bringing the price to $380 million. Construction began in 2022. The downstream monoliths are scheduled for completion in May 2027, and the whole project is expected to be complete by 2029.
Earlier this year, Thalle and the Corps celebrated 1 million labor hours worked without any lost time accidents, according to the Corps.
Work on the Kentucky Lock Addition started 25 years ago, in 1998, but funding issues slowed work over the years. Before this current contract, crews with various firms completed some of the work including the relocation of four transmission towers, construction of relocated road and rail bridges downstream, construction of the upstream monoliths and other work. Thalle also built the upstream monoliths.
