Beam Placement Marks Chickamauga Lock Milestone

Construction crews successfully placed the first of several massive concrete beams recently for the new upstream approach wall.

The team maneuvered the 420-ton beams into their final positions using two heavy-lift derrick barge cranes moved in tandem.

“This process is meticulous,” said Cayce Grall, project manager for the Nashville Engineer District. “It doesn’t just start with the lift; it goes back to the initial construction of the intermediate piers. We are verifying measurements at every stage to ensure each beam aligns perfectly.”

Crews installed the first beam June 16. Each beam is 10 feet wide, 10 feet deep and 120 feet long and weighs approximately 420 tons. The upstream approach wall serves as a critical component of the project, providing guidance for vessels approaching the new lock chamber. The structure functions as a continuous guide on both the riverside and landside of the channel, supported by precast concrete beams positioned between four intermediate piers and two nose piers.

A Complex Operation

Before a single cable could be tightened, the team conducted exhaustive safety briefings. These included contractors, Corps personnel, safety officers, crane operators and dive teams.

The prime contractor on this phase of the project is CJ Mahan Construction Company. McKiney Salvage LLC provided the heavy-lift expertise.

“The team reviewed everything: lift plans, communication protocols, environmental conditions and potential risks,” Grall said. “Before any lift began, we conducted a rigorous load test to confirm the stability of the barges.”

Once the cranes began lifting, the work moved underwater. Specialized dive teams were deployed to monitor each beam’s descent, using precision gauges to ensure it seated correctly on the bearing pad.

“Having the dive team on-site was essential,” Grall said. “They inspected the beam underwater, checking for gaps to ensure it is properly seated. Perfect alignment is non-negotiable.”

While these beams were fabricated in 2010, the Corps ensured their structural integrity through years of storage, including comprehensive material testing and inspections.

Looking Ahead

The project requires 42 beams in total. Crews have installed eight beams for the Upstream Approach Wall contract, stacking two between each intermediate pier and the riverside nose pier. Once the beams were positioned, workers installed and tightened threaded steel restrainer bars, locking the segments into one continuous, solid wall.

The Nashville District expects to complete the current phase of the Upstream Approach Wall contract by early August.

“We see years of planning materialize right in front of us,” Grall said. “Our focus remains on executing this safely and keeping the momentum moving forward. Every lift requires precise coordination, and this team delivers.”

The Chickamauga Lock Replacement project is composed of three separate contracts. Two remain currently active: the Upstream Approach Wall and the Downstream Approach Wall and Decommissioning.

Featured photo caption: A 420-ton concrete beam is hoisted into position over the Tennessee River June 16 during construction of the upstream approach wall for the Chickamauga Lock Replacement Project in Chattanooga, Tenn. The successful placement of these massive beams, guided by contractors on the pier below, marks a significant milestone in the project. (Photo by Noe Gonzalez/Nashville Engineer District)