CHATTANOOGA, Tenn. (July 2, 2026) — Construction crews recently reached a major milestone at the Chickamauga Lock Replacement Project, successfully placing the first of several massive concrete beams for the new upstream approach wall. Using a dual-derrick barge crane system, the team maneuvered 420-ton beams into their final positions — a feat of engineering precision on the Tennessee River.
"This process is meticulous," says Cayce Grall, project manager for the U.S. Army Corps of Engineers Nashville 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 by 10-feet wide by 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, USACE personnel, safety officers, crane operators, and dive teams.
"The team reviewed everything — lift plans, communication protocols, environmental conditions, and potential risks," Grall explained. "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 the beam’s descent, using precision gauges to ensure it seats correctly on the bearing pad.
"Having the dive team on-site was essential," Grall adds. "They inspected the beam underwater, checking for gaps to ensure it is properly seated. Perfect alignment is non-negotiable."
A Collaborative Milestone
While these beams were fabricated in 2010, USACE ensured their structural integrity through years of storage, including comprehensive material testing and inspections. The installation of the beams represented a huge milestone for the Chickamauga Lock Replacement Project’s Upstream Approach Wall contract.
Lifting the beams involved a complex process that involved the operation of two heavy-lift derrick crane barges in tandem to lift and place each concrete beam into position. The installation proved successful due to the strong partnership between the Nashville District, contractor CJ Mahan Construction Co., and McKinney Salvage LLC, which provided heavy-lift expertise.
The successful placement of these beams stands as a testament to the partnership between the Corps and our contractors. Through meticulous planning and technical expertise, the team executed this complex operation safely.
This milestone demonstrates the importance of getting the engineering right and reflects the dedication of the men and women working every day to deliver critical infrastructure for the nation.
Looking Ahead
With the finish line in sight, the mission continues, building the nation’s infrastructure, one massive beam at a time.
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 are positioned, workers install and tighten 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 says. "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 comprises three separate contracts. Two remain currently active, the Upstream Approach Wall and the Downstream Approach Wall and Decommissioning.
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