Work on the Chickamauga Lock Replacement Project, located at Mile 471 on the Tennessee River in Chattanooga, Tenn., reached a major milestone in June with construction crews placing the first concrete beams for the new lock’s upstream approach wall.
Urbancrest, Ohio-based C.J. Mahan Construction Company LLC, the contractor for the upstream approach wall, is partnering with McKinney Salvage LLC of Baton Rouge, La., to maneuver the 420-ton beams into place using a dual derrick barge crane system. Each beam measures 10’x10’x120’.
“This process is meticulous,” said Cayce Grall, project manager for the U.S. Army Corps of Engineers’ Nashville District, which is overseeing construction of the new lock. “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.”
According to the Corps, C.J. Mahan fabricated the upstream approach wall beams in 2010. In the years since then, as the beams were in storage, Corps officials conducted material testing and inspections to ensure their structural integrity.
In total, the new Chickamauga Lock will use 42 beams for both the upstream approach walls and the downstream approach walls. Beams are stacked between four intermediate piers and two nose piers both upstream and downstream. Once they are stacked, the beams are measured using precision gauges, then secured with cables, with dive teams in the water monitoring the placement.
“Having the dive team on site was essential,” Grall said. “They inspected the beam under water, checking for gaps to ensure it is properly seated. Perfect alignment is non-negotiable.”
Officials with the Nashville District expect the upstream approach wall to be complete in 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.”
Of the three contracts that make up the Chickamauga Lock Replacement Project, two are currently active, the upstream approach wall contract and the downstream approach wall and decommissioning of the old lock chamber, with C.J. Mahan the primary contractor for both. The Nashville District awarded the downstream approach wall and decommissioning contract to C.J. Mahan in February.
As of mid-February, the Corps reported that construction on the new lock chamber was about 76% complete. However, on May 8, the Nashville District announced it had terminated its contract with Shimmick Construction Company for the lock chamber.
“This decisive action is necessary to get the project back on track and protect taxpayer dollars,” the Nashville District said at the time.
Shortly thereafter, Shimmick announced intentions to appeal that decision.
Delays and cost escalations have plagued the Chickamauga project, along with other Corps infrastructure projects around the country.
The project was first authorized in 2003 at a cost of just over $267 million. In 2018, that cost estimate was adjusted to more than $757 million. As of fiscal year 2026, the cost estimate stands at $1.566 billion.
When the Nashville District announced it had terminated Shimmick’s contract for the chamber, the district reiterated its goal of bringing the new lock chamber online in 2028.
When complete, the new Chickamauga Lock chamber will provide substantial time and cost savings to commercial operators and recreational boaters alike. At present, the original lock chamber can only handle one barge at a time, while the typical tow moving through that part of the Tennessee River is made up of nine barges. The new 600’ lock chamber will be able to fit a full 9-barge tow.
