The Chickamauga Lock replacement project in Tennessee sees major progress with delivery of new miter gates for improved navigation efficiency and safety on the Tennessee River. USACE and partners work to enhance the critical waterway's infrastructure, supporting commerce and recreation.
Photo courtesy of the U.S. Army Corps of Engineers
Shimmick Construction Company workers transfer a miter gate component at Chickamauga Lock near Chattanooga, Tenn., Dec. 5, 2024.
The U.S. Army Corps of Engineers (USACE) Nashville District, in partnership with Shimmick Construction Co. in Irvine, Calif., and the Tennessee Valley Authority (TVA), is making significant strides in the efforts to replace the Chickamauga Lock in Chattanooga, Tenn.
USACE announced Dec. 9 that the transfer of 14 miter gate components to the site on the Tennessee River is scheduled to take place throughout December.
In a news release, the federal agency said that miter gate components are being delivered to the site each day from Dec. 5-23. The active navigation lock is not closing, although intermittent lock outages of up to four hours are possible during this period.
"These miter gates represent another step closer to the completion of the Chickamauga Lock replacement," said Joe Cotton, the facility's project manager. "Their installation is a critical milestone that underscores the progress being made to enhance efficiency and reliability on the Tennessee River. This project is not just about improving navigation — it's about securing the future of a vital waterway for commerce and recreation and ensuring the long-term stability of the Chickamauga Dam."
Approximately 1.5 million tons of material passes through Chickamauga Lock each year, USACE noted. The completion of the new, larger lock chamber is expected to increase efficiency by up to 80 percent for commercial vessels.
Miter gates are hydraulic steel structures designed to withstand high water pressure, control water levels, and allow recreational and commercials vessels to pass through lock chambers safely.
Built by certified fabricators, these type of gates are coated with anti-corrosion material to resist rust, corrosion and deterioration. The protective coating also minimizes maintenance needs, enhancing the gates' durability and ensuring long-term functionality and safety of the lock, according to USACE.
The miter gate components are being welded together and will be installed on each end of the new 110-ft. by 600-ft. navigation lock, enabling it to accommodate nine jumbo barges (each measuring 35-ft. by 195-ft.), compared to the single jumbo barge capacity of the existing 60-ft. by 360-ft. lock.
"The successful delivery of this milestone is a direct result of our greatest strength: our people," said Lt. Col. Robert Green, commander of the USACE Nashville District. "The dedication, expertise and teamwork of everyone involved in the Chickamauga Lock replacement project are the foundation of our success and the driving force behind this achievement."
Photo courtesy of the U.S. Army Corps of Engineers
An isometric 3D illustration of the Chickamauga Lock near Chattanooga, Tenn., showcasing the final assembly and installation of the miter gates at the Chickamauga Lock replacement project, managed by the U.S. Army Corps of Engineers Nashville District.
Tennessee River Lock Construction Has Long History
Prior to the design and construction of the Chickamauga Lock upgrade, a feasibility study completed by the U.S. Army Corps of Engineers in 2002 confirmed that replacing the existing lock is both feasible and economically justified.
It also was deemed necessary in that the Chickamauga Lock and Dam was constructed by TVA and opened to navigation in 1940.
In addition, a new lock is required due to structural deficiencies within the existing lock resulting from physical expansion of the concrete structure. USACE said that the phenomenon of concrete growth was observed soon after initial construction 84 years ago and is caused by a reaction between the alkali in the cement and the aggregate.
Even with significant maintenance efforts, this expansion continued to threaten the structural integrity of the existing lock and limit its life.
Replacement work at the site first began in 2004 with highway and utility relocations and continued through 2012 with the completion of the cofferdam structure and prefabricated components (miter gates, culvert valves, culvert bulkheads and approach wall beams) that have been stored at other TVA facilities until needed.
After a temporary suspension of construction activities due to funding constraints with the Inland Waterways Trust Fund (IWTF), money for the project resumed in Fiscal Year 2015.
Like all locks on the Tennessee River, the Chickamauga navigation lock is owned by TVA, but the USACE is responsible for operations and maintenance.
The replacement project is located riverward of the current lock and downstream of Chickamauga Dam. A new structure is vital to maintain 318 mi. of navigable channels upstream of dam to support stakeholders, the USACE noted, including the U.S. Department of Energy at Oak Ridge, Tenn., the TVA, and numerous other businesses.
Photo courtesy of the U.S. Army Corps of Engineers
A 3D illustration of the downstream miter gate replacement project at Chickamauga Lock near Chattanooga, Tenn. Comprised of 10 components (five on each side) that will be welded together, the gates will be over 70-ft. tall and weigh over 800,000 lbs.
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