Construction crews work Feb. 3, 2021, at the Chickamauga Lock Replacement Project on the Tennessee River in Chattanooga, Tenn. The U.S. Army Corps of Engineers Nashville District is building a larger replacement lock at the Tennessee Valley Authority project. (Lee Roberts/USACE photo)
The U.S. Army Corps of Engineers (USACE) will receive nearly $191 million for the Chickamauga Lock Replacement Project from funding revised and adopted by Congress. The money will go toward the next phase of work on the lock at the hydroelectric Chickamauga Dam, located on the Tennessee River in Chattanooga, Tenn.
Tennessee Congressman Chuck Fleischman announced on Feb. 3 that the funding has been appropriated for the project in the fiscal year 2021 budget.
The 81-year-old Chickamauga Dam has long been a major thoroughfare for barge traffic. Approximately one million tons of goods pass through its single lock each year.
Construction on the lock project began in 2003 after engineers discovered deterioration in the original concrete. After a few starts and stops over the years, due to budgetary constraints, progress is now being made.
The lock replacement is the second largest of its kind in the United States. When complete, the dam will have the capacity to move nine working barges at once. Currently, the lock can only process one at a time.
With the newly allocated funds, the Chickamauga Lock Replacement Project is now expected to be completed as early as November 2025. USACE Project Manager Adam Walker confirmed the federal appropriation announced by the congressman means all future construction contracts on the lock can be fully funded.
As a member of the U.S. House Appropriations Committee, Fleischmann pushed to ensure that the upgrade to the dam would be a top funding priority and worked to boost funding for it. The barge diesel tax also was raised to help provide more matching funds.
Almost $317 million was spent on the dam improvement through December 2020, a figure that is not even half of what it is expected to cost.
Next on the agenda are plans by the USACE's Nashville District, which operates and maintains the navigation lock, to advance construction of the upstream approach wall with a contract award scheduled for September 2021. Additional work on the downstream approach walls, decommissioning of the existing lock and site restoration is planned in future contracts.
The Tennessee Valley Authority (TVA) completed construction of the Chickamauga Lock and Dam in 1940. With a single chamber measuring 60-by-360 ft., the lock has since experienced structural problems resulting from alkali aggregate reaction between the alkali in the cement and the rock aggregate, which results in a physical expansion of concrete structures. The current lock chamber also is incompatible with today's towing equipment resulting in longer than normal tow-processing times.
When the new, larger lock is completed, it is expected to keep open 318 mi. of navigable river miles upstream of Chickamauga Lock and Dam and speed up the locking-through process with the ability to handle up to nine jumbo barges in one lockage.
Some originally feared the existing lock would fail before the new lock would be operational, but Fleischmann assures it is safe. He said the USACE is doing an exemplary job of maintaining the existing navigation lock to keep it open to commercial and recreational vessels until the new lock begins operating.
"There are over 3,000 monitoring devices on the existing lock. A typical lock might have 100 devices. I'm here today to say that the existing lock is doing exceedingly well and performing all of its functions," he said.
On the same day that the new federal funding was announced by Fleischmann, Lt. Gen. Scott Spellmon, commanding general of the USACE and its 55th Chief of Engineers, visited the Chickamauga Lock Replacement Project to meet with project managers and engineers and gain a better understanding of ongoing construction of the new lock chamber.
Along with Fleischmann, they toured the existing Chickamauga Lock before moving inside the coffer dam to get an up-close view of work crews placing concrete to build a monolith for the new 110-by-600-ft. navigation lock.
Oakland, Calif.-based Shimmick Construction, one of the country's largest dam contractors, operated a conveyor system to move concrete more than 900 ft. over the existing lock, into a tower-belt system and down inside the coffer dam. The system places 200 yards of concrete per hour.
Maj. Gen. Robert F. Whittle Jr., the USACE's Great Lakes and Ohio River Division commander; and Lt. Col. Sonny Avichal, the Nashville District commander, also were on hand in Chattanooga for the tour and a press conference.
Spellmon, who became chief of engineers in September 2020, said the Chickamauga Lock is one of 239 lock chambers that the USACE is responsible for nationwide.
"I want to thank Congressman Fleischmann for his leadership in getting the Corps the funding to bring this project to fruition," Spellmon said. "The vision of the Corps is ‘We want to deliver engineering solutions for our nation's toughest challenges.' This is certainly one of them, and with the congressman's leadership, he's giving us the resources to get a project done on time and within budget."
Shimmick Construction has worked more than one million man-hours constructing the lock chamber without a lost-time accident.
"That's a big, big deal," Whittle said. "As you can tell, there is a lot of work getting done here. They are doing a great job. And again, with all that work and everything you have witnessed observing the project, you can see that safety record is really something to behold."
Whittle also noted the great partnership between the Corps of Engineers and the TVA. The Chickamauga Dam is a TVA project, but the USACE maintains its navigational lock.
Avichal, who is responsible for managing the construction project, said he was most impressed with the teamwork between the Corps, TVA and the contractor, which is placing 240,000 yards of concrete. To put the concrete placement in perspective, he said that is enough to build a two-lane highway from the lock in Chattanooga all the way to Nashville, a driving distance of 134 mi.
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