Chickamauga Lock Replacement Project
US ARMY CORPS OF ENGINEERS BUILDING STRONG®
AUTHORIZATION: Consolidated Appropriations Act of 2003 (P.L. 108-7); reauthorized in America’s Water Infrastructure Act of 2018 (P.L. 115-270)
TYPE OF PROJECT: Navigation Lock Project
LOCATION: The Chickamauga Lock Replacement Project is located at Tennessee River Mile 471 in Chattanooga, Tennessee.
CONGRESSIONAL INTEREST: Fleischmann, R-TN-03; Blackburn, R-TN; Hagerty, R-TN
KEY STAKEHOLDERS:
- Inland Waterways User Board (IWUB)
- Tennessee Valley Authority (TVA)
BACKGROUND: The project includes design and construction of a replacement 110-foot by 600-foot navigation lock to be located downstream of the dam and riverward of the existing lock. Replacement lock construction began in 2004 with highway and utility relocations and continued through 2012 with the completion of the cofferdam structure and prefabricated components that are currently being 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), construction resumed after funding returned to the project in fiscal year (FY) 2015.
IMPORTANCE: A new lock is required at Chickamauga Dam because of structural deficiencies of the existing lock resulting from physical expansion of the concrete structure. This phenomenon of concrete growth was observed soon after initial construction in 1940 and is caused by a reaction between the alkali in the cement and the aggregate. Even with significant maintenance efforts, this expansion threatens the structural integrity of the existing lock and limits its serviceable life.
STATUS:
- The $245 million Lock Chamber contract awarded to Shimmick Construction Company, Inc., in September 2017 is currently 40% complete; the current contract required completion date of Sept. 28, 2023, is at risk due to slower than anticipated concrete placement rates.
- The $61 million Upstream Approach Wall contract was awarded to C.J. Mahan Construction Company, LLC in September 2021, with contract completion scheduled for January 2024.
- The Corps will complete a Cost and Schedule Risk Analysis (CSRA) and Total Project Cost Estimate (TPCE) update this year (required every two years).
SCHEDULE:
Completed Work: Highway relocations, steel lock gates and valves fabrication, concrete approach wall beam fabrications, cofferdam construction, and majority of rock excavation are complete.
FY 2022 Scheduled Work: Continued work on the Lock Chamber and Upstream Approach Wall construction contracts.
Remaining Work (future contracts): Downstream Approach Walls, Existing Lock Decommissioning and Site Restoration.