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Thalle Construction gets $43m from Army to work on dam

Staff Writer | July 13, 2016
The U.S. Army Corps of Engineers, Nashville District announces the award of a $42,972,545 contract to Thalle Construction to build a concrete reinforcing berm downstream of the Center Hill Auxiliary Dam.
Thalle Construction
Construction   Downstream of the Center Hill Auxiliary Dam
The contract was awarded on June 27. The work also includes stabilization of a previous rock cut near the main dam.

“This final major construction effort will reinforce the earthen auxiliary dam, also called the saddle dam, and reduce the risk of either a seepage or an overtopping failure of this structure.

“The construction will complete a series of major construction efforts since 2008 to significantly improve the long-term reliability of the dam and to ensure public safety” said Project Manager Linda Adcock. The awarded contract is the third and final major contract for dam safety-related work at Center Hill Dam.

“A second, auxiliary earthen embankment, in addition to the main one, was constructed in the 1940’s as part of original construction” explained Adcock.

“The auxiliary dam is southeast of the main dam and many folks are not of is location because it is visible primarily by air or boat. The auxiliary dam fills a low area in the landscape in order to maintain the lake; it is an integral part of the Center Hill project.” The foundation of the auxiliary dam has the similar seepage concerns as the main dam.

The main components of work in the auxiliary dam contract awarded today are:

• A 130,000 cubic yard roller compacted concrete (RCC) reinforcing berm immediately downstream of the saddle dam

• Excavation and stabilization of the cut slopes east of the main dam in the area commonly known as the left rim with transport of excavated material to be placed between the existing auxiliary dam and the newly constructed RCC berm

While the contract awarded today will complete the auxiliary dam rehabilitation, the first two major contracts addressed seepage issues at the main dam. The 2008-2010 work included grouting at the main dam and left rim. To complete the main dam improvements, a 2012-2015 foundation barrier wall was then installed through the main dam earthen embankment and deep into foundation rock.

tate highway 96/141 across the dam is planned to remain open, as well as Long Branch Campground downstream of the dam, throughout the two and one-half year contract.

The Center Hill Dam was identified in 2006 by the Army Corps of Engineers as a high risk dam, primarily due to foundation seepage. “Much of the risk has been reduced by work completed to date,” Adcock said. “The auxiliary dam work is the final leg repair of a three-legged stool”.

In addition to this major contract, there will be several small contracts required for site restoration through 2019.