The U.S. Army Corps of Engineers has delayed bidding for construction of a concrete seepage barrier at the main embankment of 135-MW Center Hill Dam on the Caney Fork River near Lancaster, Tenn. Bids now are due June 17.
The Corps previously said it expected to receive bids April 23 and May 21. (HydroWorld 3/4/10) The latest announcement also scheduled a pre-proposal site visit for April 27.
Center Hill has a history of seepage problems that have worsened in recent years. (HydroWorld 12/7/09) The Corps’ Nashville District awarded an $87.4 million contract in 2008 to Kiewit—A.C.T. to install a grout curtain seepage barrier at the project.
The 250-foot-tall dam consists of a 1,382-foot-long concrete section and 778-foot-long earth embankment. The Corps said the expected solicitation would call for a 900-foot-long concrete seepage barrier with a minimum 2-foot thickness, extending from elevation 696 mean sea level to 405 msl. The work is expected to cost between $100 million and $250 million.
The barrier is to be installed through existing earthen embankment and underlying limestone foundation. Portions of the limestone foundation exhibit unconfined compressive strengths up to 32,230 pounds per square inch, with range of 5,000 psi to 32,230 psi. Therefore the Corps prefers a combined wall of hydromill and circular pile elements.
Center Hill Dam is among six dams the Corps identified as having a high risk of failure, in a screening program of 130 dams. In 2006, the Corps approved a $240 million rehabilitation plan to improve the dam’s long-term reliability by 2014.
A solicitation notice may be obtained from the Federal Business Opportunities Internet site, www.fbo.gov, by entering Solicitation No. W912P509R0011 in the “Keyword/Solicitation #” box. Prospective bidders must register at the Central Contractor Registration database, www.ccr.gov, and the On-line Representations and Certifications site, https://orca.bpn.gov.
Bids are due by 1 p.m. June 17. For information, contact Yvette Walker, U.S. Army Engineer District, Nashville, P.O. Box 1070, 801 Broad St., Nashville, TN 37202-1070; (1) 615-736-7944; E-mail: email@example.com.
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