Bauer Spezialtiefbau realizes remediation at Center Hill Dam

Tennessee, USA – BAUER Foundation Corp., local subsidiary of BAUER Spezialtiefbau GmbH, took responsibility of an extremely challenging dam remediation from spring 2013 on. The Center Hill Dam in Tennessee, USA, was built in 1948 as a means of river control and for production of energy. Ever growing damage on the sides, rock erosion and caverns are destabilizing the entire system and leading to water loss. The United States Army Corps of Engineers (USACE), Nashville District, contracted Bauer to construct a cut-off wall in a project worth over 108 million USD. This is the biggest single order the BAUER Group has ever had.

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The first step was to expand the dam crest, to create room and stability for the large pieces of equipment. The first step in the construction work is to execute a foundation barrier wall in the earthen base of the dam. The construction is up to 100 meters deep, socketed into rock 30 to 50 meters. The entire wall is 280 meters long.

The project is extremely demanding. Verticality of the highest precision is required: for a diaphragm wall panel or a bored pile, deviation of only 25 centimeters is allowed at the depth of 100 meters. The supplier of concrete has erected a concrete factory close to the construction site for the 60,000 cubic meters of concrete, required for the project. The logistics of the construction site are also a big challenge due to the limited space.

The project is being executed with the BAUER Maschinen GmbH equipment with the biggest performance capacity, in parts specifically modified or even constructed to fit the purpose: Operating next to one trench cutter BC 50 – panel size 3.20 x 2.25 meter – on a heavy cycle crane MC 128 are one diaphragm wall grab on a MC 96 and a rotary drilling rig BG 50 with a 100 meter long kelly. Used for the first time is a new method of cut-off wall construction, executed with a Wassara-water-hammer on a Klemm drilling rig KR 806.

The entire process is computer monitored. About 220 employees work round the clock in three shifts. The project is to be completed in the spring of 2015. Alone the preliminary work, mobilization and site set-up took one whole year.