The Saluda Dam, which impounds Lake Murray, is located on the Saluda River, 10 miles upstream of Columbia, South Carolina. With more than 500 miles of shoreline, water area covering about 78 sq. miles, and storage capacity of more than 2,100,000 ac-ft of water, Lake Murray is one of the largest man-made lakes in North America. The existing dam is a semi-hydraulic fill earthen embankment constructed in 1930. Due to its method of construction, it is susceptible to liquefaction. If the Dam were to fail, there would be a huge impact to the surrounding communities. Many lives would be lost in the destructive flood with extreme damage to the environment, infrastructure, and local economy.
The Saluda Dam Remediation Project involved building a back-up dam downstream of the toe of the existing dam. Completed in 2005, the new 211-foot-tall structure is a combination of rockfill and RCC dams, and was designed to prevent catastrophic flooding and to ensure the safe shutdown of the associated hydro and fossil stations. While construction of the 5,500-foot long rockfill section was a major effort, the most challenging and innovative aspect of the project dealt with constructing the 2,300-foot long RCC section in a narrow corridor between the existing dam and existing facilities.
Members of the Fall Line staff were retained to provide on-site testing, and maintained a staff of 15 engineering technicians during the construction phase of the project. The staff worked day and night shifts year-round to provide the testing services that were specified for the project. Testing was performed on the soils, concrete, aggregates, and RCC for the new dam, in both the field and the laboratory.
Advanced testing to determine accelerated 28-day and 365-day strength of the RCC for compressive strength, modulus of elasticity and split tensile were performed. In addition, flat and elongated tests were performed on the minus #4 to the minus #200.
Construction of the rockfill portion of the dam entailed placement of 3.5 million cubic yards of soils and rock. The RCC section for the dam required 1.3 million cubic yards of RCC and mass concrete. All materials were produced on-site. Daily blasting in the quarry produced rock for the construction. Shot rock was then delivered to the on-site crushing plants, which supplied various aggregates for the RCC, rockfill, and filters. Two Aran RCC mixing plants, with 500 cubic yards/hour capacity, each provided RCC and mass concrete. Due to the hot climate, extensive chilling was required. Seven chillers, each with a 230-ton capacity, cooled aggregate and water for the RCC mix. At the peak placement in November 2004, approximately 18,600 cubic yards of RCC was placed in a 24-hour period, establishing the new world record.
The $275 Million remediation of Saluda Dam was at the time the largest active dam construction project in the U.S. The Saluda Dam is the third largest Roller Compacted Concrete (RCC) dam in the U.S. and is one of the Top 20 in the world. The Project was the recipient of the American Society of Civil Engineers (ASCE) 2006 Project of the Year, winning the coveted ASCE OPAL Award.