RCC dam and rockfill dam at the Saluda Dam remediation project

Saluda Dam, part of the FERC regulated Saluda Hydroelectric Project located near Columbia, South Carolina, is being upgraded to resist a recurrence of the 1886 Charleston Earthquake. Concurrent with this upgrade is a major outage and refurbishment of the adjacent McMeekin Plant, which draws cooling water from Lake Murray, formed by Saluda Dam. The existing, semi-hydraulic fill embankment Dam was completed in 1930 and, based on current technology, is viewed as being susceptible to liquefaction during the design seismic event. Several remediation options were considered with the selected approach being a back-up berm, essentially a “Dry Dam”, at the downstream toe of the existing Dam. The “Dry Dam” will consist of about 5500 feet of Rockfill and about 2300 feet of RCC. This Project is the largest active (year 2002) dam construction project in the United States and the final Project will involve the placement of 1.3 million cubic yards of RCC and 3.5 million cubic yards of Rock Fill. This paper presents an overview of the design aspects of the RCC Dam and the Rockfill Dam plus portions of the McMeekin Plant upgrade that have a direct impact on the Dam Remediation Project. We address topics such as the new cooling water system and ash handling systems for McMeekin and their impact on the Dam Remediation, seismic design basis, loading conditions, finite element analysis, mix design parameters, drainage and joint design, facing considerations, thermal stress analysis joint spacing, and the mix design testing programs. An unusually large number of load cases had to be considered as the “fix” must consider “dry conditions” and “wet conditions” as well as the postulated condition of the existing embankment Dam after a recurrence of the 1886 Earthquake. The mix design program addresses the use of aggregate, from an on-site borrow area and the use of landfilled, waste flyash as a constituent of the RCC. 22 pp., 12 tables, 10 figures.