Saluda Dam Seismic Remediation
Saluda Dam in Columbia, South Carolina was constructed in 1930 on an earthen embankment with no filter or drain protection and a core made of loose density material. This rendered Saluda susceptible to liquefaction in the event of an earthquake, and the 2.2 million acre feet of water in Lake Murray behind it a danger to communities downstream.
In 2002, the Federal Energy Regulatory Commission (FERC) directed the owner, South Carolina Electric & Gas (SCE&G), to strengthen the structure. The $275 million Saluda Dam Remediation Project involved seismic upgrades and building a back-up dam immediately downstream.
Remediation project general contractor Barnard Construction contacted Bluegrass to assist with removal of concrete piers and retaining wall to provide access to the 223’ penstock towers which supply water to the turbines in the Saluda hydroelectric plant.
Months in advance of cutting and excavating around the piers, we core drilled more than 600 2” diameter, 18”-20” deep holes into each pier for the expansive grout.
South Carolina Electric & Gas (SCE&G)
Bluegrass diamond wire saws were ideally suited to the job because of the minimal vibration emitted, therefore avoided the potential hazard of vibrating debris into the draft tubes. We set up the saws to cut the concrete piers surrounding the discharge pipes. The saws cut 40’ hexagons from the 1,000-square yard riser blocks and used 20 cases of expansive grout per hexagon. Two l-beams were inserted to support the 2,000 ton sections as the cutting proceeded so that the diamond wire would not be crushed when the concrete released. When the pier cuts were 3/4 through, expansive grout was loaded into the predrilled holes.
While diamond wire saws finished the cuts, the expansive grout was cracking the foundation into ½ yard cubes. Finally, our robotic hammers went to work further breaking the concrete blocks for removal. Technicians clad in personal protective equipment continued working as slurry accumulated to depths of 8-12”, completing the job on time, under budget, with a satisfied customer.