Call : 1-800-480-4808

Folsom Dam

Folsom Dam

 

Folsom Dam
Location: Folsom, CA
Office: Rancho Cordova
Client: Granite Construction
Construction Cost: $1,259,000,000
The U.S. Army Corps of Engineers is directing the construction of an auxiliary spillway and new flood-control gates that will operate in conjunction with existing spillway gates on Folsom Dam to better manage flood flows from Folsom Reservoir. The project addresses a flaw in the dam’s original design, as the eight small outlet gates in the face of the dam can’t empty the reservoir fast enough when a large storm strikes. The six new steel gates are 49 feet lower in the water, allowing water to be released more quickly as lake level rises.

RMA Group completed comprehensive quality control including the testing and inspection of all aggregates, concrete, reinforcing steel, and structural steel. Over 130,000 cubic yards of concrete were used to construct the spillway control structure, which included mass concrete placement using three-inch aggregate and liquid nitrogen for cooling. Sieve analyses on the large aggregates were performed at our Rancho Cordova lab facility on 600-pound samples.

RMA Group provided a registered Geotechnical Engineer to observe rock bolting of a 150-to-200-foot, vertical cut slope, excavated into fractured granite bedrock. The on-call geotechnical engineer was able to visit the site when failed or unusual stressing operations occurred, or as required by the construction team, with a two-to-three-hour response time. The excavation formed the foundation base of the auxiliary dam embankment and spillway control structure. Approximately 2,200 bolts were installed to support the excavation during construction, ranging from one to three inches in diameter, and 30 to 45 feet in length. Engineering duties included reviewing the stressing operations and performing calculations to analyze if bolt elongations were within specifications. Quality Control duties by our certified inspectors included observation of the drilling operation, drill length, bolt installation, and grout placement, as well as the sampling and compression testing of the grout, recording the staged load and elongation of the bolts, and confirming lock-off.