Owner: Los Angeles County Flood Control District
Contract value: $94,764,668
The Big Tujunga Dam is located at the base of the San Gabriel Mountains and was constructed in the early 1930’s to control floods and to conserve water. While it was built with a storage capacity of 5,960 acre-feet of water, the California Division of Safety of Dams (DSOD) imposed a seismic restriction on the dam in 2004 that limited the long-term storage to 1,484 acre-feet.
The project improved the safety of the dam by cleaning the foundation, placing mass concrete, modifying the spillway, removing and replacing the dam crest and appurtenant structures, stabilizing the canyon walls with consolidation drilling, grouting, and rock bolts, and establishing a new dam control system. The original storage capacity was restored.
The specifications required the concrete to be placed at 50 degrees and kept below 55 degrees for the duration of curing. To accomplish this, chilled water was used and ice added to the batches when temperatures were high (the dam is near Los Angeles and concrete was placed throughout the summer). Cooling tubes run through the blocks of concrete to circulate 40 degree water through them, and the tubes were grouted after the blocks were cured.
SCCI self-performed the Electrical scope of work.