900 Tons of Precast Cover New Sylmar Electrode Array

Los Angeles, California

The Pacific Direct Current Intertie runs from Northern Oregon to Southern California to deliver hydroelectric power to Los Angeles County. The 850 mile transmission line ends 6,000 feet offshore in Santa Monica Bay at the Sylmar Ground Return System. Built in 1970 the system risked failure due to deterioration of underwater electrode array vaults, corrosion of marine cables, and overall metal fatigue.

Jensen Precast custom designed, engineered, and manufactured 36 corrosion-resistant precast concrete vaults for the $114 million project.

Corrosion-Resistant Concrete

Replacing the underwater section of the Sylmar Ground Return System meant building a new structure to house 144 electrodes, 100 feet below mean sea level, three miles from shore in Santa Monica Bay.

Because it would be positioned on the ocean floor, it would need lasting durability, multiagency compliancy, and cost efficiency to complete the job. More specifically, the structure required corrosion-resistant materials all around.

36 Vaults, 25 Tons Each

“High quality precast concrete offers a lasting solution for subaqueous installations like the Sylmar Ground Return System,” says Tyler Haack, Jensen Precast Vice President of Operations. “Our engineering and manufacturing teams in Fontana, California, built 36 vaults at 25 tons each to house the new electrode array. The vaults are 6’W x 20’L x 54″H. We used fiberglass rebar at the request of LADWP to deliver a corrosion-resistant solution.”

The benefits of the massive undertaking are multiple. The Sylmar Ground Return System Replacement project keeps California renewable energy flowing to help meet the state’s goal of 33% renewable energy. Moreover it maintains the reliability and stability of the power generation and delivery system for Southern California, while increasing the available share of renewable resource energy from wind power in the Pacific Northwest.

Corrosion-resistant precast concrete is ideal for projects large and small. Contact us for your project needs.

Download the case study to print, share, and post: Electric Utility Vaults Case Study Los Angeles CA

Video courtesy of Curtin Maritime.

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