New Irvington Tunnel Awarded to Southland/Tutor Perini JV

The San Francisco Public Utilities Commission recently awarded the contract for the New Irvington Tunnel Project to a joint venture of Southland Contracting Inc (Ft. Worth, Texas) and Tutor Perini Corp. (Sylmar, Calif.).  Southland/Tutor Perini JV submitted the lowest qualified bid at $226.6 million, which is $26.6 million below the commission’s estimate.

Construction is expected to begin in September 2010 with final completion by April 2014.
The New Irvington Tunnel will run 3.5 miles and have an internal diameter of approximately 8.5 to 10.5 feet. It will lay parallel to the existing tunnel between the Sunol Valley south of Highway I-680 and Fremont, California.

Located between the Calaveras and Hayward Fault Zones, the mixed-face tunnel is made up of inter-bedded layers of sandstone and shale, with several smaller fault zones. Adding more complications, the tunnel offers 700 ft of cover and high hydrostatic head with potential water inflows up to 1,000 gpm.

The new tunnel will provide a seismically designed connection between water supplies from the Sierra Nevada Mountains and the Alameda Watershed to Bay Area water distribution systems. Not only does it provide a seismically sound alternative to the existing tunnel, the new tunnel will allow the SFPUC to take the existing tunnel out of service for much needed maintenance and repair.

The New Irvington Tunnel is part of the commission’s $4.3 billion Water System Improvement Program to repair, replace and upgrade aging pipelines, tunnels and dams.