What is the Gravity Pipeline Project?

The Gravity Pipeline (GP) Project consists of the design, construction, permitting, start-up, commissioning, and closeout of approximately 17,600 feet of wastewater gravity FRP pipe inside a concrete-segment tunnel. The work includs three shafts and will interface directly with the Front of Plant (FoP) Project at the Receiving Lift Station (RLS). Work is being implemented under a Progressive Design-Build procurement process.

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Gravity Pipeline Project

Last Updated January 2020

SVCW and its tunnel contractor partner, Barnard-Bessac Joint Venture (BBJV), ended 2019 with a great safety record of completing over 98,000 hours of construction work without a recordable incident since the start of work in 2018. SVCW’s highest priority is the safety of our staff, our construction team partners, and the members of our community. RESCU has been set up with a focus on safety, and our team members are fully on board, executing challenging construction work while maintaining an excellent safety record.  The numbers are evidence of our team’s commitment to safety.   

This month, construction for the Gravity Pipeline project resumes after a short holiday break.  BBJV has completed excavation of the Bair Island shaft, which is a vertical retrieval shaft for receiving Salus, the Tunnel Boring Machine (TBM) at the end of its first of two tunneling drives. After arriving at the Bair Island shaft, Salus will return to the vertical shaft located at Shoreway Road and Holly Street to start its second tunneling drive towards the treatment plant. After completing the Bair Island Shaft excavation, BBJV placed the concrete base slab for the shaft. More preparations at the Bair Island Shaft will be underway in preparation for Salus’ break through, anticipated for April 2020.  

Part of the Gravity Pipeline construction includes installation of the raw wastewater carrier pipe. The carrier pipe will be installed in interlocking segments (each segment ranges in length from 10-feet to 20-feet) within the completed tunnel to convey raw wastewater to the treatment plant.  The fiber reinforced pipe (FRP) has been manufactured in Jakarta, Indonesia, and the first of two shipments arrived in California at the end of December. These pipes will be stored in a secure storage facility in Sunol, CaliforniaIn preparation to receive the first shipment of FRP pipe, BBJV has procedures in place for protecting the pipe to avoid damage during transport, off-loading, and storage while the tunnel is under construction.  In 2020, we look forward to reaching significant milestones on the Gravity Pipeline project, including completing the first of Salus’ tunneling drives, starting the second drive, and receiving the remaining shipments of pipe.

Concrete base slab at the bottom of the Bair Island shaft



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