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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What's Happening

Gravity Pipeline Project

Last Updated October 2021

SVCW’s contractor partner, Barnard-Bessac Joint Venture (BBJV), has removed all the Tunnel Boring Machine (TBM) components and its support equipment from the Surge and Flow Splitter (SFS) shaft, after the TBM’s successful break in 2 months ago. This month, BBJV is working to install Fiber Reinforced Polymer (FRP) pipe within the completed tunnel. BBJV will be installing about 10 pipe sections, with the first stick of pipe installed in the completed tunnel at the SFS shaft. A pipe installer, equipment used to carry and install the FRP pipe within the completed tunnel, is being used to transport and install the pipe. The installer will carry pipe from the Airport Access Shaft, situated at the intersection of Holly Street and Shoreway Road, to the SFS shaft, which is approximately 2.3 miles away. Following the installation of the first 10 pipe sections, BBJV will demobilize from the SFS shaft and continue the pipe install work from the Airport Access Shaft site. Quality Control and Assurance checks on the pipe install work are ongoing daily to ensure that the installation work meets the required quality standards and the finished slope established in the design of the gravity pipeline.

Installing FRP pipe with pipe installer

At the San Carlos pump station site, work is underway to connect a new pipe to convey wastewater flows from the San Carlos and Belmont sewer collection systems to the new gravity tunnel. A hydraulic jacking frame has been installed within the vertical shaft constructed east of the San Carlos Pump Station structure to conduct pipe jacking operations, which is a trenchless construction method to install pipe below the ground surface with no excavation at the surface required outside of the vertical shaft. BBJV has also set up a support frame in the new gravity tunnel where the pipe that will be installed from the San Carlos shaft will connect to the pipeline in the new gravity tunnel.

Support frame in tunnel for connection to new pipe carrying San Carlos and Belmont flows

Latest Updates

Gravity Pipeline Project

Gravity Pipeline August 2021

With Salus, the Tunnel Boring Machine (TBM), successfully completing its second tunneling drive, SVCW’s contractor partner, Barnard-Bessac Joint Venture (BBJV),

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