Gravity Pipeline March 2022

SVCW’s contractor partner for the Gravity Pipeline project, Barnard Bessac Joint Venture (BBJV), has completed installation of the fiberglass reinforced polymer (FRP) pipe inside the gravity tunnel. Cellular grouting work, to fill the annular space between the pipe surface and the inner wall of the tunnel, continues. With the completion of grouting along tunnel drive 1, i.e. from the Airport Access Shaft (AAS) to the Inner Bair Island shaft, efforts are underway to complete grouting in the upstream segment of tunnel drive 2, which spans half the distance from the AAS to the SFS Shaft at the Front of Plant site. These activities constitute the last stretch of the construction of the gravity tunnel. All of the work is being carried out by maintaining consistent coordination with its subcontractors and inspectors on each site, to ensure safety and highest quality of work.

FRP Pipe Placer

At the Bair Island shaft, installation of the Bair Island Drop Structure continues. BBJV has completed installation of the tee structure that will connect to the pipe entering the shaft, and has placed the base of the tee at the bottom of the shaft. BBJV is now proceeding with the installation of the Bair Island inlet structure, which includes backfilling in the shaft above the tee for additional support, and removal of shaft excavation support walers. Walers are horizontal beams that serve as temporary structural supports to ensure stability of the shaft excavation. Next steps at the Bair Island shaft include installation of the connecting piece of piping that will connect the existing HDPE SVCW force main on Inner Bair Island to the new drop structure that is the upstream inlet to the new gravity tunnel.

Bair Island shaft demolition
Bair Island shaft backfill
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