City West Cable Tunnel

As part of its major upgrade of the electricity infrastructure in Sydney’s CBD, Energy Australia has recently completed a new 1.7 kilometre long transmission cable tunnel.

Known as the City West Cable Tunnel it runs under part of Sydney’s CBD from Haymarket under Darling Harbour and terminates at the City North Zone sun-station.

1.6 kilometres of the tunnel was constructed using a tunnel boring machine and the completed tunnel is lined with a precast concrete segmental lining to provide a 2.2 metre I.D. water-tight tunnel.

Segmental lining comprises rings 3.2 metre I.D. x 3.6 metre O.D. Each ring is 1.0 metre long and consists of six interlocking precast concrete segments.

In all, 9666 segments were required and these were produced at the rate of 96 segments per day using SCI’s newly designed and constructed fully automated, computer controlled carousel manufacturing and curing facility.

The steel fibre reinforced concrete used in the segments was state-of-the-art to comply with the stringent and demanding concrete specification.