McConnell Dowell Construction
17,000 x precast segments
3.4 metre diameter
100% steel fibre reinforcing
Hobson Bay TunnelFor 90 years, Aucklands wastewater was carried via overland server pipe across Hobson Bay to Mangere wastewater plant.
This pipe was replaced with a 3 kilometre long 3.4 metre diameter sewerage tunnel. The tunnel provides significant extra capacity for Auckland's growth, and eliminating overflow, this ensured Hobson Bay can be used for recreational purposes again.
The precast concrete segmental-lined sewer tunnel was excavated using an earth pressure balance tunnel boring machine. This was the first of its scale and type in New Zealand.