A170 Branch Sewer
Remuera was largely farmland when the Branch 1 sewer was laid in Remuera in 1903. But with the suburb now home to some of New Zealand’s most expensive properties, and the ageing sewer needing repair, trenchless rehabilitation was the only option.
Pipeworks used Cured-In-Place-Pipe (CIPP) technology to reline a 530m long egg-shaped section of the sewer, whereby a resin-soaked ‘sock’ was installed inside the 900mm x 600mm brick and concrete structure. The resin was cured using hot water. The snug internal fit provides a permanent barrier inside the old sewer, keeping it watertight without significantly reducing the diameter and capacity of the pipe.
Pipeworks selected a thin I-Plus (Fibre-Reinforced) Liner for the lining, as it provided the required strength with minimal reduction to the pipe’s diameter to maximize flow volume.
The heavily built up environment added significantly to the challenge. The CIPP liners were installed “blind” through 12m deep 900mm x 800mm chimney manholes. As the manholes were positioned in a major arterial road, significant traffic management was required.
The heavily built up environment added significantly to the challenge.
Branch 1 is an integral component of the Auckland wastewater network, so prior to commencing rehabilitation works Pipeworks installed an extensive bypass pumping system to capture all dry and wet weather flows. A section with a capacity of 250 l/s system was installed by horizontal directional drilling (HDD) under Remuera road.
The pipe was rehabilitated successfully without any disruption to surrounding residents.