Christchurch Brick Barrel Sewers & Stormwater Pipe Relining
New Zealand’s largest ever CIPP project
One of New Zealand’s earliest cities, many of Christchurch’s sewers were built before the invention of precast concrete pipes, using unreinforced brick and concrete. As with brick buildings, these brick sewers are particularly vulnerable to seismic activity, and some were severely damaged during the 2011 and 2012 earthquake. This highlighted the vulnerability of the infrastructure, and the need for strengthening and earthquake proofing.
Replacing the sewers would have caused major disruption to traffic and the community, so SCIRT opted to rehabilitate most of the pipelines using Cured-in-Place-Pipe technology (CIPP).
Pipeworks relined the egg-shaped and elliptical pipes, which vary in diameter from 450mm to 1,350mm, using a very thick structural liner to protect them from future earthquakes and liquefaction. With many of the pipes running down major arterial roads, careful logistics planning and extensive traffic management was required.
All sections of CIPP liner were installed to a high standard, with minimal disruption to traffic and surrounding residents. The scale of work to be completed made this the largest CIPP project ever undertaken in New Zealand. Due to the sheer volume of work, the CIPP liners had to be installed three times faster than normal – faster than any other large diameter CIPP project in Australasia.
The scale of work to be completed made this the largest CIPP project ever undertaken in New Zealand.
- All of the pipes were more or less permanently flooded
- By-passing of sewer flows of up to 300 litres per second – pumped above and below ground in busy streets
- Major alterations to large manholes up to 4m deep were required including well pointing and trench shields
- All resin mixing was undertaken inside the "Red Zone" to reduce risk
- Confined Space entries were required to open laterals in certain pipes.