Wilmers Road Reservoir, Christchurch

The Christchurch suburb of Hornby is changing rapidly, largely owing to residential and industrial growth that’s being encouraged as part of a long- term community plan.

Recognising that the community needs an additional water supply, Christchurch City Council has built a new water supply pump station in the area. The facility comprises a pump station and a freshwater holding tank, with the latter having a capacity of more than 3.7 million litres.

BBR Contech was called on to provide post-tensioning services for the precast concrete panels that form the tank wall – a huge structure standing 6m high and measuring 31m in diameter. The work involved:
– supplying the panel manufacturer with ducting for the tendons, which was cast into the panels
– once the panels were assembled on site, coupling the ducting and carefully installing the 11 tendons – comprising seven 12.7mm strands each – horizontally in the panels, effectively encircling the tank’s circumference
– stressing the tendons to the desired load, then grouting them in place.

The project is now complete, providing the residents and businesses in the area with a much-improved water supply, and a structure that, thanks to the use of post- tensioning technology, can withstand the damaging forces of an earthquake.