Pegasus Water Treatment Reservoir, North Canterbury

Client: Pegasus Town Ltd

Engineer: Beca Infrastructure Ltd

Main Contractor: Brian Perry Civil

Brian Perry Civil won the Water Facilities contract for the new residential development known as Pegasus Town, 40 kilometers north of Christchurch at  Woodend.

The Water Facilities contract incorporated a Water Treatment Plant, Pump Station, Underground Dirty Water Tank, Overflow Storage Pond and a 1.36 million litre Reservoir.

BBR Contech won the subcontract to undertake Reservoir ‘A’ post-tensioning work including supply of all stressing components, materials and equipment necessary to satisfactorily complete prestressing operations.

The 17.0m diameter Reservoir was constructed using 200mm thick Precast concrete wall panels 6.0m high with 8 rings of 51mm ID Drossbach duct holding BBR 505 multi-strand horizontal tendons. Horizontal tensioning was achieved using a 100 tonne hydraulic jack and power pack through 4  Pilasters with half tank circumference duct (tendon) profile.

Each tendon was stressed in accordance with NZS 3109 Section B to a sequence targeting a maximum tendon force of 80% UTS (744kN) at transfer.