NZCF/Hirepool construction award winners - Category 2

CATEGORY 2 WINNER
Projects with a value between $500,000 and $5 million

Brian Perry Civil

Deloitte Centre, Secant Pile Wall

Brian Perry Civil was contracted to construct the Deloitte Centre Building foundations, comprising 266 number 760mm diameter secant pile perimeter retaining wall, 16 number 1200/1500mm diameter bored foundation piles with embedded 600 x 600 (steeltech) welded beams and 24 UBs driven in pairs to underpin the ‘to-be-retained’, seven storey façade.

The resource consent detailed ground water draw down requirements to ensure neighbouring properties were not affected by settlement and that the basement was watertight. These provisions led to the choice of secant wall construction – the first major secant wall to be constructed in this country by New Zealand contractors.

Ground conditions proved difficult; with extensive pre-existing bluestone block walls and underlying timber pile supports being encountered.

The foundation work was completed to a very high standard in terms of position and verticality, on time and within a congested site containing many other subcontractors.

MERIT AWARD

Dempsey & Wood Civil Contractors
Tiverton / Wolverton Route Improvement Stage 1, Auckland

This project required the reconstruction of the existing two lane arterial road to four lanes over a 600 metre length. Work also included building two retaining walls, four metres and two metres high, between the arterial road and slip lane servicing private dwellings.

The site was confined, with access being maintained on the arterial road and slip road at all times. Eight metre deep piles for retaining walls were drilled from a bench cut into an existing embankment. Design and build slip form barriers posed significant engineering challenges, as did

individually fitted facing panels to the retaining walls. A site specific temporary locking system was designed to attach the retaining wall facing panels. This allowed placing directly from transporters, resulting in reduced turnaround times.

Traffic management formed a significant part of the project to ensure use of the existing road and slip road. Environmental aspects were particularly important when installing the 42 ground anchors to the retaining wall columns, and for general silt and runoff control.