Bank of New Zealand Piling
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Sector: Infrastructure
Location: Auckland
Contract Value: $4.70m
Completed: Sep 2007
Main Contractor: Multiplex Constructions (NZ) Limited


Brian Perry Civil were involved in discussions with the Main Contractor (Multiplex) at a very early stage in the process where several possible solutions were investigated before finally deciding on the secant pile option.

Brian Perry Civil won the Contract on a competitive tender process.

Work scope:

Ground Retention

  • 265 No. x 750mm dia secant piles x 19m deep

Bearing Piles

  • 4 No. x 1500mm dia x 20m deep piles with 14 tonne 510x510 UC cast into the pile
  • 9 No. x 1200mm dia x 20m deep piles with 7 tonne 510 x 510 UC cast into the pile

Crane Piles

  • 4 No. x 1200mm Crane piles x 20m deep

148 of the 265 secant piles were constructed through a 1.8m wide x 4-6m deep basalt wall.  82 of the secant piles were constructed against the heritage listed "Jean Batten Building" façade where part of the upper floors remained.  These piles had to be constructed with restricted head height for the piling plant.  Both bearing and secant piles on half the site had to be constructed from and through a concrete waffle slab.

Ground obstructions in addition to the basalt wall included existing timber piles and belled concrete piles from the previous BNZ building that had occupied the site.  A high water table with weakly cemented sands made ground conditions difficult.