Northern Busway Piling - Stage 1A, 1B, 1C
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Client: Transit NZ, NSCC, Transpower, ARTA
Sector: Infrastructure
Location: Auckland
Contract Value: $15 million
Completed: Dec 2004
Main Contractor: Fletcher Construction Engineering

 

The Northern Busway Project, awarded to Fletcher BPC JV in 2004, consists of six kilometres of two way carriageway for buses running parallel with the Northern Motorway between the Onewa Road Interchange and Constellation Drive, with stations at Akoranga, Westlake and Sunnynook Road.  In addition, the Esmonde Road Interchange upgrade will provide new north facing ramps from Esmonde Road, a new bridge to allow westbound traffic and widening of Esmonde Road.  The total project value is $180 million.

Structures include:

  • five new bridges for local traffic
  • two new cut and cover underpasses
  • an 85m and a 400m long viaduct
  • 3000 linear metres of retaining walls
  • culvert extensions

Over 1200No piles have been constructed by BPC to date.  Piles have ranged from 600mm diameter up to 1800mm diameter with depths up to 42m bearing in to sandstone bedrock.  Above the rock are soft marine sediments which require permanently liners or alternative techniques.  We have installed over 130,000m of wick drains into the soft soils to increase the speed of earthworks settlement and reduce the length of the project.

The Busway project is adjacent to a number of sensitive habitats.  The Hillcrest Creek runs through the project discharging to the Waitemata Harbour via Shoal Bay, home to threatened shore birds.  In addition a remnant of native bush and residential properties, schools and rest homes are all located nearby.

The nature of the narrow site has provided huge logistical challenges that have to be well organised due to the proximity of neighbours and the motorway.  Movement of the piling rigs has been critical and often done at night.

Innovative solutions have been developed to treat waste water from the piling including filter systems designed to remove sediment and reduce the pH of cement contaminated water.