Dowse to Petone

Road improvements to State Highway 2 Lower Hutt (Fletcher Higgins Joint Venture)

The Dowse to Petone project is a $65 million road improvement being carried out to enhance traffic flows to and from the Hutt Valley on State Highway 2. Amongst the improvements is the replacement of a number of intersections with bridges. This requires 45 piles at 7 sites and the creation of a new service road, which requires soil nails.

Project scope

Prior to the letting of the contract we were called in to carry out investigation drilling across the site for the design phase of the project.

After the contract was awarded, Fletcher Higgins engaged us to carry out proof drilling at the pile locations for final confirmation of founding levels. This involves coring with HQ core barrels and performing Standard Penetration Tests in each bore.

The implementation of soil nails for the service road involves drilling, grouting and testing of soil nails and application of sprayed concrete to the walls.
 

Complicating factors

As proof drilling is the first step with the piling we have to be able to respond quickly to the head contractors’ build programme, making rigs and personnel available when it is bought forward or moved back, or for additional work generated by the varying ground conditions. Sometimes this means carrying out the work on the road at night, to avoid disrupting commuter traffic flows.

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