Dudley Creek Bridges

Christchurch

Scope:

  • Construction of 8 bridges ( 7 vehicle and 1 foot bridge)
  • Bypass Dudley creek using 6” pumps with fish screens and complex sediment control
  • Installation of 36 No. 9m 250UC piles and 4 no. 6m 250 SED timber piles
  • 14 no. in-situ concrete abutments
  • Placement of 21 no. 10 ton concrete precast deck panels spanning 9m
  • Placement of 28 no. precast wing walls
  • 3 no. 1.5m high timber retaining walls of 15m length
  • 1 no. 1.8m high raked retaining wall of 17m length
  • Excavation and removal of the existing creek bed and construction of a gravel bed
  • Rock Batter protection placement

Project Description:

The purpose of the Dudley creek flood remediation project was to address the increased flooding risk in the Flockton basin area resulting from ground level and channel profile changes due to the Canterbury earthquakes. The overall project objective was to return the Flockton basin to pre-earthquake levels of flood risk measured by the number of consented residential floor levels that are modelled to flood in the 1 in 10 and 1 in 50 year storm events.

Project highlights included the efficiency with which the site team dismantled the existing damaged bridges using our 85 ton crane and the swift installation of all bridge piles to within 50mm tolerance using our piling hammer with no leader attached. Constructing a 1:8 guide frame for the driven timber piles also allowed for fast and efficient installation of the raked piles. Setting up an environmentally friendly over-pumping solution which included automatic floats and 3mm fish filter ensured there was no risk of harm to any marine life over the course of the project. An exceptionally high quality finish was obtained on each bridge from the concrete work to the timber and steel handrails including aesthetically pleasing batter protection using angular basalt boulders expertly placed by excavator.

Client: Downer NZ Ltd
Start Date: November 2016
Completion Date: February 2018