Thorndon Container Wharf and Dock Wharf Cathodic Protection

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Award:  Other Entrants

Project:  Thorndon Container Wharf and Dock Wharf Cathodic Protection

Entrant:  BBR Contech

Owner:  CentrePort Wellington

Consulting Engineer:  GHD

Contractor:  Savcor-Contech JV Ltd

Other Firms:  Savcor ART Pty Ltd; BBR Contech

 

CentrePort's Thorndon Container Wharf is Wellington's main container handling wharf.  It is a 600 metre long wharf with two operating berths and approximately 15,000m2 of deck area.  Dock Wharf is located at the Wellington Ferry terminal and services the Interislander ferries.

These two important marine structures are key infrastructure links, and had deteriorated through extensive corrosion of reinforcing steel to the point where major intervention was required to maintain their serviceability.

Thorndon Container Wharf was constructed in the 1970s.  Major concrete repairs undertaken during the late 1980s had deteriorated quickly, and the main structural elements were in a serious condition by the early 2000s.  At around 35 years of age, the wharf was in poor condition but still had many years of service and economic life still to fulfil.  Dock Wharf was much older and suffering the effects of 80 years' service and deterioration in a marine environment and also needed some life extension.

Significant and accelerating deterioration of the Thorndon and Dock Wharves had reached the point where conventional repair was not considered an economic method to deliver the required life expectancy for both structures.  Impressed current CP provided a sustainable, long term repair solution in this case.  Outstanding and notable aspects of this project:

  • The most significant investment in impressed current CP technology by a single client to date in NZ.
  • The size and complexity of the project for a concrete rehabilitation and CP project - a total value of $10M - approximately 10,000m2 of concrete surface protected by CP.  This is the largest CP installation in NZ to date by a factor of 10.
  • The largest CP project in NZ to be undertaken in accordance with AS2832.5-2002: 'Cathodic protection of metals Part 5: Steel in concrete structures'.
  • Rapid resourcing, establishing and training specialised crews and subcontractors.
  • Development of heavy duty, highly mobile under-wharf access decking.
  • Development of sectionalised and highly workable installation drawings and QA/QC systems.
  • The first major project to utilise hydro-demolition for concrete removal in NZ.
  • CentrePort's operation was able to continue unhindered during the contract due to the much less intrusive concrete removal required by CP repair over conventional repair methods.
  • This project has demonstrated an excellent marriage of modern technology with ageing concrete structurds where traditional repair techniques were no longer viable.