PATTERSON LAKES, VICTORIA
Patterson Lakes, Victoria
CLIENT: JOHN HOLLAND - KBR JOINT VENTURE
The Patterson Lakes retaining wall backs onto approximately 820 properties along the canals in the picturesque suburb, located 35 km south-east of Melbourne. Constructed in the 1970s from reinforced concrete blockwork. When John Holland-KBR Joint Venture was engaged by Melbourne Water to extend its service life for another 50 years, they partnered with Infracorr to develop a corrosion protection design.
Protection of the 6.4 km retaining wall faced the following challenges:
• The retaining wall was constructed
in electrically discontinuous 8 m
sections, meaning significant works
were required to create the electrical
continuity required for
• A preliminary design (proposed by an earlier consultant) involved the installation of soil anodes, with need for drilling and digging up to 2.5 m deep behind the walls and with a risk of disturbing residential properties;
• Given the businesses and residential properties surrounding the structure, reducing the timeframe of the design and construction of the project was critical;
• There were several important safety factors to be considered in the design, including working at heights and near water, restricting access for the construction team.
Infracorr adopted a consultative approach, considering all stakeholders when developing its proposed design:
• Working closely with JH-KBR JV and Melbourne Water, Infracorr developed a range of concept designs. The Hybrid corrosion protection option was preferred over impressed current and galvanic-only concept designs;
• The initial design was tested via a trial wall installation, allowing refinement and identification of potential constructability issues that could have delayed the project completion;
• Infracorr liaised with an anode manufacturer, developing a custom geometrical anode that was narrower (to eliminate risks of touching reinforcement during installation) and longer (to reduce the number of drill holes required during construction);
• Infracorr provided complete ongoing site QA assistance to JH-KBR JV, on-site training to the construction team, technical assistance and design modification, inspection of works and review of QA documents such as ITPs.
Infracorr’s unique solution not only met the client’s requirement but also ensures easy ongoing maintenance:
• Brainstorming, drawings and revised
designs led Infracorr to develop a
solution that was both easy and
cost-effective to install, with significant
construction cost savings to the client;
• Ongoing presence of Infracorr engineers on-site monitoring the technical aspects of the construction eliminated risks and ensured high quality of works throughout the project. Minimal rework was required and the project was completed smoothly;
• With Initial trails and material improvements early on, the project was delivered - from design and planning through to construction - in less than 12 months, with more than 16,000 anodes installed;
• Hybrid CP utilised less materials than the initial concept design and will require less maintenance that an ICCP option, accounting for both technical quality and operational convenience.