ICCP Advances for Major Wharf Repair
Abstract from Australasian Corrosion Association - Corrosion and Prevention Conference, Sydney, 2017
Infracorr Consulting Pty Ltd, Melbourne, Australia
The Webb Dock East Berth 4&5 repair project is Australia’s largest and most technically advanced Impressed Current Cathodic Protection (ICCP) System, completed for the Port of Melbourne in late 2016 for an approximate cost of $35m including the extensive concrete and steel repairs required.
The paper describes the investigation, design and technical aspects of the Webb Dock East 4&5 concrete ICCP and water anode ICCP systems by comparison to the CP based repair of a very similar wharf structure, the Swanson Dock West ICCP system, completed in 2009. The comparison of the ICCP designs by the same designer, illustrates the technical advances in this relatively short period.
The concrete ICCP systems both utilize similar design current densities and discrete anode arrangements, with the main differences being the extent of zoning and control utilized with the more recent project via use of a distributed rectifier remote control system.
The Water anode ICCP systems are both designed to pass approximately 3500Amp via titanium tubular anodes to protect steel circular and sheet pile that run the length of the wharves. The method of current distribution however is vastly different, with the Webb Dock East system utilizing AC power distribution to a distributed rectifier system and the Swanson Dock system based on high voltage DC power distribution. Both systems achieved a high degree of electrical efficiency but with very different technology.
In summary, this paper illustrates the recent developments and benefits of ICCP design for concrete and water systems for the efficient management of large scale CP systems.