HYBRID ANODE PROTECTION SYSTEM FOR DAMPIER SALT DOLPHINS
PROJECT HIGHLIGHTS• Strict timeline of 3 months to return dolphins to active service met
• Remote location of 3 marine dolphins with access only by boat
• Custom designed electro-chemical protection system with anode life capability in excess of 40 years
• Low cost innovative solution compared with other methods requiring costly electrical work
• Remote monitoring not requiring physical access
Severe saltwater corrosion damage was occurring to three mooring dolphins of the ship berthing stations of Dampier Salt, Western Australia, owned by Rio Tinto Ltd. Infracorr Consulting designed an innovative electro-chemical protection system using hybrid anodes to be installed in this remote location.
Due to the aggressive marine environment off the north–west of Western Australia, the 3 marine dolphins, constructed in 1971, were suffering from severe chloride attack to the steel reinforcement. This was causing major delamination of the concrete. Infracorr was retained to investigate and then to design and install a suitable protection system to prevent reoccurrence of the problem. A strict 3 month timeline applied.
Access was gained to dolphins using scaffolding and the delaminated and damaged concrete revealed by initial investigation removed on
each. A further process of hydro demolition exposed and cleaned the remaining reinforcing steel revealing large scale section loss to a
New reinforced steel bars were appended to old bars where sound and the substrate was prepared for concrete replacement. Following this, gunite was applied to bring the concrete back to its original profile.
Infracorr custom designed a hybrid anode system for installation and use in this difficult marine environment. Over 650 anode holes needed to be drilled per dolphin and chases cut between each of the anode holes.
Following full installation and a successful phase of impressed current, the anodes were converted to galvanic phase current. The anodes and all cable chases were then backfilled in concrete right back to the sole junction box. Corrosion rate tests and monitoring was designed to be conducted from the monitoring box without having to access the underside of the dolphins or other elements of the structure.
Infracorr Consulting successfully custom designed a hybrid anode system to extend the active lives of the dolphins for a further 40 years minimum. The design enabled the anodes to be installed in smaller sections and in a remote, difficult to access marine location.
Significant cost savings were generated by providing a low cost innovative alternative to traditional methods without need for expensive electrical work.
Further maintenance costs and time savings generated with remote monitoring not requiring actual physical access to structures.