Cathodic protection of quay

Cathodic protection of a quay is corrosion control of submerged steel, sheet piles, tubular piles, and tie-rods, by making the steel the cathode of an electrochemical cell. Two systems are used: sacrificial anodes of aluminum or zinc that corrode in place, and impressed-current cathodic protection (ICCP) that drives protective current from inert anodes through a transformer-rectifier. Design sets a protective potential near minus 0.80 V versus a silver/silver-chloride reference and sizes anode mass or current to the wetted steel area and a 25 to 50 year design life. The splash and tidal zones, where CP does not reach, need coatings or extra sacrificial thickness. Practice follows BS 6349-2 and ISO/EN cathodic-protection standards.