Metal sheathing has been employed to prevent corrosion of steel structures in tidal and splash zones in marine environments. Seawater-resistant stainless steel has been used as sheathing material. However, dissimilar metal corrosion occurs where steel comes into contact with stainless steel. The main objective of this study was to investigate the cathodic protection characteristics at the area where dissimilar metal corrosion occurs. A method of estimating the consumption of a sacrificial anode is discussed.
　A field experiment was conducted on a steel pipe pile structure at Ohi wharf in Tokyo port. One sacrificial anode is welded to the steel at about 10 m from the stainless steel sheathing, while another is in the neighborhood of the sheathing. Currents generated from the sacrificial anodes and the potentials of the steel were measured. These currents decreased to 50% of the initial values. The potentials of the steel were lower than the protective potential. These data indicate that sacrificial anode cathodic protection is effective against dissimilar corrosion of steel. The amount of consumption of the anode could be estimated from the potential of the steel, which can easily be measured.