A Principal Determinant in Cathodic Protection Design of Offshore Structures—The Mean Current Density

The historical development of marine cathodic protection design, along with the recently developed, first-principles-based slope parameter method, is reviewed briefly. It was projected that the remaining issues that require resolution before cathodic protection design can be optimized are improved methods for representing the slope parameter, anode current capacity, and mean current density. The present paper focuses on the last of these and, in so doing, evaluates data from a variety of field structures for which such information exists and from laboratory and field test programs. An analytical model for current density decay with time, as a consequence of calcareous deposit formation, is presented; and a new method is proposed for specifying mean current density in cathodic protection design of offshore structures.