Fatigue life of cathodically protected tubular joints of offshore structures

Steel jacket platforms are widely used for production and processing of oil from offshore fields. Tubular joints of these structures are susceptible to fatigue or corrosion fatigue cracking due to cyclic wave action, stress concentration, and corrosive environment. The submerged part of the structure is cathodically protected against corrosion by fixing sacrificial anodes at various places. The effect of cathodic protection on the fatigue life of tubular joints was studied by conducting fatigue tests on 13 T and Y-joints in air, under free corrosion, and with cathodic protection. The results of the studies are discussed in this paper.