ABSTRACT
Life extension and platform re-use are in demand, which creates a need for evaluation methods able to ascertain the residual life of an existing platform, to be eventually operated in a new installation site. The number of fixed platforms, installed in offshore fields for oil or gas production, nearing the end of their design life is increasing worldwide. This chapter presents a system approach, used by operators in different offshore areas. In the assessment of existing structures, specific attention should be paid to the fatigue analysis, with due consideration given to the accumulated degradation effects and to the future accumulation of the fatigue damage during the foreseen extension life. The fatigue analysis inside a reassessment process should be performed on a probabilistic basis, with respect to the present fatigue and corrosion conditions, whose limit states are revised with respect to the original design predictions.
