Reliability Based Assessment of Existing Fixed Offshore Platforms Located in the Persian Gulf

This paper presents a detailed structural reliability procedure in order to achieve an acceptable safety margin for template type offshore platforms located in the Persian Gulf. Probability of failure in this study is calculated by considering the cumulative effects of all levels of wave loading during the lifetime of the structure and uncertainties associated with soil, material properties, connection strength and environmental conditions in the reliability analysis. For this purpose, the conditional probability of failures is computed for different levels of wave loading and then converted to the rate of failure by applying the total probability theorem. Annual explicit probability of failure is then computed by using probability distribution of wave heights in the Persian Gulf region. The calculated probability of failure is also compared with Reserve Strength Ratio of the platform considering different failure modes. The results show that RSR may not indicate a unique safety margin for assessing the existing platform in the Persian Gulf and carrying out a reliability analysis may help to overcome this deficiency.