A Technical Framework for Probabilistic Assessment of Existing Offshore Platforms in Persian Gulf under Extreme Environmental (Wave) Loading

In this paper, a new probabilistic method (reliability analysis) under extreme environmental wave loading is introduced. This method is a direct probabilistic performance assessment using numerical method, in which the expression for mean annual frequency (MAF) of exceedance is derived by taking into account the aleatory and epistemic uncertainty in environmental hazard, structural response and capacity. A more realistic approach is used to calculate the system demand and capacity called “Incremental Wave Analysis” (IWA) instead of current nonlinear pushover analyses, in which multiple performances from onset of damage through global collapse can be assessed. The uncertainty propagation is estimated by Monte Carlo simulation and the reliability analyses are performed by using a numerical method. As a case study, the MAF of exceeding a given level of response and also the probability of failure are evaluated by this new approach.

Keywords:

Offshore platforms , Persian Gulf , Demand and capacity factored design method , mean annual frequency , Incremental wave analysis , Reliability Analysis , FOSM method , Monte Carlo simulation