Updated probabilistic model for extreme values of offshore environmental factors

A model that sufficiently describes the probabilistic characteristics of environmental loads is a prerequisite for rational load calibration for design and evaluation of offshore structures. The design loads for platform structures in the sea are usually estimated directly from the onshore records or using correlation analysis, while field records of environmental factors are not fully used. A method is developed to update the conventional probabilistic model of extreme values with the field records. The classical Bayesian method is extended for parameter estimation for cases when multi-prior-source data are available. By transforming the non-Gaussian random variables into equivalent Gaussian ones, the Bayes-based updating theory is extended to cases when variables are of extreme values of type I. The model is validated through examples using Monte-Carlo simulations and observed wind data.