This paper presents a computational strategy to access the probability of structural failure of offshore jacket platforms owing to overloading. Relating the ultimate system capacity directly to the ultimate overturning moment or ultimate base shear force and assuming their independence from the load-pattern and system capacity parameters, a simple failure function is developed. In this function the structural system capacity is approximated by a polynom as a function of all basic random variables accounting for the structural strength. The extreme environmental loading is defined as an implicit function of the basic random variables accounting for sea state paramenters, hydrodynamic and wind loading. The First Order Reliability Method (FORM) is employed to calculate the probability of structural failure. A jacket model is analyzed by the proposed approach and by a finite element reliability analysis. The results and computational efficiency are compared.
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