PROBABILISTIC MODELING OF QUASI-STATIC RESPONSE OF OFFSHORE STRUCTURES SUBJECT TO NONLINEAR-WAVE LOADING - 2 APPROXIMATE APPROACHES

Probabilistic description of the quasi-static response of offshore str uctures, requires the estimation of the 2nd and 4th order moments of i ts probability density function. The analytical approach for determina tion of the moments is computationally very demanding. Consequently, t he wave loading on the structure must be idealised by a relatively sma ll number of point loads, which is not enough for adequate representat ion of the continuous loading on (complex) structures with many struct ural elements. Two appropriate approximations, as described herein, ha ve led to significant reductions in computational effort so that the l oading can be idealised by a relatively large number of point loads. A s a result, the probabilistic approach can now be used in analysis of complex structures.