Extreme response statistics for drag dominated offshore structures

The paper presents a study of extreme response statistics of drag dominated offshore structures, subjected to severe sea states. The nature of the hydrodynamic forces acting on the structure is highly nonlinear under such conditions. Additionally to drag forces, the so-called inundation effect must also be taken into account. In the present paper a stochastic force model is introduced that captures both these phenomena in a fairly simple manner allowing for efficient calculation of the extreme response statistics. In fact, the proposed model opens up the possibility to calculate efficiently even long-term extreme response statistics, which is an important issue for the design of offshore structures. Comparison with the results of Monte Carlo simulations for a jacket structure indicates that good accuracy can be obtained for the extreme response predictions.