Numerical simulations of wave-structure-soil interaction of offshore monopiles

Ocean energy converters (OECs) are becoming a more popular source of electricity generated from the ocean. The main obstacle associated with the use of OECs is their high initial installation cost. In light of this, geotechnical engineers have been challenged with revisiting the foundation system, aiming toward more economical design. In this study, finite-element (FE) modeling was used to examine the influence of wave-induced lateral loads on amonopile, a common foundation systemfor OECs, where wave-structure-soil interactionwas considered explicitly. Measured data were used to arrive at two different wave scenarios in conjunction with both regular and irregular wave-surface profiles; the wave-induced lateral forces on the monopile foundation were calculated for each case using diffraction theory and used as input loads in the FE model. A parametric study was then undertaken to examine the influence of a range of wave characteristics and pile/soil parameters on monopile response. The results of the study highlight the overconservatism associated with current monopiles supporting OECs and identify slender piles as amore economical solution.