Effect of Foundation Nonlinearity on Modal Properties of Offshore Towers

Abstract

An analysis of pile axial and lateral response to transient dynamic loading is presented allowing for nonlinear soil behavior, the discontinuity conditions at the pile-soil interface, and energy dissipation through radiation damping and soil hysteresis. In addition, the effect of neighboring piles is taken into account for piles in a group. This analysis is used to derive the stiffness of foundation piles of fixed offshore towers. The effect of foundation nonlinearity and pile-soil-pile interaction on the dynamic characteristics of the tower is investigated. It was found that the tower's dynamic characteristics are greatly influenced by the foundation nonlinearity and the pile-soil-pile interaction.