| Due to recent destructive earthquakes, the lateral response of piles and foundations has been under intense investigation. The following study investigates the dynamic lateral response of piles under extreme events such as earthquakes, intense wind loading, or iceberg impact. Both kinematic and inertial pile-soil interaction effects were studied in a simple rational manner. The analysis was performed in the time domain to accurately portray the nonlinear behaviour of the soil, separation and slippage at the pile-soil interface, and allow for direct transient dynamic loading. The first part of the study investigated the kinematic interaction of piles using a three dimensional finite element analysis. It was concluded that the pile head response closely resembled the free-field response for seismic loading for the range of pile and soil parameters considered in this study. The second part of the study focused on developing a simple two dimensional analysis to accurately model the inertial interaction of pile head loading. The proposed model incorporates the static p-y curve approach and the plane strain assumption to represent the soil reactions within the frame of a Winkler model. The p-y curves are used to relate pile deflection to nonlinear soil reaction. The wave propagation and energy dissipation are also accounted for to generate "dynamic p-y curves". A parametric study was performed using the developed analysis and the results were used to establish dynamic p-y curves. These dynamic p-y curves are a function of the static p-y curve, dimensionless frequency, and relative velocity of the soil nodes. Closed form solutions were proposed for a range of soil types, that can be used to model soil reactions for pile vibration problems in readily available FEA and dynamic structural analysis packages. |
