The effect of the gap near the surface in the earthquake response of the structure-pile foundation-ground system

The gap near the pile head has been passed over in dynamic behavior of the structure-pile foundation-surface ground system during an earthquake. Therefore, in this study, the subgrade reaction model considering "the gap between surface ground and pile head" was formulated on the elasto-plasticity theory. And that the effect of cyclic loading was also considered in this model. The numerical results of the response analysis were verified by the centrifugal model experiment. A temporary tower crane that was supported on the pile foundation was numerically and experimentally analyzed. Both analytical results agreed well. And also, it became clear that the generation and expansion of the gap near the pile head effected on the vibration characteristics of the tower crane. It is meant that the subgrade reaction model considering the gap is useful to analyze the earthquake response of structure-pile foundation-surface ground system at the good accuracy.