A Parametric Study on Soil-Pile Kinematic Interaction in Layered Soils

In pile-foundation seismic design, until a few years ago, only inertial loads applied by the overstructure at the pile cap were taked into account, neglecting the dynamic interaction. So, good approaches to evaluate inertial interaction effects have been developed, but not for kinematic interaction. Modern national and international codes require to take into account the dynamic soil-pile-ovestructure interaction (inertial and kinematic), without giving any information about kinematic interaction evaluation criteria. In this work a practical method based on the Winkler foundation model is applied to analyse the seismic response of single piles. The analysis is focused on a single pile embedded in a two-layered soil profile. The two layers are h1 and h2 thick, with two different shear moduli, G1 and G2, respectively. The system is subjected to a conventional dynamic input motion. Different sharp stiffness contrast, expressed in terms of variation of the ratio G1/G2 are investigated. A parametric study on the influence trained on the maximum bending moment, by the depth of the discontinuity between the two layers and by the pile slenderness, is brought about. The results are presented in terms of bending moments expressed in a dimensionless form