Seismic response of bridge piers founded on inclined pile groups

This paper investigates the seismic response of bridge piers founded on inclined pile groups, evaluating effects of soil-structure interaction by considering different pile group geometries and piles inclinations. Analyses are performed by means of the direct approach taking advantage of a 3D numerical model developed by the authors for the analysis of inclined pile groups. In particular, both the superstructure and piles are modelled by means of beam elements and the soil is schematized as a visco-elastic medium constituted by independent infinite horizontal layers. The soil-pile and the pile-soil-pile interaction are captured in the frequency domain by means of elastodynamic Green’s functions that also allow including the hysteretic and radiation damping. In order to investigate kinematic stress resultants in piles and to evaluate the significance of the soil-foundation system filtering effect, kinematic interaction analyses of the soil-foundation systems are also performed by removing the superstructure mass from the models. The influence of key parameters such as the piles inclination and the group configuration on the structural behaviour (displacements and stress resultants) and on the foundation response (maximum shears and bending moments in piles) is discussed.