Pile foundation for the seismic isolation of girder bridges

This paper examines the possible uses and the advantages of seismic isolation at the base of girder bridges. The attention is focused in particular on the feasibility of adopting a system based on the abatement of the horizontal stiffness of foundation piles, as is obtained by using piles partly nonconfined by the surrounding soil. Eight bridges with standard characteristics, representing a sufficiently wide class of girder bridges, were selected. On these structures, subjected to real seismic excitation, a parametric analysis was conducted with the aim of evaluating the optimal characteristics of the isolation and the applicability of the technique.