Interactive Base‐Isolation Foundation System: II. Parametric Study

Abstract

The effects of seismic base isolation on the response of structures supported on pile foundations are discussed. The benefit of seismic isolation is achieved by means of flexible piles that may be partially embedded in an inelastic material and that direct substantial energy dissipation and radiation into the surrounding soil. The resulting dynamic characteristics of such a system are found to be considerably different from those of the structure with a fixed base. Using a finite element model developed in a companion paper, the influence of the key parameters affecting the response are studied. A lumped‐mass building model with a variety of subsurface conditions is analyzed for free vibration, under constant‐amplitude ground acceleration, and under horizontal ground accelerations from representative earthquakes. The studies reveal that the interactive flexible‐pile system is effective as a base‐isolation mechanism.