Response of the Double Variable Frequency Pendulum Isolator under Triaxial Ground Excitations

Abstract

Modeling techniques of double variable frequency pendulum isolator (DVFPI) are presented. Seismic responses of the three-dimensional single-story building isolated by DVFPI with different coefficient of friction and initial time period of top and bottom sliding surfaces are investigated under triaxial ground motions and compared with unilateral and bilateral ground excitations. Furthermore, the influence of vertical flexibility on horizontal response is also investigated. It is observed that the triaxial ground motion has noticeable effect on response of the building relative to unilateral ground motion. The error in peak resultant base shear, occurring by neglecting vertical ground motion component, could be significant.