Abstract:To study the characteristics of the probability-density evolution of the nonlinear responses of base-isolated structures under different design parameters, we used a two-particle model to simulate a base-isolated structure. We then used the Bouc-Wen model and the Bouc-Wen model of stiffness degradation to describe the nonlinear characteristics of the isolation layer and the superstructure, respectively. Based on the probability-density-evolution theory, we analyzed the nonlinear random seismic responses of base-isolated structures. Using a random-ground-motion model to generate artificial ground motion, we propose basic steps for analyzing the probability-density evolution of the nonlinear random seismic response of base-isolated structures. By changing the design parameters of the base-isolated structure and considering the randomness of the excitation, we investigated the probability-density-evolution law of its nonlinear random seismic response. The results show that displacements of base-isolated structures can be controlled if the damping ratio, period ratio, and ratio of yield to weight are in a reasonable range.