Wind-Induced Impact Behavior of Base-Isolated High-Rise Buildings with Adjacent Structures

Abstract

The base-isolation technology has been increasingly applied in high-rise buildings in recent years. Previous studies have shown that the unfavorable wind-induced response can be effectively reduced by a certain degree of hysteretic energy dissipation after the yielding of the isolation system under strong wind load. However, a large relative inelastic displacement at the isolation level will occur under this condition, which is likely to exceed the width of seismic gap, and cause a structural impact with the adjacent structures (i.e. retaining wall or other barriers). Such wind-induced impacts may have detrimental consequences on the structural performance and have not been investigated much before. This study prospectively investigated the wind-induced impact behavior of base-isolated high-rise buildings with adjacent structures. The multi-story superstructure is modeled as a linear elastic shear building, while the isolation system is represented by bilinear hysteresis restoring force model. An impact element combined with linear spring and damper is used. The story wind load is determined by its cross power spectral density (PSD). Responses for two kinds of typical impact including crosswind and along-wind impact are examined by time history analysis. The results demonstrate that the impact will increase the fluctuation components of superstructure displacement, shear force and bending moment to some extent compared with that of the base-isolated building without impact. The floor accelerations, especially floors close to the base, are significantly increased during impact. The impact has no effect on the mean component of each response. At last, a parametric analysis is carried out to explore the influences of various impact parameters on the inelastic impact response. The results of this study can help to better understand the impact behavior of base-isolated high-rise buildings under strong wind excitation and be useful for performance-based wind resistance design.