An improved method for non-stationary stochastic seismic response analysis of base-isolated high-rise buildings

The seismic response analysis of base-isolated high-rise buildings subjected to non-stationary excitation was performed with the pseudo excitation method and the equivalent linearization technique. The influence of higher order vibrational modes of a base-isolated high-rise building on its responses was investigated, and an improved method for stochastic seismic response analysis of such a building was presented. The upper structure of the isolated system was assumed to remain elastic under major earthquakes, and the plastic deformation was assumed to concentrate in the isolation layer. The constitutive relationship between restoring force and displacement of isolation layers was described with Bouc-Wen model. The lower order vibrational modes of the upper structure were taken into account in the dynamic response analysis, while the contribution of the remaining higher order modes to the structural responses was approximated by using the static correction procedure. It was shown that the new method improves the computing accuracy of the responses by taking the contribution of higher order modes into account, while only increases the computational effort slightly.