NON-STATIONARY STOCHASTIC ANALYSIS FOR 3D NON-ECCENTRIC BASE-ISOLATED BUILDINGS

This paper presents a method for evaluating the non-stationary stochastic response of 3D base-isolated buildings by combining the pseudo excitation method and the equivalent linearization method. The analysis is based on the reduction of the number of the equivalent linearization differential equations. It is assumed that the superstructure of the isolation system remains elastic during the earthquakes, even when subjected to major earthquakes;the plastic deformation concentrates in the isolators, of which the relationship between the restoring force and displacement is described by the Bouc-Wen differential equation. The reduction of the number of the equivalent linearization differential equations is achieved by assuming that the hysteretic components of the same type of the isolators are equal to each other in any given directions, which will decrease the order of the differential equations and improve computation accuracy and efficiency. Finally, taking a 3D base-isolated frame structure as an example, the accuracy of the proposed method is verified. The improved method can consider the diversity of the different types of the isolators and obtain the performance of each isolator during the earthquake, which is helpful for evaluating the failure probability by uplift of the isolators.