Simplified analytical approaches for seismically-isolated buildings subjected to impulsive ground motions

摘要

This paper describes an analytical modeling approach for seismically-isolated structures that combines a detailed representation of stiffening isolators with a simplified substitute-structure model of a yielding superstructure derived from pushover analyses. This formulation leads to a two-degree-of-freedom system in which the behavior of the isolators can be modeled very accurately while also capturing the interaction betwen the isolation system and the nonlinear superstructure. An illustrative example of a nonlinear time history analysis using this approach is provided for a five-story steel frame structure with a focus on impulsive inputs typical of near-field ground motions. The model lends itself to use in parametric studies in which the interaction between a stiffening isolation system and a yielding superstructure can be examined.