Dynamic response characteristics of seismic isolation systems for building structures

Isolation is an effective method of reducing effects of seismic events on building structures. Steel-reinforced elastomeric isolator (SREI) is one kind of isolation system which is used extensively, but there are some problems associated with its use, such as cost and weight. Fiber-reinforced elastomeric isolator (FREI) has been developed in an attempt to solve the problems of high cost and heavy weight for SREI. In this study, mechanical properties for the SREI and the FREI are investigated. Systematic dynamic response analyses are performed for three different models such as a fixed based, an SREI based and an FREI based low-story building structures. Two-dimensional and three-dimensional dynamic response analysis results for each model are compared in terms of displacement, drift, acceleration and shear force in this study. In the two-dimensional dynamic response analysis, the SREI and the FREI based structures are proven to be the more effective isolation systems against seismic events by comparing with the fixed based one. As a result, the FREI has shown better isolation performances than that of the SREI. Furthermore, to extract the characteristics of the FREI on building structure resisting the seismic effects, two models of three-dimensional framed structure with fixed bases and FREI isolated bases are built, respectively. After the dynamic response analysis of these two structures subjected to bi-directional ground motions, the analyzed results are compared with each other. It is shown that the FREI could effectively absorb the seismic energy, and decreases the destructive effects acting on a building structure due to ground horizontal motions that could occur in an earthquake.