Real-Time Hybrid Substructuring Shake Table Test of a Seismically Excited Base Isolated Building

Abstract

This paper present a real-time hybrid substructuring (RTHS) shake table test to evaluate the seismic performance of a base isolated building. Significant experimental research has been conducted on base isolators and dampers toward developing high fidelity numerical models. Shake table testing where the building superstructure is tested while the isolation layer is numerically modeled can allow for a range of isolation strategies to be examined for a single shake table experiment. Further, recent concerns in base isolation for long period, long duration earthquakes necessitate adding damping at the isolation layer which can allow higher frequency energy to be transmitted into the superstructure and can result in damage to structural and nonstructural components that can be difficult to numerically model and accurately predict. As such, physical testing of the superstructure while numerically modeling the isolation layer may be desired. The RTHS approach has been previously proposed for base isolated buildings, however, to date it has not been conducted on base isolated structure isolated at the ground level and where the isolation layer itself is numerically simulated. This configuration provides multiple challenges associated with higher physical substructure frequencies and a low numerical to physical mass ratio. This paper demonstrates a base isolated RTHS test with a scaled idealized 4-story superstructure building model placed directly onto a shake table and the isolation layer simulated in MATLAB/Simulink using a dSpace real-time controller.