Shake table real‐time hybrid simulation techniques for the performance evaluation of buildings with inter‐story isolation

Abstract

Interstory isolation systems have recently gained popularity as an alternative for seismic protection, especially in densely populated areas. In inter-story isolation, the isolation system is incorporated between stories instead of the base of the structure. Installing inter-story isolation is simple, inexpensive, and disruption free in retrofit applications. Benefits include nominally independent structural systems where the accelerations of the added floors are reduced when compared to a conventional structural system. Furthermore, the base shear demand on the total structure is not significantly increased. Practical applications of inter-story isolation have appeared in the United States, Japan, and China, and likewise new design validation techniques are needed to parallel growing interest. Real-time hybrid simulation (RTHS) offers an alternative to investigate the performance of buildings with inter-story isolation. Shake tables, standard equipment in many laboratories, are capable of providing the interface boundary conditions necessary for this application of RTHS. The substructure below the isolation layer can be simulated numerically while the superstructure above the isolation layer can be tested experimentally. This configuration provides a high-fidelity representation of the nonlinearities in the isolation layer, including any supplemental damping devices. This research investigates the seismic performance of a 14-story building with inter-story isolation. A model-based acceleration-tracking approach is adopted to control the shake table, exhibiting good offline and online acceleration tracking performance. The proposed methods demonstrate that RTHS is an accurate and reliable means to investigate buildings with inter-story isolation, including new configurations and supplemental control approaches.