Discussion on isolation mechanism of high-rise isolation structrue

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Journal of Vibration and Shock ›› 2012, Vol. 31 ›› Issue (4) : 8-12,1.

论文

Discussion on isolation mechanism of high-rise isolation structrue

Shang Hao-jiang; Qi Ai

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Abstract

isolation mechanism of high-rise isolation structrue is investigated in the domain of time and frequency. With Etabs software high-rise frame-shear isolation building model and multi-story frame isolation building model are established, seismic waves are input into the two model above-mentioned, and the isolation layer accelerations of time-procedure are extracted, which are considered as seismic waves and input into the original seismic structure. With making a comparison of the acceleration response spectrum of the two models above before and after the isolation technique is applicated, it is found that multi-vibration mode isolation exist in both high-rise isolation building and multi-story isolation building, but the reduction of high-order vibration modes spectral acceleration is much more than the first-order vibration mode’ for high-rise structure while the reduction of high-order vibration modes spectral acceleration is almost the same to the first-order vibration mode’ for multi-story structure,which makes the effectiveness of multi-vibration mode isolation much higher in high-rise isolation structure than in multi-story isolation structure; with making a comparison of the isolation ratio of the largest base shear force before and after the isolation technique was applicated, it is found that the isolation ratio of the largest base shear force increases obviously with the superposition of the high-order vibration modes for high-rise isolation structure while the ratio has little change for multi-story isolation structure. From the two aspects above it can be explained that the effectiveness of multi-vibration mode isolation for multi-story isolation structure is low and in the meanwhile isolation mechanism is mainly on the first-order vibration mode isolation while the high-order vibration modes isolation of high-rise isolation structure is effective, which lead to the multi-vibration mode isolation.