Experimental Researches On A System With Sliding Metal Isolation Bearings And Theoretical Analyses About Its Simplified Model

This paper analyzes a new isolation system independently designed by Prof. Chen Qinglai of Shandong University. The system consists of FPS (Friction Pendulum System) isolation bearings and metal dampers. Large-scale shake table experiment is taken on it at China Academy of Building Research and the data of EL-centro (ELC) earthquake wave are analyzed. At the same time, differential equations of non-linear vibration are acquired based on the simplified model. Main works and results presented in this paper include:1, Based on analyses of experimental data (ELC), the effectiveness of this new isolation system is researched. The results show that this system behaves excellently. Earthquake responses of the superstructure are weakened greatly. Besides, the isolation system also exhibits good stability and self-resetting functions. At the meantime, whiplash effect of the structures could also be controlled to a certain extent.2, By analyzing experimental data (ELC), isolation effects are compared among different levels of damping. Analyses indicate that the time history of acceleration for the superstructure is sensitive to the damping value, but the enlargement factor of floor acceleration and story drift are not as sensitive as it.3, By choosing a reasonable simplified model, differential equations are obtained. Using 4th-order Runge-Kutta method and realizing it with VC program language, the equations are solved. Different levels of friction coefficient and radiuses are considered during the solution procedure. The following conclusions are acquired by analyzing the computed results. Under lesser earthquake motion, the enlargement factor of floor acceleration is influenced apparently by friction coefficient; however, this phenomenon is weakened when earthquake motion is increased; under the same earthquake motion, the floor drifts of the super structure show the trend of reducing firstly and decreasing subsequently; the enlargement factor of floor acceleration is obviously influenced by the changes of the radius, but the floor drifts of the super structure (except of bottom floor) is not very evident: the base isolation bearing earns the best theoretical effects when the friction coefficient is about 0.18. Deficiencies and some more problems to be further studied are discussed in the end.