Research On Isolation Performance Of Frame Structure Based On New Type Friction Pendulum Bearing

Friction pendulum bearing has been widely used in practical engineering applications since it was proposed.As a kind of isolation bearing with brighter prospects,it can effectively control the seismic responses of the structures.However,there are few limited studies have considering the collision between the sliding block and the boundary,let alone the adverse effects of the lifting of the bearing.Therefore,based on the consideration of the bearing collision and the lift off,the isolation performance of traditional friction pendulum bearing under the strong earthquakes was analyzed in this study.Meanwhile,a new type of friction pendulum bearing with pull-out capacity was proposed.Moreover,in order to investigate the mechanical properties of the two kinds of bearings,both experiment and finite element simulation were used in the analysis.The main research contents and results of this paper are summarized below:（1）By using the similarity theory,the reduced scale model of the five-story frame structure was utilized in this study.And the modal analysis,static analysis and dynamic analysis of the prototype and scale model were carried out by using ADINA.The results show that the reduced scale model can accurately reflect the natural vibration characteristics and the dynamic responses of the prototype structure.In addition,the scaling coefficient is consistent with the theoretical derivation.（2）The traditional double friction pendulum bearing was designed,and a new type of friction pendulum bearing had been proposed by adding a U-shaped metal damper around the bearing.In addition,the mechanical properties of the two bearings were studied by experiment and finite element simulation.Noteworthy,the results of finite element analysis are consistent with the experimental results,i.e.,the finite element analysis is a reliable and effective method.Compared with the traditional one,the new friction pendulum have increased equivalent stiffness and energy disspation capacity with the illustration of the hysteretic curves graph.More importantly,the new friction pendulum is able to provide the favorable pullout resistance.（3）On the basis of considering the impact and lift off of friction pendulum bearings,the frame scale structure isolation model was established.Then,seismic waves with different dimensions and magnitutes are input to investigate the performance of the two kinds of friction pendulum bearings.The results show that,with the the dimension of inputs increasing,the horizontal displacement of the traditional friction bearing increase significantly.Besides,the collisions between the sliding block and the boundary-limiting device will occur near the ultimate displacement level.Furthermore,the bottom shear force has a significant incerase,and exceeds the maximum value of the theoretical hysteretic curve.Meanwhile,because of the vertical seismic motions,the seismic responses of the isolation structures with traditional friction pendulum increase significantly.In general,with the increase of seismic intensity,the traditional friction pendulum bearings will be lifted off obviously,while the new friction pendulum can effectively reduce the vertical displacements of the bearings.Altogether,there in no doubt that the new friction pendulum bearings can display a more superior isolation effect.