Study On Mechanical Properties Of Bearing/Pier Series System Under Horizontal Reciprocating Load

With the deepening of the design concept of seismic isolation,a large number of highway bridges are designed as a series system of bearings and piers,which improves the overall ductility of the bridge structure in the earthquake,and jointly completes the overall ductility energy consumption mechanism of the bridge.The existing research results of the mechanical performance of the rubber bearing/RC(Reinforced Concrete,RC)pier column series system mainly come from the research of the high-rise building structure.In view of the great differences between the anchorage mode,mechanical performance and damage mode of the rubber bearing in the high-rise building structure and the bearing in the bridge engineering,the existing series system theory cannot be directly applied to the bridge engineering.Therefore,it is necessary to study the damage failure mode and mechanical properties of the series system in the bridge structure under the influence of the bearing’s mechanical performance,so as to lay a theoretical foundation for the formulation of a reasonable bridge reinforcement and reconstruction scheme and the correct evaluation of the bridge’s seismic reinforcement performance.In this paper,a series of tests and numerical simulation are carried out based on the rubber bearing/RC pier column series system.The mechanical properties of the series system are obtained,and the pile-soil effect of the pile foundation is further considered.The main work is as follows:1.Introduce the significance and research background of the topic,and summarize the theoretical basis of bearing and pier series system.2.Quasi-static test of rubber bearing/RC pier column series system.The test scheme is proposed.Under different axial compression ratios(0.15,0.2),the horizontal unidirectional low cycle cyclic load test of the rubber bearing/RC bridge pier series system under the constant axial force is carried out.The horizontal force displacement curve and the lateral displacement curve of the pier body are obtained.The mechanical behavior and seismic performance of the rubber bearing/RC bridge pier series system are systematically evaluated,and the problems existing in the test are pointed out Put forward corresponding solutions.3.Experimental simulation study of the rubber bearing/RC pier column series system.The finite element model of rubber bearing/RC bridge pier series system is established.Considering the synergistic effect of bearing and bridge pier,two different bearing friction conditions of 0.1 and 0.2 and the axial compression ratio of 0.15 and 0.2 are used for isolation,and the dynamic response and bearing force performance of the series system are analyzed.Compared with the test results,the rationality of the numerical calculation method of the bearing/RC pier series system is verified,and the dynamic response of the series system is further analyzed.4.Numerical simulation of the rubber bearing/RC pier column series system and pile foundation.A simplified analysis model of pile foundation series system is proposed,which is verified by the analysis of reaction time history of the system.The influence of pile foundation on the mechanical properties of the series system under reciprocating loading and the interaction between pile and soil are considered.The results show that adding pile foundarion can reduce the stiffness of the series system and the bearing slip earlier.Although it can reduce the stress deformation of the pier to a certain extent and make it not easy to damage,it also increases the bearing performance.