Research On Seismic Analysis Of Large Damping Vibration Reduction And Isolation Device For Railway Simply Supported Beam Bridge

In recent years,railway bridges have been damaged frequently by earthquakes in China.More and more researchers begin to realize that while studying the seismic performance of new bridges,they also need to evaluate the seismic performance of a large number of existing bridges and strengthen the bridges that do not meet the requirements of the current seismic code.This paper introduces two kinds of large damping vibration reduction and isolation devices "new steel damping bearing" and "annular damper",which are suitable for railway simply supported beam bridges.These two kinds of vibration reduction and isolation devices have good damping and energy dissipation performance.And because the annular damper has low demand for installation space and can be conveniently set between the beam end and the pier top,the annular damper is very suitable for the reinforcement and reconstruction of existing bridges and the repair of bridges with damaged bearings after earthquake.The main work and conclusions of this paper are as follows:(1)In order to study the energy dissipation performance and damage mechanism of large damping vibration reduction and isolation devices represented by new steel damping bearings and annular dampers,full-size steel damping bearings and annular dampers were manufactured successively,and their mechanical behavior was studied by quasi-static test.The deformation mechanism of annular damper under space load and the development process of main annular plastic energy dissipation zone are simulated by Abaqus finite element software.The mechanical behavior of new steel damping bearing and annular damper is reproduced by Open Sees software,so that it can be modularized and applied to the seismic analysis of bridges.(2)Aiming at the problem that the dynamic equation of bridge structure with large damping spacing device is in a typical non classical damping system and is difficult to be decoupled in the real number domain,the superposition method of complex mode amplitude modulated response spectrum is proposed.The amplitude modulation factor of response spectrum is calculated by genetic algorithm,which accelerates the calculation speed of complex mode response spectrum method.The accuracy of this method is verified by two calculation examples of railway simply supported beam bridges.(3)Based on Open Sees,this paper compiles the "railway bridge seismic analysis software",which realizes the rapid analysis of the seismic performance of conventional railway simply supported beam bridges and continuous beam bridges with annular dampers.Taking the damage of the actual bridge in Haibei Prefecture,Qinghai Province as an example,the damping effect of the annular damper is studied.The damping efficiency of the annular damper is proved by comparing the peak responses of the bridge structure under multiple seismic loads.In this paper,the incremental dynamic method is used to analyze the damage probability of bridge piers and bearings with annular dampers.It is proved that the damage probability of annular dampers in practical application meets the requirements of performance-based seismic design.