Seismic Response Analysis Of Railway Rigid Frame-continuous Composite Beam Bridge

Rigid frame-continuous composite girder bridge is a combination of continuous rigid frame bridge and continuous girder bridge,usually in a continuous beam or adopted several holes in the middle of pier and girder consolidation,part set pedestal piers of bridge structure.Rigid frame and continuous beam bridge,as a kind of between continuous rigid frame and continuous beam bridge structure form,its force is continuous girder or continuous rigid-frame bridge slightly complicated,especially under the seismic action.It is of great practical value to study the overall stress,dynamic characteristics and seismic response analysis of continuous rigid frame bridge,rigid frame-continuous composite beam bridge and continuous girder bridge.Based on the engineering background of the big railway bridge of apengjiang river,this paper completes the following research work:1、According to relying on engineering construction process,establishes the finite element calculation model for the whole process of its construction,analyses the system transformation of rigid frame-the influence of the continuous composite beam bridge alignment and stress,the results show that the system transformation of a bearing on either side of the bridge pier girder deflection,impact on the whole bridge girder stress is small.2、Comparison of the internal forces and displacements of continuous rigid frame bridge,rigid frame-continuous composite beam bridge and continuous girder bridge in constant load,live load,temperature load and various loads.The results show that,under the constant load,the internal force of the rigid frame-continuous composite beam bridge is smaller than that of continuous rigid frame bridge and composite bridge.Under the combination of live load,temperature load and load,its internal force and displacement are between continuous rigid frame bridge and continuous girder bridge.3、The vibration modes and frequencies of continuous rigid frame bridges,rigid frame-continuous composite girder bridges and continuous girder bridges are compared and analyzed.The results show that: setting the longitudinal bridge to the free spherical bearing will reduce the structural vertical bridge restraint,making the structure The stiffness of the longitudinal bridge decreases,resulting in the lowest frequency of each order of the continuous beam bridge,and the frequency of each order of the continuous rigid frame bridge is the largest.4、The seismic responses of the three types of bridges of continuous rigid frame bridges,rigid frame-continuous composite girder bridges and continuous girder bridges are compared and analyzed using response spectrum method and time history analysis method.Three types of seismic response of the bridge type are discussed.The differences were analyzed and the main reasons for the differences were analyzed.5、Larger for three kinds of bridge seismic response and aseismic ability weak continuous girder bridge,using existing reducing vibration isolation technology,put forward the corresponding reduction of vibration isolation design:(1)Only a hyperboloid damping bearing is established on the fixed piers;(2)set up the isolation mount at free pier and abutment;(3)Viscous dampers are installed in the free pier and abutment;(4)The damper is set up at the pier and abutment.Comparative analysis of different damping effect of reducing vibration isolation design,come to a conclusion: at the same time using two kinds of reducing vibration isolation device can give full play to the functions of reducing vibration isolation,greatly reduce the internal force of piers,can also limit displacement of the structure.