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Seismic Response Research on the Long - span Beam - arch Composite Bridge under Rail Restraints |
DAI Gong -lian,WANG Yu |
(Central South University,Changsha,Hunan 410075,China) |
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Abstract Research purposes :For analyzing the seismic response of long - span continuous beam - arch bridge under rail restraints,taking a ( 82 + 172 +82 ) m long - span continuous beam - arch bridge on the Lanzhou - Chongqing railway as an example,the finite element model of track - bridge considering track - bridge interaction was established, the stress features of main girder,pier and track was analyzed under seismic excitation. Research conclusions :( 1 ) The low - order longitudinal frequencies of the long - span beam - arch bridge will be increased by 30% ?50% under rail restraints. (2 ) The tracks have great influence on the displacement and internal forces of girder and pier,with maximum reduction 23.69% of internal force of fixed bearing pier. (3 ) The stress of track under seismic excitation can reach 148 MPa, so the index of rail seismic force is suggested to be added to the related railway specifications. (4)The change of rail restraints has less impact on the internal force of the pier bottom,while the increase of pier stiffness can significantly reduce the track stress under seismic action. (5 ) The research conclusions could provide some theoretical references for anti - seismic design of railway bridges across the quake zone.
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Received: 06 September 2015
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