伸缩缝变化参数对连续梁桥车致动力响应影响研究

Study on Vehicle-induced Dynamic Response of Continuous Girder Bridge Considering Parameter Variation of Expansion Joint

为揭示伸缩缝变化参数对连续梁桥车致动力响应规律,基于车-缝-桥耦合动力响应分析方法,探究了伸缩缝及临近支座变化参数对连续梁桥车致动力响应的影响。结果为伸缩缝高差增大会增大车辆对伸缩缝本身的冲击作用;中横梁高差变化、支撑梁刚度下降、缝宽增大会增加车辆对梁端的冲击荷载,且高差变化参数的影响更为显著;车辆过缝对连续梁桥主梁加速度峰值及中跨 1/2 跨测点上挠位移峰值的影响不能忽视;伸缩缝支撑刚度降低和缝宽增大导致的伸缩缝中横梁冲击系数增幅分别为 58.10%、13.50%,但上述参数对主梁测点的车致位移响应影响较小;伸缩缝中横梁冲击系数受支座支撑刚度变化影响较小;连续梁桥主梁各跨测点冲击系数受支座支撑刚度降低影响显著,支座支撑刚度越小主梁各测点的冲击系数越大,且梁端冲击系数变化最为显著。

To clarify the impact of parameter variation of expansion joint on the vehicle-induced dynamic response of continuous girder bridge,the influence of height difference,gap size,and bearing stiffness of expansion joint,as well as bearing support parameters,on the vehicle-induced dynamic response of continuous girder bridge were systematically analyzed based on the analysis model of vehicle-bridge coupling vibration considering expansion joint.The results show that the increasing of height difference between the side beam and the center beam will increase the vehicle-induced impact coefficient(IF)of expansion joint.The raise or lower of the center beam,the decreasing of the bearing stiffness,and the increasing gape size will all increase the IFs of the end of the main girder.And the variation parameters of center beam of expansion joint influences the IF more significantly.The impact of vehicle passing expansion joint on the acceleration response of the main girder,as well as the displacement response of the midspan,cannot be ignored.The decreasing of the bearing stiffness and the increasing gape size will significantly increase the IFs of expansion joint,and the peak increasing ratio of the Ifs is up to 58.1%and 13.5%,respectively.However,these two parameters have little impact on the displacement response of the main girder.The variation parameters of bearing support have little impact on the IFs of the center beam of expansion joint.However,the variation parameters of bearing support have significantly impact on the IFs of the main girder,especially the end of the main girder.And a lower bearing stiffness of bearing support will cause a larger IFs of the main girder.