伸缩缝参数对大跨度拱桥车致动力响应的影响

Influence of expansion joint parameters on vehicle-induced dynamic response of long-span arch bridge

为探究伸缩缝参数对大跨度中承式钢管混凝土拱桥车致动力响应的影响,建立了考虑伸缩缝参数影响的车-桥耦合动力响应分析方法(车-缝-桥耦合动力响应分析方法);进而以某大跨度中承式钢管混凝土拱桥为研究对象,探究了伸缩缝高差、支撑刚度、缝宽等参数对车-缝-桥耦合动力响应的影响规律。结果表明:1)伸缩缝设计参数条件下,随车速的增加车辆对伸缩缝的竖向冲击作用呈先减小后增大的趋势,与主梁车致冲击作用相比,伸缩缝车致冲击作用更加显著;随车速增加主梁车致冲击系数呈增大趋势;考虑伸缩缝参数影响后,车辆对主梁的竖向冲击作用与空间位置有关,与伸缩缝位置相近的主梁测点冲击系数更大。2)伸缩缝参数变化条件下,中横梁升高会导致车辆对伸缩缝的冲击作用增大,而中横梁升高或降低均会导致车辆对梁端的冲击作用增大,并造成支座反力的增大;伸缩缝支撑刚度降低或缝宽变大时,车辆对伸缩缝中横梁的冲击作用影响均增大;伸缩缝参数对主梁1/4跨截面、1/2跨截面位移响应影响较小。

To study the influence of expansion joint parameters on vehicle-induced dynamic response of long-span concrete-filled steel tube(CFST)arch bridge,this paper proposes a vehicle-bridge coupling dynamic response analysis method(vehicle-gap-bridge coupling dynamic response analysis method)considering the influence of expansion joint parameters.Taking a long-span half-through CFST arch bridge as the research object,the influence of expansion joint height difference,support stiffness,and joint width on the vehicle-gap-bridge coupling dynamic response was investigated.Results show that under the design parameters of expansion joint,the vertical impact of vehicle on expansion joint first decreased and then increased with the increase in the vehicle speed,and the vehicle-induced impact on the expansion joint was more significant than that on the main beam.With the increase in the vehicle speed,the vehicle-induced impact coefficient of the main beam showed an increasing trend.Considering the influence of expansion joint parameters,the vertical impact of vehicle on the main beam was related to the spatial position,and the impact coefficient of the main beam measurement point close to the expansion joint position was greater.Under variable expansion joint parameters,the rise of the middle cross beam led to the increase in the impact of the vehicle on the expansion joint,and the rise or fall of the middle cross beam could both cause the increase in the impact of the vehicle on the beam end,resulting in the increase in the bearing reaction.When the support stiffness of the expansion joint decreased or the width of the joint increased,the impact of the vehicle on the middle cross beam of the expansion joint increased.The expansion joint parameters had little effect on the displacement response of the 1/4 cross-section and 1/2 cross-section of the main beam.