本文通过采用理论分析与数值模拟相结合的方法，研究车辆荷载对桥梁地震响应的影响。文章首先总结和归纳了公路桥梁车桥振动的发展过程，并对其研究现状进行了论述，给出本文研究的主要目的。接着在前人研究的基础上选择并建立了合适的桥梁和汽车分析模型。最后以某高速公路上一座四跨预应力钢筋混凝土连续箱梁桥为例，用有限元分析软件建立整体车桥模型，详细分析了汽车荷载大小、汽车行驶速度、汽车荷载数目、汽车悬挂系统的刚度和阻尼等因素对地震荷载作用下桥梁动力响应的影响。 为验证分析模型的准确性，本文分别用ANSYS和MIDAS/Civil有限元分析软件建立桥梁整体模型，然后对其进行动力特性分析，并对两分析结果进行对比。通过对比结果看出，两软件计算的动力特性分析数据较为相似，频率和周期都相差较小，而且振型基本一致，初步验证了计算模型的正确性。接着用ANSYS有限元软件分析汽车荷载对桥梁地震响应的影响，通过对不同地震荷载和不同桥梁跨径模拟分析，可得出如下结论：汽车荷载大小和汽车数量对桥梁地震响应的影响显著，且二者影响较为一致，其影响曲线都是随着变量的增加先减小后增加，即位移曲线随着荷载与数量的增加会出现一最小值；汽车速度对桥梁振动响应的影响在地震作用与非地震作用下是一致的，主梁跨中竖向位移都随汽车行驶速度的增加而逐渐减小；汽车悬挂系统的刚度与阻尼对桥梁地震响应的影响较小，在工程误差范围内可以忽略其影响。

In this paper, the influence of vehicle load to seismic response of bridge is studied by combining theoretical analysis and numerical simulation. This article first summarizes and sums up the development process of highway bridge vibration, and the research status are discussed, the main purpose of the research is given in this paper. On the basis of previous studies, a suitable bridge and vehicle analysis model is established. Finally, with a highway span prestressed reinforced concrete continuous beam as an example, the establishment of the overall bridge model by finite element analysis software, discussed in detail the vehicle load size, vehicle speed, number of vehicle loads, stiffness and damping of vehicle suspension system etc. to influence of bridge dynamic response under earthquake load. In order to verify the accuracy of the model, this paper are used ANSYS and MIDAS/Civil finite element analysis software to establish the whole bridge model, then the dynamic characteristics are analyzed, and the results of the two analyses are compared. According to the comparison results, the dynamic characteristic analysis data of the two software were similar, the frequency and the period were different, and the vibration mode was basically the same. Then analyzed the effect of vehicle load on the seismic response of the bridge with ANSYS finite element software, through the simulation of different seismic loads and different span of bridge analysis, the following conclusions can be drawn: the number of vehicle load and vehicle had significant effects on the seismic response of the bridge, and the two was consistent, the influence curve with the increase of variables is first reduced and then increased, with the increase of load and displacement curve will have a minimum number of; the car speed on the vibration response of the bridge in the earthquake and non earthquake was the same, with the increased of girder vehicle speed midspan vertical displacement gradually decreased; automotive suspension system is affected by the stiffness and damping on the seismic response of the bridge, which can be ignored influence in the scope of engineering error.