中文摘要：

基于冲击系数的不确定性，采用移动跑车试验方法得到桥梁最不利荷载位置处的动、静挠度值，结合新欣南大桥汽车冲击系数，对其进行相应的理论分析比较，得到以下结论：随着车速的增加，汽车冲击系数有先增大后减小的趋势，并在一定车速下取得最大值。而各国相关规范中冲击系数的计算值与实测值差距很大，实测冲击系数随着车速的变化会有一定的差别，各国规范并没有反映出其变化规律，因此需要依据大量的移动荷载试验展开研究。

英文摘要：

Due to the uncertainty of impact coefficient, the dynamic deflection and static deflection at the most unfavorable load position of the bridge are obtained using vehicle field tests. Combining with the impact coefficient of Xinnan Bridge, the corresponding theoretical analysis and comparison are implemented. The following conclusion is that with the increasing vehicle speed, the impact coefficient increases firstly, and decreases afterwards, and its maximum is reached at a certain speed. But the calculated values according to specifications at home and abroad have an obvious gap with the measured data. The measured data will be different along with the change of vehicle speed, but the variation rule is not displayed in almost all the specifications. So the research requires to be implemented based on plenty of vehicle field tests.