Abstract: The influence factors of vehicles impact on the bridges include the vehicle-bridge frequency coupling，the bridge deck unevenness，the randomness of the driving test and size of dynamic loading efficiency． Based on a dynamic test upon a typica three span continuous box girder bridge，through the dynamic deflection schedule signal under the action of road test， the randomness of bridge impact coefficient，the correlation between impact coefficient and dynamic loading efficiency were analyzed． Studies have shown that the impact coefficient is quite random; the impact coefficient has close relation with dynamic loading efficiency．

Key words: impact coefficient, dynamic loading efficiency, dynamic deflection, randomness, correlation

摘要： 车辆对桥梁冲击作用的影响因素包括:车桥频率耦合、桥面平整度、行车试验的随机性、动力荷载效率大小等。 以一座典型3跨连续箱形桥的动荷载试验为基础，通过行车试验作用下实测动挠度时程信号，对该桥冲击系数随机 性、冲击系数与动力荷载效率之间相关性进行分析。研究表明:车辆对桥梁的冲击系数具有较大的随机性，冲击系 数与动力荷载效率之间具有较大的相关性。

关键词: 冲击系数, 动力荷载效率, 动挠度, 随机性, 相关性