Abstract: Vehicle load is the most important live load for bridges to bear． In the case of orthotropic steel box girder of longspan bridges，vehicle load will play a very significant role in its long-term fatigue properties． Especially with the numerous vehicles being overloaded repeatedly，the steel box girder fatigue becomes an increasingly prominent issue． In order to predict the fatigue properties of orthotropic steel box girder，the characteristics of vehicle loading need to be comprehensively investigated． The characteristics of vehicle loading on Sutong Bridge are obtained，based on the data from toll collection system． Meanwhile，regular pattern of vehicle transverse distribution is identified by the dynamic image identification technique from video recorded by the bridge monitoring equipment． Means and methods of the research will provide a reference for vehicle loading study of the large-scale bridges which lack of WIM system．

Key words: Sutong Bridge, vehicle loading characteristics, image identification

摘要： 车辆荷载是桥梁承受最主要的活荷载。对于大跨径桥梁正交异性钢箱梁而言，车辆荷载对其疲劳特性将产生 非常明显的影响，在长期车辆反复作用下，钢箱梁的疲劳问题日益突出。为了更好预测正交异性钢箱梁的疲劳特 性，必须充分了解车辆荷载特性。以苏通大桥为背景，通过对收费系统数据的统计分析，获得了车辆荷载特性。同 时，利用桥梁监控设备，结合动态图像识别技术，获得了大桥车辆横向分布规律。相关研究手段和方法，可为缺乏 WIM系统的大型桥梁提供参考。

关键词: 苏通大桥, 车辆荷载特性, 图像识别