中法高速公路车流及荷载特性对比

Comparative Study on Highway Traffic Flow and Load Properties of China and France

选取中国和法国的两组利用动态称重设备实测的高速公路车辆数据进行统计,对实测车流的车型组成特性、车流时变特性及车辆到达特性,车辆特性,不同车道车流及荷载等特性进行了详细的对比与分析,总结了车流及车辆荷载的一般分布规律.数据显示,国内车重、轴重及交通量等参数都显著高于法国,相对《公路桥涵设计通用规范》(JTG D60—2004)中车辆荷载基础数据也提高很大;每天的交通量在低谷期重车比例最高,高峰期重车比例最低;各车道之间车流及荷载特性差异性很大,并不符合互不相关假定;我国实测车辆荷载的效应极值外推结果远大于现行规范值.综合这些特性,建议对特殊桥梁的设计或评估,采用特定地点的车辆荷载;各车道汽车荷载模型应分别考虑;不同加载长度的汽车荷载模型应区别分析.

Abstract： Two typical highway traffic data measured by weight-in-motion （WIM） equipment in China and France were compared, some statistics and analysis works were conducted. Traffic flow and load properties were compared in a detail way. The results show that axle weight, gross vehicle weight and traffic volume of France＇s are smaller than those of China＇s which indicate an obvious increase in comparison with the vehicle data used for the current bridge criterion （JTG D60-2004）. The constitution of daily traffic shows a timely change： trucks have a higher proportion during the low tide, but a lower proportion in peak time. Results can be concluded from the data that a basic hypothesis of vehicle load model for China design code, in which all vehicle lanes are uncorrelated to each other, may not valid. Both China and France data show traffic flow and load properties in different lanes have obvious difference. Finally, a site-specific vehicle model is recommended for design and assessment. Different lanes are proposed to be considered, and a loading length depended load-model should be adapt for diversity span bridge for the actual extrapolated effect far outweighs the code value.