高速公路分车道荷载差异及其响应特性

为研究我国高速公路各车型分车道行驶的交通规则对分车道荷载及其响应的影响,选取实测的单向两车道、三车道和四车道的动态称重(WIM)数据,首先统计了各车型对车道的选择概率;然后,对比了分车道交通流量及荷载分布的差异;最后从车重极值、荷载响应极值、荷载响应损伤累积三方面研究了分车道行驶对桥面结构局部设计、桥梁整体设计和桥梁疲劳设计的影响.研究表明,各车型对车道具有特定的选择概率,分车道在车型组成、交通流量及荷载分布上显著差别.不同车道数时,分车道的外推车重极值存在差别,桥面结构局部设计用车辆荷载模型应据此进行车道修正.分车道荷载响应极值的比值及等效应力幅的比值均不为1,说明分车道最不利荷载响应及疲劳损伤累积效应都不相同,桥梁的整体设计和疲劳设计应该考虑这些特性.

Lane Load Disparities and Their Loading Effect Characteristics of Freeway

To investigate lane load disparities and their loading effect characteristics due to the influence of freeway traffic rule of certain vehicle type travelling in certain lane, Weigh in motion (WIM) data from two lane, three lane and four lane unidirectional freeway were adopted as the basis of the study. Vehicle lane choosing probabilities were firstly counted. Traffic volumes and vehicle weights among lanes were then compared. Finally, the influences of lane load disparities on local design of bridge deck system, bridge global design, and bridge fatigue design were analyzed from the corresponding perspectives of extreme truck weight, extreme loading effect and equivalent fatigue stress. Results indicate the vehicle lane choosing probabilities are differential in multi lane roads, and the differences among vehicle composition, traffic volume, and load distribution in lateral lanes are significant. The extrapolated extreme lane truck weights are different to each other, which illustrates a modified lane factor should be considered in the local design of bridge deck system if a unified truck load model is utilized. The ratios of extreme load effects among lateral lanes and those of equivalent fatigue stress are all not equal to 1, which highlights the strength and fatigue effects in lateral lanes under random traffic loading are different to each other, and should be considered into structural optimization of bridge global design and fatigue design.