混合交通流作用下大跨径桥梁车辆荷载效应分析

Analysis of Vehicle Load Effect on Long-Span Bridge under Mixed Traffic Flow

卡车列队是一种通过自动控制、无线通讯等技术实现卡车成队近距离跟驰的交通模式,小间距行驶的车队直接导致桥面重车密度增加,且对于大跨径桥梁其可以容纳的卡车队数多,结构的整体和区段性能均可能受到影响。为研究卡车列队的荷载效应水平及其与普通车辆形成的混合交通流对桥梁结构的影响,评估现行规范的适用性,调研了国内外关于卡车列队的实际测试和理论研究,基于在役大跨径桥梁的实测交通流数据,提出了卡车列队荷载模型和混合交通流模拟方法。以一座大跨径悬索桥为主要背景工程,考虑实际的桥梁运行情况,实现了混合交通流模拟,研究了代表性混合交通场景中结构的车辆荷载效应水平和安全性,分析了卡车列队模式以及混合交通流对于大跨径悬索桥汽车荷载效应的影响。分析结果表明,混合交通流作用下的荷载效应水平较普通车辆车流有明显提高,但仍低于规范加载值。不同加载场景下的效应值约为规范值的35%~80%,现行规范对于卡车列队参与的混合交通流作用下结构的整体效应和区段效应均可提供较好的安全裕度,能够保证桥梁在未来相应运营状态下的安全服役。

Truck platooning is a traffic mode that can realize close distance following between trucks through automatic control,wireless communication,and other technologies.The decrease of gap directly leads to the increase of heavy vehicle density.Moreover,long-span bridge can accommodate a large number of truck platoons,which may affect the whole or partial structure.To study the load effect of truck platooning and mixed traffic flow composed of ordinary vehicles and truck platoons on bridge structure,and the applicability of the current design code,this paper investigated the actual test and theoretical research on truck platooning at home and abroad,and proposed a load model for truck platooning and a simulation method for mixed traffic flow based on the measured traffic flow data of long-span bridges in service.The mixed traffic flow simulation of a long-span suspension bridge was conducted,considering the actual operation condition of the bridge.In addition,the vehicle load effect level and safety of the bridge in the representative mixed traffic scenarios were studied,and the influence of truck platooning mode and mixed traffic flow on the vehicle load effect of the long-span suspension bridge was analyzed.The results show that the load effect of mixed traffic flow is significantly higher than that of ordinary vehicle traffic flow,but it is still lower than the code value.The effect value under different loading scenarios is about 35%~80%of the code value,indicating that the current code can provide a good safety margin for the global effect and partial effect of structure under mixed traffic flow with the participation of truck platooning,and that the safe service of the bridge can be ensured under the corresponding operation conditions in the future.