基于实测和CA模型的大跨桥梁车辆荷载模拟

车辆荷载对于大跨公铁两用桥梁和大跨公路桥梁的使用性与安全性均有显著的影响。与中小跨桥梁相比,大跨桥梁交通容量可观,车辆在过桥中加减速和车道变化的概率较大,车辆荷载在桥梁的分布状态极为复杂。目前的交通荷载实测系统对车辆过桥全过程中的位置及速度变化不能提供详细的信息,为此,建立融合实测交通信息和元胞自动机（CA）模型的大跨桥梁车辆荷载模型,考虑不同区域车型构成特征,交通规则、车道设置和驾驶行为。依据河北一处重载路段的交通实测数据,分析不同交通服务水平下一座大跨斜拉桥静力荷载随时间和空间的分布特征,并通过与规范设计荷载值进行比较对荷载效应进行评价。

Vehicle load simulation for long-span bridge based on merging real-monitored data and cellular automaton model

Vehicular load has significant impact on long-span railway-highway bridges and highway bridges.Compared with short and medium span bridges,the traffic volume is much denser and the occurrence probabilities of speed variation and lane changing on the long-span bridge are larger,which results in the distribution variation of vehicle loads on the bridge. The current traffic monitoring system cannot provide the detailed information of the whole process of vehicle movement on the bridge. In order to determine the vehicle distribution on the long-span bridge,the traffic model merging the real-monitored data and cellular automation（ CA） model was developed. This model could consider the traffic properties in different regions,traffic rule,roadway situation and driver＇s behavior. Based on the traffic monitoring data in a heavy-traffic roadway in Hebei province,the vehicle load properties＇ variation in space and time domain on the middle span of a long-span cable-stayed bridge was analyzed. The load impact was evaluated through the comparison with the stipulated vehicle load.