九江长江大桥疲劳车辆荷载谱

Fatigue load spectrum for Jiujiang Yangtze River Bridge

为评定九江长江大桥在交通荷载作用下的疲劳累积损伤,对该桥疲劳车辆荷载模型进行了研究。基于九江长江大桥现场车辆荷载调查,共采集到近13万辆汽车的相关动态数据。依据轴组类型划分为18种典型车型,采用数理统计方法,研究了该桥车流量的时段分布特征,提出在00：00~06：00时间段内为最佳道路管养维修时间;根据动态称重系统获取车重信息,分车型讨论了南向、北向及双向合并车重的概率统计模型,建立了能代表九江长江大桥真实运营状况的典型车辆荷载谱,然后按等效疲劳损伤原理简化成由7种等效模型车辆组成的模型车辆荷载谱。研究结果表明：出现频次较多的分别为2轴、4轴和6轴货车,其中6轴货车对桥梁疲劳损伤最大。研究成果为桥梁抗疲劳设计和疲劳寿命评估提供了可靠的车辆荷载谱,也可为类似大桥疲劳分析提供参考。

In order to estimate the fatigue cumulative damage of Jiujiang Yangtze River Bridge under the traffic load, fatigue load spectrum of this bridge was studied. Based on load investigation of the actual vehicles passing Jiujiang Yangtze River Bridge, the corresponding dynamic data of nearly 130 000 vehicles were collected. According to the number of axles and wheelbase, all the vehicles were divided into 18 typical types. The temporal distribution of actual vehicles was studied by using mathematical statistics analysis. It was concluded that the best time for bridge maintaining was at the time between 00：00-06：00 am. Every vehicle type was divided into three groups in terms of driving direction, i. e. from Jiujiang to Hubei, from Hubei to Jiujiang, and two-way traffic. Based on weigh information of the 18 typical vehicle types obtained from weigh in motion system, two survey vehicle load spectrums reflecting the actual operation state of the bridge were established. One was consisted of eighteen typical vehicle types; the other was simplified vehicle load spectrum which was composed of seven equivalent vehicle models according to the principle of equivalent fatigue damage. The results show that the fatigue load spectrum is mainly made up of 2-axle,4-axle and 6-axle truck, in which 6-axle truck caused the greatest dominates the fatigue damage. This study provides not only a reliable vehicle loadspectrum for the assessment of anti-fatigue design and fatigue life of bridges but also a reference for bridge fatigue analysis. 6 tabs, 3 figs, 17 refs.