基于WIM的大跨钢箱梁悬索桥疲劳荷载谱研究

Research on Fatigue Load Spectrum of Long Span Steel Box Girder Suspension Bridge Based on WIM

基于某桥动态称重系统监测的车辆荷载相关数据,划分典型车辆类型,以周为单位时间对不同车型交通量随时间的变化情况进行统计分析。对不同车型的车重概率分布拟合,引入赤池信息准则和贝叶斯信息准则确定模型的最佳分量数。根据拟合的车重概率分布模型建立该桥的疲劳荷载谱,由等效轴重数据计算出各车型的疲劳损伤贡献率。结果表明:各周的车流量变化明显,尤其是两轴车和六轴车,且两类车占比趋势相反,所以有必要研究长时间段内的车流情况;各车型的车重概率分布均符合混合高斯分布,且由拟合优度判断可知拟合效果较好;虽然六轴车的频率低于两轴车,但其等效轴重产生的总疲劳损伤贡献率最高,所以六轴车为此桥的最不利车型。

Based on the vehicle load related data monitored by the dynamic weighing system of a bridge,the typical vehicle types are divided firstly,and then the traffic volume of different vehicles with time is statistically analyzed by taking the week as the unit time.The probability distribution of vehicle weight of different models is fitted,the Akaike’information criterion and the Bayesian information criterion to determine the optimal number of components of the model are introduced.Then the fatigue load spectrum of the bridge is established according to the fitting probability distribution model of vehicle weight.Finally,the fatigue damage contribution rate of each vehicle type is calculated from the equivalent axle load data.The results show that:the change of traffic flow in each week is obvious,especially for two axle vehicles and six axle vehicles,and the proportion of the two types of vehicles is opposite,so it is necessary to study the traffic flow in a long period of time;The results show that the probability distribution of vehicle weight of each vehicle type conforms to the Gaussian mixture distribution,and the fitting effect is good according to the goodness of fit;Although the frequency of the six axle vehicle is lower than that of the two axle vehicle,the contribution rate of the total fatigue damage caused by the equivalent axle load is the highest,so the six axle vehicle is the most unfavorable model for the bridge.