考虑轴重相关的随机车流荷载效应

为了给桥梁验算的设计荷载提供参考，基于宜泸高速WIM实测数据，分析随机车流参数尤其是轴重相关性. 应用MATLAB平台编制随机车流模拟程序，采用影响线法分析随机车流的荷载效应，探讨考虑轴重相关与不考虑时荷载效应的差别. 研究结果表明：轴重具有多峰分布的特点，轴重之间具有较强的相关性，当模拟随机车流时，若不考虑车辆参数的相关性，则会造成较大误差；采用非参数核密度估计-Copula方法，利用t-Copula函数作为连接函数的轴重联合分布函数，可以较准确地描述车辆轴重联合分布；考虑轴重相关情况下的荷载效应代表值比不考虑时高约45%，与实测车流荷载效应代表值更加接近；各车道随机车流对简支梁桥的荷载效应代表值差别不大，但均已超过现行规范公路-I级车道荷载的荷载效应，效应比最大值为1.34.

Random vehicle flow load effect considering axle load

The random vehicle flow parameters especially axle load correlation were analyzed based on the measured data of YI LU highway WIM in order to provide reference for the design load of bridge checking computations. A random vehicle flow simulation program was worked out by MATLAB. The load effect of random vehicle flow was analyzed by the influence line method, and the difference of load effect between considering the axle load correlation and without considering was discussed. Results show that axle load has the characteristics of multimodal distribution. There is a strong correlation between axle loads. Greater error will be caused when simulating random vehicle flow without considering the axle load correlation. The joint distribution function of vehicle axle load can accurately describe the joint distribution of vehicle axle load by using the nonparametric kernel density estimation-Copula method and using the t-Copula function as the connection function. The load effect considering the axle load correlation is 45% bigger than without considering, and it is closer to the representative value of measured traffic load effect. There is no significant difference between representative values of the load effect of the each lane random vehicle flow on the simply-supported beam bridge. Representative values of the load effect have exceeded the load effect of the current specification highway level I lane load, and the maximum effect ratio is 1.34.