基于长期监测车流的公路桥梁设计车载模型校验

Calibration of design vehicle load model of highway bridges based on long-term monitored traffic flow

基于我国车流数据校验既有设计车辆荷载模型,提出随机车流荷载下桥梁车载效应极值外推方法。基于某高速公路桥梁动态称重系统长期监测车流数据,建立随机车流荷载模型,分析简支T梁桥的车辆荷载效应极值,据此校验国内外桥梁设计车辆荷载模型。研究结果表明:欧洲Eurocode3规范和英国BS5400规范的设计车辆荷载效应标准值远大于中国JTG D60—2015规范标准值和美国AASHTO荷载规范标准值;针对我国交通荷载现状,欧洲Eueocode3规范与英国BS5400规范设计车辆荷载模型的重现期趋于无穷大,而美国规范的重现期小于1 000 a,我国JTG D60—2015设计车道荷载规范的重现期为1 000～4 000 a。

In order to calibrate the existing design vehicle load models based on the native vehicle load,an approach was presented for extrapolating extreme vehicle load effect of bridges under stochastic traffic flow loads.A stochastic traffic load model was established based on the long-term weigh-in-motion measurements of a highway bridge in China.The extreme traffic load effects of a simply supported T-girder bridge was analyzed.Based on the numerical results,several national and abroad design vehicle load models were calibrated.The results show that the standard values of the design vehicle load effect in Eurocode3 code and the British BS5400 code are much higher than those of Chinese JTG D60-2015 code and the British BS5400 codes.Based on the current traffic condition in China,the return period of the standard vehicle load model in Eurocode3 and Bridge BS5400 codes tend to be infinite.The return period of the American code is less than 1 000 a,while that of the Chinese JTG D60-2015 code is between 1 000?4 000 a.