WIM-based Study On Characteristics And Models Of Heavy Vehicle Loads On Highway Bridges

Economic growth has caused an increase in heavy vehicles.Due to the relationship of interests,the overloading of vehicles has become more frequent,resulting in damage and collapse of bridges,which has brought many adverse effects to traffic.Many scholars and related traffic control departments are paying more attention to it and have conducted investigations and research..Most scholars now use the method of limiting vehicle weight and wheelbase as a method of screening heavy vehicles.The statistics of vehicle loads(axle weight,vehicle weight and vehicle speed)under the measured data and the relationship between each parameter are studied and analyzed.The fitting extrapolation obtains the extreme value of the vehicle parameter or the parameter with higher frequency of occurrence as the representative value of the vehicle load model parameter.As the research method of vehicle load is continuously updated,this paper will use the method based on "unfavorable load effect" to extract the data information of the relevant parameters of heavy truck and analyze the load characteristics and establish the vehicle load model.The main work done by this is as follows:1)Obtain the data information of the vehicle through the dynamic weighing system(WIM),calculate the unfavorable load effect of each vehicle collected during the passage of the medium and small span bridges by using the influence line loading principle,and calculate the standard vehicle model in China,California's normative vehicle model,AASHO normative vehicle model's unfavorable load effect,and the extraction of heavy vehicle data by this standard,because the three norms have different standards for heavy vehicles,the heavy vehicles are divided into three categories;through the most unfavorable load position theory Get the position of the most unfavorable load to be studied in this paper.2)According to the extracted heavy vehicle data information,the load characteristics of the three types of heavy vehicles are statistically analyzed.The main categories are the classification of heavy vehicles,the traffic statistics of heavy vehicles in different lanes,the driving time of heavy vehicles and the vehicle load parameters.Statistical analysis of axle load,wheelbase,vehicle speed and vehicle weight.3)The method of probability and statistics is used to analyze the relevant parameters of the heavy truck.The representative values values of each parameter are obtained by the method of 95% guarantee rate,weighted average and expected value,and the corresponding heavy vehicle model is established.4)The finite element software Midas civil is used to build the bridge model.The heavy load model obtained by statistical analysis is loaded step by step,and the three indexes of internal force,stress and deflection generated by the bridge structure are quantitatively analyzed.