Research On Load Spectrum In Aizhai Bridge Of JiCha Highway

The Vehicle load acting on the bridge has a certain randomness and variability, especially with the development of modern society, the increasing of the traffic. Studying to random traffic on the highway bridge load spectrum is very necessary. Aizhai bridge of JiCha highway is taken as the background of this article, load surveys are launched for 48 hours. The paper mainly has the content and conclusion as follows:1.Load surveys are launched for 48 hours, the characteristics and parameters of random load are investigated, Describes the vehicle load survey methods and procedures and Aizhai Bridge is divided into seven types of vehicle load, Respectively for various models of vehicle carried out for vehicle type composition ratio,traffic flow composition ratio.traveling lane parameters, vehicle speed parameter, parameters driving the vehicle lateral position, vehicle weight parameter carried on series analysis. The results show that the traffic of Aizhai Bridge is mainly composed of the minibus and the trucks, the cars accounted for 49.5% of the vehicles, the trucks accounted for 21.56% of the vehicles, proportions of other types of vehicles are less than 10%. The typical weights obtained by using the weighted average method, from minibus to other types of vehicles, are 1646kg,1451kg,3572kg, 12395kg,6974kg,29104kg and 52832kg.2. Using normal distribution, lognormal distribution and Weibull distribution are three types of function Aizhai Bridge traffic parameters analysis and optimization of fitting. Detection by K-S to verify, to find out the parameters and the type of distribution and the closest distribution function.The results show that the normal distribution function instead of the distribution function of vehicle speed, the weibull distribution function to instead of the lateral position of the vehicle, the normal distribution function to instead of vehicle weight distribution function.3. According to the amount of vehicles on the bridge damage to convert, analyzed vehicle load time series to get power spectral density function and the autocorrelation function,obtained the frequency of this traffic survey data and so on. Combined with the previous conclusion Aizhai Bridge’s random traffic conformed normal distribution function mainly, to get the average value and standard deviation of random traffic after conversion and used Matlab draw up related procedures to get random vehicle load spectrum.