| Since the 21st century,China’s highway and bridge construction has experienced a period of rapid development.The safety,reliability and economic benefits of highway and bridge are all related to the allocation of social resources,and the rationality of its design is of vital importance.Therefore,the safety and reliability of highway and bridge structure has attracted much attention.In the reliability analysis of highway Bridges,the study of vehicle load is one of the key points.The data in this paper was collected by the mobile weighing system(VIM)on Humen bridge on September 9,2008.Through the statistical analysis of the measured data,it is found that the traditional single peak distribution is difficult to describe the vehicle load.According to the characteristics of vehicle load distribution,the vehicle is divided into two types: ordinary vehicle and heavy vehicle.By distribution fitting test,the loads of ordinary vehicle and heavy vehicle follow logarithmic normal distribution and extremum type I distribution respectively.The bimodal probability distribution of all vehicles loads is obtained by weighted combination based on the load distributions of ordinary vehicles and heavy vehicles,the bimodal distribution is used as the load distribution of all vehicles.It is impossible to calculate the maximum distribution directly from the bimodal distribution of vehicle load.Therefore,monte carlo method is used to simulate the pseudorandom number of the maximum vehicle load in the design baseline years of 85 years and100 years.The parameter estimation and distribution fitting test were carried out for the simulated pseudo-random number of the maximum vehicle load.The probability distributions of maximum vehicle load in 85 years and 100 years are all extremum type I distributions,the 0.9,0.95 and 0.99 fractional values of the maximum load distribution are obtained.It can be seen that the load standard value of the highway bridge increases with the increase of the design period. |
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