Studies On Design Vehicle Load Of Short And Medium Span Bridge

The current highway bridge vehicle loading standards of China was put forward in 1999, which was based on the reliability study of the series works and combined with the long-term observation data of national traffic in 1990s.After these years of development, especially in the 21st century, great changes has taken place in the vehicle and traffic situation. The progress of time has promoted the development of transport and automotive industry, and constantly developed vehicle load of bridge structure which may seriously damage the existing bridge structure, especially medium-small span bridges. Therefore, according to the existing traffic in certain region, it is extremely necessary to study the bridge vehicle load under the existing traffic conditions so as to confirm the standard of design vehicle load, which can meet the present conditions and the need of this region for a period in the future.Based on the vehicle load survey data measured in Luogang Section of National Highway No.107 and the basic theory of probability and statistics, the parameters such as gross vehicle weight, axle load, wheelbase, vehicle spacing and so on, are statistically analysed in this paper so as to confirm the probability distribution function of the category vehicle load and the representative values of related parameters. The simulation program of random fleet across the bridge was compiled by MATLAB. According to the calculation analysis of the load effect, the probability distribution type, distribution parameters and the standard value of load effect in the design reference period of medium-small span simply-supported bridges can be comfirmed. And on basis of the equivalent principle of load effect, a design load value of standard vehicle is recommended in the paper, and finally, the recommended value was verified by continuous beam bridge.