Research On Reliability Of Existing Bridges Based On Traffic Investigation

In recent years, with the rapid development of countries in the automotive industry, the vehicle's wheelbase, length, load, and axle load have been significantly changed. At the same time, because of the economic development, people's living standards improved and the density of vehicles on roads is also increasing. For early construction of the bridge, because of its low level of loading and material properties declining over time, so many bridge's resistance can not meet the load level now. Leading to the bridge collapse in recent years around the world became a common occurrence.Vehicle load is the main underlying variable load of bridge, they are related with the economic levels and are time-varying variables. China's current bridge codes of the vehicle load is based on many vehicles investigations in the nineties. But in fact, many scholars have found that the great disparity between the actual effect of vehicle load on the bridge with the bridge codes. Therefore, in order to assess the reliability and security of the bridge, it must base on the vehicle effects of the bridge, and consider their resistance recession over time, while domestic research on this issue is less.In this paper, through the vehicle investigating on a road for one week, analysis the vehicle types and its corresponding weight and vehicle headway, given the distribution features of the vehicle weight and vehicle headway. Taking all automobile manufacturers and measured of the wheelbase, axle load, given the statistical results of the wheelbase vehicle and the ratio of axle load distribution. Based on the above statistical parameters in combination with Monte Carlo method, using MATLAB language to compile the random traffic simulation program SJCHL, and compiled a influence line loader HZXY. Through the two program that we can get the maximum load effect in N days of an actual bridge under the random traffic flow, and then statistical analysis of the samples to obtain the actual load effects of statistical parameters. In order to accurately calculate the actual resistance of the bridge, this paper is on the basis of previous studies what is given the flexural capacity's statistical parameters of the prediction equation and the resistance formula based on durability testing. Finally used the reliability of methods to assess the reinforced concrete bridge of 16m span under the random traffic.This article bases on the vehicles investigate and durability tested, gived a approch which uses the reliability to evaluate the security of the existing bridge.