Measurement-based bearing capacity evaluation for small and medium span bridges

Abstract

In order to evaluate the bearing capacity of small and medium span bridge at the operational stage, provide a reference for the strategy of reinforcement and maintenance, an evaluation index of bearing capacity based on dead load, live load and structural resistance for small and medium span bridges is constructed. In this paper, the characteristics of vehicle types, vehicle weight, vehicle spacing, wheelbase and axle weight distribution ratio in different lanes are acquired and analyzed by arranging the weight in motion system on a highway. Monte Carlo method is used to obtain general stochastic traffic flow data which conform to the distribution of sample data. Using a program run by Matlab software, the stochastic traffic flow data are applied to sample bridges (simply supported bridge composed of five small box girders of 20 m to 40 m) to get the vehicle load effect. Finally, combined with the dead load of the sample bridge, the bearing capacity evaluation index constructed in this paper is calculated. The results show that under the effect of current traffic volume, the evaluation index of the sample bridge is equivalent to that of the design value suggested in the code, and the safety reserve of the bridge structure is relatively sufficient. Even if the traffic volume is doubled, most of the sample bridges can still meet the daily operational requirements of the bridge.