A new model to simulate the site-specific traffic load with consideration of precise axle load and microscopic behavior

Traffic load is one of the important external loads of bridges and simulating the site-specific traffic load is important for bridge condition assessment. This study proposes a new microscopic model to simulate the stochastic traffic load of any time period at bridge site based on weigh in motion (WIM) data. A model for simulating the microscopic interaction between vehicles was first proposed, by which free driving, car following and sudden braking can be reasonably simulated. Axle-weight information from the WIM data was embedded into the model to precisely simulate the vehicle load. A new vehicle sequence generation method based on WIM data was then proposed to generate the site-specific vehicle sequence of any time period with consideration of non-stationarity. Finally, a framework for simulating the site-specific stochastic traffic load is established. The proposed framework is validated through application based on realistic WIM data in traffic-flow simulation and load effect quantification. Comparisons of simulation results with the existing methods were also conducted to show the reasonability and novelty. The results indicate that the proposed framework can produce reasonable site-specific stochastic traffic load over any time period based on WIM data.