Development of a generation method of artificial vehicle wheel load to analyze dynamic behavior of bridges

In this study, artificial wheel loads are proposed which reflect the dynamic effects of running vehicles and road roughness to overcome shortcomings of vehicle modeling methods. To derive a suitable artificial load from the moving vehicle model, a parametric study is conducted regarding span lengths, types of bridges, road roughnesses, vehicle speeds and consecutive vehicles. After that, Power Spectral Density (PSD) analyses of wheel loads are performed using Maximum Entropy Method (MEM). Based on the result, a representative PSD function is proposed considering the cumulative energy distribution and the area of the PSD curve. The artificial wheel loads are generated based on this PSD function. Also, dynamic analyses of a bridge are performed using the artificial wheel loads. The probabilistic characteristics of dynamic responses are evaluated by comparing the results with the existing moving vehicle model. The results show that the dynamic responses through the proposed method are slightly overestimated. It is concluded that the proposed method is a simple and reliable procedure for engineers to perform a dynamic analysis in practical design.