Probability Analysis of the Vibration of Bridges with Rough Surface under Stochastic Traffic

The dynamic interaction of bridge-traffic system is dependent on the stochastic characteristics of various parameters that are random in nature, such as the surface roughness, traffic flow, and so on. It is necessary to include these uncertainties in the analysis. In this paper, the bridge-traffic coupled vibration system is studied considering the stochastic characteristics of traffic flows and surface roughness. The parameters, such as the extrapolation maximal displacement and mean value of the random process, are firstly presented in the probability analysis. Two vehicle models, one with 18 degrees of freedom (DOFs) and the other with 3 DOFs, were adopted in the vehicle simulation. A cellular automaton (CA) model is adopted to simulate the traffic flows and bridge surface roughness. The numerical investigation shows that: (1) the mean value distribution of the bridge vertical and lateral dynamic displacements generally remains stationary; (2) the dynamic responses at different time and under different traffic flows have negligible correlation; and (3) the extrapolation maximal value of the bridge displacement strictly and monotonically increases with the growth of design period.