Prediction of Wave Forces on the Box-Girder Superstructure of the Offshore Bridge with the Influence of Floating Breakwater

In recent years, with global warming and frequent natural disasters, existing offshore bridges are facing the risk of extreme wave action. The research on disaster prevention and mitigation measures of the box-girder superstructure of offshore bridges under extreme wave action is still scarce. In this paper, a numerical model based on the RANS equation and k-ε turbulence model is established to study the wave forces on the box-girder superstructures of offshore bridges with the influence of a floating breakwater. A numerical method for studying the interaction of waves and structures is proposed and verified through experimental data. The effects of many parameters of the floating breakwater on wave attenuation are investigated and a prediction model of the wave reduction rate based on neural network algorithm is proposed. The results show that the reduction rate of wave forces for fixed breakwaters can reach more than 30%, which indicates that a floating breakwater has a significant effect in reducing the wave forces on the box-girder superstructure. The wave reduction performances of the displacement-restricted breakwater and the fixed breakwater are better than that of an elastic restricted breakwater. The prediction model proposed based on the BP neural network is accurate in estimating the maximum wave forces on the box-girder superstructure with the influence of the floating breakwater.