Random wave forces on the submerged box-girder superstructure of coastal bridges based on potential flow theory

Abstract

The hydrodynamic performance of the box-girder superstructure under extreme random wave conditions in the actual ocean environment is the focus of coastal bridge designers and researchers. This paper proposed an analytical method to estimate random wave forces on the box-girder superstructure based on the potential flow theory and the correction parameters. The accuracy of the proposed analytical method is validated by the classical problem about the wave force on the rectangular structure, empirical methods proposed by previous researchers, and the hydrodynamic experiment conducted by authors on the wave force of the box-girder superstructure within the application range of the proposed method. With the validated analytical method, a parametric study is carried out to explore the influence of the peak frequency of the incident wave spectra and the structural configuration on the hydrodynamic performance of the submerged box-girder superstructure. Results show that the structural parameter, including the relative deck thickness, girder width, and girder height of the box-girder superstructure affects the horizontal wave force more significantly than the vertical wave force. A larger ratio of wavelength to the width of the box-girder superstructure results in smaller horizontal wave forces when the dimensionless wave number is smaller than 1.0. It is of great significance to consider the effect of actual ocean waves on coastal bridge superstructures using random waves.