Experimental and numerical investigation of the dynamic response of coastal box-girder superstructures considering rotational effects under extreme wave loading

Abstract

Due to the rising frequency of extreme marine disasters, research on the interaction between coastal bridges and waves has gained significant attention in recent years. Bridge superstructures are typically subjected to rotation or even overturning failure under extreme wave conditions. However, existing experimental studies have scarcely accounted for these effects under extreme wave conditions. Thus, a steel rotating shaft system was employed in this study to implement the rotational effects of the superstructure. Subsequently, the influence of bridge piers and adjacent structures was considered, followed by a series of fluid-structure interaction experiments and numerical simulations to more accurately investigate the wave forces and dynamic response of the rotatable box-girder superstructure (BGSS) under extreme wave conditions. Moreover, a comparison of existing wave force calculation formulas was conducted, and an empirical formula for predicting the wave forces on the BGSS, incorporating the rotational effects under extreme wave loadings, was proposed. The results demonstrate that accounting for the rotational effects of the BGSS enables a more realistic and accurate representation of the dynamic response of the superstructure under practical conditions. Furthermore, a reduction in the wave period or the submersion coefficient of the superstructure leads to an increase in the inclination and wave forces acting on the BGSS. The empirical formula proposed in this study is capable of accurately predicting the wave forces acting on the BGSS, considering rotational effects, when subjected to extreme waves.