Study on the mechanical characteristics and failure mechanism of the coastal bridge with a box-girder superstructure under the action of breaking solitary waves

Abstract

Nowadays, bridges with a box-girder superstructure play a crucial role in coastal transportation systems, and many low-lying coastal bridges are severely threatened by breaking waves. However, the study on dynamic characteristics of coastal bridges with a box-girder superstructure under the action of breaking solitary waves is limited, which is crucial for the rational design of these bridges. In this study, a two-dimensional numerical model, including a numerical wave flume and a box-girder superstructure model with a simplified connection system, is developed. The breaking mechanism of solitary waves and the influence of different forms of breaking solitary waves on the box-girder superstructure are investigated in detail in this study. Furthermore, three common failure modes, including the deformation of bearings, sliding between the box-girder superstructure and bearings, and unseating of the box-girder superstructure, and the influence of the damping ratio of bearings on the box-girder superstructure are studied in detail. The results indicate that: (1) The box-girder superstructure is most vulnerable to solitary waves in the breaking state. (2) The unseating and sliding failures of box-girder superstructure under the action of breaking solitary waves are typically accompanied by the deformation and vertical failure of bearings. (3) Increasing the damping ratio of bearings can effectively reduce the lateral displacement and vibration of the box-girder superstructure.