Coastal bridges with a box-girder superstructure under the action of solitary waves: Study on the optimization of bearings, dynamic characteristics and failure mechanism

Abstract

Coastal bridges featuring a box-girder design are instrumental in advancing coastal transport and economic development. However, numerous coastal bridges with limited clearance above sea level are prone to the impact of the extreme waves. In order to enhance the survivability of superstructures of the bridge in the face of severe wave conditions, the present study implemented measures such as adding steel fasteners to conventional laminated rubber bearings and incorporating fluid viscous dampers to the box-girder superstructure. A three-dimensional fluid-structure coupling model, including a three-dimensional numerical flume, adjacent structures, and a box-girder superstructure supported by various bearings, is developed to explore the failure mechanisms and dynamic properties of the superstructure when subjected to extreme solitary wave conditions. Then, the effects of the implemented measures on the disaster resistance of bridge superstructures are comprehensively examined. The results indicate that: (1) After subjected to extreme solitary wave actions, the box-girder superstructure is at a high risk of failure due to sliding, unseating, and overturning. (2) Adding steel fasteners to conventional laminated rubber bearings can effectively alleviate overturning failure of the box-girder superstructure. (3) The addition of fluid viscous dampers into the box-girder superstructure can effectively decrease its maximum displacement. (4) Bridges with box-girder superstructures typically undergo bearing vertical and deformation failure during their failure process.