Numerical study on hydrodynamic characteristics of movable coastal bridge deck under joint action of solitary wave and current

Abstract

When hydrodynamic loads of the bridge deck exerted by extreme surges and waves exceed the restraining capacity of the superstructure and substructure, bridge deck will be pushed off from the substructure. However, before the final failure of coastal bridge deck, its dynamic behavior can be idealized as a mass-spring-damper system. In the harsh ocean environment, extreme surges and waves coexist. It is their joint impact that has finally caused the damages of the coastal bridges. In previous studies, only the damage effect of ocean surface waves on the movable bridge deck was considered, and the influence of background current was not considered. In this study, hydrodynamic characteristics of movable coastal bridge deck under joint impact of solitary wave and current have been well investigated. Effects of the wave height, water depth, submersion depth, background current speed, and lateral stiffness on the hydrodynamic characteristics of movable coastal bridge deck were systematically analyzed. The results indicate that the existence of background current can significantly influence the hydrodynamic characteristics and dynamic responses of movable bridge deck under the action of solitary wave. The effective wave celerity gradually increases with background current speed, which eventually enhances the horizontal load and lateral displacement of the movable bridge deck, and it finally increases the potential risk of bridge damage.