Numerical Investigation on the Hydrodynamic Characteristics of Coastal Bridge Decks under the Impact of Extreme Waves

Abstract

Qu, K.; Sun, W.Y.; Ren, X.Y.; Kraatz, S., and Jiang, C.B., 2021. Numerical investigation on the hydrodynamic characteristics of coastal bridge decks under the impact of extreme waves. Journal of Coastal Research, 37(2), 442–455. Coconut Creek (Florida), ISSN 0749-0208.Extreme waves, such as freak waves or rogue waves, occur unexpectedly in the ocean and have extremely large wave heights. Extreme waves often are attributed to the process of wave focusing. Coastal structures such as bridges are highly susceptible to extreme waves and have caused substantial damage to coastal infrastructure in the past. Although impacts of various types of waves on coastal bridges have been studied in the past, hydrodynamic loads on bridge deck under the impact of extreme waves have not yet been investigated. This work adds to the existing body of work by systematically carrying out numerical investigations on the hydrodynamic characteristics of coastal bridge decks under the impact of extreme waves generated by wave focusing. Simulations were carried out by creating a numerical wave tank (NWT) using the open-source flow solver REEF3D, which numerically solves the governing equations of the incompressible two-phase flow on a staggered mesh and captures the interface between air and water using a high-resolution level-set method. The NWT was validated for the case of focused waves and wave impact loads on a two-dimensional (2D) rectangular cylinder in a straight channel and compared to experimental measurements. The NWT was then used to study the hydrodynamic loads of a coastal bridge deck by considering the effects of four prominent factors, i.e. submersion depth, wave height, wave period, and water depth. The findings made in this paper enhance the understanding of the damage mechanisms of coastal bridges under the impact of extreme waves.