Influence of Current Velocity on Wave-Current Forces on Coastal Bridge Decks with Box Girders

In this paper, a two-dimensional (2D) model for wave-current girder interactions is established to investigate the effect of wave-current forces on box girder bridges. Reynolds averaged Navier-Stokes (RANS) equations combined with the k-epsilon turbulence model are applied for wave-current simulations, and the volume of fluid (VOF) method is used to trace the free water surface. Compared with previous studies, this paper (1) investigates the influence of the current velocity on the wave force on a coastal bridge box girder under extreme conditions, (2) analyzes the wave forces on the vulnerable positions of a box girder bridge, and (3) proposes simple and accurate equations for predicting the wave-current forces on a box girder bridge. The numerical model presented in this paper is first validated by comparing data obtained from the laboratory experiments. Next, parametric studies are conducted to examine the influence of the current velocity on wave-current forces under different effect factors, including extreme wave characteristics, relative water depths, and submerged depths. The influence of the geometrical shape of the box girder on the wave forces is considered. Finally, based on the numerical results, empirical equations predicting the wave-current forces on a box girder bridge under various effect factors are proposed as a method of protecting coastal bridges from damage under extreme wave loadings. (C) 2018 American Society of Civil Engineers.