Numerical investigation on hydrodynamic load of coastal bridge deck under joint action of solitary wave and wind

Abstract

Coastal bridges are vulnerable to extreme surges and waves during tsunamis and hurricanes. Many of them have been significantly damaged or destroyed during past extreme weather events, such as Hurricane Katrina in 2005. Although extensive experimental work and numerical simulations have been carried out focusing on identifying the damage mechanisms of coastal bridges impacted by extreme waves, the coastal bridge deck needs to withstand the combined actions of waves and wind. Strong winds can easily deform the water surface and influence how waves impact the coastal bridge deck and the final resultant hydrodynamic load. Hence, there is a strong need for investigating the hydrodynamic characteristics of coastal bridges under the joint action of wind and surge waves. The direct effects of wind on the hydrodynamic load of a bridge deck under the impact of extreme surge waves had not been taken into account in past studies. To fill this knowledge gap, in this paper, a high-resolution numerical wave-wind tank is established by solving the governing equations of two-phase incompressible flow using the finite volume method. The hydrodynamic load of coastal bridge deck under joint action of solitary wave and wind are numerically investigated by considering the effects of several prominent factors, i.e. wind speed, wave height, submersion depth, and water depth. The results show that strong wind can greatly enhance the impacting intensity of solitary waves on bridge deck, resulting in greater horizontal and vertical hydrodynamic loads. It is believed that findings of this study can further enhance our understanding on damage mechanism of coastal bridge decks during hurricanes.