Wave loads of bridge decks near a sloped beach

Abstract

This research is the first attempt to examine the hydrodynamic loads of nonlinear solitary waves on bridge decks near a coastline. We employ laboratory experiments and a large eddy simulation model to simulate the wave motion and wave loads on a partially submerged rectangular deck near a sloped beach. The measured wave heights and wave loads from wave flume experiments verify the accuracy of the computational fluid dynamics model. A series of parametric studies investigates the effects of wave height, submergence, and beach slope on the wave loads of the bridge deck. The simulation results revealed that the hydrodynamic forces are linearly proportional to the wave height, and the dimensionless force coefficients depend on the submergence ratio and beach slope. For the mild slope case (θ = 18.5°), the wave load during the run-up stage is larger than that during the run-down stage. The largest drag coefficient CD = 0.58, lift coefficient CL = 0.45, and pitch moment coefficient Cm = −0.21 occur when the deck is initially above the still wave level. On a steeper slope (θ = 30°), the run-down current could generate a large downward force and a clockwise moment when the bridge deck is close to a shoreline. Hereafter, coastal bridges should consider the impact of the run-down flow during tsunamis and storm surges.