Numerical investigation of extreme wave impact on coastal bridge deck using focused waves

Abstract

Horizontal and vertical impact forces on a coastal bridge deck with girders due to asymmetric and nonlinear wave loads induced by the action of focused wave groups have been investigated using open-source CFD model REEF3D. An extensive parametric study was conducted to investigate the variation of horizontal and vertical impact forces induced on bridge deck by steep focused waves. Results indicate that with increasing wave heights, while the horizontal positive force increases, the peak vertical uplift and downward forces decrease. Longer wave periods impart higher peak vertical uplift forces and horizontal positive forces. The bridge deck location at still water level, submerged and partially submerged cases are considered for the numerical study and the results are compared with the design formulae of American Association of State Highway and Transportation Officials (AASHTO). For both submerged and partially submerged scenarios, AASHTO formulae were found to highly overestimate the peak horizontal impact forces for lower wave heights and they were found to give better results for higher wave heights. In case of peak vertical impact forces, AASHTO formulae highly underestimate for lower wave heights and moderately capture the peak vertical impact force at higher wave heights and airgaps.