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Coastal bridges are exposed to severe wave , current and wind forces during a hurricane . Most coastal bridges are not designed to resist wave loads in such extreme situations , and there are no existing analytical methods to calculate wave loads on coastal highway bridges . This study focuses on developing a new scheme to estimate the extreme wave loads on bridges for designing purpose . In order to do this , a 2D wave velocity potential model (2D Model ) is set up for the deterministic analysis of wave force on bridge decks .
2D Model is a linear wave model , which has the capability of calculating wave velocity potential components in time domain based on wave parameters such as wave height , wave period and water depth , and complex structural geometries . 2D Model has Laplace equation as general equation . The free surface boundary , incoming and outgoing wave boundary conditions are linearized , decomposed first , and then solved by the finite difference method . Maximum wave forces results calculated by the linear 2D Model are compared with results from CFD software Flow3D that is using Navier Stokes theory up to the 5th order ; and 2D Model is validated by comparing results with experiment data . A case study is conducted for calculating extreme wave forces on I -10 Bridge across Escambia Bay , Florida during Hurricane Ivan in September 2004 .SWAN model is adapted to investigate the parameters of wave heights and wave periods around bridge sites . SWAN model has the capability of predicting or hindcasting significant wave heights and wave periods as long as the domain and input parameters are given . The predicted significant wave heights are compared with measurements by Buoy Station 42039 and 42040 nearest to Escambia Bay .
A new prediction equation of maximum uplift wave forces on bridge decks is developed in terms of wave height , wave period , water depth , bridge width , water clearance and over top water load . To develop the equations , the relationship is investigated between maximum uplift wave forces and wave parameters , water clearance , green water effects and bridge width . 2D Model is used for up to 1886 cases with difference parameters . Flow3D model is adopted to determine coefficients of water clearance and green water effects , which cannot be calculated by 2D Model . |
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