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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.

This thesis documents the development of a computational method for wave induced longitudinal bending in ships. First, there will be a discussion about the importance of longitudinal bending in ship design. The paper will then outline the basic physics at work in the system. It will review the wave forcing computation as well as the response of the vessel. It will then document the progression of the program, which was constructed in Fortran 90, as it solves the linear differential equation for the vessel bending caused by an incoming wave. The entire program then appears at the end of the paper. While the current program is not complete the theory behind it is valid and the code can be augmented to include non-linear components in the future.

Predictions of the environmental loading and induced motional and structural responses are among the most important aspects in the overall design process of offshore structures and ships. In this thesis, attention is focused on the wave loads and excited bodily motion responses of large offshore structures and special vessels. With the aim of improving the existing theoretical methods to provide techniques of theoretical effectiveness, computational efficiency, and engineering practicality in marine and offshore applications, the thesis concentrates upon describing fundamental and essential aspects in the physical phenomenon associated with wave-structure interactions and deriving new methods and techniques to analyse offshore structures and unconventional ships of practical interest. The total wave force arising from such a wave-structural interaction is assumed to be a simple superposition of the potential and the viscous flow force components. The linear potential forces are solved by the Green function integral equation whilst the viscous forces are estimated based on the Morison's damping formula. Forms of the Green function integral equation and the associated Green function are given systematically for various practical cases. The relevant two-dimensional versions are then derived by a transformation procedure. Techniques are developed to solve the integral equation numerically including the interior integral formulation and, in particular, to tackle the mathematical difficulties at irregular frequencies. In applying the integral equations to solve problems with various offshore structures and special vessels, some modified, improved or simplified methods are proposed. At first, simplified method is derived for predictions of the surge, sway and yaw motions of elongated bodies of full sectional geometry or structures with shallow draft. Then, a new shallow draft theory is described for both three- and two-dimensional cases with inclusion of the finite draft effect. Furthermore, a three-dimensional strip method is formulated where the end effects of the body are fully taken into account. Finally, an approximation to the horizontal mean drift forces of multi-column offshore structures are presented. Some new findings are also discussed including the multiple resonances occurring in the motions of multi-hulled marine structures due to the wave-body interaction, the mutual cancellation effect of the diffraction and the radiation forces arising from a full shaped slender body, and so on. Further to those verification studies for individual methods developed, more comprehensive example investigations are given related to two industrial applications. One is a derrick barge semi-submersible with zero forward speed; and the other, a SWATH ship with considerable speed. By correlation of all the proposed approaches with available analytical, numerical and experimental data, the thesis tries to demonstrate a principle that as long as principal physical aspects in the wave-structure interaction problem are properly treated, an appropriately modified or simplified method works, performs well and, sometimes, even better.

Sea water intake structures submerged in the surf zone are used to provide water for cooling processes in large facilities such as power plants and refineries. Structures submerged in the surf zone are subject to large forces from breaking waves. To study these forces induced from realistic sea state conditions, a physical model of an intake structure submerged in the wave breaking zone was constructed and subjected to a wide spectrum of regular and irregular waves. The model structure was designed in a manner so force measurement could be isolated to separate components of the structure. The data of peak forces on the structure was analyzed for correlations with varying irregular wave properties. Using the results of forcing on the structure from regular wave tests, drag and inertia coefficients for use in the Morison equation were determined for each separate component and configuration of the structure. These force coefficients were plotted against various wave properties to analyze correlations with wave conditions. Finally, the force coefficients for the structure were used with the Morison equation and current data from the experiments to successfully model forcing on the structure during irregular wave tests.

Sea water intake structures submerged in the surf zone are used to provide water for cooling processes in large facilities such as power plants and refineries. Structures submerged in the surf zone are subject to large forces from breaking waves. To study these forces induced from realistic sea state conditions, a physical model of an intake structure submerged in the wave breaking zone was constructed and subjected to a wide spectrum of regular and irregular waves. The model structure was designed in a manner so force measurement could be isolated to separate components of the structure. The data of peak forces on the structure was analyzed for correlations with varying irregular wave properties. Using the results of forcing on the structure from regular wave tests, drag and inertia coefficients for use in the Morison equation were determined for each separate component and configuration of the structure. These force coefficients were plotted against various wave properties to analyze correlations with wave conditions. Finally, the force coefficients for the structure were used with the Morison equation and current data from the experiments to successfully model forcing on the structure during irregular wave tests.

Sea water intake structures submerged in the surf zone are used to provide water for cooling processes in large facilities such as power plants and refineries. Structures submerged in the surf zone are subject to large forces from breaking waves. To study these forces induced from realistic sea state conditions, a physical model of an intake structure submerged in the wave breaking zone was constructed and subjected to a wide spectrum of regular and irregular waves. The model structure was designed in a manner so force measurement could be isolated to separate components of the structure. The data of peak forces on the structure was analyzed for correlations with varying irregular wave properties. Using the results of forcing on the structure from regular wave tests, drag and inertia coefficients for use in the Morison equation were determined for each separate component and configuration of the structure. These force coefficients were plotted against various wave properties to analyze correlations with wave conditions. Finally, the force coefficients for the structure were used with the Morison equation and current data from the experiments to successfully model forcing on the structure during irregular wave tests.

Lors du tsunami de Tohoku en 2011, des relevés de terrain sur les côtes japonaises ont montré la fragilité des structures côtières, où le plus grand brise-lames du monde (brise-lames de Kamaishi) a été fortement endommagé dû à cet événement. Dans ce doctorat, l'objectif est d'étudier l'interaction entre les brise-lames , les structures côtières les plus communes protégeant les zones urbaines et les entrées des ports, et les vagues, en particulier les tsunamis.Dans la première partie de ce travail, la transformation du tsunami en bore ondulaire dans les zones côtières est étudiée numériquement avec le code de calcul BOSZ (modèle Boussinesq). Les résultats montrent que la deuxième vague générée par le tsunami de Tohoku s'est transformée en un bore ondulaire. En revanche, la première vague n'était pas assez cambrée pour permettre une telle transformation. Les forces et les moments dus aux vagues ainsi que la contrainte normale appliquée par la base arrière du caisson sur le sol de fondation sont calculés à l'aide de deux modèles numériques différents: BOSZ et THETIS (modèle Navier-Stokes). Les résultats de BOSZ sont comparés avec THETIS pour l'interaction tsunami-structure. L'étude d'impact est réalisée à relativement grande échelle dans le but d'obtenir une première estimation des efforts d'un tsunamiPar la suite, une expérience numérique utilisant le modèle THETIS a été réalisée pour étudier les impacts du type flip-through sur des brise-lames. Ces impacts de vagues sans air emprisonné sont considérés comme le type d'impact le plus extrême dans la littérature (e.g. Cooker & Peregrine (1992), Hofland et al. (2011)). L'influence de l'inclinaison de l'interface sur la dynamique d'impact et les pressions générées sont analysées dans une configuration de brise-lames réelle. Le modèle d'onde solitaire est utilisé pour générer trois impacts caractéristiques du type flip-through: peu cambré, moyen et très cambré. Le champ de vitesses et la pression à l'intérieur de la fondation sont également étudiés dans cette partie. Les forces horizontales et verticales appliquées sur le caisson sont estimées en intégrant les distributions de pression données par THETIS.La dernière partie de ces travaux montre la stabilité des caissons de brise-lames soumis à des impacts du type flip-through, qui sont ici assimilés à un jet triangulaire (e.g. Cumberbatch (1960), Kihara et al. (2015)). Cette approche simple permet de formuler un modèle semi-analytique pour prédire le mouvement des caissons dû à ce type d'impacts. Après validation avec des simulations numériques, la méthode du jet triangulaire permet d'obtenir des informations sur les forces, la durée du mouvement et le déplacement total en fonction des caractéristiques de la vague et des dimensions du caisson du brise-lames impacté. / During the Tohoku tsunami in 2011, field surveys of the east coast of Japan showed the weakness of coastal defences, as even the world largest tsunami breakwater (Kamaishi) almost completely collapsed due to this event. In this PhD, the aim is to investigate the interaction between breakwaters, the most common offshore coastal structures protecting urban areas and harbour entries, and waves and especially tsunami waves.In the first part of the work, the generation of undular bores in the near-shore area of Sendai during the Tohoku event is numerically investigated with the numerical model BOSZ (Boussinesq-type model). It is shown that the second wave, which stroke the coast during this event, transformed into an undular bore, whereas the first wave did not due to steepness differences. Tsunami loads, moments and bearing stress applied on the offshore breakwater of the Soma Port are calculated using two models: BOSZ and THETIS (Navier-Stokes VOF model). BOSZ results are compared to THETIS for the tsunami wave-breakwater interaction. The impact study is carried out at a relatively large scale aiming to have a first estimation of tsunami efforts. Then, a numerical experiment using THETIS is carried out to investigate flip-through impacts on vertical breakwaters. This non-aerated wave impact is considered as the most severe type of impact in the literature (e.g. Cooker & Peregrine (1992), Hofland et al. (2011)) in terms of maximum pressure generated. The influence of the front interface on the impact dynamics and the pressure induced is analysed in a realistic breakwater configuration. Solitary waves are used to obtain three characteristic flip-through impacts involving least steep, medium steep and steepest wave front. The flow field and pressure inside the porous rubble mound are then investigated as well as horizontal and uplift forces applied on the breakwater caisson. The last part of this study is devoted to the stability of breakwater caissons submitted to flip-through impacts. The latter are here assimilated to water wedges (e.g. Cumberbatch (1960), Kihara et al. (2015)). This simple approach allows to formulate a semi-analytical model to predict caisson motion due to this type of impacts. After validation with numerical results, the water wedge method gives rich informations about forces, motion duration and sliding distance depending on the wave impact characteristics and breakwater caisson dimensions.