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This work studies crownwalls with a fully curved face versus a vertical wall in non-breaking wave conditions. Its aim is to provide appropriate tools that can be used to compare the performance of the two structures in terms of loading and overtopping. To this end, small scaled experiments of the two structures are carried in a flume with a flat bottom. These are performed in intermediate water depths and consist of different combinations of wave height and wave steepness. A box is positioned behind the superstructures to collect overtopping volumes. Pressure signals are retrieved from pressure sensors positioned on the surface of the crownwall and the vertical wall, while water elevation signals are retrieved from wave gauges in the flume and in the overtopping box. Several analyses are performed in order to retrieve results of individual waves regarding the wave characteristics, reflection coefficient, overtopping volume, maximum pressure, impulse, impulse duration, maximum force, force angle and point of application of the force. The effectiveness of the crownwall in reducing overtopping volumes is found to decrease for more severe wave attacks with larger wave height and wave length. The lowest loading cases result in a quasi-static pressure signal which has approximately the same maximum value for both structures. More severe wave attacks generate impacts at the seaward top outer edge of the crownwall, which result in an increase of maximum pressure up to 1100%. For these cases, impulses are calculated and the results are found to be less uncertain compared to maximum pressure, while their duration shortens for higher and longer waves. The variables describing force are retrieved by integrating the pressure signals on the surface of the superstructures and the results of maximum force are found to follow a similar trend to these of maximum pressure. Corresponding equations from curve fitting are derived for each of the mentioned variables regarding the crownwal, Civil Engineering | Structural Engineering | Concrete Structures

Several failures of recurved concrete crownwalls have been observed in recent years. This work aims to get a better insight within the processes underlying the loading phase of these structures due to non-breaking wave impulsive loading conditions and to identify the dominant failure modes. The investigation is carried out through an offline one-way coupling of computational fluid dynamics (CFD) generated wave pressure time series and a time-varying structural Finite Element Analysis. The recent failure of the Civitavecchia (Italy) recurved parapet is adopted as an explanatory case study. Modal analysis aimed to identify the main modal parameters such as natural frequencies, modal masses and modal shapes is firstly performed to comprehensively describe the dynamic response of the investigated structure. Following, the CFD generated pressure field time-series is applied to linear and non-linear finite element model, the developed maximum stresses and the development of cracks are properly captured in both models. Three non-linear analyses are performed in order to investigate the performance of the crownwall concrete class. Starting with higher quality concrete class, it is decreased until the formation of cracks is reached under the action of the same regular wave condition. It is indeed shown that the concrete quality plays a dominant role for the survivability of the structure, even allowing the design of a recurved concrete parapet without reinforcing steel bars., Coastal Engineering

Several failures of recurved concrete crownwalls have been observed in recent years. This work aims to get a better insight within the processes underlying the loading phase of these structures due to non-breaking wave impulsive loading conditions and to identify the dominant failure modes. The investigation is carried out through an offline one-way coupling of computational fluid dynamics (CFD) generated wave pressure time series and a time-varying structural Finite Element Analysis. The recent failure of the Civitavecchia (Italy) recurved parapet is adopted as an explanatory case study. Modal analysis aimed to identify the main modal parameters such as natural frequencies, modal masses and modal shapes is firstly performed to comprehensively describe the dynamic response of the investigated structure. Following, the CFD generated pressure field time-series is applied to linear and non-linear finite element model, the developed maximum stresses and the development of cracks are properly captured in both models. Three non-linear analyses are performed in order to investigate the performance of the crownwall concrete class. Starting with higher quality concrete class, it is decreased until the formation of cracks is reached under the action of the same regular wave condition. It is indeed shown that the concrete quality plays a dominant role for the survivability of the structure, even allowing the design of a recurved concrete parapet without reinforcing steel bars., Coastal Engineering

This work studies crownwalls with a fully curved face versus a vertical wall in non-breaking wave conditions. Its aim is to provide appropriate tools that can be used to compare the performance of the two structures in terms of loading and overtopping. To this end, small scaled experiments of the two structures are carried in a flume with a flat bottom. These are performed in intermediate water depths and consist of different combinations of wave height and wave steepness. A box is positioned behind the superstructures to collect overtopping volumes. Pressure signals are retrieved from pressure sensors positioned on the surface of the crownwall and the vertical wall, while water elevation signals are retrieved from wave gauges in the flume and in the overtopping box. Several analyses are performed in order to retrieve results of individual waves regarding the wave characteristics, reflection coefficient, overtopping volume, maximum pressure, impulse, impulse duration, maximum force, force angle and point of application of the force. The effectiveness of the crownwall in reducing overtopping volumes is found to decrease for more severe wave attacks with larger wave height and wave length. The lowest loading cases result in a quasi-static pressure signal which has approximately the same maximum value for both structures. More severe wave attacks generate impacts at the seaward top outer edge of the crownwall, which result in an increase of maximum pressure up to 1100%. For these cases, impulses are calculated and the results are found to be less uncertain compared to maximum pressure, while their duration shortens for higher and longer waves. The variables describing force are retrieved by integrating the pressure signals on the surface of the superstructures and the results of maximum force are found to follow a similar trend to these of maximum pressure. Corresponding equations from curve fitting are derived for each of the mentioned variables regarding the crownwal, Civil Engineering | Structural Engineering | Concrete Structures