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Most of the worldwide historical coastal and harbor structures have been severely damaged by extreme sea storms during their lifetime and hence need to be upgraded, also considering the effects of climate change (Hughes, 2014). Physical modelling is identified as the only feasible approach for the optimization of the upgraded structures, because of the existence of few studies concerning such an issue and the lack of specific design formulae (Burcharth et al. 2014; Croeneveld et al. 1984; Lara et al. 2019; Foti et al. 2020). Therefore, a novel general methodology for the design of upgrading solutions for existing breakwaters based on physical modelling is presented, considering the case study of the Catania Harbor breakwater. The results of the systematic extensive experimental campaign on possible solutions for upgrading the Catania harbor breakwater led to some general practical findings, which can be useful for the design of restoration options for existing breakwater at end of their lifetime.


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