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A set of scale-model tests carried out to enlarge the range of wave steepness values analysed in run-up, overtopping and armour layer stability studies, focusing on oblique extreme wave conditions and on their effects on a gentler slope breakwater’s trunk armour and roundhead, is presented in this paper. A stretch of a rubble mound breakwater (head and part of the adjoining trunk, with a slope of 1(V):2(H)) was built in a wave basin at the Leibniz University Hannover to assess, under extreme wave conditions (wave steepness of 0.055) with different incident wave angles (from 40º to 90º), the structure behaviour in what concerns wave run-up, wave overtopping and damage progression of the armour layer. Two types of armour elements (rock and Antifer cubes) were tested. Non-intrusive methodologies including a new application of laser scanning technique for the assessment of both armour layer damage and wave run-up and overtopping were used. It is expected that such work will contribute also with data to improve empirical formulas as well as to validate complex numerical model for wave-structure interaction.

Metodologia de avaliação do risco associado ao galgamento de estruturas marítimas. Aplicação ao porto e à baía da Praia da Vitória, Açores, Portugal * Risk assessment methodology for the overtopping of maritime structures. application to the port and bay of Praia da Vitória, Azores, Portugal Palavras-chave: Avaliação de risco, GUIOMAR, Propagação de ondas, Modelos neuronais. ABSTRACTThe present work describes the methodology developed to assess the overtopping risk of port and coastal structures that was implemented on GUIOMAR, an integrated decision support system for port and coastal management, developed by the National Laboratory for Civil Engineering (LNEC), Portugal, whose focus is to prevent and support the management of emergency situations and the long-term planning of interventions in the study area.The incident wave climate and the corresponding mean overtopping discharges per unit length of the crest of the studied structure are the basis of the above referred methodology.The sea state determination is performed by coupling numerical wave propagation models using input wave data from wave-buoys or regional forecast wave models. The overtopping calculation is carried out with the NN_OVERTOPPING2 tool, which is based on neural network modelling. This tool was developed as part of the European project CLASH to predict Froude-scaled mean wave overtopping discharges, q, and the associated confidence intervals for a wide range of coastal structure types (such as dikes, rubble mound breakwaters, and caisson structures). In addition, prototype mean overtopping estimations, allowing for scale and model effects, are provided.The presented overtopping risk assessment methodology is based on four major steps: (i) the determination of wave overtopping over the studied structure considering the incident sea waves in the period between 2009 and 2010; (ii) the determination of the probability of overtopping exceeding pre-determined thresholds and corresponding probability levels; (iii) the establishment of the levels of consequences associated to the occurrence of overtopping that exceeds those thresholds; (iv) the combination of the above steps to assess overtopping risk levels.Once obtained the risk level, it is possible to plot it on a map, as well as the acceptability level of that risk in each studied zone or structure. This information is crucial for the management of long-term interventions on port and coastal areas.The methodology was tested for three different structure cross-sections of the port and bay of Praia da Vitória, at Terceira Island, Azores: the crosssection of the south breakwater that directly protects the dock 12 of the port, the cross-section of the seawall directly in front of the entrance of the bay of Praia da Vitória and the cross-section of the root of an existing groyne in the same area. In all studied sections, the risk of overtopping caused by the incident sea waves was characterized for the two-year period between 2009 and 2010.The presented methodology proved to be simple and effecti...