Publications

Na sequência dos estragos causados pelo furacão Lorenzo no molhe principal do porto de Ponta Delgada, foi elaborado um projeto de reparação do mesmo, tendo havido necessidade derealização de ensaios em modelo físico tridimensional com o objetivo de avaliar a estabilidade da solução projetada.

Em 2 de outubro de 2019, o furacão Lorenzo atingiu as ilhas do Arquipélago dos Açores, provocando estragos nas infraestruturas portuárias, nomeadamente no molhe principal do porto de Ponta Delgada. No sentido de minorar este problema, foi elaborado um projeto de reparação do molhe (CONSULMAR, 2020), tendo nesse âmbito sido necessária a realização dos ensaios em modelo físico tridimensional com o objetivo de avaliar a estabilidade da solução projetada.Os ensaios foram realizados num tanque de ondas irregulares do LNEC à escala geométrica1:65 e contemplaram 6 séries de ensaios associados a 3 rumos de agitação marítima (WSW, S, SSW) e a dois níveis de maré (baixa-mar e preia-mar) associados a períodos de pico (Tp) entre 12 s e 20 s e alturas de onda significativa (Hs) variando entre 8 m e 15 m, Lemos et al. 2020.

A avaliação da estabilidade do manto resistente de quebra-mares de taludes requer, na maioria dos casos, a realização de ensaios em modelo físico. Entre os diferentes métodos de avaliação da evolução da estabilidade, destaca-se a medição do volume erodido do manto resistente por ação da agitação marítima. Este volume pode ser determinado a partir de levantamentos consecutivos da envolvente dos taludes. Melby[1] apresentou uma fórmula para previsão da evolução do dano em quebra-mares de taludes com base nas características da agitação neles incidente. No presente estudo pretendeu-se utilizar um programa de ensaiosem modelo físico bidimensional semelhante ao programa que conduziu à referida fórmula aplicado a um caso de estudo correspondente a uma secção do quebra-mar do porto de Peniche.Os ensaios realizados fazem parte do projeto BSafe4Sea que visa desenvolver, testar e comprovar o conceito de previsão do comportamento estrutural de quebra-mares de talude, que constitui a base de um sistema inovador de apoio à decisão. Os ensaios tiverem como objetivo analisar a resposta da estrutura a diferentes estados de agitação incidentes, cujos resultados são fundamentais para o desenvolvimento d e formulações empíricas de previsão da evolução do dano.

This paper studies the effects of an air bubble curtain on surface water waves. Water particle velocities and free surface elevations were measured simultaneously at two cross-shore sections downstream the air bubble curtain. Measurements were carried out for regular waves regarding different air bubble curtain configurations. Free surface elevations were measured using resistive gauges and the instantaneous velocities were acquired using an Acoustic Doppler Velocimeter (ADV). The characteristics of the free surface elevation, velocity field and turbulence are analyzed and discussed. The free surface elevation was found to be constantly attenuated by the air bubble curtain. The phase-averaged velocity profiles also depict the effect of the air bubbles in the flow field by generating milder longitudinal velocities (u) and by increasing the transverse component of the velocity (w). The increase in the turbulence intensity and the different energy spectrum produced by the air bubble curtain is also analyzed. The experimental results indicate that the thickness of the air bubble curtain and the total air flow rate affects the wave field.

An experimental study was carried out to investigate seabed-pipeline interactions with regard to soil liquefaction. For a soil with a high proportion (30 to 60%) of fine sediment, four groups of tests were configured to reproduce soil liquefaction around pipelines for different initial pipe depths, pipe densities and wave conditions (wave height and period). The study focused on verifying the theoretically computed areas of soil failure by analyzing the sinking depths of the pipelines. The main findings are that a pipe with a submerged specific weight of less than half that of the soil will move up to the mudline; that the loss of soil loading capacity is more frequently evidenced in a fluid-like behavior of the soil than by an abrupt breaking of the soil matrix; and that the pipes which are totally buried will sink more than half-buried pipes. Moreover, wave action and the specific weight of the pipes seem to play more important roles in the expected behavior of the wave

In coastal areas, overtopping events and coastal floods, resulting from the occurrence of maritime storms, can cause severe damage to infrastructure, building and equipment, can be responsible for coastal morphology changes (coastal erosion), as well as put in damage human lives, animals or the ecosystem.

SAFEPORT safety system aims to daily reports to Sines harbour administration, potencial emergency situations regarding ships operation in port areas caused by extreme weather-oceanographic conditions, that may occur in the next three. It consists of a set of numerical models and a qualitative risk assessment and forecasting. It uses forecasts provided offshore of the area under study of sea agitation, wind and tide. The characterization of the response of the free and moored ships at a berth is performed using the numerical modelswhich deals with formulations in the frequency and time domain. The system issue alerts, through danger levels associated with risk levels of exceedance of recommended values for movements and forces imposed on ship mooring systems. SAFEPORT can be adapted to any port. So far, it has been developed and adapted to three terminals of the port of Sines, where three different ships were simulated. This paper presents the developments made to date of the safety system, in terms of its implementation and validation. The numerical models run every day, in real-time mode, in a computer cluster and the system provide forecast results for the next 72 hours. The results are disseminated on a web page and a mobile application in a variety of formats.

Early warning systems are an important tool for local authorities to detect emergency situations in advance and initiate the necessary safety measure. The To-SEAlert project has the aim of increasing the efficiency, robustness and reliability of the HIDRALERTA coastal hazards early warning system. This study shows a first intent to implement the SWASH numerical model to simulate wave overtopping for the Ericeira prototype. SWASH was implemented for one breakwater profile where overtopping discharge and associated risk levelsare estimated. It was compared to the current approach used in HIDRALERTA, the neuronal network NN_OVERTOPPING2. Finally, both approaches were compared with previously analysed video images of the site. The results showed that SWASH generally overestimates overtopping and is not in good agreement with the NN_OVERTOPPING2 or the video images. A possible reason might be the wave direction, which cannot be included in one-dimensional simulations in SWASH.

No âmbito do

Extending for more 900 km with diverse geomorphologies and land-use occupation, the Portuguese coastal zone is highly vulnerable to overtopping and flooding.

An aerial monitoring system was developed for the maritime structures protecting the foundation columns of the airport infrastructure of the Madeira Island Airport, in the scope of research project MEGE, to complement the already existing monitoring program of visual observations. For the aerial monitoring of the berm breakwater, with about 770 m in length, a fast data acquisition system was envisaged. Imaging techniques acquired through a high-resolution camera coupled to an unmanned aerial vehicle (UAV) were used, which allowed for a very fast and efficient automated procedure, compatible with the difficult accessibility to the structure on the seaside. Point clouds corresponding to the breakwater geometry were obtained from the set of aerial images from the camera on board of the UAV, using photogrammetric techniques. In this paper, the two complementary parts of the monitoring of this structure are described and corresponding results are shown.

This paper aims to evaluate the impact of ships on fenders during the berthing process. Physical tests and numerical simulations with MOORNAV tool were performed with versions of the GulfStream ship in still water and under a set of different conditions. A comparative analysis was made between outputs of the two models considering specific conditions. The MOORNAV application resulted in a standard deviation from the physical model of 3% to 6% in relation to the maximum force exerted on each fender.

This paper aims to evaluate the impact of ships on fenders during the berthing process. Physical tests and numerical simulations with MOORNAV tool were performed with versions of the GulfStream ship in still water and under a set of different conditions. A comparative analysis was made between outputs of the two models considering specific conditions. The MOORNAV application resulted in a standard deviation from the physical model of 3% to 6% in relation to the maximum force exerted on each fender.

Neste trabalho, descreve-se a aplicação do programa OSOM+ às obras marítimas do Porto de Sines, em especial ao quebra-mar oeste. Assim, serão apresentados resultados de comparação entre as situações observadas em 2018 e 2020 no âmbito de inspeções visuais e com drone, mediante apreciação e análise de fotografias georreferenciadas, ortomosaicos, nuvens de pontos, modelos numéricos de superfície e perfis selecionados. É também ilustrada a forma como a aplicação e base de dados ANOSOM-WEB pode ser empregue quer durante as campanhas de observação, quer em gabinete. Conclui-se este trabalho com a apresentação das vantagens da recente atualização da metodologia e do que se julga ser a sua importância na tomada de decisões sobre a necessidade ou não de realizar obras de manutenção e/ou reparação nestas estruturas, ou similares.

Os mapas de risco costeiro, integrados em modelos de risco, são excelentes ferramentas de apoio à tomada de decisão no âmbito da gestão e proteção costeira em situações normais e de emergência [1], ajudando aproteger as populações e infraestruturas em risco de inundação costeira e galgamento oceânico proteger as populações e infraestruturas em risco de inundação costeira e galgamento oceânico.

SAFEPORT safety system aims at forecasting and alerting, on a regular basis, emergency situations regarding ships operation in port areas caused by extreme weather-oceanographic conditions. It uses forecasts provided offshore of the area under study of sea agitation, wind and tide. The characterization of the response of the free and moored ships at a berth is performed using the numerical package SWAMS. The system issue alerts, through danger levels associated with risk levels of exceedance of recommended values for movements and forces imposed on ship mooring systems. SAFEPORT can be adapted to any port. So far, it has been developed and adapted to three terminals of the port of Sines, where three different ships were simulated. This paper presents the developments made to date of the safety system, which includes tests performed in storm situations. The numerical models run every day, in real-time mode, in a computer cluster and the system provide forecast results for the next 72 hours. The results are disseminated on a web page and a mobile application in a variety of formats. It was concluded that the SAFEPORT safety system issued alerts according to the observed reality during the storm Dora. It has also been shown to be a computer tool for the optimization of ship mooring systems. The system is currently in testing and validation phase therefore, forecasts should be interpreted as indicative.

A autoridade portuária do arquipélago dos Açores, Portos dos Açores, SA, identificou a necessidade de dispor de um sistema de alerta precoce para os riscos associados à agitação marítima, nomeadamente os relacionados com os galgamentos costeiros e com os navios amarrados. No âmbito do Projeto ECOMARPORT, associaram-se com a Universidade dos Açores e o LNEC para o desenvolvimento de três novos protótipos do sistema HIDRALERTApara os portos de S. Roque do Pico, Madalena do Pico e Praia da Vitória. Os novos protótipos têm, para além da previsão de eventos de galgamento das proteções portuárias, a capacidade de prever esforços e movimentos de navios amarrados. As situações de emergência podem ser previstas, permitindo que as autoridades portuárias possam tomar medidas de mitigação para evitar a perda de vidas e minimizar os danos.

Early warning systems (EWS) are fundamental tool to reduce risks in coastal areas since they provide in advance the necessary information for the responsible authorities to mitigate the effects of possible emergency situation due to storms.

The case studies are Costa da Caparica coastal area and Ericeira port, both on the West Portuguese Coast.

The To-SEAlert project (Fortes et al. 2019) aims to include a set of tools/methodologies into the Early Warning Systems (EWS) HIDRALERTA, (Poseiro, 2019, Fortes et al., 2021, Santos et al., 2020, Zózimo et al., 2021, Ferreira, et al. 2021a) to make it more efficient reliable and robust.

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