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An estimation of the armour layer damage based on the eroded volume using a time of flight method
The assessment of damage evolution in scale model tests of rubble-mound breakwaters can be achieved by comparing eroded depths and volumes between consecutive surveys. Aiming to evaluate damage evolution on rubble-mound breakwater, scale model tests were recently conducted on the maritime hydraulic facilities of the National Laboratory for Civil Engineering. This paper focuses on the use of novel, non-intrusive survey methodologies such as the Time of Flight (ToF) principle technique. Damage evaluation is based on the comparison of point clouds obtained before and after each test series, enabling the extraction of profiles, the calculation of eroded depths and eroded volumes and the estimation of displaced units.
Ano: 2021
Número Páginas:
2p.
Autor(es): Lemos, R.; Fortes, C. J. E. M.; Silva, L. G.; Pinheiro, L.
Editor: CNME2020
Keywords: Measuring techniques; 3D Surveying; Breakwater; Stability
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Análise de barragens abóbada sob ações sísmicas de grande intensidade. Movimentos de juntas e roturas no betão.
N/A
Ano: 2021
Número Páginas:
10p.
Autor(es): Alegre, A.; Oliveira, S.; Proença, J.; Mendes, P.
Editor: RBE2020, LNEC
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Análise de eventos de risco através de modelação numérica XBeach. Caso de Estudo - Costa da Caparica
Neste estudo recorre-se à modelação numérica para a simulação de eventos de galgamento, inundação e erosão costeira em zonas costeiras devido a ocorrência de tempestades. Esta metodologia está a ser estudada para o troço costeiro da Costa da Caparica, na área que compreende toda a extensão da estrutura de defesa aderente, para a tempestade Hércules/Christine. Nesta modelação numérica recorreram-se aos modelos numéricos SWAN e XBeach. Estes modelos foram utilizados para simular 96 h de forçamentos oceanográficos sobre a área de estudo, representando assim a tempestade entre os dias 3 e 7 de janeiro de 2014. Os resultados preliminares apontam para um subestima dos run-up consequência da parametrização do modelo e das características da batimetria considerada.
Ano: 2021
Número Páginas:
5p.
Autor(es): Ferreira, A. M.; Fortes, C. J. E. M.; Reis, M. T. L. G. V.; Garzon, J.L.
Editor: APRH
Keywords: Costa da Caparica; Agitação marítima; Run-up; Erosão; Galgamento; Riscos costeiros
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Análise tridimensional do comportamento hudromecânico de fundações de barragens gravidade
Nesta comunicação apresentam-se os resultados da aplicação de dois modelos hidromecânicos descontínuos tridimensionais na análise do comportamento da fundação de uma barragem gravidade. Os modelos considerados simulam o comportamento mecânico de forma idêntica mas o comportamento hidráulico é simulado usando abordagens diferentes: i) num dos modelos o escoamento ao longo das descontinuidades do maciço é simulado através de elementos de interface triangulares; ii) no outro modelo admite-se que o escoamento se dá através de canais localizados nas arestas dos elementos de interface triangulares que simulam as diferentes descontinuidades. O estudo efetuado permite confirmar a viabilidade da aplicação de ambos os modelos para a análise do comportamento hidromecânico de fundações de barragens, tendo em consideração a existência da cortina de impermeabilização e do sistema de drenagem. Comparam-se os caudais e pressões obtidas com os dois modelos e os resultados respetivos são utilizados para efetuar análises de estabilidade, recorrendo ao método de redução das resistências.
Ano: 2021
Número Páginas:
10p.
Autor(es): Sá, M.; Braga Farinha, M. L.; Azevedo, N.; Rocha de Almeida, J.; Leitão, N. S.
Editor: SPG - Sociedade Portuguesa de Geotecnia
Keywords: Análise de estabilidade; Comportamento hidromecânico; Modelação numérica; Barragens de betão
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Analysis of e-scooter usage in Portugal to contribute to sustainable mobility planning
The use of micromobility in cities has been highly associated with environmental, social, and economic benefits. These sustainability impacts can be achieved by the proper city planning before the implementation of micro vehicles, which can include pilot programs, connection to public transport to promote first-and-last mile trips, curb space management, and safety measurements. Although to better understand the real environmental, social, and economic impacts of micromobility usage in cities, some methodologies need to be used in order to measure them. Thus, this research focuses on an extensive literature review to discuss the most used methodologies to measure the sustainability impacts generated in cities by micromobility. As the results show, to measure the environmental impacts, the Life Cycle Assessment methodology can be used, followed by geospatial analysis and surveys to measure the social impacts, and conversion of health, and time-saving benefits to a monetary unit to measure the economic impacts of micro vehicles.
Ano: 2021
Número Páginas:
19p..
Autor(es): Dias, G.; Ribeiro , P; Arsénio, E.
Editor: AET
Keywords: Covid-19 impacts; Urban resilience; First-mile-last-mile; Sustainable urban mobility; Shared e-scooters; Micromobility
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Application of hybrid HSCT-FE models to identify the swelling effect on a multiple arch dam.
N/A
Ano: 2021
Autor(es): Oliveira, S.; Rodrigues, M.; Proença, J.
Editor: ICAAR
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Arch dam static and dynamic modelling with discrete elements
The safety of concrete arch dams depends to a large extent on the soundness of the foundation rock mass. The large arch dams presently under design and construction apply very significant loads to their abutments and foundations. The assessment of the foundation stability requires the analysis of the potential failure mechanisms defined by the major rock mass discontinuities and joint sets. For dams located in areas of intense seismic activity, the analysis needs to take into account the potential effects of earthquakes, not only on the concrete arch, but also in the nearby rock discontinuities. The discrete element method is a major numerical tools for discontinuum modelling, allowing the analysis of block systems defined by multiple joint planes. In the paper, the key issues involved in its application to arch dam foundations are reviewed. In particular, the representation of the discontinuities in models intended for failure analysis is discussed. The evaluation of safety factors under static loading is addressed. The framework for seismic analysis of arch dams is also examined, namely the dynamic boundary conditions. Options to analyse the dynamic dam-water interaction and model calibration issues are discussed, based on practical examples.
Ano: 2021
Autor(es): Lemos, J. V.
Editor: IOP Publishing
Keywords: Barragens de betão
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ARICA:2019 | ARICA:2020
ARICAIs an assessment method developed to determine the fire safety level of an existing building
Ano: 2021
Número Páginas:
33p..
Autor(es): Vicente, M.; Branco Pedro, J.; Cordeiro, E.
Revista: online
Editor: LNEC
Keywords: Buiding; fire safety level; method; ARICA
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Assessing Robustness in Multimodal Transportation Systems: A case study in Lisbon
This research paper aims to contribute to a more sustainable mobility solution by proposing and empirically testing methods to assess the robustness of a network of a multimodal transport system, looking at aspects in the network topology. We hypothesise that the appropriate multilayered and traffic-sensitive modelling of this network can help characterise robustness and further understand the integration of different modalities. We modelled and examined the Lisbon public transports as a multiplex network, allowing us to integrate various modalities and grasp its characteristics and robustness performance. To accomplish this, we evaluate how the network decreases performance by removing nodes and edges. Comparing different failure scenarios, we concluded that we should use slightly different methods for each goal and type of removal (edge vs node). Those who involve recalculating metrics are usually the most effective. However, we identified a specific context where, counter-intuitively, that is not the case. Proposing a novel normalised version of AUC, we were able to compare side by side the robustness of each modality layer, regardless of their size and the whole network. Testing targeting strategies, we also observed that robustness tests needed to remove about half the network nodes to leave all the remaining nodes completely disconnected, and node removals are more effective than eliminating edges in this topology. Lastly, we simulate cascading events such as the breakdown of an entire transportation line. The results of this study allow decision-makers to understand the topological vulnerabilities of a transportation network.
Ano: 2021
Número Páginas:
27p.
Autor(es): Aparício, J.; Arsénio, E.; Henriques, R.
Editor: Association for European Transport
Keywords: Robustness assessment; Topological vulnerabilities; Multiplex networks; Sustainable mobility; City of Lisbon; Public transport; Data science; Multimodal transport; Transport resilience
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Assessing the flow field around an oblong bridge pier. Vectrino acquisition time sensitivity analysis
Local scour has been widely identified as one of the primary threats to bridge pier stability. To better understand how the turbulent flow field modified by bridge piers interacts with the bed surface, it is relevant to assess the flow structures that are potentially sufficient to remove the bed material. Thus, the accuracy and measurement quality in estimating the flow field is of primordial importance, mainly in a well-controlled laboratory environment. In the present study, time-averaged velocities and Reynolds shear stresses were measured by using a high-resolution acoustic velocimeter. Due to the highly turbulent nature of the flow, an assessment of the signal acquisition times influence on the statistics of turbulent quantities is performed, including the inherent uncertainties regarding the flow field measurement technique. The re-sults showed that the required sampling time for mean and fluctuation velocities, and the lateral Reynolds shear stress, differ by one order of magnitude.
Ano: 2021
Número Páginas:
2p.
Autor(es): Bento, A. M.; Pêgo, J. P.; Couto, L. T.; Viseu, T.
Editor: Institute of Geophysics, Polish Academy of Sciences
Keywords: Velocity measurements; Statistical parameters; Downlooking vectrino; Acquisition time
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