Comunicações
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MONITORIZAÇÃO ESTRUTURAL DA PONTE DO FREIXO
A presente comunicação descreve os resultados obtidos com o sistema de monitorização da integridade estrutural instalado na Ponte do Freixo, sobre o rio Douro. Trata-se de uma estrutura de betão armado pré-esforçado, composta por dois tabuleiros geminados. Estes tabuleiros têm uma extensão total de 705 m e são constituídos por uma viga em caixão unicelular de 8 tramos, de secção variável em altura.Os dados obtidos a partir dos sensores instalados possibilitaram efetuar uma avaliação da integridade estrutural ao longo do tempo, tirando-se partido da semelhança existente entre os dois tabuleiros da ponte para comparação de resultados. A monitorização desta obra compreende a identificação das características dinâmicas da estrutura.
Ano: 2022
Número Páginas:
12.
Autor(es): Freire, L.; Xu, Min; Silveira, A. P. C. da; Coelho, T.
Editor: JPEE
Keywords: Pontes, Monitorização Estrutural, Comportamento Dinâmico
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Next-generation of Monitoring Systems towards Infrastructure Resilience
Resilience has become an increasingly important concept in our society. More precisely, it is a concept that applies to many aspects related to human life quality, from ecology and environment to societal and organizational structures as well as from infrastructure and built environment to economy. In this context, this work aims to introduce a concept on Structural Health Monitoring to enhance the resilience of infrastructure. Firstly, how monitoring may offer useful information to the pre-event measures (pro-active monitoring) and the post-event measures (reactive monitoring) is introduced. Then, the Performance Indicators (PI) that may significantly benefit from monitoring data, i.e. better quantification, will be identified, including policy indicators, technical-specific indicators, and economic and social indicators. Finally, and towards the desired better quantification, both current monitoring techniques and future trends, by benefiting from Industry 4.0, will be addressed.
Ano: 2022
Número Páginas:
8p.
Autor(es): Sousa, H. M.; Oliveira Santos, L.; Makhoul, N.
Editor: ICONHIC
Keywords: Industry 4.0; Infrastructure; Monitoring; Resilience
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Novel trends on the assessment and management of maritime infrastructures: outcomes from GIIP project
Climatic conditions, load, fatigue, aging and other factors causes a de-terioration in civil infrastructures. As a consequence, repair and maintenance work actions are needed, being the former considered as more expensive than the latter ones. Indeed, an accurate method for measuring corrosion is a fundamental prerequisite for the detection of damaged areas and for planning an effective re-pairing of concrete maritime structures. In this article a comparation between two surrogate models, Markov Chains and Neuronal Networks, is presented and ap-plied to predict the results of corrosion sensors of an infrastructure data set. The proposed methodology benefits from current monitoring practice and have the objective to develop a modular decision support system for the integrated asset management, taking into account operational, economic and environmental cri-teria. The results could contribute to the possibility of adapting these degradation models to aggressive environments and repaired structures, thus generating ac-curate maintenance strategies, and reducing costs. This methodology is part of the ongoing study
Ano: 2022
Número Páginas:
8p.
Autor(es): Bastidas-Arteaga, E.; Moscoso, Y.; Oliveira Santos, L.; Marcelino, J.; Pereira, E. V.; Matos, J.; Rincon, L.
Editor: WCSCM
Keywords: Maritime infrastructures; Corrosion; Monitoring practice; Markov chains; Neuronal networks; Maintenance actions
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Numerical and Physical Modeling of Ship Impacts on Fenders
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.
Ano: 2022
Autor(es): Santos, J. A.; Fortes, C. J. E. M.; Costa , C.; Simão, J.; Pinheiro, L.; Gomes, A.
Editor: E. Rizzuto and V. Ruggiero
Keywords: MOORNAV; Physical Modelling; Numerical Modelling; GulfStream Ship; Fenders
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Numerical simulation of concrete swelling using mesoscale detailed 2D particle models taking into account aging viscoelasticity and damage
Concrete swelling due to internal expansion reactions (IER) concerns both physical and chemical phenomena which can have strong interactions as the swelling process evolves. Modelling the effects of swelling on the mechanical behaviour of concrete is of the most importance in order to predict the development of the deterioration, to assess structural safety and to determine the efficiency of rehabilitation techniques to reduce the negative impact of swelling. Mesoscale models are being used for the study of the behaviour of concrete focusing on the interactions between aggregates and the maturing cement paste in order to evaluate development of the main mechanical properties. These types of models are particularly relevant for the study of swelling since the aggregate structure of concrete and the interfacial transition zone (ITZ) are explicitly taken into account. This paper refers to the numerical simulation of concrete swelling using detailed 2D particle models in which the particles representing the coarse aggregates and the binding mortar define the concrete mesostructure. In the particle model, swelling is represented by a change in the normal contact force due to a change in the inter-particle relative displacement caused by the progressive particle area growth. Since the swelling reactions occur relatively slow over a large period of time, creep and relaxation properties of concrete are taken into account. The paper evaluates the effect of aging viscoelasticity on the development of stress inside the concrete and for predicting the progress of damage over time.
Ano: 2022
Número Páginas:
493-510pp..
Autor(es): Serra, C.; Azevedo, N.; Batista, A. L.
Editor: LNEC
Keywords: Damage; Creep; Swelling; Particle models; Mesoscale modelling
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O Impulso na construção em madeira - Novos produtos e desempenho adequado
A inovação registada na última década, no campo dos produtos de madeira para a construção,tem vindo a alterar a visão das potencialidades da madeira como elemento estrutural, sustentando um renascimento do seu uso como material estrutural. O CLT tem vindo a permitir o ressurgimento de forma expressiva da construção em madeira em altura (edifícios com mais de 6 pisos), contribuindo para a necessidade de descarbonizar o setor da construção.A presente comunicação apresenta alguns dos produtos que têm vindo a surgir no mercado, alertando-se para aspetos básicos que devem orientar a escolha destes materiais, a sua receção em obra, cuidados em obra e princípios básicos na sua aplicação tendo em vista assegurar a sua durabilidade (tempo em serviço) e, desta forma, permitir que constituam um fator verdadeiro de sustentabilidade na construção.
Ano: 2022
Número Páginas:
895-902.
Autor(es): Feio, A.; Saporiti Machado, J.
Editor: LNEC
Keywords: Desempenho; Construção; Especificação; CLT; Madeira
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O papel da monitorização na durabilidade de construções com madeira
A possibilidade de se vencer antigas limitações inerentes ao uso da madeira maciça com o desenvolvimento de novos produtos derivados de madeira, como é exemplo a Madeira Lamelada Cruzada Colada (MLCC), aliada à maior sensibilidade atual às questões ecológicas, tornam a madeira um material com potencialidades renovadas. Por outro lado, trata-se de um material natural sujeito a degradação biológica cuja durabilidade em diferentes climas e situações de aplicação é ainda questionável. Os agentes biológicos são capazes de causar danos à madeira que podem ser simplesmente estéticos, mas que em níveis mais elevados podem levar à redução considerável das suas propriedades mecânicas. Neste contexto, este estudo expõe as condições propícias à instalação e desenvolvimento dos principais agentes de degradação da madeira e discute a importância da existência de um plano de monitorização de estruturas de produtos derivados de madeira para uma promoção de uma maior vida útil destas construções.
Ano: 2022
Número Páginas:
12p.
Autor(es): Lina Nunes; Branco , J.; Lima, D.
Editor: LNEC
Keywords: Vida útil; Degradação biológica; Durabilidade; Madeira lamelada cruzada colada; Monitorização
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OSOM+: Aplicação às estruturas marítimo-portuárias do porto de Sines
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.
Ano: 2022
Número Páginas:
12p.
Autor(es): Capitão, R.; Fortes, C. J. E. M.; Lemos, R.; Silva, L. G.; Neves, M. G.; Henriques, M. J.; Martins, T.
Editor: PIANC
Keywords: Levantamento aéreo; Inspeção visual; Obras marítimas
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Phenol formaldehyde modification of radiata pine and termite resistance under laboratory testing
The development of phenol formaldehyde (PF) resins as a means of impregnating solid wood is one that has been explored for several decades, both in terms of conventional impregnation processing (Impreg) or compressional impregnation (Compreg). However, it is only recently with advances in processing conditions that the method truly affords a means of achieving conventional modification for solid timber. This paper has investigated the modification of radiata pine (Pinus radiata) using PF resin at 22.5% and 30% solids content, with subsequent curing at 150oC under pressure. Samples were tested against Reticulitermes grassei according to EN117 over a period of 8 weeks using no-choice and choice tests. Controls included unmodified blocks and those modified without resin but just water, whilst treated blocks included those subjected to water soaking as well as without. No choice testing realised significantly reduced attack ratings, particularly for higher solid content treatments even following water soaking and 100% termite mortality. Modification with water did not influence level of attack and mortality which indicates it is the resin and not the process that imparts resistance to termite attack. Two-choice termite testing showed low attack for both impregnation treatment levels, with results slightly better for the higher solid contents treatment, whilst triple choice testing further confirmed this. In choice tests, slight attack of resin treated blocks took place, though significant attack of control blocks occurred, even when 100% mortality occurred by the end of the test. This seemed to suggest that ingestion of PF treated wood led to poisoning. Results confirm the potential of PF-treatment of solid wood as a method for minimising risks from subterranean termite attack.
Ano: 2022
Número Páginas:
11p.
Autor(es): Lina Nunes; Pitman, A.; Duarte, M.; Stefanowski, B.; Jones, D.
Editor: THE INTERNATIONAL RESEARCH GROUP ON WOOD PROTECTION
Keywords: Subterranean termites; Wood; Impregnation; Phenol-formaldehyde
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Planning UAV surveys: can we rely on wind forecasts?
Like in other surveying works, UAV flights require prior work that involves flight planning and equipment preparation and, often, many complementary tasks. These may involve bringing together technicians from different domains, booking a car and possibly accommodation, and some time-consuming complementary bureaucratic work. Teams operating UAVs know how much the flights are affected by weather conditions. The wind is the weather variable that, in proportion (number of occurrences per year), causes the major number of changes to a scheduled work. Obtaining reliable information about the intensity of the wind, a few days in advance, is an asset for those who have to carry out the various tasks mentioned previously. There are several websites from which one can access weather forecasts. Is any website better because it presents more reliable data? The data and the analysis presented in the paper will give some clues. The data includes wind speed, registered daily, at 12:00 (pm) for a year, by a meteorological station with online data, which belongs to a meteorological institute. Also on a daily basis, several websites with meteorological data were consulted, and wind speed forecasts for the same hour for up to four days in advance were collected. An analysis of the data can provide information about whether there is a website that stands out for the quality of the forecasts, and if there is a need to consult several websites to have better information.
Ano: 2022
Autor(es): Henriques, M. J.; Roque, D.
Editor: Universitat Politècnica de València
Keywords: monitoring; UAV
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