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Avaliação de desempenho de técnicas de reconstituição 3D aplicadas a modelos físicos de quebra-mares
A avaliação da evolução dos danos causados pela agitação incidente em modelos físicos de quebra-mares de taludes pode ser efetuada através da quantificação de movimentos e quedas dos elementos do manto resistente (métodos tradicionais), ou pela determinação de volumes e profundidades erodidas entre levantamentos consecutivos dos respetivos taludes (métodos mais atuais). Para se efetuarem esses levantamentos dos taludes, podem aplicar-se técnicas fotogramétricas com sensores RGB, sensores de profundidade baseados na metodologia ToF (Time of Flight) e sensores de laser LiDAR (Light Detection And Ranging).No presente trabalho, aplicam-se essas técnicas ao modelo físico do quebra-mar do porto da Ericeira, que está presentemente a ser ensaiado no LNEC, e avalia-se, comparativamente, o respetivo desempenho, adequabilidade e usabilidade na determinação da evolução dos danos, identificando vantagens e desvantagens de cada uma destas técnicas.
Ano: 2023
Número Páginas:
4p..
Autor(es): Jónatas, R.; Fortes, C. J. E. M.; Lemos, R.; Capitão, R.
Editor: PIANC
Keywords: Quantificação de danos; Reconstituição 3D; Levantamentos; Modelação física
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Avaliação do impacto e identificação das causas dos problemas de incrustação em sistemas públicos de distribuição de água: Uma proposta de metodologia.
A dureza elevada da agua pode conduzir a precipitação de carbonato de cálcio nos sistemas de distribuição e subsequente adesão dos precipitados as superfícies das condutas, reservatórios, grupos eletrobomba e elementos acessórios (AWWA, 1999).
Ano: 2023
Número Páginas:
3p..
Autor(es): Rosa, M. J.; Marques, F.; Santos, J.; Martins, T.; Oliveira, M. M.; Mesquita, E.; Vieira, P.; Loureiro, D.
Revista: Viver com a água - Livro de resumos
Editor: APRH
Keywords: Sistema de abastecimento de água; Perda de carga; Qualidade do serviço; Incrustações; Dureza da água
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Biological Colonization on External Thermal Insulation Composite Systems (ETICS): Water Performance, Aesthetic Appearance and Onsite Monitoring
The European Union has been progressively introducing sustainable environmental policies which aim to improve the energy performance of new and existing buildings towards a climate-neutral building stock by 2050. As a result, the use of External Thermal Insulation Composite Systems (ETICS) has been increasing in both new and thermal retrofitted façades to enhance the level of thermal insulation of the building envelope (i.e., lowering reference U-values). However, the enhanced thermal performance of these systems can have impact on their long-term durability, thus potentiating further anomalies. For example, greater values of thermal resistance may lead to a decrease of surface temperature during the night, thus increasing the risk of surface condensation and favoring biological colonization. This paper aims to investigate the influence of the hygrothermal behavior of three ETICS with different rendering systems and thermal insulation composition to withstand biological colonization. All systems were exposed outdoors at an urban site in Lisbon, Portugal, facing North. The surface temperature, the surface relative humidity and the meteorological conditions were monitored for four months. At the same time, the capillary water absorption and the aesthetic properties of the systems were evaluated after 6, 9 and 12 months of outdoor exposure. Moreover, biological colonization was visually assessed using a previously defined rating scale. The onsite monitoring results were then compared with the water performance, aesthetic properties and biological colonization observed throughout natural aging. The highest level of biological development was obtained for the lime-based ETICS with ICB thermal insulation, which also presented the highest capillary water absorption and color alteration after one year of natural aging. On the other hand, the silicate-based system obtained the highest risk of surface condensation, and no biological growth was detected in this system during the exposure period.
Ano: 2023
Número Páginas:
6p..
Autor(es): Lina Nunes; Flores-Colen, I.; Veiga, M. R.; Parracha, J.
Editor: Itecons
Keywords: Biological growth; Condensation risk; Aesthetic properties; Capillary water absorption; ETICS
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Cálculo do galgamento na praia da Vagueira utilizando o modelo SWASH
A praia da Vagueira está localizada no Município de Vagos, distrito de Aveiro e é protegida por uma estrutura de defesa frontal aderente que foi requali
Ano: 2023
Número Páginas:
222-224pp..
Autor(es): ROSA, G.; Zózimo, A. C.; Neves, M. G.; CORREIA, J.
Editor: APRH
Keywords: Barra-fossa; Modelo numérico; Espraiamento
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CLOSER - A project for implementing pre-demolition audits in Portugal
The construction industry is one of the largest sectors in Europe and, on average, construction and demolition waste (CDW) accounts for one-third of the total waste generated. The recovery rate of these wastes surpasses the 70% target defined in the Waste Framework Directive 2008/98/EC. Nevertheless, this fact does not ensure that the sector is moving towards a transition from a linear to a circular economy at the end-of-life phase of buildings.In Portugal, a recovery rate of 95% of non-hazardous CDW prepared to reuse, recycling or other recovery operations is reported, although more than half of these residues are used as material for backfilling, therefore it does not represent a true circular transition due to downcycling.The project CLOSER, aiming to promote the application of circular economy principles by reducing material use and waste production, assessed the actual Portuguese practice for the management of CDW and evaluated the benefits of performing a pre-demolition audit in a pilot study. This project highlighted the crucial relevance of investing in training to improve green and digital skills. In what concerns building materials/elements reuse and recycling, changes to national policies were proposed.
Ano: 2023
Número Páginas:
6p..
Autor(es): Martins, I. M.
Editor: RILEM
Keywords: Circular economy; Pre-demolition audit; Construction and demolition waste
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Codificação do quadro legal e regulamentar da Construção : Um processo faseado e colaborativo
Não fornecido
Ano: 2023
Autor(es): Campos, V.; Branco Pedro, J.
Editor: LNEC
Keywords: Construção; multi-disciplinar; Continuidade; Objectivos; apresentação; SILUC
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Comparative analysis of softening contact laws in particle models: application to rock and concrete
In this work three constitutive contact models that include softening are adopted for particle model fracture studies in both rock and concrete. For a single local contact, the constitutive contact model performance is initially compared in tensile, pure shear and shear tests under constant axial. Additionally, compression, direct tensile, and confined triaxial tests of quasi-britlle material discretized with spherical particles are presented and the predicted macroscopic response is compared. For a single local contact, the three contact models predict a similar behaviour. As shown, it is possible to calibrate each contact model to reproduce complex macroscopic behaviour observed in rock and concrete, but each contact model requires different contact properties or particle generation procedures.
Ano: 2023
Número Páginas:
12p..
Autor(es): Oliveira, S.; Braga Farinha, M. L.; Azevedo, N.
Editor: International Centre for Numerical Methods in Engineering
Keywords: Concrete; Rock; Fracture; Contact laws; Discrete element; Particle modelling
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Comparison between experimental results and design equations of artificially degraded single step joints
In the case of interventions in existing buildings, the assessment of timber elements and joints, such as the Single Step Joint, is a challenge for engineers, especially when timber presents signs of biological degradation. In this context, many roof structures are subject to unnecessary substitutions due to the lack of knowledge about the behaviour of these types of joints, and specially the consequences of eventual biological attacks. This study aims to evaluate theresidual shear strength of Single Step Joints artificially degraded by wood boring insects from the Anobiidae family (e.g. Anobium punctatum). To achieve the established objectives, destructive tests were carried out on undamaged (reference level) and artificially degraded Single Step Joint specimens, varying the level of degradation. The results were analysed in terms of degradation level and compared with the results obtained with design equations for this type of joint found inthe literature. From the analysis of the results, it was possible to observe the tendency of reduction of the shear strength with the increase of the degradation level.
Ano: 2023
Número Páginas:
7p..
Autor(es): Lina Nunes; Branco , J.; Lima, D.
Editor: Curran Associates, Inc.
Keywords: Anobium punctatum; Biological degradation; Traditional carpentry connections; Single Step Joint
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Contributos da avaliação do estado de conservação e da previsão da vida útil para a gestão patrimonial de infraestruturas urbanas de água.
Os sistemas urbanos de água são compostos por diversos ativos com diferentes funções, vidas úteis, custos no ciclo de vida, idades e estados de conservação (Alegre e Coelho, 2012), sendo um dos principais desafios para as entidades gestoras a tomada de decisão quanto aos ativos que devem ser inspecionados, mantidos, reparados, renovados ou substituídos nas suas infraestruturas (Vanier, 2006). A adoção de estratégias de manutenção proativa tem sido dificultada pela falta de financiamento necessário à adequada manutenção e reabilitação dos ativos, contribuindo para a deterioração gradual do seu estado de conservação.
Ano: 2023
Número Páginas:
3p..
Autor(es): Covas, D.; Loureiro, D.; Cabral , M.
Revista: Viver com a água - Livro de resumos
Editor: APRH
Keywords: Infraestruturas urbanas de água.; Previsão da vida útil;; Avaliação do estado de conservação; Gestão patrimonial de infraestruturas
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Dam concrete in situ creep tests. Experimental setup and results from six large concrete dams
This paper describes the main features of the experimental in situ setups used to estimate the concrete deformability from six large Portuguese dams, all of which were built in the last 25 years. These experimental setups are commonly referred to as creep cells and aim at determining the modulus of elasticity for different ages and estimating the creep curve, under the same thermo-hygrometric conditions as the dam.Creep cells are composed of specimens of concrete with embedded strainmeters, placed in the body of a concrete dam during its construction, with a hydraulic flat-jack underneath. During the elastic modulus and the creep tests, while the jack introduces a given compressive stress in the specimen, the embedded strainmeters measure the sub-sequent strains, instantly or over time, for the modulus of elasticity or creep assessment, respectively.In recent years, there have been several developments in the design and in the instal-lation methodology of this type of experimental setup, namely in Alqueva, Baixo Sabor, Ribeiradio, Foz Tua, Daivões and Alto Tâmega dams.The article also presents a brief compilation of the most important creep cells results for these dams, which are being used as an input to numerically evaluate the structure
Ano: 2023
Número Páginas:
12p..
Autor(es): Azevedo, N.; Batista, A. L.; Conde Silva, J.; Serra, C.
Editor: RILEM
Keywords: Creep function; Creep cells; Deformability tests; In situ experiments; Dam concrete
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