Artigos de Revista

Traditional carpentry joints can be found worldwide in many timber truss structures connectingrafter and tie beam. One failure mode of this connection result from shear in the tie beam beyond the notch either due to bad design or deterioration. In this article, the reduction in shear strength of Single Step Joints (SSJ) resulting from biological attack by anobiids was analysed. For this purpose, tests were carried out in non-degraded scots pine (Pinus sylvestris L.) specimens (reference) and compared to artificially degraded specimens with three different levels of degradation. The reduction of shear resistance was analysed in relation to the density of holes drilled during the degradation simulation, the loss of mass, and the reduction of the hearresistant area. At lower degradation levels, no significant reduction in shear strength was observed. On the other hand, the linear regression shows a trend of resistance reduction with increasing degradation. Despite the relatively low coefficient of determination (r2 = 0.25), the parameterthat best correlated with the residual strength was the reduction in the shear-resistant area.

Traditional carpentry joints can be found worldwide in many timber truss structures connecting rafter and tie beam. One failure mode of this connection result from shear in the tie beam beyond the notch either due to bad design or deterioration. In this article, the reduction in shear strength of Single Step Joints (SSJ) resulting from biological attack by anobiids was analysed. For this purpose, tests were carried out in non-degraded scots pine (Pinus sylvestris L.) specimens (reference) and compared to artificially degraded specimens with three different levels of degradation. The reduction of shear resistance was analysed in relation to the density of holes drilled during the degradation simulation, the loss of mass, and the reduction of the shear-resistant area. At lower degradation levels, no significant reduction in shear strength was observed. On the other hand, the linear regression shows a trend of resistance reduction with increasing degradation. Despite the relatively low coefficient of determination (r2

The efects of climate change on the estuarine environment are not fully understood. In temperate regions, droughts are expected to increase in frequency and severity, due to lower precipitation, and the mean sea level is expected to rise. This study aimed to assess how the estuarine environment will be afected by river fow

Many collective irrigation systems have been operating for decades, facing high degradation of existing infrastructures and huge water-energy efficiency problems. Predominantly composed of open canals, they have been partially or entirely converted into pressurised pipe systems, implying a considerable increase in energy consumption and operation and maintenance costs. Simple, easy-to-use, and comprehensive approaches for energy efficiency assessment in collective irrigation systems are needed for diagnosis and assisting decision-making on implementing adequate improvement measures. This research proposes and demonstrates an innovative approach based on the water and energy balances and performance indicators to assess the effect of water losses, network layout and operation, energy recovery, and equipment on energy efficiency. A novel methodology for energy balance calculation is proposed for open canal, pressurised and combined systems. The application to a real-life open canal system and network areas allowed the identification of efficiency problems mainly due to water losses in canals, followed by the dissipated energy in friction losses. Less critical are pumping and manoeuvring equipment inefficiencies. Also, a considerable excess of gravity energy is recovered in hydropower plants. In raising pipe systems, in which shaft input energy predominates and costs for pumping play a key role, surplus and dissipated energy in friction losses are the most relevant issues. Significant energy is lost in the water conveyance and distribution in both systems. Consequently, the potential to improve energy efficiency through water loss management, network layout, and operation improvement, besides pumping and manoeuvring equipment replacement, is considerable.

Os ensaios de ligações aparafusadas realizados no LNEC no âmbito do projeto de investigação TimQuake abrangeram várias combinações de espécie (Pinus sylvestris e Picea abies) e teor de água da madeira, geometria da ligação (madeira-aço-madeira ou aço-madeira-aço), regime de carregamento e nível de tração axial do ligador.Este artigo apresenta o programa experimental e discute os resultados obtidos nos ensaios monotónicos, à luz do dimensionamento das ligações segundo o Eurocódigo 5 (EC5).Conforme previsto, as ligações com parafusos menos esbeltos apresentaram maior propensão para desenvolverem rotura frágil, mesmo seguindo a pormenorização recomendada no Eurocódigo 5. Os resultados dos ensaios con

Depois de um conjunto de notas introdutórias e de apresentação ao estudo global intitulado Programa de Habitação Adaptável Intergeracional desenvolvido num quadro Cooperativo e a Custos Controlados (PHAI3C), abordam-se, no presente artigo, e a propósito de um conjunto de estudos devidamente referenciados em notas bibliográficas, os seguintes 10 subtemas: (i) O envelhecimento e o habitat humano: reflexões e casos de referência.(ii) As mudanças no âmbito do envelhecimento humano.(iii) Notas sobre a gero-habitação.(iv) Domesticidade e saúde nos cuidados e residências para idosos.(v) Habitação para todos: inovação na conceção habitacional.(vi) Aprofundar, cuidadosamente, as relações entre habitação e envelhecimento .(vii) O envelhecimento humano e o habitat, avançando-se numa essencial e muito sensível tipificação e pormenorização.(viii) Facilitar o quotidiano

A avaliação do dano causado pela agitação incidente em modelos físicos de quebra mares de taludes pode ser realizada comparando volumes e profundidades erodidas entre levantamentos consecutivos de cada talude.Atualmente, estes levantamentos podem ser realizados de forma não intrusiva, recorrendo a técnicas fotogramétricas, a laser scan ou a sensores de posição baseados na metolodologia Time of Flight (ToF). Dependendo das condições de levantamento e da metodologia de pós-processamento das nuvens de pontos obtidas, estas técnicas permitem obter modelos tridimensionais de superfície, com elevada precisão.Em detalhe, as diferenças de volume entre os levantamentos inicial e

Azulejos have been applied to architectural settings in Portugal for the last five centuries and represent one of its most unique art forms. In this article a group of representative samples regarding the chronology and typology of the majolica azulejos produced by the Lisbon workshops from the second half of the 16th century (beginning of majolica azulejos production in Portugal) up to the first quarter of the 19th century (after which more industrialized manufacturing processes were introduced) are studied. SEM-EDS was used to obtain morphological and chemical information on the glazes, ceramic bodies, and their interfaces. The results show that a major shift from lead-rich to lead-alkali glazes occurred in the transition from the 16th to the 17th century, while from then to the end of the studied period the same basic technology prevailed. The Lisbon tiles production is also considered in the European context.

The sustainable use of resources requires new strategies to transform industrial byproductsinto raw materials for other applications. This approach, inspired by circular economy funda-mentals, can be successfully applied in transportation infrastructures where a significantamount of natural raw materials is generally required. Slags from the steelmaking processin electric arc furnaces are generally of two types: oxidizing (black colored) and reducing(lighter colored). In Portugal, the oxidizing steel slag or electric arc furnace (EAF) with con-trolled production has been certified as

This study compares and discusses the adequacy of surrogate resilience metrics proposed in the literature for resilience assessment of drinking water systems concerning demand increase and network redundancy. A sensitivity analysis is carried out for increasing flow rates using a conceptual case study with different layouts and demand scenarios, selecting several metrics to assess the resilience of two real network areas. Resilience metrics based on surplus energy are sensitive to network layout and demand scenarios. The network resilience index considers hydraulic reliability and network diameter uniformity. In contrast, the weighted resilience index also considers the network topology and gives importance to pipes with higher flow rates. Entropy-based resilience metrics mainly rely on the network flows' uniformity and are sensitive to pipe redundancy. The entropy metric most adequate to assess the hydraulic capacity is the diameter-sensitive flow entropy, since it is sensitive to the velocity inside the pipes. Topology metrics cannot assess the hydraulic capacity though evaluate the system redundancy (meshed-ness coefficient), robustness (central-point dominance) and water transportation efficiency (average-path length). Surrogate resilience metrics do not assess the system performance during a failure. They indicate systems which are better prepared to overcome failure events and increased demand events, providing vital information to drinking water systems management.