Artigos de Revista

No presente artigo e depois de uma essencial nota introdutória onde se salienta a complexidade e a sensibilidade desta temática específica que rodeia tudo o que tem a ver com os quadros habitacionais que nos acompanham no final de vida, desenvolvem-se algumas considerações sobre pensar no habitar no final de vida em termos de uma intervenção intergeracional e adaptável realizada no âmbito do PHAI3C. Em seguida aponta-se um conjunto de aspetos arquitetónicos responsáveis pela melhoria das condições habitacionais no fim de vida, avançando-se, depois para a a defesa do que podemos considerar como um final de vida mais doméstico e termina-se com a apresentação de alguns comentários às presentes contribuições para a melhoria das condições habitacionais no fim de vida.E há que fazer, aqui, uma referência específica a estarmos a entrar em áreas tão sensíveis como especializadas e que portanto têm de ser desenvolvidas no respeito dos respetivos especialistas, mas julga-se que para o avançar de ideias de conceção minimamente adequadas para uma habitação intergeracional, não dirigida para estas problemáticas, mas onde estas problemáticas provavelmente ocorrerão, importa abordá-las de modo a que o projetista do espaço intergeracional esteja devidamente sensibilizado para elas.

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The construction sector is responsible for a great environmental impact. The cement industry, which is included in this sector, emits about 650 to 800 kg of CO2 per each tonne of cement produced, being one of the most polluting industries in terms of greenhouse gas emissions. The cement manufacturing process releases about 7% of the total worldwide CO2 emissions. However, concrete and cement-based materials present CO2 uptake potential during their service life and post-demolition through carbonation processes. The carbonation reactions rate depends on several factors, namely type and content of cement, porosity of concrete, temperature, relative humidity and exposure conditions area. Therefore, to estimate the CO2 capture of concrete during its life cycle is not a straightforward calculation. Some studies have been developed using different methodologies in order to evaluate the CO2 potential of cementitious elements in service and post-demolition. This paper reviews the documented approaches that quantify the CO2 uptake of concrete over time, summarizing the assumptions adopted for each previous work. Overall, it was concluded that part of the CO2 emissions released during cement production are reabsorbed by concrete products during their life cycle, which partially offsets the environmental impact and reduces the CO2 footprint of the cement industry.

Photogrammetry-based methods using everyday photographic equipment and easily available software have gained relevance for roughness measurement of rock joints, as an alternative to traditional approaches. However, the influence of some aspects, such as the number and orientation of camera poses, the parameters of the Structure-from-Motion, Multi-View Stereo and meshing algorithms, the resolution and accuracy of the reconstructed models, requires proper appraisal. To assess the surface roughness of a granite rock joint specimen using such photogrammetry methods, 3D models generated using different settings (i.e. camera sensors, camera poses, open/free software and workflows) were compared with a reference model obtained by contact digitalization. The results suggest that comparable results can be achieved if the photos adequately cover the specimen and, at least, equivalent vertex densities are attained. Percentiles p5 and p95 of surface deviations of the tested models to the reference mesh were, in general, lower than ±0.1 mm. Estimated roughness parameters showed reduced variability, with a minor impact on the shear strength evaluated according to the Grasselli’s GG-shear strength criterion, which was developed from the empirical correlation of roughness parameters with laboratory testing data. Results also showed that this methodology is far more accessible, easier to use, faster to implement, and less expensive than most currently available equipment and approaches.

Neste trabalho sÆo apresentados os resultados da compara‡Æo entre trˆs metodologias para obten‡Æo de modelos tridimensionais de superf¡cie, aplicadas … situa‡Æo espec¡fica do modelo f¡sico 3D do prolongamento do molhe leste do porto de Sines.

This research explores the mechanical behavior of dry-joint masonry subjected to combined shear

As presentes notas de leitura e de reflexão partem de um enquadramento feito através de um importante relatório mundial sobre envelhecimento e saúde para se desenvolver uma referência ampla à importante Estratégia Nacional para o Envelhecimento Ativo e Saudável (ENEAS), e, depois, para uma abordagem sintética do direito à habitação na perspetiva do idoso, tendo por base diversos documentos.Há que fazer, aqui, uma referência específica a estarmos a entrar em áreas tão sensíveis como especializadas e que portanto têm de ser desenvolvidas no respeito dos respetivos especialistas, mas julga-se que para o avançar de ideias de conceção minimamente adequadas para uma habitação intergeracional, importa avançar nessas áreas ainda que, para já, apenas de uma forma exploratória ou introdutória.

Abstract: The evacuation of buildings in case of fire is a sensitive issue for civil society that alsomotivates the academic community to develop and study solutions to improve the efficiency ofevacuating these spaces. The study of human behavior in fire emergencies has been one of the areasthat have deserved the attention of researchers. However, this modeling of human behavior is difficultand complex because it depends on factors that are difficult to know and that vary from countryto country. In this paper, a paradigm shift is proposed which, instead of focusing on modeling thebehavior of occupants, focuses on conditioning this behavior by providing real-time information onthe most efficient evacuation routes. Making this information available to occupants is possible witha solution that takes advantage of the growing use of the IoT (Internet of Things) in buildings to helpoccupants adapt to the environment. Supported by the IoT, multi-agent recommender systems canhelp users to adapt to the environment and provide the occupants with the most efficient evacuationroutes. This paradigm shift is achieved through a context-based multi-agent recommender systembased on contextual data obtained from IoT devices, which recommends the most efficient evacuationroutes at any given time. The obtained results suggest that the proposed solution can improve theefficiency of evacuating buildings in the event of a fire; for a scenario with two hundred peoplefollowing the system recommendations, the time they take to reach a safe place decreases by 17.7%.

Melby presents a formula to predict damage evolution in rubble-mound breakwaters whose armour layer is made of rock, based on the erosion measured in scale-model tests and the characteristics of the incident sea waves in such tests. However, this formula is only valid for armour layers made of rock and for the range of tested sea states. The present work aims to show how the Melby methodology can be used to establish a similar formula for the armour layer damage evolu tion in a rubble-mound breakwater where tetrapods are employed. For that, a long-duration test series is conducted with a 1:50 scale model of the quay section of the Ericeira Harbour breakwater. The eroded volume of the armour layer was measured using a Kinect position sensor. The damage parameter values measured in the experiments are lower than those predicted by the formulation for rock armour layers. New

Concrete gravity dams are mass concrete structures, often built on rock mass foundations, conceived to rely upon their weight for stability. To prevent sliding, these structures are usually keyed/embedded into the foundation, a good construction practice particularly relevant in medium to high intensity seismic zones. In stability analysis, the extra strength obtained by keying the dam into the foundation is usually either neglected or taken as a passive resistance, which, such as explored in this paper, do not reflect the real structural response in pre-collapse situations. Limit state philosophy requires the ultimate equilibrium conditions to be expressed as accurately as possible. In this paper, the rigid-body equilibrium of a wedgy model representing the dam and a downstream rock wedge is analyzed according to the large displacement regime. Failure mechanisms were identified, analytically described and numerically validated. Application to two Portuguese large concrete gravity dams led to safety factors considerably larger than those computed assuming the usual practice. The proposed approach is intended to support probabilistic and/or semi-probabilistic methodologies for safety assessment of concrete gravity dams, in the design and feasibility phases, in which the limit state approach is inherently followed.