Artigos de Revista

No presente artigo faz-se a apresentação e o enquadramento justificativo e pormenorizado dos conteúdos, bases de referência e quadro qualitativo de uma série editorial dedicada ao desejável desenvolvimento da qualidade arquitectónica e da satisfação residencial na nova habitação de interesse social (HIS) portuguesa, ainda em falta, salientando-se que nos oito artigos previstos, nesta série, vai ser abordado, genericamente, o que caraterizou o passado da nossa HIS, para, em seguida, se refletir sobre o que poderá ser o futuro da Habitação de Interesse Social (HIS) portuguesa. Depois de um enquadramento geral da nova série editorial e sua principal temática registam-se e comentam-se as principais bases de apoio à reflexão sobre a nova HIS portuguesa, passando-se, em seguida, para o sublinhar da atenção que se julga dever ser dirigida para os melhores casos de referência habitacional e arquitectónica existentes e bem experimentados. Em seguida apresentam-se os estudos teórico-práticos ligados à análise retrospetiva habitacional e o processo de avaliação utilizado, durante cerca de 24 anos, no âmbito do trabalho do júri do Prémio INH/IHRU, considerados como principais elementos de base de conhecimento e apreciação do que foi a última “geração” de promoção de HIS portuguesa, concluindo-se com algumas notas práticas sobre o quadro de análise qualitativa usado neste estudo. O artigo é concluído por uma breve apresentação dos sete artigos desta série editorial, pelo registo dos essenciais agradecimentos relativamente a pessoas e entidades que apoiaram e possibilitaram, direta e indiretamente, a respetiva elaboração e com a apresentação de uma bibliografia cronológica sobre a matéria da habitação de interesse social (HIS) portuguesa e sobre qualidade arquitectónica residencial.

Designing for exceedance events consists in designing a continuous route for overland flow to deal with flows exceeding the sewer system’s capacity and to mitigate flooding risk. A review is carried out here on flood safety/hazard criteria, which generally establish thresholds for the water depth and flood velocity, or a relationship between them. The effects of the cross-section shape, roughness and slope of streets in meeting the criteria are evaluated based on equations, graphical results and one case study. An expedited method for the verification of safety criteria based solely on flow is presented, saving efforts in detailing models and increasing confidence in the results from simplified models. The method is valid for 0.1 m2/s _ h.V _ 0.5 m2/s. The results showed that a street with a 1.8% slope, K _ 75 m1/3s??1 and a rectangular cross-section complies with the threshold h.V = 0.3 m2/s for twice the flow of a street with the same width but with a conventional cross-section shape. The flow will be four times greater for a 15% street slope. The results also highlighted that the flood flows can vary significantly along the streets depending on the sewers’ roughness and the flow transfers between the major and minor systems, such that the effort detailing a street’s cross-section must be balanced with all of the other sources of uncertainty.

Spillway design is key to the effective and safe operation of dams. Typically, the flow is characterized by high velocity, high levels of turbulence, and aeration. In the last two decades, advances in computational fluid dynamics (CFD) made available several numerical tools to aid hydraulic structures engineers. The most frequent approach is to solve the Reynolds-averaged Navier–Stokes equations using an Euler type model combined with the volume-of-fluid (VoF) method. Regardless of a few applications, the complete two-phase Euler is still considered to demand exorbitant computational resources. An assessment is performed in a spillway offset aerator, comparing the two-phase volume-of-fluid (TPVoF) with the complete two-phase Euler (CTPE). Both models are included in the OpenFOAM® toolbox. As expected, the TPVoF results depend highly on the mesh, not showing convergence in the maximum chute bottom pressure and the lower-nappe aeration, tending to null aeration as resolution increases. The CTPE combined with the k–? SST Sato turbulence model exhibits the most accurate results and mesh convergence in the lower-nappe aeration. Surprisingly, intermediate mesh resolutions are sufficient to surpass the TPVoF performance with reasonable calculation efforts. Moreover, compressibility, flow bulking, and several entrained air effects in the flow are comprehended. Despite not reproducing all aspects of the flow with acceptable accuracy, the complete two-phase Euler demonstrated an efficient cost-benefit performance and high value in spillway aerated flows. Nonetheless, further developments are expected to enhance the efficiency and stability of this model.

This work addresses the durability of structural epoxy adhesives and carbon fibre reinforcedpolymer (CFRP) laminates typically used in strengthening of existing reinforced concrete structuresexposed to natural ageing. The experimental program included four natural (real) outdoor environmentsinducing ageing mainly caused by carbonation, freeze-thaw attack, elevated temperatures, andairborne chlorides from seawater. Moreover, a control (reference) environment (20 C of temperatureand 55% of relative humidity) and an environment involving water immersion of the materials undercontrolled temperature (20 C of temperature) were also included in this investigation. The characterizationinvolved the assessment of the physical, chemical and mechanical properties along a studyperiod of up to two years. Furthermore, comparisons between the natural ageing tests developed inthe scope of the present work and accelerated ageing tests existing in the literature were performed.Regarding to the epoxy adhesives, an increase in the glass transition temperature with the time wasobserved, while the tensile properties decreased, regardless of the outdoor environment. The CFRPlaminates were marginally affected by the studied environments. Despite the remarkable dispersionof the results observed in the accelerated ageing tests for the period investigated, this testing protocolyielded higher mechanical degradation than under natural ageing.

Transition zones between embankments and bridges or tunnels are examples of critical assets of the railway infrastructure. These locations often exhibit higher degradations rates, mostly due to the development of differential settlements, which amplify the dynamic train-track interaction, thus further accelerating the development of settlements and deteriorating track components and vehicles. Despite the technical and scientific interest in predicting the long-term behavior of transition zones, few studies have been able to develop a robust approach that could accurately simulate this complex structural response. To address this topic, this work presents a three-dimensional finite element (3D FEM) approach to simulate the long-term behavior of railway tracks at transition zones. The approach considers both plastic deformation of the ballast layer using a high-cycle strain accumulation model and the non-linearity of the dynamic vehicle-track interaction that results from the evolution of the deformed states of the track itself. The results shed some light into the behavior of transition zones and evidence the complex long-term response of this structures and its interdependency with the transient response of the train-track interaction. Aspects that are critical when assessing the performance of these systems are analyzed in detail, which might be of relevance for researchers and practitioners in the design, construction, and maintenance processes.

Resumo: Understanding how climatic and anthropogenic drivers will influence coastal lagoons is fundamental to guarantee their preservation and sustainability. The Ria Formosa (coastal lagoon, South coast of Portugal) is a very important ecosystem that supports diverse economic activities in the region. The 3D coupled hydrodynamic-biogeochemical model SCHISM was validated and used to assess the influence of climate change and anthropogenic pressures on the water quality of the Ria Formosa. Five scenarios were simulated: reference scenario (S0), mean sea level rise (SLR) of 0.5 m (S1), increase of the air temperature of 1.68 °C (S2), increase of the outflow from the wastewater treatment plants (WWTP) by 50% (S3) and a combined scenario (S4). Results suggest that SLR of 0.5 m promotes an increase of 0.5–3 in the salinity near the area of influence of the WWTP. SLR decreases the inorganic nutrient concentrations in these areas by about 40–60%, due to an increase of the dilution. In contrast, the increase of the outflow from the WWTP by 50% increases the nutrients concentrations by about 20–40%. The increase of the air temperature alone by 1.68 °C increases the water temperature by 0–1 °C. The combined scenario suggests antagonist effects in the nutrient concentrations. Overall, the trophic index (TRIX) of the lagoon calculated for the scenarios exhibits only minor differences relative to the reference scenario, except in some areas near the WWTP discharges. In these areas, TRIX tends to increase with the increase of the outflow from the WWTP in scenario S3. These results provide further insight into the response of coastal lagoons, and the Ria Formosa in particular, to future changes and contribute to support their management.

External Thermal Insulation Composite Systems (ETICS) have been extensively used for either new constructions or building facades retrofitting in the last decades. These systems can provide improved thermal performance to the building envelope. However, their long-term durability remains a pervasive concern, with some systems presenting relevant anomalies after few years from their application. The durability assessment of ETICS is defined by the EAD 040083-00-0404 guideline, which stated an accelerated ageing procedure based on the hygrothermal and freeze-thaw behaviour. Nevertheless, further important environmental urban conditions, such as UV radiation and atmospheric pollutants, as well as bio-susceptibility, are not envisaged in the guideline. This paper presents the results of an experimental campaign with the aim of evaluating the durability of the rendering system of several commercially available ETICS exposed to an innovative accelerated ageing procedure, which consists of hygrothermal cycles, UV radiation and air pollutants (SO2) exposure. Physical and chemical-morphological tests were carried out prior and after each ageing cycle in order to evaluate the durability of ETICS. Biological susceptibility to moulds was also assessed. The experimental results showed that both surface hardness and surface gloss decreased after the combined effect of the hygrothermal, UV, and SO2 ageing cycles, whereas an increase of surface roughness was observed. Substantial colour change for all systems after the ageing procedure was observed, confirming aesthetic alteration. Traces of biological growth were detected on the systems after ageing and the contact angle decreased after the hygrothermal cycles, indicating a lower surface hydrophobicity of the systems.

This paper addresses the viscoelastic behaviour of a commercially available cold-curing structural epoxy adhesive, under different preparation, curing and hygrothermal conditions. The main parameters studied were the preparation method (influence of the degassing and the temperature of the initial curing), the creep stress level, and the hygrothermal conditions. Tensile creep tests last up to 2400 h. Test results revealed that the preparation method has great influence on the tensile properties of the adhesive, particularly on the viscoelastic response where degassing and curing at 20

The effects of a farm of bottom-fixed oscillating flaps on the wave propagation in Almagreira beach (Portugal) are evaluated. The SNL-SWAN (Sandia National Laboratories, Simulating WAves Nearshore) numerical model is validated from 2010 to 2018 against Nazaré wave buoy data and run for 19 years to characterize the wave resource and identify the most common and energetic sea states. By varying number (10 to 100) and configuration of wave energy converters (WECs) an optimal array is identified. Model sensitivity to two methods of determining the transmission coefficient, OBCASEs 1 and 3, is studied by analyzing changes in significant wave height, period and direction. OBCASE 1 overestimates the effects of the farm on the waves and changes result higher in the lee of the array with an increasing number of devices. As a future work OBCASE 2 and 4 will be compared to OBCASE 1 and 3.