Artigos de Revista

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.

This paper presents and discusses the application of a novel energy balance scheme for assessing energy efficiency in wastewater systems. The energy balance is demonstrated with a Portuguese real-life case study, using mathematical modelling to estimate the different energy components and to compute two energy efficiency indices. The total inflow intrinsic energy can represent a significant amount (>95%) of the total energy used in systems mainly composed of gravity sewers. The total input energy is significantly (four-times) higher in the wet season than in the dry season, mostly due to undue inflows (e.g., direct rainfall and infiltration). The potential for energy recovery strongly depends on the available head and flow rate at the delivery point, being 0.01 kWh/m3 in the current case, with a project payback period of 4 years. The energy balance components and the respective energy efficiency indices strongly depend on the considered reference elevation. Thus, a unique regional reference elevation is recommended in the calculations.

Neste artigo, dedicado à temática do vestíbulo de entrada na habitação, faz-se, de início, uma introdução geral aos espaços domésticos, seguindo-se um enquadramento da temática do vestíbulo e dos aspetos considerados motivadores para o seu uso.Depois abordam-se diversas opções de vestíbulo, as associações formais e funcionais e os hábitos considerados interessantes nas soluções de vestíbulos domésticos e os problemas mais correntes que aí se detetam e as respetivas questões levantadas (dimensionais e outras)Por fim aborda-se a temática do vestíbulo doméstico em termos de respetivas novidades, dúvidas e tendências (ex., trabalho em casa, uso por idosos).

No artigo desenvolve-se uma reflexão ainda, de certa forma, introdutória e estruturadora sobre o interesse da exploração e do subsequente aprofundamento de uma razoável variedade de propostas organizativas para as zonas e subzonas da habitação, numa perspetiva diretamente ligada ao que se considerar serem os desejáveis equilíbrios dimensionais/funcionais e de privacidade/convívio na habitação.Desenvolvem-se, sequencialmente, algumas considerações sobre o equilíbrio com que se distribui o espaço na habitação e as respetivas consequências na adequação aos tipos de família e de modo de vida.No artigo consideram-se e comentam-se diversas situações-tipo, designadamente, em termos do papel dos quartos no que se refere ao referido equilíbrio entre espacialidade/funcionalidade e privacidade/convívio domésticos, mas também no que se refere à relação entre cozinha e sala comum e à presença espacial e funcional das zonas de entrada e circulação domésticas.

In order to contribute to the knowledge about the influence of several factors on the in-service performance of renders, as well as about the applicability of in-situ testing techniques in the evaluation of their performance, an experimental work was carried. In this work, the influence of some factors (type of substrate, number and thickness of mortar layers) on the mechanical and physical performance of two mortars (site-made and industrial) was evaluated, using the following in-situ testing techniques: pendulum rebound hammer test (with two types of rebound hammer), ultrasonic pulse velocity test (with two types of device) and water absorption under low pressure test (with Karsten tubes). It was possible to verify that the above-mentioned factors influence the performance of the mortars. The in-situ testing techniques were, in general, able to identify differences in the behaviour of renders due to these factors. However, for the same technique, different devices sometimes led to distinct results. Nevertheless, the combination of the results of different techniques helped to reduce the uncertainty of the analysis.

Climate change studies already reported sea level rise as an accepted scenario, which induces changes in nearshore wave conditions. A large range of new experiences including water level, run-up, overtopping, hydrodynamic data for different wave steepnesses and directions was performed in the Leibniz Universität Hannover (LUH) wave basin for a rubble mound breakwater with a slope of 1(V):2(H). This work presents, focusing on oblique extreme wave conditions, numerical simulations of the hydrodynamics in that experiment using OpenFOAM®. Results of the wave generation boundary conditions and their propagation, namely levation of the water level free-surface and velocity data at specific locations are compared and discussed with data from experimental measurements acquired by acoustic wave gauges and acoustic doppler velocimeter (ADV) / Vectrino equipment. Although an exact match between numerical and laboratory values was not reached, an appropriate incident wave angle and a reasonable amplitude of velocities and water depths was achieved and the same happened to the statistics of those values.

The prediction of scour evolution at bridge foundations is of utmost importance forengineering design and infrastructures

Soil water content measurement is crucial during compaction control of embankments. The current techniques used to measure the soil water content in the field are outlined, and their advantages and limitations are indicated. Most techniques require destructive sampling and yields late results, or involve expensive equipment and are hard to set up. Low-cost capacitive and resistive moisture sensors entered successfully in last decades in agronomy applications to automatize crops irrigation. The purpose of this study is to identify whether these sensors are reliable to be used in geotechnical engineering and, in particular, to what extent can they aid compaction control of embankments. Three resistive sensors and two capacitive sensors are tested on five types of soils prepared with a wide range of water contents. The experimental procedures are described, and the sensors output data are compared with water contents obtained from the oven-drying technique. A new device that allows calibration of the sensors on compacted soils is developed. Soils characteristics that can influence moisture measurement using capacitive and resistive sensors are also explored. Test results suggest that some of the sensors can estimate the soil water content on compacted fine grained soils, when proper calibration procedure is successfully achieved. Sensors accuracy tend to increase as the soil void ratio decreases. Such sensors may be useful for expedite measurements, especially, when later counter-prof is available, or when a wide interval for the water content is acceptable.