Artigos de Revista

Prediction of wave forces on caisson-type breakwaters is challenging, especially in the case of impact loads that strongly depend on wave reflection, and wave breaking which affects the wave characteristics near the structure. In recent years, numerical models have been further developed and their use is becoming increasingly attractive, such as the Smoothed Particle Hydrodynamics (SPH) numerical models which enable the simulation of complex free surface flows. The SPH numerical model developed at the National Laboratory for Civil Engineering (LNEC) is validated by comparing the numerical results of the wave interaction with a vertical wall using data obtained from physical modeling tests carried out in one of the LNEC

Trata-se de um relativo culminar de toda uma tradição de zonamentos funcionais ou funcionalistas, zonamentos estes que, infelizmente, ajudaram a destruir bairros de cidades e a uniformizar espaços domésticos no sentido do serviço a uma pessoa

Aqui se quer definir por “instalações” se refere a todo um conjunto de "aparatos" técnicos, associados a redes técnicas diversas com especial enfoque nas águas, esgotos, electricidade e redes de telecomunicações por cabo, que são fundamentais para o habitar doméstico e cujas ligações ou “pontos” de serviço estão disseminados pelos vários espaços da habitação, proporcionando padrões de uso das respetivas instalações que devem ser eficazes no sentido das respetivas utilidades.

Purpose - The rigid spherical particle models proposed in the literature for modeling fracture in rock have some difficulties in reproducing both the observed macroscopic hard rock triaxial failure enveloped and compressive to tensile strength ratio. With the purpose of obtaining a better agreement with the experimental behaviour, a 3D generalized rigid particle contact model based on a multiple contact point formulation is presented which allows moment transmission and includes in a straightforward manner the effect of friction at the contact level.Design/methodology/approach

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Os romanos deixaram importantes contributos na área da Engenharia de Barragens, tanto nos aspectos relacionados com a concepção estrutural, como nos métodos construtivos e nos materiais utilizados. A barragem romana de contrafortes mais alta que se tem registo localiza-se em Belas, junto a Lisboa, e é conhecida como a Barragem de Olisipo. Apesar de se encontrar semidestruída e não desempenhar a função para a qual foi concebida, as suas ruínas constituem, ainda assim, um conjunto com interesse técnico e histórico. Este trabalho apresenta um estudo sobre as características geométricas e estruturais da Barragem de Olisipo. A análise estrutural foi realizada através do método do equilíbrio limite. Este estudo incidiu sobre duas secções transversais tipo da barragem, designadas por secção corrente e secção equivalente, esta última idealizada a partir da área de influência de um contraforte. Foram determinadas as linhas de pressões, as tensões verticais totais e efectivas na base da barragem e os factores de segurança em relação aos mecanismos globais de deslizamento e de derrubamento. O objectivo fundamental deste trabalho é divulgar e valorizar este importante património.

The Last Glacial Maximum low stand and coeval re-incision of the Portuguese hydrographic network created the space and defined the shape of the main morphological features available to accommodate the inundation resulting from the Holocene transgression and the marine sediments deposited in tune with changing base levels. The reconstruction of the transgressive paleosurface is relevant in paleoenvironmental studies, namely to establish the paleobasin morphology and evaluate accommodation volume. In the case of the study area (Pederneira lowland), the geological data set available to reconstruct that surface consists of borehole logs carried out for geotechnics and groundwater and three cores performed for aleoenvironmental reconstruction. The borehole data scatter non-uniformly across the lowland providing spatially biased information. The surveying of several Transient Electromagnetic Method (TEM) profiles yielded inconclusive results in separating sediment units below and above the transgressive surface due to poor contrastin sediment resistivity and high conductivity of groundwater. This study addresses a method for estimating that paleosurface using the combination of a standard geostatistical interpolation procedure (kriging) with a conceptual geomorphological model. The geomorphological model comprised the sketching of a paleoriver drainage system in which the position of the thalwegs was defined departing from present-day slope morphology and depths estimated by adjusting a mathematical curve describing their longitudinal profile to control points. Final adjustments to the paleodrainage system were constrained by borehole data and expert judgment. This methodology proved to be effective in an area where limited objective geological and geophysical data are available.

The traditional daylighting calculation methods and the metrics used for its quantification have some limitations. For example, these methods do not take into account, effectively and realistically, the consequences of the dynamic characteristics of natural light and in particular those associated with its energy-related impacts and with the influence of the occupants of the buildings in the final daylighting performance. In view of that, an integrated method for characterization and realistic prediction of the dynamic performance of daylighting was developed. The new method takes into account: i) the characteristics of the luminous climate in the southern European regions, where non-overcast sky conditions prevail; ii) the guarantee of an adequate indoor visual environment and minimization of visual discomfort; iii) the energy-related impacts of daylighting; iv) the influence of environmental management systems and their control strategies in the final daylighting conditions and energy use; and, v) the expectations, preferences, attitudes and behaviours of individuals towards their indoor environmental conditions and control systems at their disposal.

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The boundary layer concept is applied to the flow around the nose of a streamlined train. In general, that flow is not axisymmetric due to the shape of the nose and the crosswind component of the relative incoming velocity. This departure from axisymmetry produces a transverse pressure gradient that is responsible for skewing an otherwise plane boundary layer. An empirical correlation, dependent on the longitudinal velocity and one unknown parameter, is used to represent the transverse velocity profile. The value of that unknown parameter is obtained from the momentum equations integrated streamwise inside the boundary layer. A visual comparison was carried out between the numerical simulations and the skin shear pattern of a scale model in a wind tunnel. The qualitative results compare well, the numerical model being able to locate the position of the main longitudinal vortices on the lee side of the train.