Artigos de Revista

The out-of-plane flexural bending capacity of masonry is a fundamental property for understanding the behavior of masonry structures. This study investigates the behavior of unreinforced masonry wallettes subjected to combined compression-flexural loading using the discrete element method (DEM), and provides a novel framework to estimate the masonry strength. A simplified micro-modeling strategy is utilized to analyze a masonry wallette, including the variation of the mechanical properties in masonry units and joints. Stochastic DEM analyses are performed to simulate brickwork assemblages, assuming a strong unit-weak joint material model typical of most masonry buildings, including historical ones. Once the proposed computational approach is validated against the experimental findings, the effect of spatial and non-spatial variation of mechanical properties is explored. Two failure types are identified: joint failure and brick failure. For each failure mechanism, the variability of the response and the effects of the modeling parameters on the load-carrying capacity is quantified. Afterward, Lasso regression is employed to determine predictive equations in terms of the material properties and vertical pressure on the wallette. The results show that the most important parameters changing the response are the joint tensile strength and the amount of vertical stress for joint failure, whereas the unit tensile strength dominates the response for brick failure. Overall, this research proposes a novel framework adopting validated advanced computational models that feed on simple test results to generate data that is further utilized for training response prediction models for complex structures.

O presente artigo tenta abordar, de forma funcional, o conceito de

Discrete element models are being increasingly applied to model rock failure processes.Bonded-particle models, based on circular or spherical particle systems, have been successfully usedfor two decades. More recently, bonded-block models, using polygonal or polyhedral elements, have proven to be a powerful alternative. This paper describes the basis of the application of these models in the numerical simulation of failure in rock materials. The critical governing parameters are identified, and their influence is discussed. The model calibration procedure based on the analysis of laboratory tests is discussed. An application example of an underground excavation problem is presented using a simple bonded-block model employing rigid blocks and a bilinear softening contact model. The results show the capability of this approach to reproduce observed failure modes involving block fractures.

Population growth and social and economic development demand increasing volumes of water for public supply, especially in scenarios where surface sources such as rivers may not meet the basic demands for the population. In southeastern Brazil, with emphasis on the Piracicaba region, there is a conflict over water use regarding agricultural and industrial activities, where the sugar-alcohol sector is widely highlighted. The region has thousands of hectares of sugarcane cultivated, which requires intensive use of fertilizers and pesticides, in addition to the need for large volumes of water in the production of sugar and ethanol, where the main effluent produced is represented by vinasse, used as fertilizer complement and soil hydration in sugarcane fields. This work presents the results of a geophysical diagnosis in a closed wetland, located in a sugarcane field region, to evaluate the hydrogeological function of this environment in aquifer recharge and the risks that land use can cause in the quality and availability of surface and underground water resources.The geophysical survey consisted of nine lines of electrical resistivity tomography in Schlumberger arrangement, submitted to 2D processing and inversion followed by interpolation and generation of 3D visualization models. The results indicate a direct connection between water accumulated in the wetland and the aquifer underneath, separated by an aquitard interface about 44 m thickness. The study points out to the high vulnerability to the input of pesticides and vinasse effluent from the surrounding sugarcane fields to the interior of the wetland, given the absence of riparian forest or buffer zone, in addition to the risk of contamination of surface and groundwater. Understanding the local hydrological dynamics should subsidize the sustainable use of the soil providing preservation of water resources, with emphasis on aquifers, a source of increasing importance in the face of the imminent scarcity of surface resources.

Em primeiro lugar faz-se uma introdução ao presente conjunto de artigos sobre habitação intergeracional.No artigo abordam-se aspetos ligados especificamente à conceção residencial para idosos, inovação tipológica por integração de variadas funções residenciais e a realidade específica dos jovens idosos

Azores Islands are seismically active due to the tectonic structure of the region. Since the 15th century, they have been periodically shaken by approximately 33 moderate to strong earthquakes, with the most recent one in 1998 (Mw = 6.2). Nonetheless, due to insufficient instrumental seismic data, the region lacks a uniform database of past real records. Ground motion simulation techniques provide alternative region-specific time series of prospective events for locations with limited seismic networks or regions with a seismic gap of catastrophic earthquake events. This research establishes a local ground motion model (GMM) for the Azores plateau (Portugal) by simulating region-specific records for constructing a homogeneous dataset. Simulations are accomplished in bedrock using the stochastic finite-fault approach by employing validated input-model parameters. The simulation results undergo validation against the 1998 Faial event and comparison with empirical models for volcanic and Pan-European datasets. A probabilistic numerical technique, namely the Monte-Carlo simulation, is employed to estimate the outcome of uncertainty associated with these parameters. The results of the simulations are post-processed to predict the peak ground motion parameters in addition to spectral ordinates. This study uses XGBoost to circumvent the difficulties inherent to linear regression-based models in establishing the form of equations and coefficients. The input parameters for prediction are moment magnitude (Mw), Joyner and Boore distance (RJB), and focal depth (FD). The quantification of GMM uncertainty is accomplished by analyzing the residuals, providing insight into inter- and intra-event uncertainties. The outcomes demonstrate the effectiveness of the suggested model in simulating physical phenomena.

A praia da Vagueira está localizada no Município de Vagos, distrito de Aveiro e é protegida por uma estruturade defesa frontal aderente que foi requalificada em 2015, com alteamento da sua cota de coroamento para + 10 m(ZH), devido à ocorrência de inundações na zona por ela protegida. Para caracterizar o galgamento com a estrutura atual, aplicou-se o modelo numérico SWASH a uma secção desta estrutura, simulando-se os temporais ocorridos entre 1979 e 2018 que, segundo as fórmulas comumente utilizadas para este tipo de estrutura, dariam galgamentos significativos. Assim, nesta comunicação apresenta-se o modelo utilizado, as características da estrutura de defesa aderente e as condições de agitação e nível de mar utilizadas nas simulações. Os resultados obtidos com o SWASH são comparados com os resultados de várias fórmulas empíricas. Para todas as condições testadas, as fórmulas empíricas apresentam sempre caudais médios de galgamento não nulos, enquanto o SWASH apenas origina caudais médios de galgamento superiores a zero quando o espraiamento máximo não atinge o coroamento da estrutura. Consequentemente, a utilização dos resultados das fórmulas empíricas para a emissão de alertas pode conduzir a situações de alarme que não correspondem à realidade.

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), aborda-se, no presente artigo, em primeiro lugar, a necessidade e a oportunidade de uma nova oferta residencial muito diversificada para os idosos, matéria esta que é, depois, abordada em termos dos seus principais aspetos.Depois avança-se para o apontamento de algumas experiências diversificadas para o habitar dos idosos e, sequencialmente, aborda-se a temática do viver com independência numa sociedade envelhecida, matéria esta que é, em seguida, ligada ao uso/design universal habitacional e aos aspetos da influência da autonomização dos idosos numa renovada e talvez mais sustentável estratégia de cuidados de saúde

Along the Portuguese coastline, several military fortifications were built with the intentionto protect the territory from the constant military threat from the sea. These constructions have beensubjected, during centuries, to a very aggressive environment; the renders, whose main functionis the protection of walls, are particularly exposed to such actions. Nossa Senhora dos Anjos dePaimogo

Along the Portuguese coastline, several military fortifications were built with the intention to protect the territory from the constant military threat from the sea. These constructions have been subjected, during centuries, to a very aggressive environment; the renders, whose main function is the protection of walls, are particularly exposed to such actions. Nossa Senhora dos Anjos de Paimogo