755 research outputs found

    Advantages of using raw materials in ancient and recent buildings

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    Many of the existing buildings constructed mostly with natural raw materials, in European sites, are frequently lacking proper maintenance and, there-fore, a high degree of degradation is verified in these buildings compromising their integrity and reducing their lifetime probability. Often in the rehabilitation or reconstruction of old buildings the solution adopted is the partial or integral demo-lition and substitution of several building components. The aims of this study are to describe the most common constructive solutions in Portuguese buildings con-structed with raw natural materials, to specify the principal problems that affect each building component, and to present possible solutions to correct each defect. This study is focused on the principal elements that compose the building struc-tures in Portugal, including load-bearing walls, wooden floor and roof structures. The architecture solution, the structure solution, the building material’s identifica-tion/characterization, the sequence of structural failures and the main pathologies identification/characterization related to an early XX century Portuguese watermill were described and detailed. It may be considered as a real scale experimental model which may contribute to the rehabilitation and conservation fields of tradi-tional Portuguese buildings. The structural failure sequence was analyzed, the cor-rective solutions presented and studied privileges the adoption of materials and techniques similar and most compatible with the original ones. It’s also presented the structural solution savings of energy consumption and CO2 emission. The re-sults of this study were found to be easily extrapolated to the repairing of the Por-tuguese traditional buildings which are in general environmental friendly

    Contributo para a recuperação de edifícios antigos

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    Muitos dos edifícios construídos maioritariamente em materiais naturais, no espaço Europeu, revelam falta de manutenção adequada e apresentam por isso um elevado estado de degradação, comprometendo assim a sua integridade e reduzindo o período de vida útil do edifício. Uma das razões principais para este acontecimento é o custo da manutenção. É comum o aparecimento de patologias até em edifícios recentes. A causa para o aparecimento prematuro de patologias pode-se dever a erros de construção, erros de cálculo, materiais inapropriados ou de má qualidade, entre outros. É frequente, durante os trabalhos de reabilitação ou reconstrução de edifícios antigos, a demolição parcial, integral ou a substituição de vários dos seus elementos. Pretende-se com este estudo descrever as soluções construtivas frequentemente utilizadas em edifícios nacionais antigos construídos com materiais naturais, especificando os principais problemas que afectam cada componente do edifício e apresentando soluções possíveis para a correcção desses problemas, utilizando sempre que possível, materiais naturais e processos económicos. O estudo baseia-se nos elementos que compõem o edifício, incluindo paredes resistentes, pavimentos de madeira, elementos de cobertura e materiais de acabamento. Descrevem-se cronologicamente as sequências de colapsos das estruturas e a ligação causa/efeito às patologias. Estas possibilitarão ainda compreender como melhorar a robustez das estruturas e também a definição de propostas de reforço de estruturas de edifícios tradicionais. O edifício analisado neste estudo pode ser encarado como um modelo experimental de estruturas tradicionais. Este edifício apresenta como materiais mais comuns o calcário, madeira, argamassa de terra, tijolos cerâmicos maciços e reboco de cal. É efectuada ainda a identificação/caracterização da composição mineralógica dos materiais recorrendo ao microscópio electrónico e ensaios de raios-X. Pretende-se por isso analisar a solução arquitectónica, a solução estrutural, os materiais, a identificação de patologias e consequentes soluções para as mesmas, de edifícios antigos no contexto português. As soluções correctivas apresentadas e estudadas privilegiam a adopção de materiais e técnicas similares e mais compatíveis com as originais.Many of the existing buildings constructed mostly with natural raw materials, in European sites, are frequently lacking proper maintenance and, therefore, a high degree of degradation is verified in these buildings compromising their integrity and reducing their lifetime probability. One of the main reasons is the maintenance cost. Its common the occurrence of pathologies even in recent buildings. The causes of those pathologies could be constructions errors, designs errors, inappropriate materials or pour quality, among others. Often in the rehabilitation or reconstruction of old buildings the solution adopted is the partial or integral demolition and substitution of several building components. The aims of this study are to describe the most common constructive solutions in Portuguese buildings constructed with raw natural materials, to specify the principal problems that affect each building component, present possible solutions to correct each defect, using natural materials e economic tasks, where possible. This study is focused on the principal elements that compose the building structures in Portugal, including load-bearing walls, wooden floor, roof structures and finishing materials. The structural failure sequence was described and also the cause/effect connection of pathologies. This study will allow the understanding of the structures systems and consequent reinforcement proposals of traditional buildings. The building under study may be considered as a real scale experimental model The building is formed by: limestone, wood, earth mortar, ceramic bricks and lime mortar. Is also presented the building material’s identification/characterization using electronic microscopic test and X ray tests. Its intended do analyse the architectural solution, the structural solution, the materials, the identification of pathologies e its solutions of ancient buildings in the Portuguese context. The reinforcement solutions presented in this study privilege the use of materials and techniques similar to the original ones

    Distributed energy resources network connection considering reliability optimization using a NSGAII algorithm.

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    Trabalho apresentado conferência IEEE CPE-POWERENG, 4 a 6 de abril de 2017, Cádiz, EspanhaDistributed Energy Resources (DER) has been widely introduced in distribution networks in response to the increase of environmental awareness of the consumers. The benefits with the use of DER are increased with network reconfiguration, but in some countries exists the impossibility of island operation as well as the obligation to buy all the electricity generated. These limitations, in a network fault situation, causes a waste of resources, because of the unavailability of the DER. On other hand, the location of DER connection under the context of the improvement of the reliability indexes has not been studied. Thus, this paper will propose a multi objective optimization of the location of DER connection considering the switching devices placement to increase network reliability and availability of DER, minimizing at the same time the investment in equipment in a no island operation environment. For the resolution of the proposed formulation, it will be used the multi objective algorithm NSGA-II (Fast Non-dominated Sorting Genetic Algorithm). The formulation of the problem also considers a composite index made up of DER and interruption duration. This approach is applied to a real utility distribution network, with the results presented and discussed.N/
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