962 resultados para Construction techniques


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O presente trabalho foi desenvolvido na obra do Aproveitamento Hidroelétrico de Foz Tua onde a autora teve oportunidade de realizar o estágio curricular junto da equipa da Fiscalização no período de 2 de Fevereiro de 2015 a 31 de Julho de 2015. A elaboração do presente trabalho pretende transmitir conhecimentos adquiridos relacionados com a constituição de um Aproveitamento Hidroelétrico, os tipos de barragens existentes, monitorização e controlo da segurança da estrutura da Barragem, controlo de qualidade de betão e o processo construtivo de uma Barragem. A construção da Barragem do Aproveitamento Hidroelétrico de Foz Tua tem sido realizada através do método tradicional, que consiste na aplicação de betão convencional compactado por vibração interna. Ao longo deste processo, foram aplicadas diversas técnicas construtivas, nomeadamente: escavação, betonagem, refrigeração artificial, injeção de juntas e tratamento de fundações. Neste trabalho foram ainda analisados os cuidados de segurança necessários neste tipo de estruturas, tendo como base o Regulamento de Segurança de Barragens. Este regulamento define as regras a seguir durante a execução da barragem e a monotorização que deve ser efetuada à mesma, permitindo assim o controlo da segurança da estrutura na sua construção e vida útil. É necessário ainda existir um controlo da qualidade, produção e aplicação do betão na estrutura de modo a aumentar a segurança, qualidade e durabilidade da mesma.

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Cette thèse entend contribuer à la compréhension du processus de conception architecturale par le biais du concept de tectonique, notion dont l’historicité confirme une certaine diversité de significations, mais qui suscite une réflexion fondamentale sur le rapport entre l’esthétique architecturale et les moyens constructifs. La connaissance technique de la construction, constituée principalement au 18ème siècle, permettra une nouvelle réflexion sur le rapport entre l’esthétique architecturale et les moyens constructifs. Au 19ème siècle, moment de l’apparition du concept de « tectonique » dans le contexte du débat sur la notion de style, l’indéniable contribution de l’architecte et théoricien Gottfried Semper reconnaît la complexité matérielle de l’édifice. La reprise du terme au 20ème siècle par l’historien et théoricien Kenneth Frampton va quant à elle déplacer le sens de la tectonique vers l’idée d’un « potentiel d’expression constructive ». Ces deux auteurs représentent deux grandes approches tectoniques convergeant sur la nécessité, pour toute théorie de l’architecture, d’encourager une réflexion critique de la construction. Cette thèse se développe en deux parties, l’une retraçant l’histoire et les enjeux de la tectonique, l’autre, de nature plus concrète, cherchant à tester l’actualité du concept à travers une série d’analyses tectoniques de projets modernes et contemporains. À la croisée de deux contextes géographiques différents, le Canada et le Brésil, le corpus de projets de concours que nous avons constitué considère la tectonique comme un phénomène transculturel. Nous formulons l’hypothèse d’une « tectonique du projet », c’est-à-dire d’un espace théorique dans lequel les questions relatives au bâtiment s’élaborent dans des « tensions » dialectiques. L’actualité des catégories semperiennes, dans lesquelles les différents « éléments » du bâtiment représentent différentes techniques de construction, est revisitée à partir de l’étude des projets de Patkau Architects (1986) et de MMBB Arquitetos (1990). Une tension entre les expressions symbolique et formelle issues du matériau brut est plus explicite dans l’étude des projets de Ramoisy Tremblay architectes (2002) et de Brasil Arquitetura (2005). La théorie de la transformation de matériau (Stoffwechseltheorie) de Semper est réexaminée parallèlement dans les projets d’Arthur Erickson et Geoffrey Massey (1967) et de Paulo Mendes da Rocha (1969). Dans l’ensemble de tensions tectoniques présentes tout au long de la conception, nous avons retenu plus particulièrement : le contact avec le sol, la recherche d’une homogénéité constructive, ou son opposé, la recherche d’une variété matérielle et, finalement la tension entre la dimension représentationnelle et la dimension technique de l’architecture. La modélisation du concept de tectonique, par un ensemble de tensions auxquelles les concepteurs doivent s’adresser en phase de projet, confirme que des questions en apparence simplement « techniques » concernent en fait tout autant le génie de l’invention que la connaissance historique des idées architecturales.

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The main objective of carrying out this investigation is to develop suitable transducer array systems so that underwater pipeline inspection could be carried out in a much better way, a focused beam and electronic steering can reduce inspection time as well. Better results are obtained by optimizing the array parameters. The spacing between the elements is assumed to be half the wavelength so that the interelement interaction is minimum. For NDT applications these arrays are operated at MHz range. The wavelengths become very small in these frequency ranges. Then the size of the array elements becomes very small, requiring hybrid construction techniques for their fabrication. Transducer elements have been fabricated using PVDF as the active, mild steel as the backing and conducting silver preparation as the bonding materials. The transducer is operated in the (3,3) mode. The construction of a high frequency array is comparatively complicated. The interelement spacing between the transducer elements becomes considerably small when high frequencies are considered. It becomes very difficult to construct the transducer manually. The electrode connections to the elements can produce significant loading effect. The array has to be fabricated using hybrid construction techniques. The active materials has to be deposited on a proper substrate and etching techniques are required to fabricate the array. The annular ring, annular cylindrical or other similar structural forms of arrays may also find applications in the near future in treatments were curved contours of the human body are affected.

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Esta dissertação é muito mais do que um trabalho sobre ajardinamento de edifícios, pois pretende-se que seja uma ferramenta de ajuda em benefício da transformação de milhares de metros quadrados, das coberturas e das fachadas, muitas vezes negligenciados, em espaços verdes públicos beneficiando, não somente, os promotores imobiliários mas, acima de tudo os seus ocupantes e usufrutuários, que desta forma podem tirar partido de novos espaços de estar, ao ar livre. Enquanto a cidade, ao nível térreo, apresenta um aumento de tráfego rodoviário, com inegável poluição e confusão, é possível, desta forma, usufruir de um espaço aberto. Esta dissertação procura estudar os edifícios que já integram o elemento vegetal no seu conceito e que sejam um sucesso na forma como usam o elemento vegetal, de modo a divulgar as técnicas de construção, entender as decisões dos projectistas e o impacto nos utilizadores que habitam e usufruem dos espaços – Análise-Pós-Ocupação. Esta dissertação pretende demonstrar o quanto é importante que as cidades apresentem espaços verdes para uso da população. As zonas verdes existentes nas cidades são inequivocamente um importante indicador da qualidade ambiental existente nessas mesmas cidades. As coberturas e fachadas verdes arrefecem os edifícios, capturam e filtram as águas da chuva, proporcionam habitat à vida selvagem, reduzem o efeito de estufa das cidades, proporcionam uma preciosidade estética, uma experiência recreativa e por vezes comida, para os habitantes das cidades. Pretende-se assim, focar os benefícios humanos, sociais e naturais que se obtêm ao introduzir vegetação nas paredes, terraços, pátios e coberturas dos edifícios. Assim foi considerado útil usar uma metodologia para também analisar o tipo de espécies usadas nos estudos de caso, e determinar a necessidade de uma ferramenta para que a selecção vegetal respeite critérios de biodiversidade e melhor adaptabilidade aos ecossistemas locais, sabendo de antemão que não podem nem pretendem substituir os habitats naturais, que as cidades também podem e devem apresentar.

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A practical experiment is described which was used to help university students increase their understanding of the effect of construction methods and window design on passive solar heating and electrical heating. A number of one tenth scale model rooms were constructed by students and sited out-of-doors in the late autumn. The models were fabricated to mimic available commercial construction techniques with careful consideration being given to window size and placement for solar access. Each model had a thermostatically controlled electric heating element. The temperatures and electricity use of the models were recorded using data-loggers over a two week period. The performances of the models based on energy consumption and internal temperature were compared with each other and with predictions based upon thermal mass and R-values. Examples of questions used by students to facilitate this process are included. The effect of scaling on thermal properties was analysed using Buckingham’s p-theorem.

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The effect of climate change and global warming has received increased attention in society with constant reminders about the importance of energy efficiency and sustainability in buildings. Whilst the focus is often placed on smaller items such as plastic bags, air conditioners and motor vehicles, the emphasis has recently shifted to structures in the built environment. Office buildings have been identified as contributing significantly to global warming during their building lifecycle with a substantial contribution to CO2 omissions. In response, building designs and construction techniques have evolved over time to improve energy efficiency and reduce CO2 omissions. Whilst property valuers, managers and analysts must remain up-to-date regarding changes, relatively little research has been conducted about whether and how increased sustainability, such as signified in a Green Star rating affects a property’s highest and best value and long-term lifecycle. This study investigates the degree to which sustainability is understood in the property marketplace, especially in relation to property values with the emphasis placed on a cost- benefit analysis from both an owner’s and tenant’s perspective. Whilst it may be argued that incorporating sustainability into a new office building is cost prohibitive on a financial cost-benefit analysis, often various minor steps can be taken to upgrade the sustainability of an existing building. This project examines recent trends in capital expenditure to increase the sustainability of offices and where Green Star ratings have been applied to establish whether any corresponding increase in value is evident. In order to develop a researchframework, a thorough literature review will be conducted of recent Australian and overseas studies. This will enable links between sustainability and office buildings to be highlighted, and vitally how they affect a property’s value in both the short and long-term.

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Purpose — This study seeks to investigate the degree to which energy efficiency is incorporated into office building refurbishment and capital expenditure with the emphasis placed on a cost-benefit analysis from the owner’s perspective.
Design/methodology/approach
– In order to develop a research framework, a thorough literature review was conducted of three disciplines being construction technology, building refurbishment and property management. The study identifies differences between varying levels of capital expenditure to ensure an existing building is more energy efficient, with the emphasis placed on the cost of implementation and the potential for tenants to acknowledge the increased energy efficiency via higher rents.
Findings
– Office buildings have been identified as a contributor to global warming during the construction phase, however during the building lifecycle there is a greater contribution to CO2 omissions. Whilst various building designs and construction techniques have evolved to improve energy efficiency, the focus has largely been placed on new buildings where it is easier to incorporate change and innovative approaches. However, the proportion of new buildings constructed each year is relatively small in comparison to existing building stock, which requires regular capital expenditure to maintain and attract new tenants within a competitive marketplace.
Practical implications
– The increasing importance of energy efficiency affects the office market in a variety of different ways.
Originality/value – This paper identifies important links between the environment and the built environment, and the implications for office building owners.

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The effect of climate change and global warming continues to receive attention with many governments and organisations acknowledging the long-term problems associated with the trend, although offering limited realistic solutions. Office buildings have been identified as a contributor to global warming during the construction phase, however during the building lifecycle there is a greater contribution to CO2 omissions. Whilst various building designs and construction techniques have evolved to improve energy efficiency, the focus has largely been placed on new buildings where it is easier to incorporate change and innovative approaches. However, the proportion of new buildings constructed each year is relatively small in comparison to existing building stock, which requires regular capital expenditure to maintain and attract new tenants within a competitive marketplace. Overall the degree to which capital expenditure for an existing building actually includes energy efficiency is difficult to measure, although appears to lag substantially behind sustainable building techniques for a new building.

This study investigates the degree to which energy efficiency is incorporated into office building refurbishment and capital expenditure, with the emphasis placed on a cost-benefit analysis from both the owner’s and tenant’s perspective. Whilst it may be argued that a newly constructed energy efficient office building may be cost prohibitive, various steps may be taken to upgrade the energy efficiency of an existing building. This project identifies differences between varying levels of capital expenditure to ensure an existing building is more energy efficient, with the emphasis placed on (a) the cost of implementation and (b) the potential for tenants to acknowledge the increased energy efficiency via higher rents. In order to develop a research framework, a thorough literature review was conducted of three disciplines being construction technology, building refurbishment and property management.

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The significance of this research is that it is the first comprehensive analysis of cost performance across Australia. It is well known that measuring cost performance is not an easy task; comparisons of building projects on a `like-for-like’ basis are uncommon, and rarely occur in the real world. However, this paper analyses 120 different structural frame models that represent various; structural designs, construction methods, grid spans, and locations.

The research produced price models that were representative of structural frames used in medium-rise non-residential buildings. It is based on pricing a number of standard building frame designs in five Australian cities. The results represent the cost of producing the same building in different locations, using similar building construction techniques. By utilizing a standard model, project variables like building quality, ground conditions and access were eradicated, thereby facilitating an unbiased comparison of cost performance. I addition, the results are an indicator of building productivity based on costs per square metre of various construction types.

This research provides the Australian industry with robust data about the relative cost performance of various structural building frames. In addition, this research has wider implications because the models may also become useful data for the measuring relative cost performance in other countries.

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 Abstract: Prefabricated and modular solutions have formed a small part of the overall housing industry. This is particularly evident in Australia, where the market is dominated by hand-built housing using traditional construction techniques built by large-scale builders. This paper evaluates the ideal and the reality of prefabricated modular housing procurement in China for the Australian market. While there have been prefabricated components for the housing industry, primarily, most solutions are of volumetric nature. The findings question our understanding and methodology to prefabrication for Australia. The experiences of introducing building services into modules (pods) from overseas fabrication also have shortcomings. The case study presented indicates several of these problems and suggests a hybrid solution to volumetric delivery.

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Assuming that the form of a building shell and its content the spatial form are distinct dimensions of architecture - however indivisible and interdependent -, this study focus, in the light of the Social Logic of Space (HILLIER; HANSON, 1984), on the intrinsic properties through which domestic space was structured in a sample of single-family dwellings built in João Pessoa (PB) during the 1970s - when the vocabulary of modern architecture still prevailed in Brazil though sharing the urban scene with other architectural trends -, in order to investigate regularities or divergences underlying their conception. These dwellings were originally classified (ARAÚJO, 2010a) in five categories defined according to the form of their building shells and to their prevailing construction techniques: (1) Brazilian modern legacy (considered as truly Brazilian modern style); (2) Paulista architecture (that refers to the modern production of São Paulo, Brazil, from the 1950s through the 1970s); (3) experiences of rationalization and prefabrication ; (4) experiences of adaptation to the climate (referring to a design strongly influenced by the hot and humid climate of North-eastern Brazil); and (5) hybrid (to account for a kind of stylistic hybridism that includes formal attributes, which evoke our colonial past). This study aims to determine, through the analyses of nineteen cases that represent each category, whether this taxonomy corresponds to distinct modes of spatial configuration. This research therefore proposes an approach to the classification of domestic architecture based on topological properties. The dwellings spatial organization was represented, quantified and analyzed, their spatial properties explored in consonance with one another and with the literature. Results pointed out that there is no evidence of a reciprocal relationship between the formal look of the built shells and their respective spatial structures

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Comunidades vulneráveis estão sujeitas aos impactos causados por eventos climáticos e aos efeitos nocivos que eles provocam como perturbar o funcionamento da sociedade e a possível ocorrência de perdas materiais, econômicas e sociais. Quanto maior a capacidade de adaptar-se, menores as vulnerabilidades. Em Belém, a presença de cursos hídricos dentro da área urbana e a ocupação irregular ao longo das faixas marginais evidenciam os fatores que levam às frequentes enchentes na região. Provavelmente, as enchentes tenham aumentado a partir da postura das instituições públicas, que favoreceram a ocupação de áreas alagáveis da cidade através dos aterramentos e canalização de igarapés. Dessa forma, o processo de periferização foi intensificado nas áreas de várzea e o espaço, profundamente alterado pela ocupação das áreas não edificáveis, como as bordaduras dos cursos d’água urbanos. Em função disso, a pesquisa objetivou definir a vulnerabilidade e a adaptação autônoma aos impactos das inundações considerando indicadores sociais, habitacionais e de saneamento. Foram analisadas as formas estruturais de adaptação, a partir da observação das edificações, suas tipologias e técnicas construtivas. Para tal, a metodologia para a realização do trabalho foi dividida em três etapas, que compreendem a delimitação da área de estudo; a descrição das medidas autônomas contra inundações e a análise da população como produtora destas medidas. Os resultados retratam a tentativa da comunidade de diminuir as perdas sobre algo que a representa valor, ou seja, as tomadas de decisão de adaptação quanto à capacidade e ao tipo de ação da população, onde as medidas adaptativas refletem não somente as habilidades da comunidade, mas uma série de outros indicadores sociais, econômicos e cognitivos.