| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 3.43 MB | Adobe PDF |
Authors
Advisor(s)
Abstract(s)
As estruturas têxteis tracionadas começaram a ter grande desenvolvimento durante a segunda metade do século XX, constituindo actualmente um sector relevante na área científica das estruturas de engenharia civil. Este tipo de estrutura era inicialmente constituído por cabos independentes, evoluindo depois para grelhas de cabos e posteriormente para membranas pré-esforçadas, das quais existem actualmente variados exemplos, nomeadamente com formas "livres".
O conhecimento científico tem apoiado a evolução do projeto e execução prática deste tipo de estruturas complexas, nomeadamente através da evolução dos métodos de cálculo e do estudo das características dos materiais, associado à concepção de ligações eficientes. A complexidade da análise das estruturas de tipo membrana tracionada reside no facto de apresentarem grande flexibilidade e comportamento estrutural geometricamente não-linear.
Denominadas como ‘estruturas leves’, destacam-se por vencer grandes vãos, pela facilidade de fabrico e montagem, pelo uso de tecido de fibras sintéticas de alta resistência como elemento estrutural, para além da grande diversidade de formas possíveis e em geral do custo reduzido.
Com o presente trabalho pretende-se estudar este tipo de estruturas, explorando o atual conhecimento sobre o assunto, com compreensão das vantagens em relação às estruturas convencionais, através de uma aplicação prática ao caso concreto da cobertura de um campo desportivo.
Inicia-se o trabalho através de uma recolha bibliográfica sobre o tema. Em seguida foi definido o tipo de cobertura a estudar, bem como os materiais a utilizar, as características e pormenores da membrana, os cabos de tensionamento e as estruturas de suporte da cobertura. No capítulo seguinte é feita a análise estrutural e a verificação da resistência em estados limite últimos, sob a acção do vento e da neve, tendo em conta o processo construtivo e o pré-esforço. Por fim foi definido o padrão de corte da membrana para que esta possa ser pré-esforçada de maneira correta e eficaz.
The textile tensile structures had strong development during the second half of the twentieth century, and are currently an important sector in the scientific area of civil engineering structures. This type of structure was initially based on independent cables, evolving to grids and then to cable textile tensiled membranes, currently with a broad range of examples, including the so called "free" forms. These structures are usually refered to as 'lightweight structures', adequate for large spans, easy to manufacture and assembly, using a fabric of high strenght fibers as structural element, obtaining a wide variety of forms at relative low cost. Scientific knowledge has been supporting the practical design and construction of such complex structures, namely through the development of calculation methods and the study of the material characteristics, associated with the design of efficient details for the connections. The complexity of the tensioned membrane structures is due to their high flexibility and non-linear behavior. The present work aims to study textile membrane structures, exploring the current knowledge on the subject understanding the advantages over conventional structures, through practical application to the case of a roof for a school sports field. The work begins with a bibliographic research of literature on the subject. Then the application example is presented, as well as the chosen materials as all the features and details of the membrane, cable prestressing and support structures. Structural analysis and safety verification of resistance on ultimate limit state under the action of wind and snow was performed, taking into account the constructive process and prestressing. In the last part of the work the cutting pattern of the membrane is addressed, in order to achieve an effective prestress.
The textile tensile structures had strong development during the second half of the twentieth century, and are currently an important sector in the scientific area of civil engineering structures. This type of structure was initially based on independent cables, evolving to grids and then to cable textile tensiled membranes, currently with a broad range of examples, including the so called "free" forms. These structures are usually refered to as 'lightweight structures', adequate for large spans, easy to manufacture and assembly, using a fabric of high strenght fibers as structural element, obtaining a wide variety of forms at relative low cost. Scientific knowledge has been supporting the practical design and construction of such complex structures, namely through the development of calculation methods and the study of the material characteristics, associated with the design of efficient details for the connections. The complexity of the tensioned membrane structures is due to their high flexibility and non-linear behavior. The present work aims to study textile membrane structures, exploring the current knowledge on the subject understanding the advantages over conventional structures, through practical application to the case of a roof for a school sports field. The work begins with a bibliographic research of literature on the subject. Then the application example is presented, as well as the chosen materials as all the features and details of the membrane, cable prestressing and support structures. Structural analysis and safety verification of resistance on ultimate limit state under the action of wind and snow was performed, taking into account the constructive process and prestressing. In the last part of the work the cutting pattern of the membrane is addressed, in order to achieve an effective prestress.
Description
Keywords
Estruturas têxteis - Fibras sintéticas Coberturas - Estruturas de membrana Membrana tracionada - Casos de aço Membrana tracionada - Análise não linear Membrana tracionada - Padrão de corte Cobertura de campo desportivo