Estudo experimental de consolos de concreto com fibras moldados em etapas distintas dos pilares
Data
2017-11-15
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Biblioteca Digital de Teses e Dissertações da USP
Universidade de São Paulo
Escola de Engenharia de São Carlos
Universidade de São Paulo
Escola de Engenharia de São Carlos
Resumo
Descrição
A produção industrial do consolo tradicional apresenta dificuldades devido à grande quantidade de armadura em um espaço pequeno. Além da armadura do tirante principal, normalmente se utilizam estribos verticais e horizontais. O presente estudo experimental propõe um consolo moldado em etapa anterior à do pilar, com a armadura e superfícies preparadas para a ligação posterior com o pilar, durante a concretagem deste elemento. O consolo dispõe somente da armadura do tirante principal e de fibras metálicas incorporadas à matriz de concreto, sem estribos verticais ou horizontais. Em alguns modelos foi utilizado um tipo de armadura de costura alternativo. As principais variáveis analisadas foram a taxa de armadura e o arranjo das barras dos tirantes. A adição de fibras ao consolo reduziu a fissuração na biela de compressão e aumentou a resistência à ruptura dos consolos em 8%, apresentando boa ductilidade, mesmo depois da máxima solicitação. Com o aumento da armadura do tirante no consolo com fibras, a resistência à ruptura foi 69% maior. Considerando o patamar de solicitação de serviço do consolo tradicional, os modelos moldados em etapas distintas apresentaram aberturas de fissuras na interface consolo-pilar 33% maiores, apesar de demorarem mais a aparecer. Entretanto, quando aumentada a taxa de armadura principal, os modelos moldados em etapas distintas demonstraram fissuras 23% menores que o consolo tradicional.
The industrial production of traditional corbel presents some difficulties due to the great quantity of reinforcement in a small space. Beyond the main bars, it is generally used vertical and horizontal stirrups. This experimental study proposes a corbel shaped in the prior stage to the column, with the reinforcement and surfaces prepared to the later connection with the column during the molding of it. The corbel has only the reinforcement of main bars and steel fibers incorporated to the concrete matrix, without vertical or horizontal stirrups. In some models were used a kind of alternative secondary reinforcement. The main variables analyzed were the reinforcement rate and the arrangement of the main bars. The addition of fibers to the corbel reduced the crack in the compressed diagonal and increased the resistance to rupture of corbels in 8%, presenting a reasonable ductility even after the maximum load. With the increase of reinforcement of main bars in the corbel with fibers, the resistance to rupture was 69% greater. Considering the baseline of service load of traditional corbel, models shaped in distinct stages presented crack openings 33% larger, in spite of taking a longer time to show up. However, when the rate of primary reinforcement was increased, the models shaped in distinct stages had cracks 23% smaller than the traditional corbel.
The industrial production of traditional corbel presents some difficulties due to the great quantity of reinforcement in a small space. Beyond the main bars, it is generally used vertical and horizontal stirrups. This experimental study proposes a corbel shaped in the prior stage to the column, with the reinforcement and surfaces prepared to the later connection with the column during the molding of it. The corbel has only the reinforcement of main bars and steel fibers incorporated to the concrete matrix, without vertical or horizontal stirrups. In some models were used a kind of alternative secondary reinforcement. The main variables analyzed were the reinforcement rate and the arrangement of the main bars. The addition of fibers to the corbel reduced the crack in the compressed diagonal and increased the resistance to rupture of corbels in 8%, presenting a reasonable ductility even after the maximum load. With the increase of reinforcement of main bars in the corbel with fibers, the resistance to rupture was 69% greater. Considering the baseline of service load of traditional corbel, models shaped in distinct stages presented crack openings 33% larger, in spite of taking a longer time to show up. However, when the rate of primary reinforcement was increased, the models shaped in distinct stages had cracks 23% smaller than the traditional corbel.
Palavras-chave
Consolo, Ensaio experimental, Fibras metálicas, Pré-moldado, Corbel, Experimental test, Precast, Steel fibers