A influência das ações repetidas na aderência aço-concreto
Data
2017-11-15
Autores
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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
Este trabalho descreve o comportamento da aderência do concreto armado sob ações monotônicas e repetidas através de uma revisão bibliográfica e de ensaios de arrancamento padronizados. A influência de alguns parâmetros foi analisada, como diâmetro da armadura, tipo e amplitude de carregamento. Os resultados dos ensaios monotônicos foram comparados com as recomendações do CEB-FIP MC 1990, EUROCODE 2 e NB-1/78. Também foi realizada a análise numérica da aderência monotônica por meio de elementos finitos. Considerou-se a barra lisa, elementos de contato entre o aço e concreto e comportamento elástico-linear dos materiais; pois a ruína experimental da ligação ocorreu pelo corte do concreto entre as nervuras. A resistência monotônica da ligação ficou compreendida entre condições boas e ruins de aderência. Os resultados calculados de acordo com as normas foram muito diferentes em relação aos valores experimentais, e apresentaram uma dispersão muito grande. A força repetida ocasionou a perda de aderência pelo crescimento progressivo dos deslizamentos. Os modelos numéricos não representaram o comportamento experimental, devido à resposta força-deslizamento não-linear.
This research describes the bond behaviour in reinforced concrete under monotonic and repeated loading through a state-of-art and standard pull-out tests. The influence of some parameters was analysed as deformed bar diameter, type and amplitude of loading. The monotonic test results were compared with recommendations of CEB-FIP MC 1990, EUROCODE 2 and NB-1/78. The numerical analysis of monotonic bond was realized through finite elements. It was considered smooth bar, contact elements between the steel and concrete, and materials as of linear-elastic behaviour, because the experimental degradation of bond was caused by concrete between the ribs sheared off. The monotonic bond resistance resulted between good and bad bond conditions. The results calculated according to the codes were very different from the experimental values and very disperse. The repeated loading causes bond degradation by progressive increase of slip. The numerical specimens did not represent the experimental behaviour because of the non-linear load-slip response.
This research describes the bond behaviour in reinforced concrete under monotonic and repeated loading through a state-of-art and standard pull-out tests. The influence of some parameters was analysed as deformed bar diameter, type and amplitude of loading. The monotonic test results were compared with recommendations of CEB-FIP MC 1990, EUROCODE 2 and NB-1/78. The numerical analysis of monotonic bond was realized through finite elements. It was considered smooth bar, contact elements between the steel and concrete, and materials as of linear-elastic behaviour, because the experimental degradation of bond was caused by concrete between the ribs sheared off. The monotonic bond resistance resulted between good and bad bond conditions. The results calculated according to the codes were very different from the experimental values and very disperse. The repeated loading causes bond degradation by progressive increase of slip. The numerical specimens did not represent the experimental behaviour because of the non-linear load-slip response.
Palavras-chave
aderência, força repetida, força monotônica, elementos finitos, concreto armado, arrancamento, finite elements, bond, monotonic loading, pull-out, reinforced concrete, repeated loading