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Publication
Avaliação experimental do comportamento de vigas contínuas com secção em T de betão armado com varões de GFRP
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Abstract(s)
O crescente interesse por parte da engenharia civil, nos aspectos de durabilidade das estruturas de betão, sobretudo no fenómeno de corrosão nos varões de aço, teve um contributo determinante no aparecimento dos varões de fibra de vidro (GFRP). Em função de características como a sua grande resistência à corrosão, a sua não condutividade electromagnética, o seu reduzido peso específico e elevada tensão de rotura, os varões de GFRP são vistos, como uma alternativa eficaz aos varões de aço nas estruturas de betão. Contudo, aspectos importantes como o elevado custo, elevada deformabilidade e o mais importante, a carência de conhecimento do comportamento das estruturas de betão armado com varões de GFRP em consequência da ausência de ductilidade destes varões, têm dificultado a sua aplicação no domínio da engenharia civil.
Apresenta-se inicialmente, uma revisão bibliográfica sobre o estado do conhecimento actual, no que diz respeito ao comportamento das vigas de betão armado com varões de GFRP, com particular destaque para o comportamento à flexão.
O presente trabalho de investigação teve como objectivo principal, ensaiar, avaliar e analisar o comportamento à flexão de vigas contínuas de betão armado longitudinalmente com varões de GFRP. Sete vigas contínuas de betão com secção em T, divididas em quatro séries, foram ensaiadas com esse propósito. O efeito do confinamento do betão, em aspectos como a ductilidade, a capacidade de redistribuição de esforços e a resistência das vigas foram estudados e analisados, em consequência da maior cintagem do betão no apoio central numa das séries de vigas. Por outro lado, foi ainda comparado o comportamento à flexão das vigas contínuas armadas com varões de GFRP e aço, dimensionadas para a mesma carga de projecto.
Dos resultados obtidos, salienta-se a elevada deformabilidade e fissuração das vigas ensaiadas, e a boa capacidade de redistribuição de esforços naquelas em que tal foi esperado. Nas vigas com o betão confinado na zona do apoio central, os resultados experimentais mostram ainda que diminutamente, um incremento na capacidade de carga, na ductilidade das secções e consequentemente na capacidade de redistribuição de esforços.
The growing interest of civil engineering in aspects such as durability of reinforced concrete structures, particularly the phenomenon of corrosion in steel bars, had a decisive contribution in the appearance of the glass fiber (GFRP) rebars. Because its features to their such as corrosion resistance, to their electromagnetic conductivity, to their low specific weight and the high tensile strength, the GFRP rods are an effective alternative to steel rods in concrete structures. However, important aspects such as high cost, at high deformability and most importantly, the lack of knowledge of the behavior of concrete structures reinforced with GFRP bars a result of lack of ductility of these men, have hampered its application within of civil engineering domain. It is presented a literature review on the state of current knowledge regarding the behavior of beams Concrete reinforced with GFRP bars, with particular emphasis on flexural behavior. The present research work had as main objective, test, evaluate and analyze the flexural behavior of reinforced concrete continuous beams along with GFRP bars. Seven continuous beams of concrete T-section, divided into four series, were tested for this purpose. The confinement effect of concrete, of aspects such as ductility, the ability of stress distribution and resistance of the beams were studied and analyzed, in consequence of increased strapping of concrete in the central support of a series of beams. On the other hand, was further compared the flexural behavior of continuous beams reinforced with GFRP and steel rebars, scaled to the same design load. Of obtained results, if stresses the high deformability, the cracking of the beams tested, and the good ability to the efforts redistribution when this was expected. In beams with confined concrete in the zone of central support, the experimental results still show that diminished, an increase in cargo capacity, in ductility of sections and the consequently in ability to the efforts redistribution.
The growing interest of civil engineering in aspects such as durability of reinforced concrete structures, particularly the phenomenon of corrosion in steel bars, had a decisive contribution in the appearance of the glass fiber (GFRP) rebars. Because its features to their such as corrosion resistance, to their electromagnetic conductivity, to their low specific weight and the high tensile strength, the GFRP rods are an effective alternative to steel rods in concrete structures. However, important aspects such as high cost, at high deformability and most importantly, the lack of knowledge of the behavior of concrete structures reinforced with GFRP bars a result of lack of ductility of these men, have hampered its application within of civil engineering domain. It is presented a literature review on the state of current knowledge regarding the behavior of beams Concrete reinforced with GFRP bars, with particular emphasis on flexural behavior. The present research work had as main objective, test, evaluate and analyze the flexural behavior of reinforced concrete continuous beams along with GFRP bars. Seven continuous beams of concrete T-section, divided into four series, were tested for this purpose. The confinement effect of concrete, of aspects such as ductility, the ability of stress distribution and resistance of the beams were studied and analyzed, in consequence of increased strapping of concrete in the central support of a series of beams. On the other hand, was further compared the flexural behavior of continuous beams reinforced with GFRP and steel rebars, scaled to the same design load. Of obtained results, if stresses the high deformability, the cracking of the beams tested, and the good ability to the efforts redistribution when this was expected. In beams with confined concrete in the zone of central support, the experimental results still show that diminished, an increase in cargo capacity, in ductility of sections and the consequently in ability to the efforts redistribution.
Description
Keywords
Varões de fibra de vidro Vigas Flexão Ductilidade Confinamento Redistribuição de esforços Deformação Abertura de fendas Fiber Glass (GFRP) roads Beams Flexural Ductility Confinement Stress distribution Deformation Crack with Engenharia Civil . Faculdade de Ciências Exatas e da Engenharia