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Modelação numérica de vigas de betão armado com diferentes armaduras: varões de aço e de GFRP
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Resumo(s)
A constante inovação no desenvolvimento de materiais tem introduzido novos
desafios à engenharia, exigindo a adaptação de métodos de análise e dimensionamento a
novas soluções construtivas. Com isso, os varões de GFRP (polímero reforçado com fibra
de vidro) têm surgido como uma alternativa promissora, apresentando vantagens como
elevada resistência mecânica e à corrosão. No entanto, por se tratar de um material
relativamente recente no contexto estrutural, ainda são necessários estudos que permitam
compreender de forma mais aprofundada o seu comportamento global. O presente estudo
tem como objetivo a modelação numérica, através do Método dos Elementos Finitos
(MEF), de vigas de betão armado com diferentes tipos de armadura, aço e GFRP,
submetidas à flexão. Como caso de estudo utilizou-se o trabalho experimental
desenvolvido por Teixeira (2024) na instituição UTFPR-PB. Foram desenvolvidas
modelações e simulações numéricas para vigas com armaduras de aço e de GFRP. A
modelação das vigas de betão com armaduras de aço serviu para a definição da malha e
da calibração das leis constitutivas do betão, incluído os modelos de tension softening e
de tension stiffening. No caso das vigas com armaduras de GFRP, foi ainda analisado o
comportamento da interface betão-GFRP. Para tal, foram realizadas várias simulações
numéricas com o objetivo de avaliar a influência das leis constitutivas adotadas para o
betão e para a interface betão-GFRP. As análises efetuadas permitiram reproduzir de
forma satisfatória a evolução da curva carga–deslocamento e o desenvolvimento do
padrão de fendilhação observado experimentalmente, tendo em conta as limitações
associadas aos dados disponíveis. Foi também possível observar que os parâmetros que
mais influenciaram o comportamento numérico destas vigas, pela sua incerteza, foram o
módulo de elasticidade dos varões de GFRP, a tensão máxima de aderência, 𝜏𝑚 , e o
escorregamento associado a essa tensão máxima, 𝑠𝑚. A resposta numérica que melhor se
ajustou à curva média experimental foi obtida considerando-se o modelo mBPE baseado
no trabalho de Cosenza et al. (1997), para varões de superfície lisa.
Constant innovation in material development has introduced new challenges to engineering, requiring the adaptation of analysis and design methods to new construction solutions. In this context, GFRP (Glass Fiber Reinforced Polymer) bars have emerged as a promising alternative, offering advantages such as high mechanical strength and corrosion resistance. However, as this is a relatively recent material in structural applications, further studies are still needed to achieve a deeper understanding of its overall behaviour. The present study aims to perform the numerical modelling using the Finite Element Method (FEM), of reinforced concrete beams with different types of reinforcement, steel and GFRP, subjected to bending. The experimental tests conducted by Teixeira (2024) at UTFPR-PB was used as a case study. Numerical models and simulations were developed for beams reinforced with steel and GFRP. The modelling of concrete beams with steel reinforcement served to define the mesh and calibrate the constitutive laws of the concrete, including the tension softening and tension stiffening models. In the case of GFRP-reinforced beams, the bond behaviour between concrete and GFRP was also analysed. Several numerical simulations were performed to evaluate the influence of the constitutive laws adopted for the concrete and for the concrete-GFRP interface. The analyses carried out allowed for a satisfactory reproduction of the evolution of the load–displacement curve and the development of the cracking pattern observed experimentally, taking into account the limitations associated with the available data. It was also observed that the parameters that most influenced the numerical behaviour of these beams, due to their uncertainty, were the modulus of elasticity of the GFRP bars, the maximum bond stress, 𝜏𝑚 , and the slip associated with that maximum bond stress, 𝑠𝑚. The numerical response that best fit the experimental average curve was obtained by considering the mBPE model for smooth-surfaced bars, according to Cosenza et al. (1997) proposal.
Constant innovation in material development has introduced new challenges to engineering, requiring the adaptation of analysis and design methods to new construction solutions. In this context, GFRP (Glass Fiber Reinforced Polymer) bars have emerged as a promising alternative, offering advantages such as high mechanical strength and corrosion resistance. However, as this is a relatively recent material in structural applications, further studies are still needed to achieve a deeper understanding of its overall behaviour. The present study aims to perform the numerical modelling using the Finite Element Method (FEM), of reinforced concrete beams with different types of reinforcement, steel and GFRP, subjected to bending. The experimental tests conducted by Teixeira (2024) at UTFPR-PB was used as a case study. Numerical models and simulations were developed for beams reinforced with steel and GFRP. The modelling of concrete beams with steel reinforcement served to define the mesh and calibrate the constitutive laws of the concrete, including the tension softening and tension stiffening models. In the case of GFRP-reinforced beams, the bond behaviour between concrete and GFRP was also analysed. Several numerical simulations were performed to evaluate the influence of the constitutive laws adopted for the concrete and for the concrete-GFRP interface. The analyses carried out allowed for a satisfactory reproduction of the evolution of the load–displacement curve and the development of the cracking pattern observed experimentally, taking into account the limitations associated with the available data. It was also observed that the parameters that most influenced the numerical behaviour of these beams, due to their uncertainty, were the modulus of elasticity of the GFRP bars, the maximum bond stress, 𝜏𝑚 , and the slip associated with that maximum bond stress, 𝑠𝑚. The numerical response that best fit the experimental average curve was obtained by considering the mBPE model for smooth-surfaced bars, according to Cosenza et al. (1997) proposal.
Descrição
Palavras-chave
Modelação Numérica Método dos Elementos Finitos GFRP Aço Vigas de betão armado Aderência betão-GFRP Numerical modeling GFRP Steel Reinforced concrete beams Concrete-GFRP bond Finite Element Method