An efficient tension-stiffening model for nonlinear analysis of reinforced concrete members

A constitutive model for reinforced concrete elements that takes into account the tensile capacity of the intact concrete between cracks, effect known as tension-stiffening, is proposed in this paper. In the model, the tensile stress–strain curve of concrete displays an exponential decay in the post-cracking range, defined by a parameter that depends on the reinforcement ratio and on the steel-to-concrete modular ratio. This parameter was derived taking as a basis the CEB tension-stiffening model. The model was implemented into a computational program that allows for nonlinear finite element analysis of reinforced concrete beams. The numerical results obtained by the program compared extremely well with several experimental results from simply supported beams tested under 4-point bending that displayed a dominant flexural behavior. Extension of the model to members subjected to combined flexural and shear is also presented.