Failure behavior modeling of slender reinforced concrete columns subjected to eccentric load

This work presents a numerical model to simulate the failure behavior of slender reinforced concrete columns subjected to eccentric compression loads. Due to the significant influence of the lateral displacements on the loading state provided by an eccentric load, geometric nonlinearity is considered. The responses of the concrete in tension and compression are described by two scalar damage variables that reduce, respectively, the positive and nega-tive effective stress tensors, which lead to two different damage surfaces that control the dimension of the elastic domain. To describe the behavior of the reinforcements, truss finite elements with elastoplastic material model are employed. Interaction between the steel bars and concrete is modeled through the use of interface finite elements with high aspect ratio and a damage model designed to describe the bond-slip behavior. The results showed that the numerical model is able to represent the nonlinear behavior of slender concrete columns with good accuracy, taking into account: formation of cracks; steel yielding; crushing of the concrete in the compressive region; and interaction between rebars and concrete.