Finite-element study of the diagonal-tension failure in reinforced concrete beams

In this work, we aim to tackle one of the most devastating failure modes in reinforced concrete (RC) structures: the diagonal-tension failure. In order to study this phenomenon numerically, a model capable of dealing with both static and dynamic crack propagation as well as the natural transition of these two regimes is necessary. We chose a discrete cohesive model for concrete fracture, an interface bond-slip model for the deterioration between concrete and steel rebar, both combined with an insertion algorithm. The static process is solved by a dynamic relaxation (DR) method together with a modified technique to enhance the convergence rate. The same DR method is used to detect a dynamic process and switch to a dynamic calculation. The methodology is applied to model the experimental results of Carmona et al. (Engineering Fracture Mechanics 74:2788–2809, 2007), where the recognition of the transition to a dynamic fracture in a presumably static calculation is essential to reproduce the diagonal-tension failure observed.