Cyclic constitutive model for concrete

A constitutive model for concrete subjected to cyclic loadings in both compression and tension is presented. The proposed model is intended to provide improvements on modelling the cyclic behaviour of concrete structures in the context of computational programs based on a smeared crack approach. Particular emphasis has been paid to the description of the strength and stiffness degradation produced by the load cycling in both tension and compression, the shape of unloading and reloading curves and the transition between opening and closing of cracks. Two independent damage parameters in compression and in tension have been introduced to model the concrete degradation due to increasing loads. In the case of cyclic compressive loading, the model has been derived from experimental results obtained by other authors by considering the dependency of the cyclic variables with the damage level attained by the concrete. In the case of cyclic tension a simple model is adopted based on experimental observations. The main novelty of the proposed constitutive model lays in the fact that all the required input data can be obtained through the conventional monotonic compression and tension tests.