Effect of fatigue degradation of the compression zone of concrete in reinforced concrete sections

This paper proposes a new model for reproducing the behaviour of concrete under fatigue capable to be used to analyze the response of reinforced concrete columns and beams. Such a model is firstly defined for concrete prisms under centric and eccentric compression, and then is applied to the structure of concrete–steel at the section level. The main parameters of the model have been fitted by means of comparison with experimental data. The paper illustrates how degradation of concrete by fatigue causes a process of redistribution of stresses along the section depth, and it may induce fatigue of the tensile reinforcement. The increase of permanent and total deformations observed in experiments is also studied and predicted at the section level, obtaining as well conclusions about the structure deflections.