Finite Element Simulation of Reinforced Concrete Beams under Fatigue Loading

Extensive attention has been directed towards the fatigue phenomenon since repeated loadings usually occur in highly important concrete infrastructures. Appreciable amount of experimental and numerical researches have been carried out to examine the RC beams behaviour subjected to monotonic loading. Conversely, limited studies have been conducted to investigate the performance of RC beams under fatigue loading. Up to this end, the principal objective of this study is to create an accurate two-dimensional finite element model to improve understanding the fatigue performance of RC beams. This is achieved by utilizing appropriate structural elements such that the concrete and supporting plates are modelled as 2D plane membrane elements, whereas truss elements are used to simulate the steel reinforcements. Regarding constitutive laws, suitable models are selected to accurately simulate the behaviour of concrete and reinforcing steel. For simplicity, full bond is assumed between the concrete and steel reinforcement. Additionally, the loadcontrol method is used for fatigue load application. The cyclic load is characterized as a sinusoidal load with the maximum and minimum amplitude changed with a fixed frequency. The accuracy of the model is verified by comparing the numerical results to the experimental ones in terms of load-deflection relationship, load-carrying capacity, stress profiles, crack patterns and failure modes for various number of load cycles. Eventually, it can be concluded that the numerical model is capable of precisely simulating the real RC beam behaviour with acceptable degree of convergence when compared to the experimental results.