Concrete Damage under Fatigue Loading in Uniaxial Compression

Despite rigorous efforts in the derivation of various fatigue damage models for concrete, damage predictions of sufficient accuracy are still limited to loading conditions similar to those of the experiments used for developing the models. Most models are void of salient factors affecting the fatigue behavior of concrete such as frequency, stress ratio, and loading waveform, and the approaches used in developing such models tend to be rudimentary. Therefore, further investigation is required. In this study, damage models are expressed for residual concrete strength and fatigue secant modulus using experimental data from tested cylindrical specimens, a damage function, and a stress- life model in the literature. The number of cycles leading to failure, required for normalizing the fatigue cycles for each specimen, is obtained using a proposed secondary strain rate model. The aforementioned influencing factors incorporated into the damage function result in robust models that account for variations in loading parameters.