A practical fatigue strain prediction model for normal and high-strength concrete under compression

Fatigue-induced deterioration has played an important role in governing the reliability of modern concrete structures, such as wind turbines, highway pavements, and high-speed railway bridges. Although the fatigue of concrete gains increasing attention, a thorough understanding of its mechanism is still lacking, and an accurate model for the prediction of strain development under fatigue loading is required. This paper presents a practical model that is accurate in fatigue strain prediction for normal and high-strength concrete. In the proposed model, a visco-elastic–plastic fatigue strain equation is correlated to a well-established monotonic stress–strain model via assumed strain equivalences between concrete fatigue strain development and monotonic stress–strain behavior. The model has explicit closed-form equations and depends on four practical inputs [i.e., the cylinder compressive strength of concrete (fcm), the maximum stress level (Smax), the minimum stress level (Smin), and the frequency of fatigue loading (fp)]. The performance of the proposed model is evaluated by comparing its predictions for normal and high-strength concrete with those made by seven existing models. The comparisons show that the proposed model has the lowest Mean Absolute Percentage Error (MAPE) and the highest Integral Absolute Error (IAE) among all models for both normal and high-strength concrete, suggesting high accuracy in fatigue strain prediction.