A new approach to concrete fatigue S-N curves considering load application rate

Most classical formulations of S-N fatigue curves in concrete assume that, when the maximum cycling is equal to the static strength of concrete, the element fails during the first cycle.However, this assumption ignores that the concrete strength depends on the load application rate.In this work, an S-N curve expression is proposed assuming that failure for N= 1 occurs when the dynamic strength of concrete is reached, which depends on the frequency and the stress range.To validate it, the new equation is fitted to several sets of experimental data.The results reveal that this curve reflects more accurately the test results, with higher R 2 coefficients than the classical S-N curves.