ABSTRACT This study develops new equations for predicting the constant-strength inelastic displacement ratio (C R ) by considering nonlinear single-degree-of-freedom systems subjected to near-fault ground motions. To this aim, an energy-based parameter, the MEA/MEV ratio, is firstly considered for characterizing the properties of pulse-like records. “MEA” and “MEV” represent the Maximum Energy of the half-cycle pulse in Acceleration and Velocity time histories, respectively. The effects of the MEA/MEV ratio on the C R spectra are investigated in terms of elastic-perfectly plastic hysteretic behavior. Finally, a simplified equation for estimating the C R spectra is developed, and its accuracy is evaluated by calculating the error measures.