In this article, ongoing studies to apply semi-active control devices to reduce undesired vibrations of civil engineering structures are investigated. In doing so, the barrier of the nonlinear inner mass single unit impact dampers is equipped by the magnetorheological fluid dampers. For convenience, this kind of impact dampers is briefly named smart impact dampers. Dynamic behavior of a vibratory system equipped with the smart impact damper is modeled based on the modified Bouc–Wen model for the magnetorheological damper. Performance of the smart impact damper to suppress free vibration of an Euler–Bernoulli beam is investigated. Furthermore, effects of varying applied current to the magnetorheological fluid damper on vibratory behavior of the beam are illustrated in user-oriented charts. The analysis results show that the smart impact dampers with optimal parameters can suppress undesired vibrations much better than conventional impact damper systems.