In this paper it is investigated the performance of a hybrid control system for the reduction of the seismic vulnerability of existing reinforced concrete (RC) asymmetric structures with coupled modes. For this kind of structures the purely passive control system is not always able to warrantee an effective response control, due to the modal coupling. To overcome this problem, a hybrid control strategy is proposed which allows the mitigation of the response regardless of the dynamic characteristics of the structure and the seismic input. The control system is made of bidirectional Active Tuned Mass Dampers (ATMD) located in the positions that minimize the structural response. Several multi-storeys structures with different mass eccentricities are considered to demonstrate the effectiveness of the control system. Simulations under natural earthquakes are carried out considering the directionality of the seismic input.