In this paper, a novel type of control strategy for the active control of uncertain civil structures is introduced. Robust time varying sliding sector for the active control of large, uncertain structures is proposed. The introduced method is chatter free and continuous. Chattering phenomenon is the main drawback in sliding mode controllers. This method is based on defining appropriate sliding sectors with their respective control rules. Sliding sector controller moves system’s states from outside the sector to inside of it with suitable control input. A large structure equipped with active tendons and with mass, stiffness and damping uncertainty is considered. The worst case design is considered where structure’s mass increases and its stiffness and damping coefficients decrease. Furthermore, by applying actuators’ failure, damage-tolerance capacity of the second-order sliding sector is investigated. The structure is subjected to different earth excitations to demonstrate the feasibility of proposed method under various earthquakes with different frequencies. The controlled responses of the structure are compared with LQR method which is a highly robust controller. Comparative results of the numerical simulation are presented to confirm the proposed method robustness and its ability to reduce the structures response under earthquake excitation, effectively.