Recently, the passive negative stiffness device (PNSD) is used to decrease the shear force in the structure by providing an apparent yielding in the entire system. Usually, due to extreme environmental factors the structure is damaged which leads to disrupt the PNSD performance; so that, the shear force and permanent irreversible deformation increase remarkably in the structure. This study proposes a new controller and develops a semi-active adjustable stiffness device (SASD) based on the combination of a damage detection method and the semi-active control strategy. The stiffness of the SASD is retuned based on the identified damages in the structure. The performance of the proposed controller are evaluated through numerical examples. By comparing with passive and uncontrolled cases, results show that the SASD is robust against any changes in the structural characteristics of the system and effectively decreases the dynamic responses and the damage severity caused to the structure simultaneously.
