The determination of dynamic properties of rc structures retrofitted with buckli̇ng restrained braces by using healt monitoring procedures

Our country is located in the high seismic zone and this resulted in catastrophic earthquakes in the last two decades. Many of the existing reinforced concrete (RC) structures in the seismic zones are vulnerable to earthquakes in our country. It is known by researchers that the existing RC structures, especially the structures constructed before 1999, pose a serious risk in terms of life and property. There are serious deficiencies in the existing RC structures due to insufficient controls and engineering applications. Furthermore, these structures are weak against the lateral demands. There are two alternatives for the deficient existing structures; the RC structures can be destroyed and then reconstructed or they can be retrofitted. One of the well-known seismic retrofitting techniques is adding steel braces to the RC frames. The main reason of using steel brace for the purpose of retrofitting is axial rigidity which is very high. Hence, the steel braces are used as a lateral load carrying members to improve the seismic performance of deficient RC frames. These new generation steel braces are named as buckling restrained braces (BRBs). They have approximately the same capacity under both compressive and tensile demands and their hysteretic behaviour are quite stable. The health monitoring of the braced frames with BRBs enables to provide characteristic of the retrofitted braced frames before and after retrofit and after lateral demands imposed by earthquake.