Hashem Jahangir - Assistant Professor, Department of Civil Engineering, University of Birjand, Birjand, Iran,
Hamed Hasani - M.Sc in Structural Engineering, Department of Civil Engineering, University of Birjand, Birjand,Iran,
Fatemeh Shahbazi Aval - B.Sc student of Civil Engineering, Department of Civil Engineering, University of Birjand, Birjand,Iran,

In this paper, with the help of vibrational data of reinforced concrete (RC) frame structural elements, a method for estimating the severity of damage is presented. This method is based on data obtained from the dynamic responses of the structures. The mode shapes of the RC frames in the damaged and undamaged states were considered the input of the damage index. Then, using the proposed damage index, the severity of damages at different static loading stages is assessed. The damages were caused by gradually applying loads to the numerical model of the frame and have been investigated to evaluate the capability of the proposed method. The results showed that the damage index, with the help of the structure's mode shapes and dynamic responses, can determine the severity of damage to it, and the index can be used to assess the severity of damage in RC frames.

Damage severity, RC Frame, Modal Data, Damage Index.