Seyede Banafsheh Mirkazemi - M.Sc. Student, Department of Civil Engineering, Ferdows Branch, Islamic Azad University, Ferdows,Iran
Hashem Jahangir - Assistant Professor, Department of Civil Engineering, University of Birjand, Birjand, Iran
Ali Zahmatkesh - Department of Civil Engineering, Ferdows Branch, Islamic Azad University, Ferdows, Iran

Reinforced concrete (RC) beams are among the most important structural elements in the civil and constructional industry. Therefore, determining the initial cracks in RC beams is a vital issue among researchers. In this paper, signal processing techniques were proposed to identify multiple damage locations in numerical models of RC beams. To achieve this goal, the vibrational responses of numerical models under modal tests at different degrees of freedom were introduced as inputs to the wavelet transform method as a novel signal processing technique in damaged and undamaged conditions. The area under the wavelet transform coefficients, using bior۲.۸ as mother wavelet, was analyzed to locate single, double and triple damage scenarios. Moreover, a new damage threshold based on statistical features, average and standard deviation, of obtained damage index is introduced to avoid possible mistakes in damage localization. The results show that the proposed damage index could determine all of the multiple damage locations precisely.

Multiple damage scenarios, RC Beams, Signal Processing Technique