The purpose of this study is to evaluate the damage level of concrete delamination or internal defects using impact elastic waves. First, the relationship between the sound waveform obtained from steel ball drop test and artificial corrosion crack in concrete was discussed. It was confirmed that the method considering attenuation property of wave form is important in order to evaluate damage, and a method of evaluating attenuation graphs using normalized wave energy curve was proposed. The proposed method was applied to steel ball drop test and laser hammering test to the specimen and succeeded not only to detect damage area but also to evaluate damage level. In addition, the applicability of the method to the surface vibrations on the existing tunnel lining using a laser hammering system was confirmed.
