DAMAGE EVALUATION METHOD FOR CONCRETE MEMBER BASED ON ACOUSTIC CHARACTERISTIC

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The method of the forced vibration test (frequency sweep testing) for the concrete member using a portable shaker was proposed. The relationships between the damage condition (e.g. concrete cracks, corrosion of reinforced steel bars, deterioration by freezing-thawing) of the concrete specimens and the vibration characteristics (e.g. resonance frequency, damping rate, modal frequency ratio) were investigated. Moreover, sound synthesis processing based on the velocity spectrum measured in the forced vibration tests was showed. It was able to listen to the sound pitch and tone of the concrete specimens.When the integer resonance of the concrete specimen was caused, the damage was identified based on the decreased in the pitch of a sound. Especially, the distributed cracks and the flexural cracks in the concrete member were clearly identified.