Harmonic vibration testing for damage detection and localization in concrete

Current structural health monitoring techniques face significant difficulties in damage diagnosis for heterogeneous materials such as concrete. In this article, we propose a damage diagnosis methodology that overcomes such difficulties and is capable of detecting and localizing the damage, using linear swept and harmonic vibration tests with swept and sinusoidal waveforms. The proposed damage detection procedure uses novel features based on singular value decomposition of linearly swept waveform test data. The latter singular vectors of the intact basis are found to be sensitive to the presence of damage. The damage localization uses a K-factor metric calculated using sinusoidal waveform test data. The K-factor is used to measure the deviation of a signal away from a sinusoid. The damage diagnosis methodology is demonstrated and validated using experiments on thin concrete slabs with drilled holes and thicker concrete blocks with alkali–silica reaction damage.