A technique for improving the damage detection ability of the electro-mechanical impedance method on concrete structures

To date, a relatively new non-destructive evaluation technique known as the electro-mechanical impedance (EMI) method has shown promising results in local damage detection. However, major issues still exist which are holding back its commercialization. For one, using the EMI method on large concrete structures to detect damage can be very difficult due to the absence of multiple peaks in the impedance signature, resulting in a vague change after subjection to any damage. Such minor variations can increase the uncertainties in damage identification, as other factors may also contribute to the changes in the signature. In this study, a technique is proposed to solve the aforementioned problem to allow a higher threshold value by significantly increasing the sensitivity of the impedance signature when subjected to damage. Experiments have shown that the proposed technique is very effective for concrete, enhancing the damage detection performance of the EMI method.