Structural health monitoring of concrete arch dams using the wavelet transform and modal assurance criterion methods

Structural health monitoring of dams is a necessary issue in water supply network. Not identifying the local damages in these super structures and their extension could lead to abrupt and total collapse and impose major life or financial losses. This research investigates the effects of damage on the concrete arch dams and the methods for their detection. For this purpose the finite element model of a concrete arch dam was analyzed using the wavelet transform once by static frequency analysis and the second time when it is subjected to dynamic accelerograms. In the wavelet transform method using the static frequency analysis, cracks were formed on the dam body and the obtained results were compared to those obtained from Modal Assurance Criterion (MAC) method. In the wavelet transform method, by applying dynamic loads, different damage scenarios, including 16 damage locations and 3 damage levels (change in the materials properties) were compared to the healthy state of the dam. In order to process the wavelet transforms the displacements obtained from the modal and dynamic analyses were utilized. The results showed that employing wavelet transform method by applying dynamic loads could better detect the damages.