Signal processing based damage detection of concrete bridge piers subjected to consequent excitations

Damage detection at an early stage is of great importance especially for infrastructures since the cost of repair is considerably less than that of reconstruction. The change in stiffness and frequency could obviously indicate the occurrence of damage and its severity. Wavelet transform is a powerful mathematical tool for signal processing which provides more details compared to Fourier transform. In this paper, a model-free output-only wavelet-based damage detection analysis has been performed in order to achieve perturbation of detailed function of acceleration response in bridge piers. First, a nonlinear time-history finite element analysis was performed using 9 consequent earthquake records; from which, time-history acceleration response was derived. Also pushover and hysteresis curves were drawn based on the results. Furthermore, applying wavelet transform to structural response, some irregularities appeared in decomposed detailed function which imply on damage presence in the models. Finally, peak values of details could lead us to time instants of damage