Damage detection of a reinforced concrete column under simulated pseudo-dynamic loading using smart aggregates

Structural health monitoring of bridge columns in areas of high seismic activity is highly demanded. In this project, piezoceramic-based transducers known as smart aggregates (SA) were employed to detect the damage of a reinforced concrete (RC) bridge column subjected to pseudo-dynamic loading. The SA-based approach has been previously verified for static and dynamic loading but never pseudo-dynamic loading. An active sensing approach was developed to real-time evaluate the health status of the RC column during the loading procedure. The existence of cracks attenuated the stress wave transmission energy during the loading procedure and reduced the amplitudes of the signal received by SA sensors. To detect the crack occurrence and evaluate the damage severity, a wavelet packet-based structural damage index was developed. Experimental results show that the values of the damage index increase with the increasing of the cracks in the RC column. In addition to monitoring the general severity of the damage, the local structural damage indices monitored the cyclic crack open-close phenomenon subjected to the pseudo-dynamic loading.