Hybrid health monitoring of prestressed concrete girder bridges by sequential vibration-impedance approaches

A hybrid health monitoring system using sequential vibration-impedance approaches is newly proposed to detect two damage types in prestressed concrete (PSC) girder bridges, which are tendon damage and girder damage. It mainly consists of three sequential steps: global damage warning, damage classification, and damage estimation. In Step 1, a global occurrence of damage is warned by monitoring changes in acceleration features. In Step 2, damage-types are classified into either tendon damage or girder damage by recognizing patterns of vibration and impedance features. In Step 3, the location and the extent of damage are estimated by using a mode shape-based method and a frequency-based method. The feasibility of the proposed system is evaluated on a laboratory-scaled PSC girder model for which acceleration responses and electro-mechanical impedances were measured for several damage scenarios of tendon damage and girder damage.