Vibration-based damage monitoring algorithms for prestress-loss in PSC girder bridges

Among many damage types, prestress-loss in tendon is the major one that should be monitored in its early stage in, order to secure the safety of PSC girder bridges. This damage-type obviously change vibration characteristics, but with apparent difference depending on sensing mechanism as well as information analysis. Recently, there have been research efforts to develop wireless smart sensor nodes embedded damage monitoring algorithms for various sensing mechanisms. In this study, vibration-based damage monitoring algorithms which are appropriate for the smart sensor nodes to alarm the occurrence of prestress-loss in PSC girder bridges are presented. Firstly, two sensing mechanisms are considered for vibration characteristics: one is acceleration and the other is electro-mechanical impedance. Also, four acceleration-based algorithms and three impedance-based algorithms are selected to extract features from those signals. Secondly, the performances of those selected methods are evaluated using a large-scaled PSC girder for which a set of acceleration-impedance tests were measured for several prestress-loss scenarios by using both commercial instruments and a wireless smart sensor node.