Assessment of fatigue damage of prefabricated concrete composite beams with piezomagnetic signal

For prefabricated concrete structures constructed by the wet joining process, appropriate damage indicators need to be adopted to characterize fatigue damage development considering the effects of interface damage. In this study, through the cyclic load testing of 12 prefabricated concrete composite beam specimens with three different cross-section types, comparisons among the traditional damage indicators, such as deflection, stiffness, energy consumption, interface deformation and steel strain, and a new indicator - the piezomagnetic signal - are conducted. All damage indicators, including the piezomagnetic indicator, could characterize fatigue damage development. Furthermore, the piezomagnetic signal indicator could also reflect the impact of interface damage, similar to local indicators such as interface deformation and steel reinforcement strain. However, compared with local indicators, the piezomagnetic signal technique has the advantages of providing long-term monitoring provability and being a non-destructive method.