Abstract
In order to verify whether the initiation of the fatigue cracks at the inside of the U-rib of the steel plate deck (the invisible part) could be detected and the propagation of them toward the thickness direction of the deck plate could be monitored by FSM or not, a series of experiments and 3D static electric field analyses were carried out. The initiation of these fatigue cracks could be detected and the propagation of them toward the thickness direction of the deck plate could be monitored with high accuracy by the potential difference change (FC value) of the pairs sandwiching the fillet welds of the left and right sides of the U-rib. The fatigue cracks could be detected extremely earlier by FSM than the visual inspection by which the crack penetrated the deck plate. The features of the potential difference change with the initiation/propagation of the crack could be simulated by the 3D static electric field analysis. The results indicated that the initiation/propagation of the invisible cracks at the left or the right sides of U-rib could be detected and monitored by noting the behavior of FC value.
