A Fundamental Research on Crack Detection of Base Piles of Bridge Piers Using an Acceleration Pickup

This fundamental research is concerned with the crack detection of a concrete pillar combined with a concrete hexahedron, which is a model of the base pile of a bridge pier. Stationary waves are generated in the pillar by hitting the head of the concrete hexahedron with a hammer. An acceleration pickup on the hexahedron observes the stationary waves generated inside the concrete pillar through the concrete hexahedron. The proposed method measures the depth of the crack in the pillar by modeling the sensor output as an output of a linear dynamic system with unknown parameters and applying a maximum likelihood method. Experiments will show that the length of the pillar is accurately measured for a pillar with no cracks. By combining the result with our previous reports, we can easily expect that the location of cracks will also be accurately measured if the pillar has cracks