Inspection methods for underwater structures of ports and harbors

In Japan, problems about deterioration of infrastructure become prominent recently. Inspections for outside states of underwater structure in ports and harbors are dependent on the visual observation by divers. Furthermore, in aged quay wall, the infill sand behind the wall escape into the sea, and sometimes subsidence or collapse of top surface of quay wall can occur. Against these back-ground, the Civil Engineering Research Institute for Cold Region (CERI) and the Institute of Industrial Science (IIS, the University of Tokyo) study and develop inspection methods for underwater structure by using acoustic measurement device. This paper introduces the inspection methods for outside and inside states of underwater structures of ports and harbors.