ABSTRACT
Normally crack and deformation inspections are necessary before planning repair and maintenance works for bridges, tunnel linings and other construction structures. In Japan, a conventional method, close visual inspection, is normally used for inspecting cracks of concrete infrastructures. The conventional method, temporary footholds must be constructed or a man-lift truck must be used for inspecting cracks of high rise bridges or tunnel crowns. This causes injury risks of inspectors, more working duration and more overall inspection cost. Moreover, the close visual inspection cannot be performed at some parts of structures at high place.
