Visual verification of civil engineering structures by UAV

摘要

It has passed over 50 years since more than half of civil engineering structures in Japan were constructed. Because almost structure were constructed between the high-growth era after World WarⅡin Japan. If their structures are not maintained, it is difficult that they use safely. Actually, the accident that the ceiling board of tunnel was fall and crashed was occurred. Therefore, it is necessary to maintain and to pre-inspect the structure to prevent an accident. Initial check is usually performed by viewing and sounding using a hammer by a skilled engineer. However, since a skilled engineer and a budget for initial check are insufficient, we are anxious about check folly not being performed. As it being shown, serious accidents have occurred, such as tunnel collapse. Therefore, it is expected to develop the method of initial check for civil engineering structures from simple and low cost. In this study, we have developed and verified the method of initial check for civil engineering structures by using the UAV. A digital camera and IR digital camera were loaded on the UAV. The IR digital camera was modified to remove an infrared cut filter and to put on an infrared pass filter from an ordinary digital camera. Visual verification was performed in places where viewing is usually difficult, such as the floor slab of a bridge, using the developed system. As the results, the omission of the bolt, exfoliation of the concrete surface, etc., were detected. But the verifications were difficult at the dark place by a shadow. It turned out that the devices of lighting on visible and IR is required. UAV turned out, essential to visual verification of civil engineering structures.