Abstract
In japan, about half-million bridges are present in the municipal roads. In 2023, 43% of them will be the age of more than 50 years. In small scale bridges, when the distance between the water surface and the slab bottom is small, there is that inspectors cannot be visually closer to the target site. Previously, these bridges are sometimes not been inspected in terms of the inspection cost and efficiency. However, since 2014, in order to be visually closer to the target sites have been mandatory, reduction of test cost has become a major issue. Accordingly, we have proposed an imaging apparatus which can enter the narrow space between the water surface and the slab bottom. By the vehicle with cameras moves over the float, it is possible to shoot a wide range of slab bottom. We made a prototype to confirm its basic performance. It is an apparatus that a vehicle with five cameras moves on the float of about the same size as the tatami. In a small scale bridge of the real, experiments were carried out to get the images of the slab bottom. As a result, it was possible to obtain resolution images necessary for general inspection.
