Development of Laser Remote Inspection Technique for Defect of Underwater Concrete Structures

Abstract

We experimentally detected the inner defects of an underwater concrete structure with a laser method. A concrete sample that includes an artifi cial hollow was placed under water. We irradiated its defect area with a pulsed laser under water and detected a natural vibration that was decided by the size of the defect area. When we irradiated the without-defect area, no natural vibration was detected. This result shows that underwater inspection with a laser method is possible in principle.