Abstract
Soundness evaluation method for concrete structures is newly developed by non-contact inspection method by laser Doppler vibrometer and pulsed laser. The results by laboratory tests using concrete specimen revealed the following. The presence of defects can be estimated by the presence of damped waves. The presence or absence of defects can be judged with high accuracy even under the noisy measurement data by the assumption that the measurement data is impulse response and the LSCF, which is a kind of system identification algorithms. Moreover, vibration characteristic of the defects with physical significance can be quantified when there are defects. In addition to laboratory tests, field tests in Shinkansen tunnels are performed. The results demonstrated the availability of the soundness evaluation method and suggested that natural frequency of the lowest mode is one of the most useful indexes to evaluate the soundness from the vibration characteristic.
