In this study, the authors utilize the impact vibration test using a portable FWD machine as a simple soundness survey method of bridge decks. Reinforcing works including replacement of the deck was carried out in the target bridge. The tests were conducted before and after the deck replacement. We measured the response acceleration at various points on the deck. The deterioration check was examined by two methods. First, we examined natural frequencies by performing Fast Fourier Transform on the obtained acceleration. Next, we compared acceleration waveforms at each measurement point and investigated the acceleration gap that occurred between two measurement points.
