Vibration characteristics of spread foundation pier model with progress of local scouring

摘要

The soundness of the pier may be evaluated using the natural frequency of the pier, because it is not easy to visually confirm the scour condition of the ground around the pier directly after the river level rise. In this study, to investigate the influence of local scouring directly on the vibration characteristics of the foundation pier model, an experiment in which the model ground supporting the model pier is excavated in stages and a local scouring experiment using an open channel model are conducted. The microtremor measurement of the model bridge pier was carried out at the time of those experiments. As a result, it was revealed that the damping constant of the soil-structure system tends to increase when the range of local scouring reaches the bottom of the pier. In addition to the natural frequency, it is considered effective to evaluate also the damping constant in the assessment of the soundness of the bridge pier.