PERFORMANCE EVALUATION OF RAILWAY BRIDGE SUBSTRUCTURES SUPPORTED DECREASING RIVERBED

Abstract

There has been a problem of instability of bridge substructures supported decreasing riverbed in many rivers up to now. For railway bridges in a river, the performance can be evaluated by percussion test and estimation of decreasing riverbed. In the percussion test, a natural frequency can be identified to measure free vibration of bridge substructures applied an impact force. The estimation of the riverbed was based on accumalted field data. For a practical application, a performance of the Bridge over the Chikuma River constructed between Ueda and Shiroshita station in the Bessho Line was evaluated by the percussion test and estimation of the riverbed.