PROPOSAL OF AN ALGORITHM FOR ESTIMATING THE NATURAL FREQUENCY OF RAILWAY BRIDGE PIERS UNDER FLOOD CONDITIONS

Abstract

  Under flood conditions, a river flow can have a scouring action on a bridge pier foundation, reducing its stability and even toppling it, and as a result causing a severe train accident. In addition to installing protection works and rebuilding deteriorated piers, imposing operational restrictions according to water level is a practical method to secure safe train operations. This paper presents a study on a practical method for evaluating the natural frequency of a bridge pier based on microtremor, in order to support a decision when to lift such res restrictions imposed. In this paper we have proposed an algorithm for estimating the natural frequency accurately and swiftly on the basis of microtremor measurement obtained from a hydraulic model test and existing bridge piers test during high water level. Moreover, the effectiveness of the algorithm has been verified through its application to several different bridge piers.