Study of resonance condition of railway bridge subjected to train loads with a four-beam system

Abstract

Herein, an approach for the dynamic response of a four-beam system with arbitrary boundary conditions when subjected to successive moving loads is proposed. Based on the proposed method, the resonance condition of high-speed railway simply-support beam bridge with ballastless track-structure under moving train loads has been studied. Sine-Fourier series is an effective method that can play a key role in solving, particularly in transforming the infinite-degree-of-freedom four-beam system into a superimposed four-degrees-of-freedom system. The effect of boundary conditions of the track-structure on the dynamic response of the bridge was analyzed. It is concluded that obtaining the resonant speed of the bridge with ballastless track-structure via single-beam system is not the best route because the track-structure has an impact on the resonance characteristics of the bridges. Compared with previous studies, the four-degrees-of-freedom system obtained by proposed method greatly reduces the difficulty of calculating the natural vibration frequency. Thus, the resonant speed of any HSRSSBB could be quickly obtained, avoiding the dynamic response calculations. The analysis of the resonant speed conversion factor indicates that neglecting the track-structure can drastically overestimate the resonant speed of the bridge. The overestimation is particularly noticeable on the girders of lower mass, which are critical in engineering.