Dynamic responses and fatigue assessment of OSD in heavy-haul railway bridges

Abstract

With increasing freight volume and speed in heavy-haul railways, the impact of train loads on the orthotropic steel deck (OSD) has significantly increased, resulting in fatigue damage of bridges. In this study, the dynamic responses and fatigue assessment of OSD in heavy-haul railway bridges were carried out based on a coupled train-track-bridge analysis and hot spot stress (HSS) method. First, using Dongting Lake Bridge on Hao-Ji Railway as an example, a finite element (FE) model of OSD was established. Then, a simplified method of train loads is proposed to improve the calculation efficiency. The dynamic response results from the coupled train-track-bridge analysis and the moving train load method were compared. The most fatigue-prone detail was determined to be the rib-diaphragm joint weld at the notch. Subsequently, the HSS results of OSD for different scenarios were compared and analyzed. Moreover, the fatigue life of OSD was obtained. Due to multiple stress cycles and large local stresses caused by the heavy-haul train load, the fatigue life of OSD fatigue-prone detail is estimated to be 25.74 years. Finally, the effects of different parameters (e.g., axle weight, train speed, and track irregularity) on the fatigue life of OSD were analyzed. This study provides a reference for the design and evaluation of OSD in heavy-haul railway bridges.