Deformation adaptability of ballastless track on highway and railway long-span cable-stayed bridge

The deformation of long-span cable-stayed bridges in high-speed railway systems is significantly influenced by their complex operating environment. However, the ability of ballastless tracks to adjust to post-construction deformations is still limited. Therefore, the complex deformation conditions of long-span cable-stayed bridges will directly affect the adaptability of the ballastless track structure on top of them. Based on the application of ballastless track in the Yangtze River North Branch Highway and Railway Cable-stayed Bridge as the engineering background, a refined spatial finite element model for the integrated system of the ballastless track and the long-span cable-stayed bridge was established. The smoothness of long-span cable-stayed bridge ballastless track system, the stability of continuous welded rail and the coordination of deformations between the layers of the ballastless track under the combined action of various loads, including railway, highway, and temperature effects were analyzed. According to the research, a comprehensive investigation is conducted on the deformation adaptability of the long-span highway and railway dual-purpose steel truss cable-stayed bridge with ballastless track system. The results are drawn as follows. Under the combined action of operating loads and temperature loads in the most unfavorable combination, the main beam of the long-span cable-stayed bridge maintains smooth alignment and exhibits gradual deformation. The overall stiffness of the bridge is good, and the geometric position of the ballastless track on the bridge satisfies the static acceptance criteria. The strength and stability of the continuous welded rail on the cable-stayed bridge meet the requirements which means the fasteners work well and the rail expansion joints can effectively release the longitudinal stress of the rail. The rubber isolation layer can improve the deformation coordination performance of the ballastless track on the bridge. The ballastless track is in a state of compression between layers, achieving the ideal service condition of “isolation without separation”. The long-span highway and railway dual-purpose steel truss cable-stayed bridge with ballastless track system exhibits good deformation adaptability. The research findings presented in this work can serve as a technical reference for the application of ballastless tracks on long-span dual-purpose steel truss cable-stayed bridges. © 2024, Central South University Press. All rights reserved.