Practice of Defect Reconstruction in Embedded Rail Jointed Track on Large-span Steel Truss Bridge Ends

［Objective］ To address the fractured joint bolt issues of embedded rail jointed tracks on large-span steel truss bridge ends, it is necessary to analyze the causes of the defects, design treatment plans, and explore reconstruction measures under non-disruptive operating conditions. ［Method］ Field investigations are conducted to collect data on fractured joint bolts and the variations in rail joint gaps with temperature changes, enabling a preliminary qualitative analysis. A finite element model of the interaction between bridge girder and rails is developed for theoretical calculations, to analyze the stress and displacement of the rails and verify the bolt strength. Based on the analysis results and reconstruction requirements, an engineering reconstruction plan is designed. ［Result & Conclusion］ As the expansion displacement of large-span steel truss bridges increases, the rail joint gaps in jointed tracks cannot accommodate the displacement of the bridge ends, leading to frequent bolt fractures near the bridge ends. By installing rail expansion regulators, the displacement between bridge and rails can be effectively mitigated. The rail expansion regulators should be installed in a straight configuration, positioned near the bridge ends, and a specially designed prefabricated regulator should be adopted to avoid secondary assembly on-site, ensuring structural stability and restoring the bridge deck. Rapid construction can be achieved by locally removing the ballast bed, drilling holes, and grouting fast-setting high-strength mortar under large steel plates. Approximately half of the available reconstruction window is used for track bed partial removal and drilling, enabling the completion of the main single-side rail expansion regulator installation within one operational window period.