Abstract: To enhance the quantitative assessment methodology for seismic performance of round-ended solid railway bridge piers, particularly considering shear damage effects, this study proposes a fiber-section and layered shell element coupled finite element model that comprehensively considers both flexural and shear damage. The model's reliability was validated through three sets of quasi-static experimental data. Quasi-static numerical analyses were conducted on 90 bridge pier specimens with three structural parameters to investigate damage evolution patterns. The Park-Ang damage index (DI) was selected as the performance metric, leading to the establishment of modified DI calculation formulas for both longitudinal and transverse directions of round-ended railway bridge piers. Results demonstrate that the composite model integrating fiber and layered shell elements effectively simulates the seismic behavior of round-ended solid bridge piers. Shear deformation significantly influences bridge pier damage progression. Recommended modified DI thresholds of 0.00, 0.125, 0.41, and 1.00 for transverse direction, along with 0.00, 0.13, 0.48, and 1.00 for longitudinal direction, are proposed as performance limit states corresponding to intact, minor damage, moderate damage, severe damage, and complete failure conditions respectively. These findings provide theoretical support for performance-based seismic design of railway bridge piers.