Objective With the advancement of new-type urbanization and metropolitan area development, suburban railway systems in China have entered a 'golden period' of rapid expansion. However, elevated bridges typically account for more than 70% to 80% of the alignment, making the cost control of bridge engineering directly related to the economic feasibility and sustainability of the entire project, with increasing urgency. Traditional cast-in-place bridge construction has shortcomings such as long construction periods, poor controllability of quality, and significant environmental impacts, which contradict the 'efficient and intensive' construction concept of suburban railways. Therefore, it is necessary to explore the economic performance of applying prefabricated technology in the construction of elevated bridges for suburban railways.

Method Based on LCC （life-cycle cost） theory, a refined economic analysis model is established, decomposing costs into four-level items, incorporating the monetization and quantification of indirect benefits, and introducing dynamic discount rates and Monte Carlo simulation. On this basis, simulation calculations are carried out using multi-scenario case studies of a 32 km suburban railway project, and the LCC cost differences between prefabricated technology and traditional cast-in-place methods are comparatively analyzed.

Result & Conclusion  The case simulation results show that for a 32 km suburban railway project, compared with traditional cast-in-place methods, the adoption of prefabricated technology results in a 10% increase in initial investment, but achieves comprehensive benefits of RMB 518 million through a 28.6% reduction in construction period. Meanwhile, operation and maintenance costs over 50 years can be reduced by 33%, ultimately reducing LCC by RMB 705 million （a saving rate of 24.6%）. Multi-scenario verification indicates that under different conditions such as urban areas, suburban areas, and special river-crossing sections, prefabricated technology consistently maintains an LCC savings rate of 22%-29%. Monte Carlo simulation shows that the probability of its economic advantage reaches 99.7%, and the conclusion demonstrates strong robustness. Therefore, promoting the application of prefabricated technology in suburban railway elevated bridge engineering holds significant practical value for achieving the economic feasibility of projects and implementing green construction concepts.