# Flexural Behavior of Corroded High-Speed Railway Simply Supported Prestressed Concrete Box Grider
## 5 Conclusions  
To address the lack of research on the flexural behavior of corroded high-speed railway simply supported PC box girders, the failure mode, flexural stiffness, cracking moment, flexural bearing capacity, and displacement ductility factor of corroded scaled beams with different mass losses were experimentally and theoretically investigated. The main conclusions are as follows:  
1. Strand corrosion significantly reduced its mechanical properties, which in turn degraded the flexural behavior of the PC beams. In this test, when the mass loss was 12.30%, the cracking load, ultimate load, and ductility decreased by 27.8%, 29.9%, and 11.5%, respectively. 2. There existed a critical strand mass loss (7% in this study) for the reduction in the flexural bearing capacity of a corroded PC beam. A strand mass loss of less than 7% could lead to a linear degradation law with concrete crushing failure. As mass loss increased, the flexural bearing capacity exhibited an exponentially decreasing trend with strand rupture failure. 3. Strand corrosion had a negligible effect on initial flexural stiffness before concrete cracking. But after concrete cracking, the higher the mass loss was, the faster the flexural stiffness decreased. 4. The analytical model considering the effects of strand cross-section reduction, strand property deterioration, and concrete cracking can predict the cracking moment, flexural bearing capacity, and failure mode well. Figure 14: Displacement ductility factor. The experimental data and theoretical investigations in this study can provide a reference for the durability and secure operation of high-speed railway simply supported prestressed concrete box girders. However, the corrosion pit model was relatively ideal and test beams were designed according to the similarity theory. The investigation results approximately estimate the original structure, but the accuracy is still limited. Thus, we would like to have the opportunity to conduct a static load test of the prototype structure in the future. Writing--original draft, Y.K., J.Y. and R.T.; writing--review and editing, Y.K., H.J. and Z.Y. ; theoretical analysis, J.Y., R.T. and K.N. ; data collection, K.N. All authors have read and agreed to the published version of the manuscript. This research was funded by the Natural Science Foundation of Hunan Province, China (Grant No. 2023 JJ30674), the National Natural Science Foundation of China (Grant No. 51878663), and Fundamental Research Funds for Central Universities of Central South University (Grant No. 2023 ZZTS0331 and 2023 ZZTS0408). Not applicable. The data provided in this study could be released upon reasonable request. The authors gratefully acknowledge the financial support provided by the Natural Science Foundation of Hunan Province, China (Grant No. 2023 JJ30674), the National Natural Science Foundation of China (Grant No. 51878663), and Fundamental Research Funds for Central Universities of Central South University (Grant No. 2023 ZZTS0331 and 2023 ZZTS0408). The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. The following symbols are used in this manuscript: