*Article* **Prediction Study on the Alignment of a Steel-Concrete Composite Beam Track Cable-Stayed Bridge**

**Xiaogang Li 1,2,\*, Haoran Luo 2, Peng Ding 3, Xiaohu Chen <sup>3</sup> and Shulin Tan <sup>3</sup>**


**Abstract:** Due to the alignment of track bridges directly affecting the safety and comfort of rail traffic operation, the alignment prediction of track bridges needs to be accurate. However, the structure of steel-concrete composite beam (SCCB) cable-stayed bridges is more complex, and the alignment prediction needs to be more accurate. To further improve the accuracy of alignment prediction for large-span SCCB track cable-stayed bridges, a method based on the response surface method (RSM) is proposed. In this paper, the Nanjimen Yangtze River Track Special Bridge was taken as a case for research. Considering the randomness of the influencing factors, the 95% confidence interval was obtained by using Monte Carlo (MC) sampling analysis, and the predicted values were within the confidence interval. The results show that the method integrates the confidence interval under each confidence level by simulating the long-term deformation of different years after bridge completion. The method could accurately predict the alignment of large-span SCCB track cable-stayed bridges, and thereby provide technical support for alignment control and ensure the safe and comfortable operation of rail transit.

**Keywords:** large-span track bridge; steel-concrete composite beam; cable-stayed bridge; alignment prediction; response surface method; Monte Carlo
