## 7 Conclusions  
In this paper, the anti-slip saddle structure and rolling saddle structure in large-span bridges are studied in three aspects, including design principles, mechanical properties, and the casting process. The main conclusions are as follows:  
1. Based on the analysis of design principles and mechanical characteristics, it can be concluded that the anti-slip saddle increases the unbalanced horizontal force in the tower top, leading to saddle material loss and structural wear. The slip phenomenon is prone to occurring in the cable. The original sliding friction is changed into rolling friction. The two sides of the main cable horizontal force and the saddle rolling friction force are designed to be self-balancing, but the stability of the structural performance is insufficient.
2. A rolling saddle in a bridge project was taken as an example and its mechanical situation in the roller area was investigated. The maximum von Mises stress mainly occurs in the contact area of the base of the rope saddle and the roller shaft. The maximum von Mises stress in the upper structure of the rope saddle occurs at the bottom of the saddle groove and that of the roller shaft appears at the ends of the lower surface of the roller shaft.
3. The stress concentration phenomenon is prone to occurring in the rolling saddle because of the line contact in the contact area, and the rolling saddle is mainly subjected to vertical force, which is also consistent with the analysis of general mechanical characteristics. Thus, attention should be paid to the von Mises stress in the contact area between the saddle base and the roller shaft, the lower surfaces of both ends of the roller shaft, and the top surface of the tower, to avoid material damage.
4. Combined with the analysis of stress distribution and the saddle casting process, it is obvious that the casting process of the anti-slip saddle structure is mature, but also faced with problems due to the welding of thick plates, and urgently needs to be improved and upgraded. The rolling saddle is used with the all-welded casting process but its technology is relatively immature and the requirements for the roller shaft material performance are strict.  
Conceptualization, J.W. and G.L; methodology, J.W. and G.L; validation, J.W. and G.L.; formal analysis, J.W. and G.L.; investigation, J.W. and G.L.; resources, Z.Q.; data curation, J.W. and G.L.; writing--original draft preparation, J.W. and G.L.; writing--review and editing, J.W. and G.L.; supervision, Z.Q.; project administration, Z.Q. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
The original contributions presented in the study are included in the article, and further inquiries can be directed to the corresponding author.  
\begin{table}
\begin{tabular}{c c c c} \hline \multicolumn{1}{c}{**Content**} & \multicolumn{2}{c}{**Anti-Slip Saddle**} & \multicolumn{1}{c}{**Rolling Saddle**} \\ \hline \multirow{4}{*}{Mechanical characteristics} & Contact type & Face contact & Line contact \\ \cline{2-4}  & Friction type & Sliding friction & Rolling friction \\ \cline{2-4}  & Stress condition & Welding stress, unbalanced force & Higher vertical forces, stress concentrations \\ \hline Casting process & Structural fabrication & Cast-welded, mature process & All-welded, complex process \\ \hline Used materials & Material Selection & Thick steel plates with high welding performance & Highly pressure-bearing contact surface materials \\ \hline \end{tabular}
\end{table}
Table 2: _Cont._Conflicts of Interest: Author [PERSON] was employed by the China Energy Engineering Group Zhejiang Electric Power Design Institute Company Limited. The remaining author declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.