# Proposed New Analytical Method of Tower Load in Large-Span Arch Bridge Cable Lifting Construction
## 5 Conclusions  
In this study, to make the analysis of cable lifting construction of large-span arch bridges simple and efficient, a more accurate method of calculating tower loads was proposed and applied to the elaborated analysis of a tower. Meaningful conclusions were obtained as follows:  
1. Based on the principle of deformation coordination and some assumptions, a method of calculating the loads acting on towers caused by the cable system when the arch bridge is constructed by a cable lifting method is proposed. The method has the characteristics of high calculation accuracy and easy operation, which is conducive to the rapid analysis of cable lifting construction by engineers. 2. A new Y-shaped arch bridge with a cable suspension construction was used as the research case to verify the correctness and accuracy of the calculation method by comparing the actual measured and calculated values of displacement at the top of the tower, and a detailed verification method and process were given. 3. The purpose of the calculation method is to calculate and analyze the mechanical properties of the towers in cable lifting construction, so the calculation method is specifically applied to the engineering case using the formula method and finite element method to analyze the overall stability, carrying capacity, and deformation of the tower, and give some suggestions about the design of arch bridge cable lifting. 4. The deformation of the tower will directly affect the linearity of the arch rib. To reduce the nonlinear effect of the wind cable sag and increase the restraining effect of the wind cable to the tower, the wind cable should be set with a certain initial tension. Figure 18: Deformation of the steel pipe columns along the longitudinal direction of the bridge. Use the means of pre-deflection of the installation displacement of the tower under the action of initial tension of wind cable, which can achieve the purpose of allowing the maximum forward and maximum backward displacement of the tower to tend to be close. 5. The tower is the main carrying structure, and the cable tower is prone to longitudinal overall overturning instability, and the steel pipe columns of the buckle tower are prone to twisting instability. Therefore, in the process of designing the tower, efforts should be made to find a balance between increasing the stability safety redundancy and reducing the self-weight of the structure. 6. The normal stress of the tower's part of the pressurized rod or pressurized bending rod is larger, which is mainly diagonal rods for the universal rod, due to its length-width ratio being relatively large. During design, to ensure structural safety, the allowable stress should be increased 30% under the combined load of the temporary structure. 7. The steel pipe columns of towers are prone to compression bending instability, so their load-carrying capacity and deformation are analyzed in detail. The normal stresses on the top and bottom of the steel pipe columns will increase suddenly and should be given attention during design. The deformation analysis results of the tower show that the deformation trend on both sides of the tower is opposite and antisymmetric by the center line, which is consistent with the torsional instability results. Since the tower has relatively higher redundancy of compressive load-carrying capacity and smaller deformation safety reserve, therefore, the design can reduce the angle between the main cable behind the tower and the horizontal plane so as to reduce the horizontal thrust of the cable system to the tower, and then reduce the displacement of the tower by the thrust. In this paper, the research on tower load analysis in arch bridge cable lifting construction has achieved stage achievements, and the calculation method can effectively analyze the actual engineering problems, but there are still some places that need to be considered and improved.