# Review of the Main Cable Shape Control of the Suspension Bridge
## 4 Construction Control Analysis of the Main Cable Shape  
Different from other bridge types, the main cable shape cannot realize the design alignment through the tracking adjustment of the construction stage. To ensure that the main cable shape finally reaches the expectation, reliable calculation parameters, accurate calculation methods, and strict construction quality control must be employed. The following is discussed from two aspects: parameter sensitivity analysis and the construction process analysis method. 1. Parameter sensitivity analysis  
Parameter sensitivity analysis is a crucial approach to enhance construction control accuracy, which can help engineers to accurately grasp the main factors affecting the main cable shape and their influence degree. An analysis of the parameters influencing the main cable's condition on a self-anchored suspension bridge was performed by [PERSON] et al., using the finite element model [13]. The main cable configuration for various constructional conditions at any temperature was evaluated by [PERSON] et al. [76], using an engineering example. The average temperature sensitivity values for every hanging point elevation on the main span cable in different constructional conditions are compared in Figure 14. The obtained results reveal that the free cable's temperature sensitivity value is higher than the reference strand's, and that it is similar to the finished bridge state's, but the former is marginally higher than the latter. Subsequently, the constructional factors of a three-tower double-cable suspension bridge with two asymmetric main spans were analyzed using the same method [90]. Further, [PERSON] et al. [11] conducted parameter analysis on the triple-tower suspension bridge's static performance using a finite element model. [PERSON] [91] investigated the effects of temperature, saddle location, and the main cable's elastic modulus on the free cable shape on basis of a highway-railway suspension bridge. The results showed that the saddle mileage had a more significant influence than the saddle elevation on the elevation of the main cable, and the main cable's elastic modulus had a much bigger impact on the middle span's elevation compared with the side span. Additionally, under the condition of free cables, the relationship between temperature, and the mid-span and side span elevation was quite close. The parameter sensitivity analysis in the above literature is deterministic, that is, when an input parameter has a small perturbation, the quantitative relationship between the system output and the system input can be obtained. However, the randomness analysis can more properly reflect the fundamental traits of the structure. Using the quantitative findings from finite element analysis during the construction, [PERSON] et al. [92] quantified and evaluated the uncertainty of main cable stress and girder deflection in the key construction stages of an illustrated suspension bridge, but did not analyze the main cable shape. The uncertainty analysis of the main cable shape during the construction period has not been reported. Most of the research focuses on the change law of the structure in the finished bridge state [93; 94]. (2) Construction process analysis method  
The construction process analysis method can be divided into the FEM and analytical method. Based on the numerical iterations and FEM, a self-anchored suspension bridge interactive analysis framework (Figure 15) was constructed by [PERSON] et al. [95]. The framework was based on the stress-free assembly format (Figure 16), which avoids reliance on the forward iteration calculation, and had a high computational efficiency and good convergence. Any specific construction phase can be efficiently analyzed. [PERSON] et al. [1] constructed a modified medium model to determine the suspension bridge performance based on the complementary energy principle and variational calculus, which can more thoroughly take into account the deformation of suspension bridges during construction.