###### Abstract
[11] used the reliability theory to study the tremor stability of large span cable-stayed bridges and the law influencing key tremor stability parameters, such as main girder stiffness and wire break rate on the reliability of tremor. They developed the change law of the critical wind speed of the tremor with these parameters. [PERSON] [12] proposed a multi-parameter hybrid optimization design method for a partially cable-stayed bridge, which combines quadratic sequential programming algorithms in an optimization model, and optimizes a single-tower, single-cable deck in terms of force, deformation and cost. [PERSON] et al. [13] proposed an optimization model to study the effect of short tower cable-stayed bridges on the structural internal force, and, with the side main span ratio as the main research content, determined a range of values for the side main span ratio that would result in a reasonable force performance of the main girder. [PERSON] et al. [14] focused on the application of cable-stayed bridge optimization techniques in cable-stayed bridges from a large number of detailed review studies, which showed that the optimal design of new cable arrangement bridges such as cross-cables, large-span bridges and multi-span bridges have high application prospects in future, and future studies should explore the dynamic effects in future. [PERSON] et al. [15] conducted a multi-objective optimization study of cable-stayed bridge structures by considering the objectives of minimum cost, minimum deflection and minimum stress. They proposed a numerical calculation method, including structural analysis, sensitivity analysis and optimization and used prestressing of cable-stayed wires and cross-sectional dimensions of ties, towers and deck slabs as design variables. Studies show that lower stiffness of the main girder has a significant effect on the internal force and deformation of the structure, which tend to be more stable at a higher stiffness of the main girder. In addition, researchers such as [PERSON] et al. have proposed the concept of live load ratio of cable and girder, which emphasizes that the stiffness of the main girder should be considered simultaneously with the cable-stayed parameters to achieve optimal design [2; 16]. This is because the length of the cable-free zone of some cable-stayed bridges affects the stiffness of the main girder, and, therefore, its value and the setting of stiffness of the main girder should not be considered separately. Studies have focused on different bridge optimization parameters for cable-stayed bridges, including various design variables and factors for optimal design. In summary, the existing studies mainly focus on cable-stayed bridges and twin-tower low-tower cable-stayed bridges, and the sensitivity analysis of the main structural parameters of four-tower partial cable-stayed bridges has not yet been published to date. Moreover, the sensitivity analysis of the existing structural parameters of some cable-stayed bridges primarily involves the cable-stayed force and prestressing tendons, and no coupling study has been conducted on the length of the cable-free zone, main girder and cable-stayed stiffness. Therefore, we applied the multi-parameter coupled coordination model [17; 18] to the parametric analysis of partially cable-stayed bridges. The cable-free zone length, main girder stiffness, and cable-stayed stiffness are considered as different random variables, and a four-tower partially cable-stayed bridge is used as the background to characterize the structural performance by using the bending moment and deformation of the bridge under the action of structural self-weight, vehicle load, temperature and wind load to perform coupled sensitivity analysis of structural parameters.