# Static Wind Reliability Analysis of Long-Span Highway Cable-Stayed Bridge in Service
## 1 Introduction  
With the increasing main span lengths in modern cable-stayed bridges, it is very necessary to conduct a comprehensive analysis and evaluation of their wind-resistant performance. Generally speaking, flutter has been widely considered because it is more prone to occur in bridge design, especially for long-span bridges [1; 2; 3; 4]. However, when there are more and more bridges with a main span exceeding 1000 m, aerostatic stability also becomes a primary factor which can be even more leading than the flutter instability in some projects, especially for cable-stayed bridges [5]. Static wind instability of bridges is caused by the interaction with the deformation of bridges and static wind loads [5; 6]. [PERSON] observed the torsional divergence caused by the static wind in the wind tunnel test of the suspension bridge in 1967 [7]. The researchers from Tongji University have also observed the static wind instability phenomenon of Shantou Bay No. 2 cable-stayed bridge through wind tunnel test and Jiang Yin suspension bridge [8; 9]. [PERSON] [10; 11] explored and improved the static wind instability of bridges, and preliminarily discovered the static wind instability mechanism. Other scholars [12; 13; 14] also analyzed and discussed the aerostaticstability of long-span bridges, taking into account the nonlinearity of the bridge structure and the uncertainty of parameters. The in-depth research on the static wind instability of long-span bridges by the above-mentioned scholars has helped people to understand the mechanism of static wind instability more profoundly, and also promoted subsequent scholars to conduct further research on basis of reliability theory for the static wind instability of long-span bridges. At present, there are many studies on the static wind reliability of long-span bridges using the deterministic analysis method. [PERSON] [15] used the Mont Carlo method to explore the reliability of the static wind stability of bridges. [PERSON] [16] explored the influence of different parameters on the static wind stability of long-span suspension bridges. [PERSON] [17; 18] evaluated the reliability of long-span suspension bridges in Japan, considering the influence of the geometric nonlinearity of structures. [PERSON] [19] took the long-span cable-stayed bridge as the background, and focused on the reliability theory and its calculation method to make the system more complete. [PERSON] [20] conducted a static wind reliability analysis on a steel truss suspension bridge, and considered the influence of factors such as the initial wind attack angle and the wind-resistant cable structure with or without a central buckle. These scholars all use the deterministic analysis method to analyze the static wind stability of bridges. But in practice, the uncertainty of some parameters such as structural parameters, wind speed, aerodynamic coefficients, and so on, has a great influence on the aerostatic instability of long-span cable-stayed bridges. In addition, the actual service conditions of existing bridges shall also be considered. As a result, the deterministic method for static wind instability analysis is not comprehensive, it is very necessary to conduct static wind reliability analysis on long-span cable-stayed bridges based on parameter uncertainty. Based on the previous research, the actual conditions of cable-stayed bridges in service, and the factors that may affect the static wind stability, in this paper the randomness of the three key parameters i.e., the static three-component force coefficient, the steel wire breakage rate of the stay cables and the broken position of stay cables is considered and Latin hypercube sampling method is used to randomly obtain the samples of these parameters according to their distribution.