###### Abstract  
Structural robustness is defined by the international engineering community as the capabilities of structural systems that enable them to survive unforeseen or unusual circumstances. In order to highlight the unforeseen and unusual characteristics of wind hazards, this study introduces the concept of structural robustness into the wind-resistant design and evaluation of bridges and proposes the robustness evaluation of aerodynamic flutter and aerostatic torsional stability of long-span bridges. Furthermore, the return period of the design wind speed that a bridge can resist is used to represent wind-resistant robustness. Aiming at the problem of aerodynamic and aerostatic stability, the analysis methods of aerodynamic flutter stability robustness and aerostatic torsional stability robustness of long-span suspension bridges are respectively established. Based on the established methods of aerodynamic flutter stability and aerostatic torsional stability robustness evaluation, robustness analysis is carried out on eight completed long-span suspension bridges and two long-span suspension bridges to be built. The evaluation method proposed in this study makes it possible to measure the ability of bridge structures to resist multiple disasters using the same index. long-span suspension bridges; robustness evaluation; aerodynamic flutter; aerostatic torsional stability +
Footnote †: journal: Applied Sciences  
assessments. Several frameworks for reliability analysis were proposed by [PERSON] et al. [7], [PERSON] and [PERSON] [8], and [PERSON] et al. [9] to predict the probability of bridge failure against flutter. All of these studies on probabilistic assessment models provided a better understanding of the influence of both the uncertainties and physical randomness of the wind environment and bridge dynamic parameters. Furthermore, the applications of reliability analysis models determined the clear failure probability of a bridge due to flutter for a specified return period rather than providing an intuitive safety factor. In addition to the probabilistic-based approach, the ability of bridges to resist unforeseen wind hazards may be better evaluated by further considering the robustness of the structures. The concept of structural robustness was proposed by the international engineering community [10; 11; 12; 13] to deal with devastating damage and collapse of structures caused by unforeseen disasters (e.g., earthquake, typhoon, and terrorist attack). According to [PERSON] et al. [10], structural robustness is the ability of a structural system to resist damage that is disproportionate to the initial damage. The British Standing Committee on Structural Safety (SCOSS) [11] defines structural robustness as the ability to resist disproportionate damage. [PERSON] [12] defines structural robustness as the basic characteristic of a structural system to prevent damage transmission and mitigate the risk of disproportionate failure and progressive collapse. [PERSON] and [PERSON] [13] give a more accurate definition of robustness: robustness is the ability of a system to resist unforeseen or unusual circumstances. These definitions include two parts: the first is the action that has not been previously encountered or is beyond normal, and the second is the ability of the system to resist this action, which is especially suitable for evaluating the resistance to natural hazards or man-made disasters. In order to highlight the unforeseen and multi-disaster characteristics of wind hazards, it is necessary to introduce the concept of structural robustness into the wind-resistant design and evaluation of long-span suspension bridges. On the one hand, the wind-resistant robustness design and evaluation of bridges can extend the existing safety coefficient based on the allowable stress method and the partial coefficient based on the limit state method to the failure probability or return period based on the probabilistic limit state, which makes wind-resistant design and evaluation more scientific and reasonable.