This project is mainly funded by the National Science and Technology Support Plan topic 'Research on Key Technologies for Wind Resistance of Cross-Sea Extra-Large Span Steel Box Girder Suspension Bridges (2008BAG07B02)' and related National Natural Science Foundation projects. It falls within the field of structural wind engineering and bridge engineering science and technology, and is conducted in conjunction with the Zhoushan Xikoumen Bridge project. The main span of this bridge is 1650 meters, making it the world's largest span steel box girder suspension bridge and one that was independently researched, designed, and constructed by China. Suspension bridges are the bridge type with the greatest spanning capacity, and one of the main bottlenecks in engineering construction is wind resistance. This project aims to address the global wind resistance challenges faced by extra-large span suspension bridges under strong wind conditions, with the goal of enhancing China's innovative capabilities and technical competitiveness in wind resistance research for large-span bridges and promoting technological progress in the transportation industry. Research on wind safety and control for ultra-large span suspension bridge structures and traffic has been carried out, breaking through the bottleneck that restricts the construction and development of ultra-large span suspension bridges—the structural wind safety in both the completed bridge state and construction phase. This has solved the core issue of normal operation—the traffic wind safety on the bridge deck, directly supporting the construction of the Xikoumen Bridge, making it the first ultra-large span sea-crossing suspension bridge in China's strong wind areas. It has also provided technical accumulation and reference for the construction of other similar bridges. Regarding the structural wind safety of ultra-large span suspension bridges in the completed bridge state: a new type of split steel box girder with good wind resistance performance and economic indicators has been creatively developed, improving the flutter stability of ultra-large span suspension bridges. New laws have been discovered regarding the variation of flutter performance with slot width, and the difficult problem of structural flutter stability in the completed bridge state has been overcome. A three-dimensional nonlinear unsteady static wind stability analysis method has been established, The law that turbulence significantly reduces the static wind stability performance of bridges was discovered, and a probabilistic evaluation method for the static wind instability of large-span bridges was proposed. Theoretical analysis and wind tunnel test results accurately predicted vortex-induced resonance (VIR) in actual bridges, various vortex control measures were proposed, and the optimal scheme—active wind barriers—was selected for engineering practice. Measured results verified the effectiveness of vortex control. For the structural wind safety during the construction phase of extremely large-span suspension bridges: new laws of wind stability evolution during the construction phase of split steel box girders were revealed, a scientific erection sequence for stiffening girders was established, supporting safe construction on the project; based on field synchronous measurements of wind field parameters and structural aerodynamic parameters, the flutter response of the bridge under oblique wind conditions was studied, perfecting and developing the flutter analysis theory of extremely large-span steel box girder suspension bridges, and an optimization design method for temporary connecting parts between beam segments during construction was proposed. For the wind resistance safety of bridge deck traffic during the operation phase of the bridge: a pioneering active control variable attitude movable wind barrier was created, which simultaneously ensured the safety of both bridge deck traffic and structural wind resistance; a wind tunnel test system specialized in testing the aerodynamic parameters of wind-vehicle-bridge coupling was developed. Based on the aerodynamic parameters identified by this system, a method for coupled vibration analysis of wind-vehicle-bridge and anti-wind safety evaluation of traffic was established. The research results of this project have obtained one authorized national invention patent, five utility model patents, three computer software copyright registrations, published one monograph, and published 40 papers indexed by SCI and EI. It has been evaluated as 'reaching international leading level', 'reflecting the latest construction concepts of contemporary bridges', and 'playing an important role in promoting the development of modern bridge technology'. The research results are for safe, high-quality, The efficient completion of the Zhoushan Xikoumen Bridge provided important technological support, with direct economic benefits of 260 million yuan and subsequent annual economic benefits of 42 million yuan. The social benefits were significant, achieving a leapfrog development in bridge technology, promoting the advancement of industry science and technology, and having an important driving effect and profound influence on large-span bridges in China and even the world. It has broad application value and international competitive advantages.