This project belongs to the field of bridge engineering science and technology. The cracking phenomenon of concrete slab components in large-span bridges (such as the concrete bridge deck of steel-concrete composite bridges, the top slab, web, and bottom slab of concrete box girder bridges, and the top and bottom slabs of wave-shaped steel belly plate bridges) is widespread around the world and is a difficult problem that modern bridge structures urgently need to solve. Many scholars at home and abroad have conducted extensive research, but the problem of cracking still exists, which is often attributed to external factors such as construction quality and environmental impact. In fact, we should look for breakthroughs from the source of design. At the structural and component level, traditional design methods do not specify complete verification stress indicators, with key indicators missing, which cannot reflect the true load-bearing conditions of complex bridge structures, especially they cannot reflect the in-plane load of concrete slab components, leading to a lack of theory for in-plane reinforcement. At the material level, For long-term service bridges, the durability design of reinforced concrete under complex environmental erosion often relies on empirical methods, without considering the impact of time-varying structural protection layer thicknesses under chemical erosion on the service life, leading to an increased risk of steel reinforcement rusting and cracking. This project, supported by Jiangsu Province's key construction project—the large-span steel-concrete composite girder cable-stayed bridge, aims to solve the problem of concrete slab cracking. Through theoretical analysis, numerical simulation, experimental verification, and real bridge monitoring research and practice, a multi-scale crack prevention technology based on comprehensive analysis and design of structure-component-material for concrete slab components has been formed and directly applied in actual bridges. The following innovative breakthroughs have been achieved: (1) At the structural level, for the first time, the spatial grid calculation theory is proposed, which can accurately obtain the in-plane stress laws of concrete slabs under any operating conditions of the bridge. Combining the main stress tracking test on the surface layer of the bridge deck during construction, the accuracy of the theory was verified and the deficiencies of traditional calculation theories were compensated for. The related research results have been included in the 'Highway Reinforced Concrete and Prestressed Concrete Bridge and Culvert Design Code' (JTG 3362-2018). (2) At the component level, based on the characteristics of grid theory that can directly face the reinforcement, a grid reinforcement design theory for concrete slab components 'in-plane force domain' was established, effectively balancing tensile stresses in any direction within the concrete slab to avoid cracking. (3) At the material level, a competitive replacement adsorption steel bar anti-rust technology was invented, which increased the critical chloride ion concentration threshold for steel bar corrosion by more than three times, solving the technical problem of anti-rust and swelling protection for concrete structures under complex environmental conditions. At the same time, In conjunction with the concrete durability design method based on dynamic time-varying effects under multiple factors, the service life guarantee rate of concrete components has been significantly improved. The project achievements have been applied to major domestic and international projects such as the Guanhai Bridge, Nanchang Chaoyang Bridge, Jiaojiang Second Bridge, Zhengzhou Longhai Road Expressway Project (Phase II) elevated mainline bridge, Yunbao Yellow River Bridge, Lianyungang Binhai Avenue Cross-sea Bridge, Sixinjiu Special Bridge, Mozambique Maputo Bridge, Wanda Film and Television Industrial Park, etc.; published 35 academic papers, including 16 SCI/EI indexed; published 1 academic monograph; obtained 1 authorized software copyright; granted 2 national invention patents; 2 national standards, 1 industry standard; formed 1 engineering application guide; generated direct economic benefits of 213.95 million yuan in the past three years. The research results have promoted the application and development of multi-scale crack prevention technology in concrete slab components, improved the quality of infrastructure construction such as bridges, shortened the construction period, reduced construction management costs, extended the service life of structures, and minimized resource and energy waste caused by maintenance and reinforcement, achieving significant economic and social benefits.