First of all, it will greatly promote the upgrading of industrial economy. Liaozi Bridge of Cheng Kai Expressway is located in Liaozi Township, Chengkou County, the hinterland of Daba Mountain. This is a typical mountain bridge. The total length of the bridge is about 330.8 meters. It is the first long-span arch bridge in China that adopts the mixed rotation technology of single rib frame and vertical rotation. Further down, the maximum vertical rotation is 28 degrees, and the four arch ribs of the whole bridge rotate 17 times, which is the largest number of single bridge rotation operations in China at present.

Secondly, it is of great significance to stimulate economic development and improvement. Uncoated weathering steel forms a dense and stable rust layer protective film on the steel surface, which effectively blocks the penetration and transmission of corrosive media. Therefore, the anti-corrosion problem of steel bridge can be solved without painting, which greatly saves the later maintenance work. Bridge building materials have significant economic and environmental benefits in the whole life cycle. The key technologies of design and construction of weather-resistant steel box arch bridge without painting in mountainous areas are studied, and the key technologies of application, design, manufacture, installation and maintenance of weather-resistant steel box arch bridge materials are formed. ?

In addition, it will have a far-reaching impact on the development of local tourism economy. It also overcomes the limitation of narrow terrain space, reduces the amount of mountain excavation, protects vegetation and reduces the construction safety risk. On the one hand, it is of great significance to stimulate economic development along the route and help rural revitalization in Qinba Mountain area; On the other hand, it can also speed up the development of mineral resources and tourism resources in Qinba Mountain area and play an important role in the future economic development and tourism reform.

What we need to know is, based on the uncoated weather-resistant steel technology, to explore the technical means to improve the durability and service life of steel bridges and reduce the life cycle cost of steel bridges. In terms of steel bridge, based on Liaozi Bridge, the key technologies of design and construction of painted weather-resistant steel box arch bridge are studied, and the key application technologies of materials, design, manufacture, installation and management of weather-resistant steel bridge are formed, which provides reference and guidance for the construction of uncoated weather-resistant steel bridge in the future. Application of steel in bridge construction.