Abstract:Research purposes: Uncoated weather-resistant steel bridge has become a development trend of steel bridge in developed countries such as Europe, America and Japan, and has been widely used. However, uncoated weather-resistant steel bridge in China started late, lack of successful application experience, and has no design and manufacturing specifications. Relying on the Zangmu Bridge of Lhasa-Linzhi Railway, this paper carried out research on the key technologies of the construction of railway uncoated weather-resistant steel bridge, and accumulated the experience in the design and manufacturing of uncoated weather-resistant steel bridge, laying a foundation for the preparation of technical specifications for uncoated weather-resistant steel bridge and the popularization and application of railway bridges in China.Research conclusions: (1) According to the stress and durability requirements of steel, the requirements of mechanical properties, welding properties and weather resistance of uncoated steel are put forward, and the chemical composition design and test of uncoated steel with weather resistance index greater than 6.5 are completed. (2)Based on the ease to form and protect the stable rust layer, the detailed design requirements of uncoated steel bridge structural components and drainage layout are put forward.(3)The manufacturing requirements for the characteristics of weathering steel are put forward.(4)The research results can play a reference and demonstration role for the popularization and application of railway uncoated weather-resistant steel bridge in China.