This part specifies the terms and definitions of steel plates for weather-resistant bridges, how to represent grades, ordering content, dimensions, appearance, weight and allowable deviations, technical requirements, test methods, inspection rules, packaging, marking and quality certificates, etc. This section applies to rural atmospheric environment and industrial atmospheric environment grades Q345qNH~Q420qNH and weather-resistant bridge steel plates with a thickness of not more than 80mm (hereinafter referred to as "steel plates"). Steel plates not suitable for marine atmospheric environments.