A few days ago, with the last rod piece transferred to the assembly table to tighten bolts, the assembly was completely finished of the steel truss girder of the main bridge of Beijing-Zhangjiakou Railway Guanting Reservoir Grand Bridge built by Shougang steel plate.

The construction of Beijing-Zhangjiakou Railway Guanting Reservoir Grand Bridge, connecting Beijing to Zhangjiakou and crossing over the Guanting Reservoir, is the key supporting infrastructure project of the Beijing 2022 Winter Olympics. Upon completion, it will merely take one hour from Beijing to Zhangjiakou by high-speed train, which is of great significance to the integration development of Beijing, Tianjin and Hebei. The bridge site is located between Dongyuan Town and Langshan Town of Huailai County, Hebei Province. With the main bridge span made up of 8 108-meter curved chord truss girders, the total bridge weighs about 16,099 tons. The proportion of steel supplied by Shougang is up to 75%, and the main material is high-performance bridge steel of new generation Q370qE-hps.

Q370qE-HPS bridge steel was researched and developed by Shougang and first used in China-Russia Tongjiang Bridge to meet the needs of the construction of steel bridge in cold areas. The index of yield ratio≤0.85 is very high. At the same time, there are many group intervals in the bridge steel contract specifications, so unified control of the production process is difficult to achieve, resulting in greater fluctuation of the yield ratio, but the yield ratio as a bridge steel structure safety index must be guaranteed. For this purpose, the technicians repeatedly studied the influence of different process parameters and microstructure on the yield ratio, designed a new composition system, which used TMCP instead of normalizing process in the production process to obtain the biphasic microstructure of acicular ferrite and polygonal ferrite. Soft phase yield ratio control technology is developed to solve the problem of the fluctuation of steel yield ratio exceeding the upper limit. The yield ratio of Q370qE-HPS is controlled stably below 0.85, which guaranteed the timely delivery of the contract. Since the new generation of 370-MPA grade bridge steel developed by Shougang bridge steel team greatly improves the strength and toughness of steel plate, and enhances the welding performance of steel plate, it has by far been widely used in Shanghai-Nantong Yangtze River Bridge, Pingtan Strait Bridge, Shangqiu-Hefei-Hangzhou Wuhu Yangtze River Bridge and other large domestic bridge projects. Additionally, it has replaced the normalizing 370-MPA bridge steel to become the preferred material of 370-MPA bridge steel, which has greatly promoted the upgrading of bridge steel in China.

Given the limited construction period, the windy and dusty climate of the service area, and the short delivery cycle and high technical requirements of the steel bridge, Shougang Group leaders and bridge R & D team attached great importance to the construction of the Bridge by opening up a green channel and keeping track of the project progress and the steel plate use from the production of the first plate welding panel to the construction of the bridge. Thanks to their efforts, the Company eventually completed the whole contract with guaranteed quality and quantity.