Recently, the concrete pouring of the first 9-meter section of the South bank main tower of the G3 Tongling Yangtze River Railway Bridge Project, invested by the Municipal Investment Group and constructed by the China Railway Bridge Bureau, was successfully completed, setting a new record in the field of domestic bridge construction。

　 G3 Tongling Yangtze River Railway Bridge starts from Huayuan Village, Chenyaohu Town, Tongling City, crosses the Yangtze River, passes Yangshanji, and ends at Datong Town Ethnic Village, Tongling City, with a total length of 11.88 kilometers, with "highway, intercity railway, freight railway" three river crossing functions。It is the first double-deck cable-suspension bridge in China, and the main tower of No. 4 on the south bank of the bridge is 247 high.5 meters, total concrete 3.6万方。It consists of five parts: tower base, tower column, lower beam, upper beam and tower crown。Tower column construction of the first 9 meters section intelligent hydraulic climbing mode, the largest single concrete pouring volume of 995 cubic meters, breaking the traditional tower column construction of 6 meters section mode, once again a new record。The single pouring height of the main tower is 9 meters, which effectively reduces the number of the main tower pouring segments and improves the construction efficiency。The tower column of the first 9-meter section of Pier No. 4 is designed with a total weight of 105 steel bars.5 tons, 756 concrete poured.2方。

　 The use of 9-meter section hydraulic climbing die is a challenge, a leap, a revolution。The construction equipment of the main tower has reached a new level. In order to realize the intelligent, green and fast construction of the main tower, the project department has carried out various innovative studies。The first is the use of large tonnage high climbing hydraulic climbing die, the frame body is connected as a whole, more stable and safe in climbing and pouring。The second is to configure the hydraulic stripping system to replace the traditional manual mechanical stripping and improve the efficiency of stripping。The third is the use of intelligent hydraulic control system to achieve synchronous climbing。Equipped with video, wind speed, pressure, displacement and other information feedback intelligent monitoring system, to achieve real-time monitoring of structure, environment, maintenance。Fourth, it has its own intelligent maintenance system to realize automatic steaming of concrete in winter and fog maintenance in other seasons。The fifth is to set up special cable trough, vertical spiral ladder, toilet, fire water tank, special sewage pipe, to achieve standardized operation and green construction。

　 In order to ensure the quality of concrete, the project department and the university jointly carried out the special design of the crack resistance of the main tower concrete, proposed key materials and construction measures, and adopted the technology of temperature field and expansion process coordination to prepare low-shrinkage and high-crack resistance C60 concrete。The concrete mix ratio was further verified and optimized by scale model test。Measures such as controlling mold temperature, intelligent maintenance of thermal insulation and moisture, setting cooling water pipes and anti-crack steel plate mesh are adopted to reduce the risk of cracking of the main tower concrete。

　 G3 Tongling Yangtze River Highway and Railway Bridge is one of the river passages planned in the Yangtze River Trunk Passage Layout Plan (2020-2035). It is a key project to implement the national "Belt and Road", Yangtze River Economic Belt and Yangtze River Delta integration development strategy, and is also a major infrastructure construction project in Anhui Province。The construction of the bridge is conducive to improving the national and Anhui expressway networks, improving the capacity of regional river crossings, playing the central role of Anhui River connecting east and west, connecting Yangtze River Delta and Sichuan, Chongqing, Hubei and Jiangxi, promoting the optimal development of regional traffic and improving the layout of river crossings。