on February 18, with the pumping of the last concrete in place, the pouring of the bearing platform of the main tower pier on the north bank of Yanji Yangtze River Bridge, which was invested by Hubei Trading and Investment and constructed by China Railway Bridge Bureau, was completed, marking the completion of the foundation construction of Yanji Bridge and entering the construction stage of the superstructure of the main tower pier. The bearing platform of the north pylon pier
of Yanji Yangtze River Bridge is dumbbell-shaped, consisting of left and right parts. The single bearing platform is a cylinder with a diameter of 38.8 meters and a height of 8 meters. A ground tie beam is set between the left and right bearing platforms. The tie beam is 20 meters wide and 6.9 meters thick. The bearing platform of the north
main pier is poured in two layers. This is the second layer of the bearing platform in the lower reaches of the Yangtze River, and it is also the last pouring of the bearing platform concrete. The pouring concrete is about 4400 cubic meters, and the total pouring volume of the bearing platform concrete is 20186. 5 cubic meters. The construction environment of the north pylon pier
of Yanji Yangtze River Bridge is complex, the structure size is large, the continuous pouring time of the pile cap concrete is long, and the pouring volume is large, which puts forward high requirements for the production, scheduling and organization ability. Zhang Zhaoxian, technical director of the main pier work area of the bridge, said that because of the continuous large-scale pouring, the production of concrete backstage and the maintenance of front-end equipment were under great pressure. Pouring site of bearing platform of main pylon pier on the north bank
of Yanji Yangtze River Bridge.
In order to ensure the construction quality of the main pier cap, the project team of Yanji Yangtze River Bridge of China Railway Bridge Bureau planned ahead of time, formulated a detailed and reliable special construction plan, and made careful arrangements for staffing, mechanical allocation, monitoring and testing, safety management and control. The requirement of hydration heat control of
mass concrete is high, and the requirement of temperature control is strict. Li Ping, director of YJTJ-2 site laboratory of Yanji Yangtze River Bridge, said that although it was early spring, the temperature at night was still cold. When the temperature of concrete entering the mould was predicted to be lower than 5 C, a series of winter construction measures such as heating were taken.
"We closely monitor the temperature of concrete entering the mould, and the relevant data will be reported every four hours." As he spoke, Li Ping showed reporters his WeChat work group. The group was filled with several screens of data, and the temperature of each truck of concrete entering the mould, the number of stations, the volume and the time were clearly recorded.
In addition, the project team also set up intelligent temperature control facilities developed by China Railway Bridge Research Institute in the bearing platform to monitor the temperature of mass concrete in real time, and use the cooling water circulation system in the bearing platform to control the temperature of concrete, so as to prevent structural cracks caused by hydration heat of concrete and ensure the quality of the project. The north main pier
of Yanji Yangtze River Bridge completed the bottom sealing of the steel cofferdam on November 23, 2022. During the lowering of the cofferdam, the water surface of the Yangtze River at the bridge site was at the lowest level in the past 15 years. The water depth at the pier site was too shallow and the siltation was serious, which made it difficult to lower the cofferdam. In addition, after the adjustment of the national epidemic policy, construction workers have been infected with COVID-19, and the number of workers has decreased. When the construction of the bearing platform crosses the Spring Festival holiday, after the 28th day of the twelfth lunar month, some construction workers go home for the Spring Festival, and the construction manpower is relatively insufficient.
In order to get back the delayed time, the project department did not close during the Spring Festival and changed the construction period with holidays, and organized more than 30 front-line construction personnel to stay at the construction site and continue to push forward the construction of the bearing platform. After the Spring Festival, the project department quickly organized personnel to resume work and increased manpower to put into production.
"Before the end of the construction of the bearing platform, we have begun to plan next stage of the process ahead of time, put the preparatory work in place ahead of time, and organize the tooling equipment and materials in place ahead of time, so as to ensure the smooth and rapid transition of the construction process from the bearing platform to the tower base to the main tower, and continue to pull the full bow and rivet the construction of the superstructure of the tower column." Zhang Zhaoxian said. After the pouring of the bearing platform was completed
that evening, Zhang Zhaoxian and his colleagues still did not stop, and continued to carry out the construction of the surface layer, which was busy until after midnight. At the end of the moment, Zhang Zhaoxian said: "I want to have a good sleep now, and celebrate with my colleagues tomorrow, to encourage and refuel everyone, and strive to work faster and better in the construction stage of the tower base and the main tower."
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