Recently, the last pile cap of the main towers of the Songhua River Grand Bridge on the Southwest Ring Line of the Harbin Metropolitan Area was successfully poured, marking the official transition of the main tower construction of the Songhua River Grand Bridge from foundation construction to substructure construction.

　　The Songhua River Grand Bridge is one of the controlling, major and difficult projects of the Southwest Ring Project of the Harbin Metropolitan Area. The bridge has a total length of 6,796.68 meters; its main bridge is a 550-meter double-tower suspension bridge, and the main towers are 96.4 meters high. The maximum water depth for the construction of the main tower pile caps is 23.3 meters, and the pile caps adopt the largest-scale double-wall steel cofferdam structure in the province to ensure construction safety and quality control. The total designed concrete volume for the four pile caps of the bridge's main towers is 5,428 cubic meters, and the total designed steel reinforcement is 923 tons.

　　The Harbin Metropolitan Area Southwest Ring Line Engineering Construction Project Office earnestly implemented the overall deployment requirements of the Provincial Department of Transport, the Provincial Highway Construction Center and the Provincial Construction Investment Group, anchored on the overall goal of building the "three metropolitan areas" of a technology metropolitan area, an economic metropolitan area and a brilliant metropolitan area, and organized meticulously with advance planning and detailed preparation to ensure the smooth progress of construction production. To ensure that the double-wall steel cofferdam settles smoothly onto the riverbed, multi-beam unmanned boat scanning technology was used to survey the in-situ elevation and flatness of the riverbed; high-pressure air pipes were used to disturb the sand layer of the riverbed; and sand suction boats combined with the air-lift method were used for sand removal and sinking. During the sealing of the cofferdam bottom, underwater concrete construction technology and the tremmie method were adopted for the first pour to ensure the sealing quality, and the application of technology was strengthened: 3D laser scanning technology was introduced to monitor the lowering of the steel cofferdam in stages, and an intelligent concrete temperature control system was jointly developed with Harbin Institute of Technology, which automatically controls the duration and flow rate of cooling water through AI algorithms, thereby precisely controlling the heating and cooling rates, preventing temperature cracks in mass concrete and ensuring the smooth implementation of the project.

　　After the successful completion of the pile cap construction task for the main towers of the Songhua River Grand Bridge, all participating units will continue to anchor on the annual production targets, further consolidate work responsibilities and make every effort to advance the overall progress of the project construction.