At 5 am on August 10, after several days and nights of continuous pouring, the underwater sealing of the steel cofferdam of the No. 3 main pier of the G3 Tongling Yangtze River Gongtie Bridge was successfully completed, marking that the main pier on the north bank of the bridge is about to enter the construction stage of the bearing platform, laying a solid foundation for the subsequent tower column and superstructure construction。

　 According to the structural characteristics of the No. 3 pier cofferdam, the number of bottling concrete and the production and transportation capacity of concrete, the entire steel cofferdam is divided into 7 compartmentalsfor bottling, and the maximum of single compartment bottling concrete is 4033.0 m3。According to the requirements of the construction scheme, the bottom of each partition of the cofferdam is sealed according to the principle of from low to high。"The construction adopts the underwater concrete bottom sealing process of central hopper pulling ball, multi-pipe arrangement, and gradual advancement from the low corner to the opposite side。Pan Meng introduced that during site construction, the central hopper is temporarily fixed in the corresponding position, and a number of automobile pumps are used to centrally feed the central hopper. After the concrete in the hopper meets the requirements of the first irrigation, the first irrigation "pulling ball" is carried out, and the rest of the pipe is constructed by the "intubation method", and the cycle is repeated until the bottom is completed。

　 The successful sealing of the cofferdam of the main bridge laid a firm foundation for the cap construction, and also played a demonstration role for the subsequent construction。