Construction of the South Main Tower of Hubei Zhijiang Yangtze River Bridge Achieved a Major Breakthrough
Recently, the left cap cofferdam of the south main tower of the Zhijiang Yangtze River Bridge in Hubei Province successfully completed the third purlin pumping test, marking the successful bottom sealing of the left and right caps of the separate structure. With the "bottom", the cap platform can hold up the 257.5-meter-high main tower, and the construction of the bridge will switch from underwater to above water, achieving a major breakthrough.
According to reports, the Zhijiang Yangtze River Bridge is one of the control projects of the Dangzhisong Expressway. The main bridge is 1,549 meters long. It is currently the world's largest span twin-tower single-sided steel-UHPC composite beam cable-stayed bridge. The span of this type of bridge was increased from 700 meters to 890 meters at one stroke. The south main tower cap of the bridge adopts a rare separated design. It is a symmetrically arranged two "Big Mac" concrete columns with a diameter of 39.5 meters, a thickness of 7 meters, an area of about three basketball courts, and a height of more than two stories. The 131-meter pile foundation on the river bed is connected with the 257.5-meter-high tower column, which is one of the important stress-bearing structures of the bridge.
"The bridge is located in a thick cobblestone layer without coverings. Currently, there is no experience in the construction of deep cobblestone foundations with such a depth and water level drop in China." Chen Gan, the person in charge of the DZSGSTJ-4 bid for Dangzhisong Expressway of the China Communications Second Public Transport Bureau, said that the geological conditions in the area where the south main tower of the bridge is located are complex and resemble a "Shaqima" shape. The project technical team worked hard to tackle the problem, and successfully researched the construction technology of large-diameter and ultra-long pile foundations with less filling pebble gravel layer and the construction technology of deep foundation pit cofferdam in water with high head difference.It has created a speed record of two large-diameter pile foundations for a 130-meter-deep main pier under the geological conditions of the Yangtze River Basin in three days and a record of the depth of a rotary drill drilling to the bottom.Independently developed equipment with dual vibrating hammers adapted to the "half-rod rotary drill", enabling a single section of 38-meter ultra-long locking steel pipe piles to be driven into place at one time. This creates good conditions for the smooth implementation of the platform cap cofferdam construction.
The Zhijiang Yangtze River Bridge is constructed in accordance with the two-way six-lane highway standard. The construction team is constantly exploring innovative technologies while taking into account people's livelihood needs. For the first time, a slow traffic system has been added to the Yangtze River Bridge on the expressway. The sidewalks and non-motorized lanes are located outside the cable-stayed area and are arranged at staggered levels with the expressway. The combination of architecture and humanities resulted in an ultra-wide bridge deck of 47.5 meters. In the future, it is necessary to overcome the application technical difficulties of 140MPa ultra-high-performance concrete materials that are rare in the world.
It is reported that the bridge is expected to be completed and opened to traffic in 2026. It will become the 10th cross-river bridge in the Yichang section of the Yangtze River. Bailizhou, the second largest island in the Yangtze River, is interconnected between the two places. The construction of the bridge will realize the dream of more than 100,000 people living a mile away from the "bridge connecting both sides of the strait".
