Recently, the third ring-beam pumping test for the cofferdam of the left pile cap of the south main tower of the Zhijiang Yangtze River Bridge in Zhijiang City, Hubei Province, was successfully completed, marking the successful bottom sealing of both the left and right pile caps in a separated structure. With the "base" in place, the pile caps can support the 257.5-meter-high main tower, and bridge construction will shift from underwater to above water, achieving a major breakthrough.

According to reports, the Zhijiang Yangtze River Bridge is one of the controlling projects of the Dangzhi-Song Expressway. The main bridge is 1,549 meters long and is currently the world's largest-span double-tower single-side steel-UHPC composite girder cable-stayed bridge, raising the span of this type of bridge from the 700-meter class to 890 meters in one leap. The south main tower pile cap of the bridge adopts a rare separated design, consisting of two symmetrically arranged concrete cylinders each 39.5 meters in diameter and 7 meters thick—covering an area about the size of three basketball courts and taller than a two-story building—connecting the pile foundations driven 131 meters deep into the riverbed with the 257.5-meter-high tower column, making it one of the important load-bearing structures of the bridge.

"The bridge site is located in a thick cobble layer with no overburden, and there is currently no domestic experience in deep foundation construction in cobble layers of such depth and water-level difference," said Chen Gan, head of Section DZSGSTJ-4 of the Dangzhi-Song Expressway project of CCCC Second Highway Engineering Co., Ltd. The area where the south main tower of the bridge is located has complex geological conditions resembling "sachima" (a layered pastry). The project technical team tackled the difficulties head-on, successfully developing construction technology for large-diameter ultra-long pile foundations in gravel layers with few fillers and research on cofferdam construction technology for deep water foundation pits with high water-head differences, setting a speed record of 3 days for 2 large-diameter pile foundations of the main pier at a depth of 130 meters under the geological conditions of the Yangtze River basin and a record for one-pass drilling depth with a rotary drilling rig; they also independently developed equipment adapting a dual vibratory hammer to a "half-section mast rotary drilling rig," achieving one-time installation of single-section 38-meter ultra-long interlocking steel pipe piles, creating favorable conditions for the smooth implementation of the pile cap cofferdam construction.

The Zhijiang Yangtze River Bridge is being built to the standard of a two-way six-lane expressway. While continuously exploring innovative technologies, the construction team also took into account public welfare needs by pioneering the addition of a slow-traffic system on the Yangtze River expressway bridge. The pedestrian walkway and non-motorized vehicle lane are located outside the cable zone and arranged on a different level from the expressway carriageway. The combination of architecture and humanistic design has produced an ultra-wide bridge deck of 47.5 meters. In the future, technical challenges remain to be overcome in the application of globally rare 140 MPa ultra-high-performance concrete materials.

It is reported that the bridge is expected to be completed and opened to traffic in 2026, when 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, will also completely end its history of being an isolated island for thousands of years, realizing the dream of "a bridge connecting both banks" for more than 100,000 people of Bailizhou.