It is reported that the main tower pile cap of the Nizhou Waterway Bridge of the Second Humen Bridge, which will become the "world's longest-span steel box girder suspension bridge" upon completion, has been poured. This marks the full completion of the main tower foundation construction for the project's two ultra-kilometer large-span suspension bridges, with pile foundation, pile cap, and anchorage construction completed, crossing an important engineering milestone. The Nizhou Waterway Bridge of the Second Humen Bridge has a total length of 1,688 meters. Its pile foundation has a diameter of 2.8 meters and a length of 88.5 meters, making it one of the largest group pile foundations in mainland China. Its pile cap is of a round-ended dumbbell shape, 7 meters thick, with an area equivalent to eight basketball courts. The anchorage foundation pit has a diameter of 90 meters and a depth of 29 meters, the largest in the world.
According to reports, because the anchorage is adjacent to the Pearl River levee, with surface silt reaching tens of meters deep, surrounded by fish ponds and rivers, and with fractured and fissured underground rock layers, carrying out ultra-large-scale foundation pit construction under such conditions faces many challenges such as environmental protection, levee safety, water sealing of diaphragm walls, and foundation pit dewatering and drainage. "Especially in the densely ship-populated Pearl River estuary, drilling such large-scale pile foundations in ultra-thick and ultra-deep rock layers poses severe challenges to construction organization and equipment. At peak times, almost all the highest-power rotary drilling rigs in mainland China were mobilized to ensure project quality and progress."
It is reported that upon completion, the Second Humen Bridge will become the world's longest-span steel box girder suspension bridge, ranking second in the world and first in mainland China among all bridge types in terms of main span. The completion of the main tower pile cap pouring for the Nizhou Waterway Bridge marks the full completion of the main tower foundation structure construction of the Second Humen Bridge, transitioning to the tower column construction phase, laying the foundation for the project to open to traffic as scheduled.