Main towers of the Shiziyang Bridge, the world's longest-span double-deck suspension bridge

 have been successfully capped

The east and west main towers of the Shiziyang Bridge — the world's longest-span double-deck suspension bridge, constructed by leading subsidiaries of CRHIC, China Railway Shanhaiguan Bridge Group（CRSBG）and China Railway Baoji Bridge Group (CRBBG),  have been successfully capped, marking the official start of the superstructure construction phase.

As another mega-scale transportation project in the Guangdong-Hong Kong-Macao Greater Bay Area following the Hong Kong-Zhuhai-Macao Bridge and the Shenzhen-Zhongshan Link, the Shiziyang Passage features its key control project—the Shiziyang Bridge. With a main span of 2,180 meters spanning the river in a single leap, the bridge will set five world records for double-deck suspension bridges upon completion, covering main span length, number of traffic lanes, main tower height, anchorage diameter and main cable diameter. CRHIC has undertaken the manufacturing task of nearly 60,000 tons of steel structures for the main tower steel shells and anchorage system of the Shiziyang Bridge.

Standing at 342 meters, the bridge's main towers are equivalent to a 110-story skyscraper. Overlooking the Pearl River Estuary from the tower top, vessels on the water look as tiny as miniature models. For comparison, the main towers of the Hong Kong-Zhuhai-Macao Bridge opened in 2018 stand at a maximum height of 163 meters, while those of the Shenzhen-Zhongshan Bridge of the Shenzhen-Zhongshan Link, opened in 2024, reach a maximum height of 270 meters.

Intelligent Manufacturing for Breakthroughs: Solve All Ground Problems Before Working at Height

By deeply integrating the concepts of factory-based production, digitalization and intelligent manufacturing, CRHIC empowers super projects with a intelligent manufacturing accelerator.

Precision Cutting: The introduction of high-precision CNC laser cutting machines achieves a machining accuracy of 0.5 millimeters, controlling component dimensions strictly from the source.

Deformation Precision Control: For ultra-thin and complex steel shell wall panels, CRHIC has established a complete solution covering intelligent material cutting, anti-deformation control and robot cluster operation. Custom anti-deformation jigs are designed to preset welding shrinkage, and the welding sequence for thin steel plates and multi-ribbed structures is optimized, so as to effectively control structural deformation and stress.

Virtual and Physical Integration: Adopting an innovative combination of on-site physical trial assembly and digital virtual pre-assembly, CRHIC conducts advance construction rehearsals to eliminate potential interference and misalignment issues for high-altitude operations in the factory.

Digital Empowerment: Equipping Super Projects with a "Smart Brain"

During construction, the intelligent manufacturing production management and control system independently developed by CRHIC enables full-process comprehensive management covering intelligent production scheduling, equipment Iot connection, quality traceability and safety monitoring. The production line integrates automatic assembly and positioning welding units, multi-electrode gantry welding special machines, intelligent robot welding systems and shear stud welding manipulator clusters. Combined with AI-powered adaptive welding adjustment technology, it realizes full-process intelligent control of welding procedures, ensuring consistent weld quality and stable construction performance.

In the assembly phase, the project team innovatively adopted BIM and 3D digital scanning technologies to conduct pre-inspection and optimization in the virtual space, ensuring one-time high-quality completion of physical assembly. By applying the advanced operation mode of "all-position welding robots + three-dimensional pre-assembly + 3D scanning modeling", the project has comprehensively improved operational automation and welding quality.

Millimeter-level Precision: Making "Threading a Needle in the Air" a Reality

The ultra-high-altitude precise connection represents the greatest challenge in main tower construction. CRHIC innovatively adopts a "1+1" continuous pre-assembly system and integral machining method. By simulating bridge site working conditions on dedicated factory jigs, it conducts continuous fitting of shell wall panels and integrated machining of connecting interfaces. A closed-loop control mechanism of "factory pre-assembly – data feedback – precision correction" has been established. The vertical and horizontal alignment measurement benchmarks are extended to the actual bridge position, ensuring one-time successful connection on site.

During the on-site installation phase, the project team adopted Beidou positioning and cloud control technology to feed back real-time data and implement refined adjustments, firmly controlling the positioning accuracy of ultra-high-altitude steel towers at the millimeter level. Rail-mounted welding robots are applied for circumferential seam welding in coordination with intelligent trackers, enabling full automation of the welding process and significantly improving quality stability and construction efficiency.

As the first dual-deck composite highway passageway across the Pearl River Estuary, the Shiziyang Passage stretches approximately 35 kilometers in total length, connecting Nansha District of Guangzhou in the west with Shatian and Humen Towns of Dongguan in the east. Adopting a dual-deck layout with 16 traffic lanes in total, this dual-layer design doubles the vehicle passing capacity. Moving forward, it will link up with the surrounding road network to form a one-hour living circle, bolstering the development of the world-class Pearl River Delta urban agglomeration.