Fanling Bypass (Eastern Section) featuring Hong Kong engineering firsts

Delivered through close collaboration among government, industry, academia, and research sectors, AECOM provided multidisciplinary expertise as the consultant for the Phase 1 Development of Kwu Tung North and Fanling North New Development Areas.

Serving as the primary distributor for Fanling North — and the first major infrastructure completed in the Northern Metropolis — the FLBP is an approximately four kilometers, dual two-lane carriageway connecting the Fanling North New Development Area to Fanling Highway. The bypass eases traffic congestion in Fanling town center, improves connectivity across the Northern Metropolis, and supports 95,100 future residents in the Fanling North New Development area.

Rotating a 140-meter, 7,000-ton bridge horizontally over rail in one night

Video credit: Civil Engineering and Development Department (CEDD)

A key challenge of the project was constructing a vehicular bridge across the East Rail Line railway, while navigating extensive facilities including large diameter watermains, high voltage underground power cables and an existing footbridge. Traditional segment erection methods would have required heavy lifting operations within short night time windows, posing high operational risks.

To overcome this, the team used an innovative horizontal bridge rotation method — a first for Hong Kong. A 140-meter-long bridge section, weighing more than 7,000 tons (about 470 double decker buses), was built beside Fanling Highway and the East Rail Line, where space was constrained by pipelines and high voltage cables.

Digital precision for safer, faster construction

Advanced digital tools — including Building Information Modelling (BIM), LiDAR systems, AI-enabled CCTV and automated deformation monitoring — optimized temporary works and traffic arrangement planning by simulating construction methodology and associated logistics. The 4D BIM model enabled progress monitoring and helped identify potential issues early, supporting a 70% reduction in the risk of delay.

The bridge was rotated horizontally into position overnight, spanning the railway safely in a single operation. This approach shortened construction by about 12 months compared with conventional techniques, reduced on-site risks, lessened disruption to railway operations, and improved safety for workers and the public.

Sustainability was embedded throughout design and delivery. Precast bridge deck segments were fabricated in Chinese Mainland and installed using launching girders and mobile cranes — reducing on-site concrete works and achieving an estimated 2,100-ton reduction in carbon emissions.

Working across multiple disciplines, the project brought together expertise from Hong Kong, Chinese Mainland and Singapore, a cross-regional partnership that enabled efficient delivery and knowledge exchange.

World’s first use of ultra-high-strength S960 steel in footbridges construction

Innovation extended beyond the main bridge works. Two new footbridges — including the landmark Footbridge F6 at Lung Yeuk Tau Interchange — mark the world’s first structural application of ultra-high-strength S960 steel in footbridges.

Footbridge F6 serves as a pedestrian and cycling link forming part of the cycle track-cum-footbridge over Lung Yeuk Tau Interchange. Featuring a 40-meter-diameter circular deck and four connecting links of up to 36 meters, it improves access between the Fanling North New Development Area and the existing North District cycle track network.

Using S960 steel — nearly three times the strength of conventional structural steel — cut the superstructure weight by nearly 90%, easing lifting and foundation demands. Fewer piers and pile caps reduced conflict with underground services, while off-site modular fabrication strengthened safety, quality and efficiency.

To reduce on-site welding, the team pre-assembled deck modules in the factory into units 7.8 metres wide. With some road sections only 7.3 metres wide, custom frames secured the modules at an angle for safe transport. Using geospatial data from the Hong Kong 3D Digital Map together with 3D Swept Path Analysis, the project team efficiently planned and coordinated the 34-kilometre route from Jiangsu to Fanling. This ensured all 40 modules were delivered safely over 12 nights.

To further improve precision and productivity, robotic welding technology was adopted on site for the S960 steel components. Precise control of heat input and weld geometry delivered consistent quality, reduced human errors and increased output speed. With qualified operators and setters trained, parameter control also minimized rework and inspection time.

Overall, the approach simplified site operations and cut carbon emissions by approximately 2,400 tons of CO₂.

Contributing to CEDD’s technical guidance and best practices

Building on these experiences, AECOM contributed to two key technical publications by the Civil Engineering and Development Department (CEDD):

• Practice Notes on Horizontal Bridge Rotation Method for Viaduct Construction Across Existing Railway Lines
• Technical Guidance on the Structural Design of Plate Girder Structures using Ultra-High-Strength S960 Steel
• Technical Guidelines for Robotic Welding Operations of Structural Steel in Construction

Both provide practical design and construction guidance that offers a valuable reference model for future projects, supporting more sustainable and efficient construction practices.

Collaboration drives safer, faster, and more sustainable delivery

The Fanling Bypass (Eastern Section) exemplifies how collaboration can drive engineering breakthroughs in design, fabrication and welding technologies. The project enhances connectivity, supports new communities in the Northern Metropolis, and shows how complex infrastructure can be delivered more safely, sustainably and efficiently.

Awards: