The Hong Kong–Zhuhai–Macao Bridge: Bridge and Tunnel Construction and the 2018 Opening

The Hong Kong–Zhuhai–Macao Bridge crosses the Pearl River Estuary, linking Hong Kong in the east with Zhuhai and Macao in the west. The complete link is 55 kilometres long. Its main offshore works extend approximately 29.6 kilometres, comprising about 22.9 kilometres of bridges and 6.7 kilometres of tunnel.

The engineering team used a tunnel on the eastern side to accommodate both a shipping channel for large oil tankers and aviation height restrictions near Hong Kong International Airport. Artificial islands at either end provide the transitions between bridge and tunnel. The design has six lanes, three in each direction, and a design service life of 120 years. Piers for the non-navigation spans were prefabricated and installed as complete units, reducing the stages of on-site work offshore.

References: [1]

The three jurisdictions jointly financed the Main Bridge, while each was responsible for its own boundary-crossing facilities and link roads. The offshore bridge and tunnel, land connections and cross-boundary facilities were built as separate components; traffic and inspection arrangements also had to be coordinated before opening.

In January 2018, Under Secretary for Transport and Housing Raymond So Wai-man told Hong Kong's Legislative Council that the Hong Kong–Zhuhai–Macao Bridge Authority was responsible for the Main Bridge's bridge and tunnel works in mainland waters. The initial approved cost estimate was approximately RMB 38.118 billion, financed through contributions from the three jurisdictions and syndicated loans, with operating revenues to be used for repayment.

References: [2]

Bridge construction made extensive use of factory prefabrication and installation of complete units, including the piers for non-navigation spans. The tunnel was formed by sinking and joining prefabricated elements; a typical element was 180 metres long and weighed approximately 76,000 tonnes. Prefabrication moved some quality control into the factory, but did not eliminate the challenges of towing elements afloat, positioning them in deep water or managing foundation settlement. Large-diameter steel cylinders and connecting components enclosed the artificial islands. Sand filling, drainage and surcharge preloading then took place within the enclosures, using the ease of insertion into soft soil to form temporary island walls.

A paper by Lin Ming and colleagues explains that the island-and-tunnel construction team combined meteorological and hydrological observations with forecasts to select operating windows, and used survey towers, sonar and sensors to track the position and orientation of tunnel elements. The ballast system adjusted buoyancy by admitting or discharging water; pulling equipment brought each new element toward the installed section, compressing the water-sealing components. Operators aboard the installation vessel controlled the process remotely using real-time data.

Installation support also included forecasts of resiltation, warnings of abnormal waves and structural safety monitoring. During the floating transport of an element, the navigation system recorded the paths of its bow and stern, helping coordinate adjustments to tug headings and towing forces. During immersion, supervisors could observe settlement, displacement and joint changes at key locations.

References: [1] [3]

So's 2018 legislative address also explained that the offshore environment, construction difficulties, design adjustments and rising labour and material prices had increased the Main Bridge's cost. After review, the revised approved estimate was approximately RMB 48.068 billion, an increase of about RMB 9.95 billion. These figures refer to the Main Bridge project, rather than a simple total of all boundary-crossing facilities and connecting roads in the three jurisdictions.

References: [2]

On 19 October 2018, Secretary for Transport and Housing Frank Chan Fan announced the arrangements: an opening ceremony would take place at the Zhuhai boundary-crossing facilities on 23 October, and the bridge would formally open to traffic and operation at 9 a.m. on 24 October. He also noted that the three jurisdictions had conducted joint trial operations in late September to test their readiness.

The Annual Transport Digest 2019 subsequently confirmed that the Main Bridge and Hong Kong Link Road had opened on 24 October 2018. Before the opening, Chan identified shortening the overland detour between Hong Kong and the western Pearl River region as a principal objective. The digest also listed the Southern Connection of the Tuen Mun–Chek Lap Kok Link as a supporting project completed and opened in the fourth quarter of 2018, reflecting the work on road connections beyond the main sea crossing.

References: [4] [5]

Preparations involved more than allowing vehicles onto the bridge. At the same briefing, Deputy Commissioner for Transport Macella Lee Sui-chun explained that the department and public transport operators had conducted trial runs and driver training, and arranged connections between the Hong Kong boundary-crossing facilities and the airport, Sunny Bay and Tung Chung. Passengers could take local public transport to the facilities and transfer to shuttle buses bound for Zhuhai or Macao. Route B4 linked the airport and the Hong Kong facilities, B5 connected with Sunny Bay Station, and B6 with Tung Chung Station.

She also explained that shuttle buses, cross-boundary coaches, hire cars and private cars were subject to different operating arrangements, and that cross-boundary vehicles were covered by quota controls.

References: [6]