A marvel of modern construction, China’s Hong Kong-Zhuhai-Macau Bridge is 34 miles long and cost £14.8billion to build.
It crosses the Lingdingyang channel in the Pearl River Estuary and holds the record as the longest bridge-tunnel system sea crossing in the world. The crossing is made up of the 7.4 mile (12km) Hong Kong Link Road, 18.3 mile (29.6km) Main Bridge and 8.3 mile (13.4km) Zhuhai Link Road.
Open 24 hours a day, HZMB connects major cities in the Pearl River Delta to Hong Kong. It takes just 40 minutes to cover the roughly 26-mile (42km) distance from Hong Kong Port to Zhuhai Port and Macao Port.
The structure’s viaduct section consists of three cable-stayed bridges: Qingzhou Channel Bridge, Jianghai Channel Bridge and Jiuzhou Channel Bridge.
Between the three, the Qingzhou Channel Bridge has the longest main span, at about 458m long.
Jianghai Channel Bridge’s steel tower weighs about 3,100 tonnes. The steel used for the bridge’s decks totals 420,000 tonnes, which is equivalent to the weight of 60 Eiffel Towers.
The total bridge deck area is 700,000 square metres, the size of about 98 football pitches and the total weight of the bitumen used to surface the roads is about 100,000 tonnes, according to hzmb.gov.hk.
The tunnel is in a stretch of open sea with a maximum water depth up to 45m. Engineers had to overcome technical difficulties to complete the tunnel, including strong wind and water currents.
The size of a standard tunnel segment is about 180m long by 38m wide and 11m high. Each bit weighs 80,000 tonnes.
Tunnel segments were precast at a yard on Guishan Island then taken by tug boats to the construction site to be placed in their final position.
The final connection of the tube tunnel proved to be challenging, according to the authorities.
Prefabricated steel structures were used so the need to work deep under water could be reduced and construction time shortened.
With the weight of the final connection as much as 6,000 tonnes, the contractor used the largest lifting barge in the world to erect and install the final part.
But the contractor had to overcome challenges such as airport height restrictions, unstable water currents and a tight tolerance to connect the final part, within ±25mm.
