The world’s longest ongoing sea-based construction project, the 55 km Hong Kong-Zhuhai-Macau Bridge (HKZMB), is due to open in December. Construction commenced in 2011 to link three major cities on the Pearl River Delta in the South China Sea. And the project is as ambitious as the structure is long. The Hong Kong part of the bridge alone cost nearly AU$18 billion.
Thirty-eight kilometres of the bridge span the sea and the 29.6 km main section in Zhuhai waters comprises 22.8 km of bridge work, including three cable-stayed bridges with spans ranging from 280 m to 460 metres. There are two viaducts spanning 75 metres and 110 metres, a 5.5 km tunnel, which is the longest undersea tunnel in the world, and two artificial islands.
Much of the bridge structure was prefabricated off-site allowing for the concrete deck sections to be produced at the same time as the foundations were laid. The tunnel is made of precast sections, each 100 metres long.
The HKZMB is designed for a service life of 120 years and can stand against strong winds up to 201 kph. The bridge has also been designed to withstand the impact of a magnitude-8 earthquake or a 300,000 tonne vessel. The bridge will have six lanes of traffic with a maximum speed of 100 kph which will cut driving time from Hong Kong to Zhuhai from four hours to just one.
In addition, the $4 billion Hong Kong Link Road connects the main bridge in mainland waters to the city’s boundary crossing facilities on an artificial island and includes a 12 km dual three-lane carriageway comprising a 1 km-long tunnel, a 9.4 km viaduct section as well as a 1.6 km road section on reclaimed land.
And while it is an amazing feat of engineering and Chinese ingenuity, the project hasn’t been without its downsides. The main span of the bridge in the Pearl River Estuary has overrun its budget so the additional cost has to be split between the three governments of Hong Kong, Zhuhai and Macau. And during its six years of construction, 10 workers have died and more than 600 have been injured in 275 incidents.
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