guardian.co.uk, Tuesday 15 December 2009 18.39 GMT
Barely 18-months after completing current record-holder,
work begins on link between mainland, Macau and
Much of the bridge will be fabricated offsite and will
be designed to withstand wind speeds of up to 201 kmph (125 mph)
The Y-shaped link between Hong Kong, Macau and China
will be around 50 km (31 miles) long in total, 35 km of which will span the
sea, said the state news agency Xinhua. Due to be completed by 2015, the 73bn
yuan (£6.75bn) cost of the bridge will be shared by the authorities in the
three territories.
The structure also includes a 5.5 km underwater tunnel
with artificial islands to join it to bridges on each side. According to the engineering
group Arup—which has helped with the design—it is the first major marine
bridge-and-tunnel project in
Work is expected to begin with land reclamation to
create an artificial island of around 216 hectares (540 acres) off Zhuhai. This
will become the customs point for those making the crossing.
But much of the structure will be prefabricated
offsite, so, for example, the concrete deck sections can be produced at the
same time as the foundations are laid. The tunnel will be made of precast
sections—each 100 metres long.
"It is designed with a service life of 120 years.
It can withstand the impact of a strong wind with a speed of 51 metres a
second, or equal to a maximum Beaufort scale 16 (184 to 201 km/h)," said
Zhu Yongling, an official in charge of the project construction. "It can
also resist the impact of a magnitude-8 earthquake and a 300,000-tonne
vessel."
A computer-generated image of the £6.75bn bridge, much
of which will be fabricated offsite
Six lanes of traffic will pass across the bridge at a
maximum speed of 100 kmph, cutting driving time from
The bridge was first proposed in 1983 as a way of
fostering economic ties between
The bridge is one component in a plan issued in January
by China's top economic planning body, the National Development and Reform
Commission, which aims to fuse the area and the two special administrative
regions, Hong Kong and Macau, into one of the world's most vibrant economic
centres by 2020. In particular, the government hopes it will help to develop
the western side of
"It is a move for Hong Kong, Macau and the Pearl
River Delta region to cope with global economic downturn, boost investment and
inspire people," said the vice-premier, Li Keqiang, at the inauguration
ceremony in
According to an article in New Civil Engineer magazine
earlier this year, the bridges cross three navigation channels while the tunnel
goes under a fourth.
"There is an airport nearby, so we could not build
a bridge [in that area] which was the reason for the tunnel. The immersed tube
is the longest in the world at 5.5km long," Naeem Hussain, global bridge
leader at Arup, told the publication.
He said the bridge's piers would each be 170 metres
high and that the design team had minimised the structures impact on estuary
flows by limiting the size and number of columns in the water.
But the WWF and other environmental campaigners have
warned that construction could devastate marine ecosystems and endanger the
rare Chinese white dolphin, which is found in the estuarine waters of the
"We will control the construction noises and
turbidity of seawater, and prevent oil pollution," Zhu told Xinhua.
It is only a year and a half since China opened a 36km
span across Hangzhou Bay—in the eastern province of Zhejiang—which is currently
the longest sea-bridge.
Wang Yong, the head of that project, said the design
had led to more than 250 technological innovations and engineering
breakthroughs, many of which will no doubt prove useful in building the new
construction. He added that the
The longest water-spanning bridge in the world is the
Lake Pontchartrain causeway bridge in
http://www.guardian.co.uk/world/2009/dec/15/worlds-longest-sea-bridge