Big Boys Toys Trip Far From Boring
Mayor Len Brown leaves for Shanghai on Thursday for a trip that has the potential to push the much-wanted Auckland City Rail Link project one step further.
He’s going along with top NZTA executives to look at China’s infrastructure projects especially the impressive Shanghai Changjiang tunnel project where 2 German-made Herrenknecht tunnel boring machines have completed the world’s largest mechanized twin tunnels.
The giant Shangahi tunnel project
The under-river tunnels link the mainland with the island of Changxing.
The largest tunnel boring machines in the world were used with a diameter of 15.43 metres.
The largest tunnel boring machines in world
The project involves an 8.9km tunnel and a 10km cable stay bridge for both traffic and rail.
The necessary power to drive the machine with a weight of 2,300 tonnes and a length of 135 metres through the ground was provided by a 3,500 kilowatt main drive, which weighed 170 tonnes alone.
The cutterhead with its 6 cutting wheel arms can be accessed via the rear of the shield under atmospheric conditions – allowing for cutter changes under extreme conditions and ensuring the highest possible safety standards on the machine.
The Herrenknecht Mixshields excavated two tunnels with a distance of 23 metres – measured between centre axes – and operated at a pressure of 6.5 bar. The machines achieved top performances of 26 metres per day, 142 metres per week and 556 metres per month.
The tunnel boring machines each drove a 7,472 metre long tunnel beneath the Yangtze river, underpassing dikes and a residential area with low overburden, with downtimes of maximally 6 hours.
The first machine broke through a year earlier than scheduled after a construction period of 20 months. The second machine reached its target 10 months ahead of schedule. The tunnels have a vertical deviation of less than 2 centimeters and a horizontal deviation of less than 2.7 centimeters.
While China missed out on being in the front line for building Auckland’s new electric trains, KiwiRail has been buying Chinese rail expertise – but more significantly, China is being eyed for future massive infrastructure projects.
Engineers from the China Road and Bridge Corporation were in New Zealand last year scoping for projects and transport minister Steven Joyce was also China just before their visit.
Prime Minister John Key, when he last visited China this weekend, was asked about the speculation China wants to built Wellington’s Transmission Gully.
Mr Key responded: “They might do, and at the end of the day from New Zealand’s perspective I mean we’re looking for value for money.”
In July, I asked why NZ’s huge construction costs here did not add up.
China is busy showing off its new Jiaozhou Bay bridge, 42km long, 35m-wide and the longest of its kind. It links China’s eastern port city of Qingdao to the island of Huangdao.
It cost about $1.4 billion.
Vhina's new bridge cost $1.4b
The Millau Bridge in France – the highest road bridge in the world, opened in 2004, cost in today’s currency $659 million.
France's Millau bridge cost NZ$659m
So to ignorant commuters like me, who are angry that the CBD Link and Tunnel are unlkely for decades because of the cost, can someone explain why other countries can get projects done at a reasonable cost and everything here sounds over-inflated and still comes out at the end with aspects unfinished because costs had to be trimmed to prevent overruns or to give the impression we’re getting value for money?
If Prime Minister Key and Transport Minister Joyce are looking for cost savings, it’s great his NZTA department is getting a close look at the incredible development being done in China on a massive scale for reasonable cost.
Having Mayor Brown along will hopefully give them the chance to have – away from the heat of the election debate- some rational discussions about the CBD link and Auckland harbour rail tunnel proposals and how they could be achieved.
Dealing with NZ’s still heavily regulated environment before projects can be undertaken and NZ’s labour costs compared to China’s will still be issues that need to be taken into account but in the end, this trip will inspire, open eyes, allow networking with the Chinese and hopefully open doors to making the CBD Rail Link just that bit easier for the Mayor to achieve.