Sydney metro identifies harbour crossing route 19 Aug 2015

TunnelTalk reporting

More than 460 industry representatives from across the world’s major construction and supply businesses have attended a briefing on Phase II of Sydney’s ambitious plans to develop its metro system.

Fig 1. 29km alignment includes 12.5km underground section under Sydney harbour and CBD (St Leonards–Sydenham)
Fig 1. 29km alignment includes 12.5km underground section under Sydney harbour and CBD (St Leonards–Sydenham)

Delivery by 2024 of the Sydney Metro City & Southwest project includes 12.5km of twin running tunnels under the New South Wales capital’s central business district and a new crossing of the iconic harbour, for a total alignment length of 29km. Preliminary engineering studies indicate that four TBMs will be ordered to complete the tunnelling works.

Extensive geotechnical investigations and seabed studies are currently being carried out to identify an optimal route for the new Sydney harbour crossing. An alignment to the west of the existing Harbour Bridge under McMahons Point and Millers Point is currently preferred because it includes a known area of sandstone that could be ideal for tunnelling, makes use of a relatively shallow section of the harbour, is well clear of other major underground structures such as the Sydney harbour road tunnel, and delivers good access to the CBD. A reference design is due to be unveiled at the end of this year (2015), as are details of the contract packaging strategy.

Sydney Metro Phase II – currently scheduled to move into major contract procurement in the third quarter of 2016, ahead of a 2017 construction start – will link to the southern terminus of Phase I of the under-construction North West Rail Link (now renamed Sydney Metro Northwest) at Chatswood. Tunnelling for the 15km of twin running rail tunnels included in Phase I, using four NFM TBMs, is already more than half complete.

Harbour geotechnical investigations ongoing
Harbour geotechnical investigations ongoing

The scope of underground works for Phase II currently includes three all-new underground stations (Pitt Street/Victoria Cross/Barangaroo). Earlier this month the NSW Government announced that the option for a station at Barangaroo is now confirmed. Meanwhile studies are still determining whether to deliver a fourth optional new station at either the University or Waterloo (Fig 1). Existing stations at St Leonard’s, Martin Place and Sydney Central will have new platform caverns excavated to accommodate the running tunnels.

“Sydney Metro City & Southwest is an iconic project, with city-shaping implications,” NSW Minister for Transport and Infrastructure Andrew Constance told delegates at the briefing meeting. “We’ve shown we can work together to deliver Phase I of our city’s new metro rail network – now it’s time to hear industry’s views on how to deliver Phase II as quickly as possible, bringing with it brand new metro rail services for thousands more Sydney customers.”

Industry representatives attended from companies based in the UK, the USA, Singapore, Hong Kong, Spain, South Korea, Japan, Italy, Germany, China, Austria and France.

The New South Wales Government plans to fund the metro project – which also includes major upgrades to existing grade level sections between Chatswood and St Leonards (3km) to the north, and Sydenham and Bankstown (13.5km) to the southwest – using one-off windfall receipts from the sale of State-owned electricity distribution and transmission businesses. The State’s budget for 2015–2016 includes A$84 million to continue planning and development of the project’s most challenging aspect: the harbour crossing.


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