The latest in a long list of underground construction projects in Australia will be delivered by the CPB Contractors/John Holland JV, following award of the design-build contract to construct the West Gate Tunnel project in Melbourne.

Fig 1. West Gate Tunnel Project alignment

The 50/50 joint venture is selected by private Australian toll road operator Transurban to deliver the Aust$5.5 billion highway mega-project ahead of rival bids from the Buoygues Construction/Lend Lease Engineering JV and the Salini-Impregilo/Fluor Australia/Lane Worldwide Infrastructure JV. The project is the result of an unsolicited proposal to the Victoria State Government, which has committed $1.44 billion towards the total cost, with the balance of funding expected to be generated from toll income.

The reference design calls for the use of two TBMs of 15.6m diameter to excavate two three-lane tunnels as part of a wider highway and environmental improvement project that was previously known as the Western Distributor (Fig 1). The eastbound northern tunnel is 2.8km long and the westbound southern tunnel is 4km long. TBM excavation is specified for the project and the machines needed are believed to be the largest to have operated in Australia to date.

The project will provide a much-needed second river crossing for the city of Melbourne, providing relief to the under-capacity West Gate Bridge. More lanes on the West Gate Freeway will cut travel times, and separate express lanes will improve road safety. The project also includes improved access to the docks area for road-based freight traffic.

With planning approvals expected to be in place later in 2017, construction on a 60-month construction program is expected to start in 2018 and the project scheduled to open to traffic in 2022.

Three joint venture teams are shortlisted for construction of Melbourne’s planned A$5.5 billion Western Distributor highway link.

Fig 1. The A$5.5 billion Western Distributor concept alignment

The link – which is only at concept design stage and is subject to planning and environmental permissions – aims to solve some of the Australian city’s most critical traffic problems by creating a second river crossing, relieving pressure on the West Gate Bridge, and cutting down the number of trucks that service the busy Melbourne Port area from using local roads (Fig 1).

Fig 2. The short tunnel option

Fig 2. The long tunnel option

The three shortlisted teams are:

• John Holland/CPB Contractors
• Buoygues Construction/Lend Lease Engineering
• Salini-Impregilo, Fluor Australia/Lane Worldwide Infrastructure

Two other single company expressions of interest were received but not shortlisted. They were Bechtel Infrastructure Australia and Rizzani De Eccher Australia.

The project is the result of an unsolicited proposal to the Victoria State Government by national toll road operator Transurban. In December the State Government agreed terms with the privately owned infrastructure provider to develop the proposal through to preliminary design via a design-build construction procurement process that will run in parallel with local consultation and the planning and environmental review process. The Government has committed A$1.44 billion toward the total cost of the project, with future toll income expected to provide the balance.

Project scope includes construction of a twin running tunnel under the residential Yarraville area of the city, although at this stage it is undecided whether a ‘long tunnel’ or ‘short tunnel’ solution will be adopted (Figs 2 and 3).

A Government spokesman said: “We have shortlisted three teams of world-class constructors who will now prepare fully costed designs for the Western Distributor, which includes the widening of the West Gate Freeway, a tunnel under Yarraville, a second river crossing, and connections to the port, CityLink and the Central Business District of Melbourne.

“These shortlisted teams will deliver innovative design and construction methods that will ensure the best outcome for motorists and the community, but in the meantime a reference design is being developed which will take into account feedback from extensive consultation with local government, local residents, businesses and the freight industry.

“The construction contract will be signed by late 2017 with the project to commence construction soon after and be completed in 2022.”

The latest highway project for Melbourne comes barely 18 months after the 4.4km-long East-West Link construction contract was cancelled by an incoming Labour Government. Announcement of the shortlist for the Western Distributor coincides with award this week of the first Early Works contract for construction of the all-underground 9km-long, A$11 billion, Melbourne Metro.