Three consortia are prequalified for design-build tunnel construction for the West Connex Phase 1 highway project in Sydney, Australia; five more consortia are shortlisted to deliver the tunnels required for Phase 2.
Phase 1 comprises construction of the 5km long M4 East tunnel that will form part of a 13.5km extension of the existing M4 motorway with the City Link West route into central Sydney (marked in green in Fig 1). The shortlisted joint ventures are:
Detailed planning based on the West Connex Authority’s concept design will now take place, with a four-year construction period expected to start next year (2015). Full bids are expected by the end of this year (2014). It is expected that the tunnelled section, designed to relieve the heavily congested Parramatta Road, will be a mixture of cut-and-cover and open cut construction.
In addition to the link with City Link West at the eastern end of the Phase 1 alignment, project scope comprises construction of an open link to the future Phase 3, 8.5km long TBM-bored, twin running tunnels that will complete the connection between the M4 and the M5 (dark blue in Fig 1). This final phase is not yet in the tendering phase, but is scheduled for a construction start in 2018.
Meanwhile, four JVs and a single company bidder have lodged expressions of interest for construction of up to 6km of three-lane twin running tunnels required for Phase 2 (light blue in Fig 1). Project scope here will include duplication of the existing 3.8km long M5 tunnels which are only two lanes wide and suffer badly from congestion at peak periods.
Contract award is expected in mid-2015, with construction taking place between 2016-2020.
The cost of the completed West Connex project, which will be tunnelled for more than half its 33km length, is estimated at Aust$11.5 billion. Confirmed public sector funding makes up £5.3 billion of this (New South Wales Government $1.8 billion, national Government $1.5 billion and a $2 billion concessional loan). Tolls will be required to make up the shortfall, but at this stage it is not yet known how this will be financed through the construction phase.