The Salini-Impregilo/NRW joint venture is selected as preferred bidder for $2 billion construction of the Forrestfield-Airport link in Perth, Australia.

Alignment of the 8.5km Perth/Forrestfield Airport Link

Following a 15-week period spent evaluating the proposals of three shortlisted JV teams, the Public Transport Authority of Western Australia (PTA), as project owner, will now enter into final negotiations with Salini-Impregilo/NRW.

“The final value of the contract is to be determined as part of these discussions and further information about the construction timeline and tunnel boring requirements will also be announced then,” David Hynes, for the PTA, told TunnelTalk.

He added: “In considering the selection of a preferred bidder, the PTA is required to take into account a range of factors, not just cost.”

The unsuccessful bidders were the John Holland/Leighton JV, and the Acciona/BAM/Ferrovial Agroman JV. Salini-Impregilo, which was involved in construction of the STEP project in Abu Dhabi, and in December 2014 completed a hard-fought and technically demanding TBM drive under Lake Mead in the USA, has been successful in securing a number of large underground construction contracts throughout Europe and the USA.

Until now, however, it has struggled to break into an Australian tunnelling market that has been extremely buoyant in recent years and for which there are a number of major projects still in the pipeline, including the mega-TBM WestConnex highway tunnel in Sydney and a 15km rail link that will include an undercrossing of Sydney Harbour.

Contract scope of the Perth Airport–Forrestfield Link includes construction of a junction between the new Airport Link and the existing Midland Line near Bayswater; a new tunnel portal to take the line underground; 8km of segmentally lined twin running tunnels of 6.2m i.d.; nine cross passages – three of them with exit shafts to ground level, and all of them to be constructed with a cast iron lining using the freezing method for ground stabilisation; and construction of two underground stations and a third one at grade. The alignment will require an undercrossing of the Swan River, and tunnelling underneath the busy Perth Airport.

Construction is expected to start later this year, with EPB or slurry machines likely to be specified for a geology that comprises soft calcerous sands and the calcernite cobbles of the Ascot Formation. The Forrestfield–Perth Airport link is fully funded by the Government of Western Australia.

The Government of Western Australia confirms it is on target to award the Aust$2 billion state-funded design-build Forrestfield–Perth Airport Link in the second quarter of this year (2016).

Thousands of pages of bid documentation

Five construction joint ventures expressed interest in construction of a new 8.5km link between Perth’s eastern suburbs, via the airport and under Swan River, for connection at Bayswater with the existing Midland Line into the city centre. Three have now submitted detailed bids. They are:

• Forrestfield Connect (Acciona/BAM/Ferrovial Agroman)
• JHL JV (John Holland/Leighton)
• SI-NRW JV (Salini Impregilo/NRW)

Connecting Forrestfield, a JV of Lend Lease and Ghella, and the CRCC-BGC-VDM JV, a joint venture comprising China Railway Construction Corporation, BGC and VDM, expressed interest but were not shortlisted to bid.

A project spokeswoman told TunnelTalk that at this stage it is not known how many TBMs will be required to complete the job, but that slurry or EPBM machines will be required to negotiate a geology that comprises the soft calcerous sands and calcernite cobbles of the Ascot Formation. More than 400 boreholes have been drilled along the alignment, and a barge drilling program under Swan River has been carried out, ahead of the bidding process.

Construction is expected to get under way in the second half of 2016, with rail services scheduled to start operation in 2020. All environmental and government permissions have been secured.

Advancement of Perth’s Airport Link Project coincides with a current boom in underground construction in Australia. In Sydney, TBM progress continues on the 23km-long North West Rail Link (NWRL), 15km of which is in twin running tunnels; planning continues on a 29km extension from the southeastern terminus of the NWRL that will incorporate 12.5km of twin running tunnels and a new undercrossing of Sydney Harbour; excavation contracts are already awarded for the first two phases of Sydney’s WestConnex highway project, both of which require a significant element of underground construction; and roadheader excavation of the city’s 9km NorthConnex highway tunnels is under way. In Melbourne, which cancelled the East-West Link highway mega-project in controversial circumstances just weeks after awarding the Aust$5.3 billion public-private partnership contract, planning continues on the preferred alternative: the 9km Melbourne Metro Rail Project.