A joint venture of Astaldi, Gulermak and Segermo has been awarded the contract for the Haga Lot on the Gothenburg West Link rail tunnel project in Sweden.

Gothenburg West Link rail project contracts

The JV bid SKR 2.3 billion or approximately US$289 million, excluding VAT for the central 1,520m long section of the 8km long rail tunnel project below central Gothenburg (Fig 1). The bid is about two-thirds the level of two other tenders received by Swedish transport authority Trafikverket for the package of underground works.

A spokeswoman for Trafikverket told TunnelTalk that the closest runner-up tender at SKR 3.3 billion (US$ 414 million) was submitted by a JV of NCC and Wayss & Freytag. The third bid, at SKR 3.5 billion (US$439 million), was presented by a JV of Hochtief, Veidekke and Implenia.

Along with the 10m high x 14.7m wide x 1,520m long twin track tunnel, the Haga Lot includes excavation of a 1,310m parallel service tunnel, an underground station constructed in a 300m long concrete box, and shafts for entrance and ventilation.

Five JVs were shortlisted to bid for the Haga Lot and tenders were received in May 2017 for works to be structured in two parts – construction-only for the rock excavations and design-build for the box station structure.

Trafikverket selected the Astaldi-Gulermak-Segermo JV for the contract in June but the second bidder sought a review of the decision. The Administrative Court last week declined the review and upheld award of the contract by Trafikverket to the JV as the lowest bid.

Bo Larsson, Project Manager with Trafikverket, said in a statement following the Court’s decision: “It feels very good that the decision was so clear and came so fast. Now we can proceed with the planning for construction of Haga Station with the contractor.”

Haga is the first of three large tunnelling contracts on the West Link project. Next contract out to tender is the Kvarnberget Lot, to the north of Haga which calls for tunnelling through complex geology close to the river. Bid deadline for the four shortlisted JVs is 19 September.

Bids for the last Korsvagen Lot to the south of the Haga Lot are due in early November. Works include both rock tunnel excavation and station construction and are to be structured in the same way as the Haga Lot.

The Trafikverket spokeswoman told TunnelTalk it will take about a month to evaluate the tenders and award the contracts for each lot.

Earlier contract awards on the project were on the north end and include:

• award in early 2016 of the Centralen Lot, to the north of the Kvarnberget Lot, to the NCC/Cowi/Thyrens JV for major cut-and-cover works of a 15.6m wide x 9.5m high concrete box to link to Central Station; and
• award of the Olskroken Lot of surface works awarded to Peab/WSP/Infranord JV.

Swedish national transport authority Trafikverket is removing a serious bottleneck in the rail network through the urban heart of Gothenburg with investment in the 8km long West Link project. Three-quarters of the entire rail link and its three stations will be underground in both rock excavation and major concrete box construction. The line will increase rail capacity is vital for the west coast city of Denmark as it is a key industrial port and transport hub for Scandinavia.

Fig 1. West Link alignment and construction elements

The West Link project emerged from a transport strategy developed by Trafikverket in cooperation with the city and regional authorities, and is funded 50:50 from national and local funding. The estimated SEK 20 billion project (in 2009 prices), about US$2.5 billion, is anticipated to be in service by 2026.

The West Link has a 6km long section in single tube, twin-track tunnel and three new underground stations at Centralen, adjacent to Gothenburg Central terminus, Haga and Korsvagen (Fig 1).

Located beside the Gota River, the geology along the alignment has a variable rockhead, with small infilled channels and a major reach of infill and soft marine clay at the northern end (Fig 2). The bedrock is gneiss with joint sets, some foliation and zones of weakness in the rock mass. Groundwater levels adjacent to the river are high.

As a consequence, the majority of the tunnel, approximately 4km, will be excavated through rock. The remainder, in the northern part, will be built as a large concrete box structure through infill and clay over a 2km stretch (Fig 3).

The West Link is designed to take full size trains for its entire length. Dimensions of the tunnels are:

Rock Tunnels:

• Main tunnel - 14.7m wide by at least 10.1m high;
• Service tunnel running 10m parallel, to the main tunnel - 6m wide by at least 7.5m high;
• Technical rooms - 9m wide by at least 10.5m high

Concrete Box:

• Tunnel section - 15.6m wide x 9.5m high

The procurement and construction strategy splits the project into five main civil engineering packages: Olskroken, Centralen, Kvarnberget, Haga and Korsvagen. Trafikverket has awarded the Olskroken and Centralen Lots to date and prequalification for the next large tunnelling lots are due in by 30 September.

Fig 3. Proposed concrete box tunnel

Olskroken Lot

The Olskroken Lot, focusing on surface works at an existing central railway node, was awarded in 2015 to a JV of Peab, WSP and Infranord. It is a two-stage design-build partnering contract involving early contractor involvement (ECI). The contract sum is to be set at the end of Stage 1 design and planning, which is expected at the end of 2017. The construction Stage 2 will end in 2023-24 and may also include further ECI, subject to agreement.

Centralen Lot

The Centralen Lot for the station and adjacent tunnels was awarded to a JV of NCC, Cowi and Thyrens in 2015. Procurement is again a design-build/ECI two stage process with the contract sum to be set at the end of Stage 1 in December 2017 and with the Stage 2 construction anticipated in 2023-24.

The deep soft clay and bedrock of the Centralen Lot is seen as among the most demanding parts of the project. For the station alone, the works involve a cut-cover-cover excavation of about 400m long x 60m wide and to a depth of about 15m.

Proposed rock tunnels for the project

Various preparatory works are also underway including utility re-routing along the Olskroken-Residenset corridor. The SEK 150 million (US$17.5 million) contract is being performed by NCC and is due for completion in January 2017.

Ongoing procurement activities are most immediately focused on the upcoming prequalification deadline of 30 September for the Haga and Kvarnberget civil lots located in the middle of the project. Tender documents are to be issued to prequalified parties in November for submission of proposals by April 2017.

Trafikverket Project Director Bo Larsson told TunnelTalk there will be a maximum of five prequalified parties for the main contracts. Larsson confirmed that the excavation method for much of the rock tunnel is expected to be drill+blast and added that optimisation of the tunnel design is still underway.

Impression of Korsvagen station on the West Link rail project
All photos by Trafikverket

Haga Lot

Key civil works involved in the Haga package involve construction of 1,520m of main tunnel with 1,220m in rock and a 300m long section of concrete box tunnel for the station, plus 1,310m of the parallel service tunnel in rock, and construction of three entrances and three ventilation shafts.

Total excavated volumes of rock and soil at the Haga Lot are expected to be about 650,000m³ and 340,000m³, respectively.

Within the one contract lot, Trafikverket has separated the rock excavation as construction-only and the concrete box works as design-build.

Kvarnberget Lot

Works for the relatively short Kvarnberget Lot, on a bend of the tunnel alignment and running closest to the river, features complex works through rock-soil interfaces.

Site investigations underway

Korsvagen Lot

Deadline for prequalification to the last main civil lot on the project, the Korsvagen Lot at the southern end of the project, is 15 December. Tender documents are to be issued to prequalified parties in February 2017 for submission of proposals by October 2017.

The Korsvagen contract package includes a total length of 3,240m in main tunnel, split 2,120m in rock and 1,020m in a concrete box structure for the station, plus a 2,540m long section of the parallel service tunnel in rock and three entrances and two ventilation shafts.

The total volumes of excavated materials in the Korsvagen Lot are 761,000m³ of rock and almost 400,000m³ of soil.

Like the Haga Lot, Trafikverket has separated the procurement method of the Korsvagen Lot to construction-only for the rock excavation and design-build for the concrete box works.