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Stockholm begins mega-bypass contract rollout 2 Sept 2015
Peter Kenyon TunnelTalk
Implenia of Switzerland is awarded the first major drill+blast tunnel construction lot (Contract FSE403) as rollout of the 21km-long Stockholm bypass mega-project gets under way. In addition to 18km of twin tunnel alignment – of three lanes in each direction – project scope also includes a further 14km of entry and exit ramps and 4km of intermediate access tunnels, for a total excavated length of 54km.
E4 bypass internal schematic

Construction lots for the 21km Stockholm bypass mega project

The SEK2.1 billion (€228.4 million) award follows a prequalification and bid process run by the project owner, Trafikverket, the Swedish highway administration. A total of five bidders were shortlisted. Implenia cited its acquisition of Bilfinger in 2015 as a key factor in securing the contract win.
The full bid result, in price order, is as follows:
• Bilfinger/Implenia – €228.41 million
• Veidekke Engtreprenad AB – €245.15 million
• Leminkainen Sverige AB – €250.3 million
• Strabag Sverige AB – €271.11 million
• Skanska Sverige AB – €294.18 million
A separate €15 million contract (FSE210) was awarded to the Subterra (Czech Rep)/ STI (Slovakia) JV last year for early excavation of two access tunnels, and construction of a temporary jetty facility for the onward transportation of excavated rock at the extreme southern end of the alignment. Project Director Johan Brantmark told TunnelTalk that these tunnels will enable the main contractor for the FSE209 Skärholmen tunnel – once selected in 2016–17 – to make an earlier start on drill+blast operations on the main headings, soon after contract is awarded.
On the award of FSE403 an Implenia spokeman said: “This is the first project Implenia has won in Sweden thanks to the acquisition of Bilfinger Construction. In line with the ‘One Company’ strategy, the project involves specialists from tunnel construction, foundation engineering and road construction under the lead of our ‘Global Projects’ division. This unit brings together the Group’s technical and logistical capacities for executing complex infrastructure projects.”
Project scope for FSE403 includes 3.6km of twin three-lane traffic tunnel, two entry and exit ramps, three access tunnels, cross passages, four electric power stations and six ramp connections. Construction is scheduled to begin next month (October), with the completed bypass due to open to traffic in 2021.

Stockholm bypass project description

Procurement is now under way for all five of the remaining major tunnel contracts, with three more awards expected next year (2016). These are the 1.8km Lunda mountain tunnels (FSE410), the 3.5km North Lovö mountain tunnels (FSE302), and the 2.8km South Lovö mountain tunnels (FSE308). According to Trafikverket, procurement for the North and South Lovö tunnels – which will be by open procedure – includes provision to combine the two lots into a single contract. Tender documents for the Lovö tunnels were sent out in April (2015) with a deadline response of 9 November (2015).
Trafikverket expects to complete the main tunnel awards in 2017 with the 1km Akalla tunnel (FSE613) at the north end of the alignment, and the 5.5km Skärholmen tunnel (FSE209) at the south end.
Construction is already under way at the extreme southern end of the alignment at Kungens Kurva following award in July (2015) of a €139.5 million contract to Skanska of Sweden. Project scope includes a major realignment of the E20 and E4 highways and construction of a 360m long cut and cover starter tunnel.
The total cost of the project is estimated by Trafikverket at €2.54 billion.
References
Bilfinger withdraws from civil tunnelling - TunnelTalk, June 2014
Implenia completes Bilfinger acquisition - TunnelTalk, March 2015
Advancing Stockholm bypass mega-project 18 Sep 2013
Peter Kenyon, TunnelTalk
Fig 1. E4 Stockholm western bypass alignment

Fig 1. E4 Stockholm western bypass alignment

Construction procurement for one of the longest road tunnels in the world, requiring more than 50km of tunnelling, is set to begin later this year or early next year.
The 21km-long E4 Stockholm western bypass (Fig 1), which after decades of planning is now at an advanced design stage, features three traffic lanes and an emergency lane in each direction and includes tunnelled sections of 16.5km and 1.5km. In addition to a complex junction at the southwestern portal at Kungens Kurva, the tunnel will feature two exit and entry junctions at Lovo and Vinsta (Fig 1).
In an exclusive interview with TunnelTalk, project owner Traffikverket (the Swedish Transport Authority) previewed some of the design and procurement elements that are planned by its engaged tunnel construction design consultants ÅF Infrastructure and URS. The mega-project is expected to cost SEK28 billion (US$4.35 billion).
Design elements
"The excavation method for the main tunnel and access ramps will be drill+blast since the rock quality along the alignment is old bedrock and granite," said Ann Möller of Traffikverket.
E4 bypass internal schematic

E4 bypass internal schematic

"Since the design is ongoing it is still too early to define reinforcement methods, although we are of course familiar with NATM as one possibility. No TBMs will be used, although the design of large diameter vertical shafts is ongoing.
"According to the design the main tunnel is divided into two sections, connected by a short surface alignment that will allow a link with the E18. The typical profile will be 125m2 for each direction of the main tunnels, and 82m2 for the entry and exit ramps at Lovo, Vinsta and Kungens kurva. Adits allowing access for construction works are somewhat smaller than 82m2 , but larger than usual due to the ventilation demands of such a long tunnel.
Fig 2. E4 bypass tunnel runs under Lake Mälaren in three locations

Fig 2. E4 bypass tunnel runs under Lake Mälaren in three locations

Fig 3. Tunnel alignment and junctions relative to surrounding region

Fig 3. Tunnel alignment and junctions relative to surrounding region

"The rock tunnel will pass underneath Lake Mälaren in three locations. As crush zones have been identified by geological surveys, at these locations the tunnel will pass approximately 60m beneath the water surface of the lake and almost 100m below ground level. The inclination is approximately 3%, which results in long exit and entry ramps," explained Möller.
"The total length of the ramps will create an additional 14,000m of tunnel, and in accordance with our safety concept the whole system consists of one-way tunnels with traffic never meeting head-on at any point. Maximum inclination on the ramps will be 5%, with excavation taking place on a single front for each of them, so no extra vertical shafts will be needed for construction of these."
Fig 4. Entry and exit ramps add 14km of tunnels

Fig 4. Entry and exit ramps add 14km of tunnels

In addition to 36km of bi-directional main tunnel and 14km of access ramps, Möller said that cross passage rescue tunnels will be constructed every 100m in the main tunnel and every 150m between the entry and exit tunnels tunnels. "With the main tunnels running parallel this results in relatively short rescue tunnels, but the corresponding rescue tunnels for the ramps tend to become very complex," said Möller. "Along the tunnel length there will three air exchange stations constructed, and for ventilation purposes the project demands a number of vertical shafts between 50-100m deep, each with large diameters."
Procurement schedule
"The tunnel will be divided into six main construction contracts and an additional five contracts for early works such as access tunnels and the temporary harbours [that will be used for removal of excavated material]," said Möller. "The design is the client's, but the tunnel lining will be design-build. ÅF Infrastructure, AB and URS in joint venture hold the design contract. They are well into the design process and just handing over the first access tunnel contracts.
"That will allow the procurement process to start 2013/2014 for the early works. The main tunnel contracts will be preceded by a prequalification process starting early 2014. The main contracts can be procured as soon as the environmental permits have been established by the government, which should be by the middle of the 2014. The technical installations will be procured later, beginning in 2016, until 2018.
"By the winter of 2014/2015 we will start construction of the access tunnels and the three harbours. The construction work for the main contracts is planned to start in the spring of 2015. Contractors will be able to bid on more than one of the six main construction lots."
Transport projects in and around Stockholm

Transport projects in and around Stockholm

Integration
Construction of the project is scheduled to last 10 years, with delivery of the completed bypass set for 2023. Funding is 20% from public funds, with the balance coming from money raised by Stockholm's congestion charge. It is estimated that by 2030 the population of the Swedish capital will have risen from 2 million to 2.5 million, putting further pressure on the existing eastern bypass (Essige-leden) that was built in 1967 for a design capacity of just 80,000 vehicles/day, but which now has to cope regularly with double that. Because Stockholm is divided by water, north-south travel by car is difficult except via the this existing route, or through the city centre itself. Trafficverket expects the new bypass tunnel will be used daily by 145,000 vehicles.
In recent years Stockholm has been undergoing an underground transportation revolution. The inner bypass has been extended with a tunnel to the south (Sodra lanken, completed 2004), while in the north of the city the Norra lanken tunnel section of inner bypass is expected to be complete by 2015. Other road connections are also scheduled, while in the city centre the Citybanan underground system is under construction with a scheduled finish date of 2017.
References
Citybanan starts complex sinking operation - TunnelTalk, May 2013

           

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