Norwegian roads authority Statens Vegvesen (NPRA) is to submit its last quality report to Government on the extensive 26.7km long Rogfast subsea tunnel project by the end of November 2016, helping towards launch of its prequalification call for the first of three major tunnelling packages in February/March 2017.
The first and largest construction package on the world-beating Rogfast project comprises a complex of tunnels, shafts and adits deep below the island of Kvitsøy. The island is in the middle of the subsea route across Bokna fjord, just north of Stavanger (Fig 1).
The Kvitsøy contract package includes the main twin tube highway tunnels that will advance in opposite directions from the island. It has a budget estimate by the client of approximately NOK2.8 billion (US$328 million), excluding of VAT.
prequalification for two further construction packages will follow for excavation of the tunnel headings from Harestad and Laupland at the southern and northern ends of the fixed link respectively. The Harestad and Laupland contract packages have construction budget estimates of approximately NOK2.5 billion (US$292 million) and NOK2.3 billion (US$271 million).
“The plan is to see the first of the main contract awarded and construction started by the second half of 2017,” Statens Vegvesen press spokesman Øyvind Ellingsen told TunnelTalk. Tunnelling is to be by drill+blast with separate contracts covering finishing and fit-out of the highways.
Rogfast is a strategic fjord crossing on Norway’s E39 coastal highway. Once completed in 2024 it will be the longest ever subsea road tunnel (Fig 1). The twin tube tunnels are principally T10.5 Norwegian profiles of 10.5m wide at invert, with widths increases to 13.5m in some sections, and connected with cross passages every 250m.
Norconsult is providing consulting services on project development for Rogfast to the client.
In the middle of the fixed link, and under the island of Kvitsøy, the proposal centres on a vast underground interchange from where the main tunnels will advance in opposite directions (Fig 2). The island sits in a geological zone of greenstone and volcanic derived sediments in which there are identified faults.
The package comprises about 8.5km of twin tube highway tunnelling, about 17km in total, a 4.1km access tunnel from the island surface, various link tunnels, and, more than 1.5km of associated ventilation excavations, including two 10m diameter shafts, each about 250m deep. Works include 2km of roads and five bridges.
The geology at the southern end of the Rogfast link is firmly in the typical mica schist and phyllite of the Randaberg and Stavanger region. Passing underground from the Harestad portal while well inland, the Rogfast alignment briefly passes through Precambrian gneisses before entering an area comprising gabbro and ultramafics.
The deepest point of the tunnel link on this section is 300m-320m below sea level, towards where the Harestad drives will converge with those from Kvitsøy.
The alignment from the north passes through more rock types and potentially more expected small faults. Passing underground in granitic to granodioritic gneisses, the alignment then moves in quick succession through mica schist and phyllite to porphyritic granite.
Both coastal headings will advance towards the central zone of greenstone and volcanic derived sediments. The junction of the various undersea drives is yet to be determined.
The Laupland drives towards Kvitsøy hold also the deepest point of Rogfast link at about 390m below sea level.
In earlier plans, while design development was still underway, it was thought that work might start in 2015 or 2016, and that the then seen as 25.5km long link could be completed 2023. By 2015, Statens Vegvesen had progressed planning stages and funding agreements with local communities for the toll route and had hoped to start construction in 2016 for project finish in 2024. Plans developed to mid-2016 sought prequalification for main tender calls to be made from early 2017, pending Parliamentary approvals by or soon after the third quarter of 2016.
In late September this year, the roads authority called for prequalifications for the first Kvitsøy package however withdrew the call as a further and final quality report was wanted by the Government. The timetable is now rescheduled for a Kvitsøy prequalification call in February/March 2017 with the shortlisting process well underway during March/April and call for proposals soon after. With construction starting quickly after the awards, the envisaged schedule could have main tunnelling on the Rogfast tunnels completed during 2021 to achieve project finish by 2024-25.
The Stavanger region has been a hot-spot for tunnelling in the last few years. Also for the E39, Statens Vegvesen is completing drill+blast excavation of the Eiganes Tunnel, as recently reported by TunnelTalk, and work continues on the Hundvåg and Ryfylke tunnels of the Ryfast project. Main tunnel excavation is expected to be completed by quarter three of 2017 and the Ryfast link opened in 2019.
The set of Stavanger road projects are a key part of tunnel projects attracting interest to Norway, which is to host the WTC World Tunnel Congress in June 2017, in Bergen. Other key projects include the Romsdal subsea road tunnel and also major rail tunnels in Bergen and Oslo.