Norway seeks shortlist for first big Rogfast contract 01 Nov 2018

Competition to be shortlisted for the first, and biggest, of three tunnel contracts on the world-beating Rogfast undersea road tunnel project, in Norway, has begun with a bid offer deadline of 21 November.

Prequalification call out for Rogfast’s Kvitsøy lot
Source/Credit: NPRA

Norwegian roads authority, Statens Vegvesen (NPRA) last week issued the prequalification call for the project’s Kvitsøy lot, a package of 21km of tunnelling work. NPRA planned for a tender conference on 16 October.

NPRA project spokesman, Øyvind Ellingsen, confirmed a maximum of three bidders are to be shortlisted.

The contract form is ‘price and negotiation’, offering shortlisted bidders opportunity to fine-tune their initial financial bids. Budget for the lot is approximately US$365 million – US$427 million, excluding VAT.

NPRA anticipates contract award in early 2019 for excavations to start in the second quarter of 2019. It then expects to issue the prequalification call for the second tunnel package, then six months later the third package.

Rogfast is a key part of the country’s E39 West Coast Highway. The 26.7km long link comprises twin road tunnels of T10.5 profile (10.5m wide at floor level) running below the Bokna fjord, near Stavanger.

Rogfast early works at Mekjarvik lot
Source/Credit: NPRA

Mid-way along the route, the tunnels will pass below the island of Kvitsøy. The tunnelling works involve excavating down to the main tunnel horizon with a spiral ramp and also sinking two ventilation shafts, each approximately 250m deep and 10m diameter. The lot also includes excavation of stretches of the main tunnels, advancing in opposite directions, plus cross passages.

NPRA has specified use of drill and blast for the entire Rogfast project. The main tunnelling will involve major use of pre-injection grouting.

The roads authority performed site investigation along the route in recent years and is taking all geological risk. In last week’s prequalification call for the Kvitsøy lot, NPRA commented: “There is much uncertainty regarding geology of the area.”

It added there are weak zones with extremely low seismic speeds, some of which have not been investigated by drilling and are up to tens of metres wide.

To complete the tunnel works, the main tubes are to be fully lined on their walls and ceiling with concrete panels; the spiral ramp up to the island, however, is to have panel walls but shotcrete on the ceiling. While excavations will be made to widen tunnels to house equipment, the lot does not involve electrical installation. Rogfast will use longitudinal ventilation, in part by employing hanging pulse fans near the shafts below Kvitsøy. The contract lot also includes surface roads and bridges on the island.

Following procurement of the Kvitsøy lot, NPRA will next move on to contracts for the other two large tunnel packages on Rogfast – Harestad lot, and Laupland lot.

Ryfast tunnel in fit-out near Stavanger, Norway
Source/Credit: NPRA

Harestad lot, at the south end of Rogfast, involves 16km of main tunnel excavation plus a ventilation shaft. The prequalification call remains due in Spring 2019. The contract budget was previously set a little less than Kvitsøy. The Laupland lot involves 19km of tunnelling.

While procurement plans for the large lots move ahead, early tunnelling works on two small packages (Mekjarvik, Arsvågen) at the portal areas have made good advances already.

At the south portal area, last week contractor Betonmasthaehre finished blasting on the 700m long Mekjarvik transportation tunnel. Works started in June. The tunnel will serve the Harestad lot.

On the Arsvågen lot, at the north end, contractor NCC has reached the halfway point in excavating the twin 1.9km long tunnels. Works began in early 2018.

NPRA expects Rogfast to be completed in late 2026.

With Rogfast getting underway, Stavanger will continue to be a construction hotspot, especially for road tunnelling. Over the last few years, NPRA has been building the Ryfast subsea tunnel to run below another fjord into Stavanger, where it links with the new Eiganes shallow urban tunnel. The road authroity confirmed all excavations are completed and fit-out is well advanced.