The Triangle Link () is a fixed link with three branches connecting the islands of Stord and Bømlo to each other and the mainland at Sveio, Norway. It consists of the underwater Bømlafjord Tunnel from Sveio to the island of Føyno, the Stord Bridge from there to Stord, and a road including the Bømla Bridge and the Spissøy Bridge to Bømlo. The section from Sveio to Stord is part of European Route E39, while the branch to Bømlo is part of County Road 542.
The Bømlo Tunnel is long and reaches below mean sea level. It is the longest subsea tunnel in Norway and was the deepest in the world when it opened. The Stord Bridge and Bømla Bridge are both suspension bridges, with lengths of and main spans of . The Spissøy Bridge is a beam bridge. The link is long toll road with a toll plaza on Føyno. The section from Stord to Bømlo has a pedestrian and bicycle path.
Plans for a link between Bømlo and Stord were first launched as a pontoon bridge in the 1960s. In the late 1980s, the plans evolved into a triangular project. There was controversy surrounding the project, in particular from environmentalists. The Parliament of Norway passed the plans in 1996, and construction started the following year. The bridges and link between Stord and Bømlo opened on 28 December 2000, while the tunnel opened on 30 April 2001. The link cost 1.8 billion Norwegian krone (NOK) after substantial cost overruns and remained a toll road until 30 April 2013.
Route description
The Triangle Link is part of two routes, European route E39 and County Road 542. The section from Stord to Sveio, including the Stord Bridge and the Bømlafjord Tunnel, is part of the E39 highway (the Coastal Highway) which runs along the west coast of Norway. The section from the interchange on the island of Føyno, including the Bøla Bridge and the Spissøy Bridge, is on County Road 542. The link acts both as a mainland connection for Stord and Bømlo to the mainland at Sveio, as well as a link between the two island communities, which have a combined population of 30,000.Hauge: 7
The Bømlafjord Tunnel is a long subsea tunnel which crosses Bømlafjorden. It is wide, tall and reaches below mean sea level. The tunnel has three lanes, one downhill and two uphill, with the direction of the extra lane switching at the bottom.Hauge: 109 When it opened, it was the longest and second-deepest subsea tunnel in Europe. Stord Bridge is a suspension bridge which crosses Digernessundet, connecting Stord with Føyno. It is long and has a main span (distance between the pylons, or towers) of . The bridge is wide and has a clearance of . It has two tall pylons, one foundationed on Digernesklubben and one on Føyno.Hauge: 104 The pylons were built in concrete, while the deck is built as 19 in steel sections, each long and weighing . Stord Bridge has the second-longest span in Norway, after the Askøy Bridge.
Bømla Bridge is a suspension bridge which crosses Spissøysundet, connecting Spissøy and Nautøya. It is long and has a main span of . The bridge is wide and has a clearance of . The higher clearance was built to allow ship traffic which runs through Nyleia between Bømlo and Stord to continue to run. The bridge has two tall pylons, one foundationed on Brunsholmen and one on Spissøy. The bridge has a similar aesthetically design to the Stord Bridge, and also features a steel deck with concrete pylons.Hauge: 106 It has the fifth-longest span in Norway. Spissøy Bridge is a beam bridge which crosses Gassasundet, connecting Bømlo with Spissøy. It is long, consists of five spans and has a clearance of .
The fixed link project also included of highway. On Stord, E39 received a new two-lane, limited-access road from Meatjørn to the bridge. This included a new grade separated (two-level) interchange in the southern part of Leirvik and a culvert—the Digernes Tunnel—immediately before the bridge. In Sveio, the link included of new limited-access road from the tunnel to a grade-separated interchange at Dalshovda. In Bømlo, there was a new road built across the islands of Spissøya and Nautøya—including an intersection on Spissøy. It further consisted of a new section of road from the Bømlo side of Spissøy Bridge at Gassasundet to Røyksund, and from Gassasundet to Grøvle, including a new tunnel through Stokkajuvet. A combined pedestrian and bicycle path runs along the whole section between Stord and Bømlo, with a grass division on the land parts between the road and the path. Underpasses and walls were built with natural stone.Hauge: 102
The tolls are collected at a toll plaza located on Føyno. The plaza is constructed as a grade-separated intersection, so that any car passes through the plaza once. However, traffic only traveling between Føyno to Bømlo does not have to pay. Cars driving along E39 drive straight ahead through the plaza, while cars to or from Bømlo need to use the interchange. There is also an intersection allowing access to the island. The plaza has six lanes, of which two in each direction have a toll booth and one in each direction has an automatic collection. The toll station uses the Autopass toll collection, which allows passage without stopping, in addition to manual collection.Hauge: 110 Passengers, pedestrians, bicycles, motorcyclists and mopeds are free.Hauge: 111 After a restructuring of the toll costs in 2006, the fees were NOK 85 for cars and NOK 270 for trucks, having previously had two separate fees for small and large trucks. Frequent travelers can prepay for at least 40 passings to the toll company, and receive a 40 percent discount. After the down payment was finished in April 2013, the tolls were removed and the roads became free to travel on starting 30 April 2013.
History
Pontoon bridge proposals
The first recorded proposal for a connection between Bømlo and Stord was made in the 1960s by sheriff, and later mayor of Fitjar Municipality, Finn Havnerås. Christened the Island Road, he proposed a series of eleven bridges and causeways which would run from Kalveid in Fitjar Municipality via Brandasund to Rolfsnes in Bømlo. While local politicians were not opposed to the plan, the recent municipal merger between Bømlo Municipality, Bremnes Municipality and Moster Municipality made them prioritize other sectors and the project was abandoned without any official investigations.Hauge: 32
A new route was launched by Bømlo Mayor Malvin Meling, who proposed a pontoon bridge which would cross Stokksundet. He was inspired by the plans to build what would become the Nordhordland Bridge north of Bergen. In 1973, the municipal councils of Bømlo, Stord and Fitjar decided to launch a planning process, which concluded that a pontoon bridge between Sørstokken and Foldrøyholmen would be optimal. The report also considered bridges across the Fitjar Archipelago and a crossing via Spissøy and Føyno. There were protests from Wichmann Motorfabrikk who were concerned about their operations if the sound was closed for shipping traffic. Similar protests also came from the shipping industry, who wished to continue using Stokksundet; the protests were not remedied by the plans including a suspension bridge across Foldrøysundet. To illustrate their point, one shipowner let two of his ships cross in the middle of Foldrøysundet.Hauge: 33 The shipping industry received support from Norwegian Coastal Administration and the plans were abandoned in 1974.
In the early 1980s, plans for Stord Airport, Sørstokken were launched. The bridge plans across Stokksundet were again brought up in 1982 as the industry on Bømlo wanted to not have use a ferry to reach the airport. A committee with representatives from all three municipalities was established in May 1983 to look into the possibilities for a bridge. Led by Bømlo Mayor Arne M. Haldorsen, it issued Engineer Harald Møyner the task to author a report and recommendation. He made three proposals: a pontoon or suspension bridge between Foldrøyhomen and Litlaneset; a suspension bridge between Setraneset and Sokkbleikjo, which would terminate just south of the new airport; and a combined fixed link between Spissøy and Digernes, without passing via the Fitjar Archipelago. The latter was the first time a fixed link to the mainland was proposed. The Norwegian Civil Aviation Administration protested against a possible suspension bridge near the airport, but stated that one closer further away would be fine.Hauge: 34
Mapping of traffic patterns on Bømlo was undertaken by Hordaland Public Roads Administration in 1984, and based on this and other feedback, a pontoon bridge between Foldrøyholmen and Sørstokken was recommended. It was estimated to cost NOK 190 million, in addition to auxiliary roads for NOK 40 million. Following the opening of the Vardø Tunnel in 1982, the first subsea tunnel in Norway, Engineer Finn Nitter d.e. proposed a fixed link which involved a combined bridge, road and tunnels between the islands, including a suspension bridge over Digernessundet, a causeway and low bridge onwards to a subsea tunnel under Spissøysundet and a low bridge over Gassasundet. In addition, a long tunnel would have had to be constructed from Føyno to Ulveråker in Sveio.
The company Johannes Sørlie launched an all-tunnel proposal in 1985, which would cost NOK 700 million and give of subsea tunnel connecting Bømlo to Stord and the mainland. The committee was positive to the proposals, while Josef Martinsen, director of Hordaland Public Roads Administration, stated that the project was unrealistic. Sveio Municipality was subsequently invited as a member of the planning committee. On 14 May 1985, the committee voted to encourage the municipal councils to pass planning which involved a bridge across Sørstokken, and aimed to get the plans into Norwegian Road Plan 1990–1993. The committee continued its work until it dissolved itself in October 1986 and was replaced by the limited company Ytre Sunnhordland Bru- og Tunnelselskap AS (SBT). The company was owned by the municipalities of Bømlo, Stord, Fitjar and Sveio, Hordaland County Municipality and the banks Bergen Bank, Sparebanken Vest, Vestlandsbanken, Haugesund Bank and Christiania Bank.Hauge: 35
A new master plan for the project was completed by the Public Roads Administration in December 1986. It proposed four main routes: via the Fitjar Archipelago; via Foldrøyhamn with a pontoon bridge to Sørstokken; a suspension bridge from Søtreneset to Stokkbleikjo; or via Spissøy, Naustøy and Føyno to Digernes. They recommended choosing the pontoon bridge. SBT stated that this was only to be a first stage, and that a second stage should involve a tunnel to the mainland. In a meetingbetween SBT and representatives for the shipping industry at the end of 1986, it was decided that SBT would start working for a mainland connection that would not hinder sailing.Hauge: 36
A report published by SBT in 1987 looked at details for a subsea tunnel to the mainland. It was the first official document to use the "Triangle Link" term, although this had previously been used by the press. A delegation traveled to Washington state in the United States and British Columbia in Canada to look at their seven pontoon bridges, while seismic surveys were undertaken in Bømlafjorden. SBT changed its name to Sunnhordland Bru- og Tunnelselskap and a majority of the board shifted towards being in favor of a fixed link. The issue became the subject of major local debate and was supplemented by a demand from residents in southern Bømlo that they did not want to lose their ferry service, which would be faster than driving via the fixed link.Hauge: 37
Opposition