page_title: Triangle Link
section_title: Construction
hierarchical_section_title: Triangle Link / History / Construction
caption_attribution_description: Stord Bridge. Taken from from a small, sheep roamed islet, accessible by foot at low tide, north-west of Nautøyo.
context_page_description: The Triangle Link is a fixed link with three branches that connects the islands of Stord and Bømlo to each other and to 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 7,860 meters long and reaches 260 meters 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 1,077 and 998 meters and main spans of 677 and 577 meters. The Spissøy Bridge is a 283-meter beam bridge. The link is 21.5-kilometer 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.
context_section_description: Construction started on 15 February 1997. Before the first blast could be taken by County Mayor Magnar Lussand, representatives for Vestlandet Natue and Youth, and The People's Movement Against the Triangle Link had to be moved. The only police officer at the festivities was Sheriff Reidar Færestrand, who was not dressed in his police uniform and had not brought with him his badge. The demonstrators did not move until a police boat had been sent with the necessary documentation and Færestrand could prove his identity as a law enforcer. Elin Lerum Boasson of Nature and Youth stated that it was "a day of sorrow".
  Core samples showed that the tunnel would have to be built 30 meters (98 ft) deeper than originally planned to avoid deposits. The tunneling was undertaken by NCC Eeg-Henriksen from the Føyno side and by the Norwegian Public Roads Administration from the Sveio side. Construction from Sveio started on 16 September 1997 and from Føyno on 6 March 1998. The tunnel was built at an average speed of 55 meters (180 ft) per week, with the record being 96.7 meters (317 ft). The lowest point was reached on 5 May 1999 and the breakthrough took place on 2 September, five months before schedule. Sixty people participated in a course to master fear of tunnels organized by the toll company. When it opened, the tunnel was the longest and second-deepest subsea tunnel in Europe and Norway, after the Hitra Tunnel.
  The Stord and Bømla Bridges were both constructed using the same method and by the same contractors, Arbeidsfellesskapet Triangle Contractor, a joint venture between NCC Eeg-Henriksen and HBG Steel Structures. Construction started on the Stord Bridge on 20 February 1999. After the pylons were completed, two catwalks were erected between them, with the constructors choosing a continual catwalk instead of three separate ones. The cables were spun on-site using a reel; this also allowed for cost savings, as the reels could be used two times. The cables were spun using the air spinning with controlled tension, which allowed spinning with little space use and with a crew with limited experience with spinning. The two bridges were the first time that on-site spinning was used in Norway. The fastening poles were delivered five weeks after schedule; a new mounting method was developed which allowed them to be installed in a quarter of the time, in part by using a helicopter, and the whole five-week delay was eradicated. This allowed the deck sections to be installed as scheduled. The decks were produced in Schiedam, Netherlands, for the Stord Bridge and in Italy for the Bømlo Bridge. These were sent by barge to Sunnhordland. The section length was different between the two bridges, the Stord Bridge having them in lengths of 36 meters (118 ft) and the Bømla Bridge in sections of 24 meters (79 ft). This was to accommodate the latter's smaller vertical curvature.
  The entire project cost NOK 1,814 million. The costs were distributed to NOK 476 million for the Bømlafjord Tunnel, NOK 433 million for the Stord Bridge, NOK 336 million for the Bømla Bridge, NOK 46 million for the Spissøy Bridge, NOK 36 million for the Digernes Tunnel, NOK 325 million for roadways and NOK 172 for administration and common costs. The investment cost was split between state grants and NOK 1,036 million in debt taken up by the toll company. When the project was passed by Parliament it had a budget of NOK 1,260 million. The Office of the Auditor General of Norway criticized the Western Norway Public Roads Administration in 2001 for a total cost overrun of NOK 900 million in three projects, the Triangle Link, the Lærdal Tunnel and parts of National Road 555. The majority of the cost overruns were tied to the Triangle Link. As a consequence, Minister of Transport Torild Skogsholm stated that future large road investments would have an external quality assurance before being presented to Parliament.
caption: Stord Bridge with Stord to the left
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