Bømla Bridge
Encyclopedia
The Bømla Bridge is a suspension bridge
which crosses Spissøysundet between the islands of Nautøy
in Stord
and Spissøy
in Bømlo
, Norway
. The bridge is 998 metres (3,274.3 ft) long, has a main span
of 577 metres (1,893 ft) and a clearance below of 36 metres (118.1 ft). It carries two lanes of County Road 542
(former National Road 542) and a combined pedestrian and bicycle pathway. It is part of the Triangle Link, a fixed link which connects Stord to Bømlo, and both to the mainland at Sveio
. Plans for a crossing arose in the 1960s, and was until the 1990s planned as a pontoon bridge
further north. The Bømla Bridge entered the plans after the decision to combine the crossing with the Bømlafjord Tunnel. Construction started in 1999; the bridge cost 342 million Norwegian krone
(NOK) and was taken into use on 30 April 2001. The bridge and the link will remain a toll road
until 2012 or 2013.
across Stokksundet
, 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 across via Spissøy and Føyno. There were protests from the shipping industry, who wanted to continue to use the strait for ship traffic.
In the early 1980s, plans for Stord Airport, Sørstokken
were launched, and in 1982 the plans for a bridge crossing Stokksundet were again raised, this time from the industry on Bømlo, who would have to travel by ferry to reach the new airport. In May 1983, a committee was established, giving Engineer Harald Møyner the job to make a new report. 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 further away would be fine.
Mapping of transport on Bømlo was performed by Hordaland Public Roads Administration in 1984, and based on this and other feedback, a pontoon bridge between Foldrøyholmen and Sørstokken became the most probable outcome. It was estimated to cost NOK 190 million, in addition to auxiliary roads for NOK 40 million. In 1982, plans were launched for a fixed link to the main land, which would include a bridge over Digernessundet, a causeway and low bridge across Spissøysundet and a low bridge over Gassasundet. In addition, a tunnel would have to be built from Føyno to Sveio. In 1985, an all-tunnel proposal, following the same route, was proposed. Hordaland Public Roads Administration stated that the proposals were unrealistic. The limited company Ytre Sunnhordland Bru- og Tunnelselskap AS (SBT) was founded in Ocotber 1986 by the municipalities of Bømlo, Stord, Fitjar and Sveio, Hordaland County Municipality
and five banks.
In December 1986, the Public Road Administration recommended a bridge solution. 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 Coastal Administration stated that they would not allow a pontoon bridge. On 26 June 1987, SBT decided to work to get permission to collect advanced tolls on the ferry services. On 16 September, they unanimously supported the triangular proposal, which was estimated to cost NOK 660 million. This was criticized by Hordaland Public Roads Administration, who stated that it would take longer time to plan, and thus complete, the Triangle Link.
From 1988, environmentalists started actively opposing the Triangle Link. The most active were the local chapter of the Norwegian Society for the Conservation of Nature
and Nature and Youth, who stated that the road would have serious consequences for the local boat traffic to the recreational islands of Føyno and Nautøy. Instead, they recommended that the municipalities chose a pontoon bridge. Another opponent to the project was the Action Committee Against a Hasty Construction of the Triangle Link, who wanted to delay the decision until after the 1991 municipal elections
, to ensure that the municipal councils had backing in the public. Gisle Tjong stated that the risk in the project was large and that it was uncertain how long the tolls would last: they could just as well be 60 as 15 years, and instead wanted to collect tolls in advance.
The Triangle Link was passed by the various municipal councils in February and March 1988. Hordaland Public Roads Administration still supported a pontoon bridge, and stated that two and a half years of work on a master plan had been wasted. A new master plan for the Triangle Link was published in early 1989. During late 1989, advance tolls on the ferries was approved by the municipal councils and the county council, who recommended that collection start from 1 July 1990, but this was not immediately supported by the government.
In July 1991, the master plan was passed by the Council of State. On 10 December 1992, Parliament approved advanced payment of tolls on the ferry, which were made effective from 1 January 1993. Ticket prices increased with between NOK 10 and 12. This resulted in protests from the ferry employees who stated that they would have to collect the tolls which would remove their jobs. Work on the development plan started in 1992. It included safety and environmental improvements which increased the project's cost by NOK 200 million. In May 1994, it was made subject to consultative statements. In May, SBT proposed building a culvert
on Digernes as a compromise to avoid a new plan which could have postponed the project several years. On 11 June 1996, Parliament decided with 144 against 20 votes to build the Triangel Link. The original name proposal for the bridge was ; this was later changed to after input from the municipal councils and name committees.
The construction of the Bømla Bridge was done under the same contract as the Stord Brige, which in December 1998 was awarded to Triangle Contractors, a joint venture between NCC and HBG Steel Structures. Most of the work was performed by NCC with HBG having responsibility for the steel parts of the deck and the cables. HBG had previously built the steel for the Osterøy Bridge
, which opened in 1997. The responsibility for the cables was given to Brown Beach Associates and Hordaland Mekaniske Verksted (HMV). Construction started on 25 March 1999. After the pylons were completed on 20 December 1999, two catwalks were erected between them, with the constructors choosing a continual catwalk instead of three separate ones. Extra stability to the catwalk was achieved by building connections between the two.
The cables were spun on-site using a reel
, based on the problems which had arisen using a bundle on the Great Belt Bridge. 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 place and with a crew with limited experience with spinning. This involved installing a cable car
and connecting two double loops with a spinning wheel each, with one loop doing the outward spinning the other the inward spinning. The system has two reel racks, each with four reels, with two reels on one rack at any given time, allowing for minimum down-time when changing reels. Wires were connected using pressure casing. The balance in the system is kept in place using a counter-weight tower. Spinning of the main cable started on 24 May 2000 and was concluded on 13 July. In all 11600 kilometres (7,207.9 mi) of steel wire were used to create the cables for both bridges. It was the first time that on-site spinning was chosen in Norway, and it gave a cost saving of NOK 10 to 11 million.
The cables consist of seven bundles of cables, each consisting of 420 wires, each with a diameter of 5.35 millimetre (0.210629921259843 in). When compressed, this gives a diameter of 320 millimetres (12.6 in) and a quality of 1,570 megapascals. 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 helicoper, and the whole five week delay was eradicated. This allowed the deck sections to be installed as scheduled. There arose problems with small holes being created in the coating; as these had also been found on the Great Belt Bridge, it was decided that nothing would be done with the issue.
The deck sections were produced by HBG in Cimolais
, Italy, and transported first by truck from the plant to the port, and then by Barge to Stord. Each section is 48 metres (157.5 ft) long and consisted of subsections 6 by to allow for transport to the port. They were mounted using the crane ship Uglen, allowing an average of four sections to be installed per day. and completed in September 2000. Construction took 550,000 man-hours and cost NOK 342 million. The bridge was taken into use on 30 April 2001, after the E39-section of the Triangle Link had opened on 27 December 2000. The bridge allowed two ferry services to terminate.
Suspension bridge
A suspension bridge is a type of bridge in which the deck is hung below suspension cables on vertical suspenders. Outside Tibet and Bhutan, where the first examples of this type of bridge were built in the 15th century, this type of bridge dates from the early 19th century...
which crosses Spissøysundet between the islands of Nautøy
Nautøy
Nautøy is an unpopulated island in Stord, Norway. It is connected to the island of Spissøy by the Bømla Bridge and to the island of Føyno via a small bridge. Country Road 542, part of the Triangle Link, runs across the island....
in Stord
Stord
Stord is a municipality in the county of Hordaland, Norway. Stord is sometimes called "Norway in miniature" - as it has such a variety of landscapes: coastline, fjords, forests, agricultural land, and mountain areas....
and Spissøy
Spissøy
Spissøy, sometimes spelled Spyssøy, is an island in Bømlo, Norway. It is connected to the island of Bømlo by the Spissøy Bridge and to the island of Nautøy via the Bømla Bridge....
in Bømlo
Bømlo
Bømlo is a municipality in Sunnhordland, in the southern part of the county of Hordaland, Norway. It is also the name of the main island of this archipelago, consisting of about 900 islets, located west of Stord....
, Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...
. The bridge is 998 metres (3,274.3 ft) long, has a main span
Span (architecture)
Span is the distance between two intermediate supports for a structure, e.g. a beam or a bridge.A span can be closed by a solid beam or of a rope...
of 577 metres (1,893 ft) and a clearance below of 36 metres (118.1 ft). It carries two lanes of County Road 542
Norwegian County Road 542
County Road 542 , prior to 1 January 2010 National Road 542 , is a long county road running through the northern part of Bømlo, Norway, and connecting the island community to the Føyno in Stord via part of the Triangle Link. County Road 542 contains two mayor bridges, the Bømla Bridge and Spissøy...
(former National Road 542) and a combined pedestrian and bicycle pathway. It is part of the Triangle Link, a fixed link which connects Stord to Bømlo, and both to the mainland at Sveio
Sveio
Sveio is a municipality in the county of Hordaland, Norway. Sveio is located in the traditional district of Haugaland-Location:Geographically, Sveio is situated on the Haugaland peninsula. The administrative centre is the village of Sveio. Sveio was separated from Finnås in 1861. Vikebygd was...
. Plans for a crossing arose in the 1960s, and was until the 1990s planned as a pontoon bridge
Pontoon bridge
A pontoon bridge or floating bridge is a bridge that floats on water and in which barge- or boat-like pontoons support the bridge deck and its dynamic loads. While pontoon bridges are usually temporary structures, some are used for long periods of time...
further north. The Bømla Bridge entered the plans after the decision to combine the crossing with the Bømlafjord Tunnel. Construction started in 1999; the bridge cost 342 million Norwegian krone
Norwegian krone
The krone is the currency of Norway and its dependent territories. The plural form is kroner . It is subdivided into 100 øre. The ISO 4217 code is NOK, although the common local abbreviation is kr. The name translates into English as "crown"...
(NOK) and was taken into use on 30 April 2001. The bridge and the link will remain a toll road
Toll road
A toll road is a privately or publicly built road for which a driver pays a toll for use. Structures for which tolls are charged include toll bridges and toll tunnels. Non-toll roads are financed using other sources of revenue, most typically fuel tax or general tax funds...
until 2012 or 2013.
Background
The background for the Triangle Link was the desire to have a fixed link between the islands of Stord and Bømlo. The first documented proposals were made in the 1960s and involved building a pontoon bridgePontoon bridge
A pontoon bridge or floating bridge is a bridge that floats on water and in which barge- or boat-like pontoons support the bridge deck and its dynamic loads. While pontoon bridges are usually temporary structures, some are used for long periods of time...
across Stokksundet
Stokksundet (Hordaland)
Stokksundet is a sound between the islands of Stord and Bømlo in Hordaland, Norway....
, inspired by the plans to build what would become the Nordhordland Bridge
Nordhordland Bridge
The Nordhordland Bridge is a combined cable-stayed and pontoon bridge which crosses Salhusfjorden between Klauvaneset and Flatøy in Hordaland, Norway. It is long, of which the pontoon section is long. The cable-stayed section consists of a single tall H-pylon which has a length of and a main...
north of Bergen
Bergen
Bergen is the second largest city in Norway with a population of as of , . Bergen is the administrative centre of Hordaland county. Greater Bergen or Bergen Metropolitan Area as defined by Statistics Norway, has a population of as of , ....
. In 1973, the municipal councils of Bømlo, Stord and Fitjar decided to launch a planning process, which concluded that a pontoon bridge between Sørstokken
Sørstokken
Sørstokken is a peninsula on the island of Stord, Norway. It is the location of Stord Airport, Sørstokken....
and Foldrøyholmen would be optimal. The report also considered bridges across the Fitjar Archipelago, and across via Spissøy and Føyno. There were protests from the shipping industry, who wanted to continue to use the strait for ship traffic.
In the early 1980s, plans for Stord Airport, Sørstokken
Stord Airport, Sørstokken
Stord Airport, Sørstokken is a municipal regional airport located at Sørstokken in Stord, Norway. Located from Leirvik, it is the only airport with scheduled services in Sunnhordland. The airport consists of a single asphalted long 15–33 runway. It is classified as an airport of entry.Danish...
were launched, and in 1982 the plans for a bridge crossing Stokksundet were again raised, this time from the industry on Bømlo, who would have to travel by ferry to reach the new airport. In May 1983, a committee was established, giving Engineer Harald Møyner the job to make a new report. 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 further away would be fine.
Mapping of transport on Bømlo was performed by Hordaland Public Roads Administration in 1984, and based on this and other feedback, a pontoon bridge between Foldrøyholmen and Sørstokken became the most probable outcome. It was estimated to cost NOK 190 million, in addition to auxiliary roads for NOK 40 million. In 1982, plans were launched for a fixed link to the main land, which would include a bridge over Digernessundet, a causeway and low bridge across Spissøysundet and a low bridge over Gassasundet. In addition, a tunnel would have to be built from Føyno to Sveio. In 1985, an all-tunnel proposal, following the same route, was proposed. Hordaland Public Roads Administration stated that the proposals were unrealistic. The limited company Ytre Sunnhordland Bru- og Tunnelselskap AS (SBT) was founded in Ocotber 1986 by the municipalities of Bømlo, Stord, Fitjar and Sveio, Hordaland County Municipality
Hordaland county municipality
Hordaland County Municipality is the regional governing administration of Hordaland, Norway. The main responsibilities of the county municipality includes the running of 46 upper secondary schools, with 17,000 pupils...
and five banks.
In December 1986, the Public Road Administration recommended a bridge solution. 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 Coastal Administration stated that they would not allow a pontoon bridge. On 26 June 1987, SBT decided to work to get permission to collect advanced tolls on the ferry services. On 16 September, they unanimously supported the triangular proposal, which was estimated to cost NOK 660 million. This was criticized by Hordaland Public Roads Administration, who stated that it would take longer time to plan, and thus complete, the Triangle Link.
From 1988, environmentalists started actively opposing the Triangle Link. The most active were the local chapter of the Norwegian Society for the Conservation of Nature
Norwegian Society for the Conservation of Nature
The Norwegian Society for the Conservation of Nature , also known as Friends of the Earth Norway and commonly abbreviated NNV is the largest Norwegian environmental organization with 28,000 members. The organization is based on a volunteer work among the members, constituting work both at local and...
and Nature and Youth, who stated that the road would have serious consequences for the local boat traffic to the recreational islands of Føyno and Nautøy. Instead, they recommended that the municipalities chose a pontoon bridge. Another opponent to the project was the Action Committee Against a Hasty Construction of the Triangle Link, who wanted to delay the decision until after the 1991 municipal elections
Norwegian local elections, 1991
Country-wide local elections for seats in municipality and county councils were held throughout Norway in 1991. For most places this meant that two elections, the municipal elections and the county elections ran concurrently.-Municipal elections:...
, to ensure that the municipal councils had backing in the public. Gisle Tjong stated that the risk in the project was large and that it was uncertain how long the tolls would last: they could just as well be 60 as 15 years, and instead wanted to collect tolls in advance.
The Triangle Link was passed by the various municipal councils in February and March 1988. Hordaland Public Roads Administration still supported a pontoon bridge, and stated that two and a half years of work on a master plan had been wasted. A new master plan for the Triangle Link was published in early 1989. During late 1989, advance tolls on the ferries was approved by the municipal councils and the county council, who recommended that collection start from 1 July 1990, but this was not immediately supported by the government.
In July 1991, the master plan was passed by the Council of State. On 10 December 1992, Parliament approved advanced payment of tolls on the ferry, which were made effective from 1 January 1993. Ticket prices increased with between NOK 10 and 12. This resulted in protests from the ferry employees who stated that they would have to collect the tolls which would remove their jobs. Work on the development plan started in 1992. It included safety and environmental improvements which increased the project's cost by NOK 200 million. In May 1994, it was made subject to consultative statements. In May, SBT proposed building a culvert
Culvert
A culvert is a device used to channel water. It may be used to allow water to pass underneath a road, railway, or embankment. Culverts can be made of many different materials; steel, polyvinyl chloride and concrete are the most common...
on Digernes as a compromise to avoid a new plan which could have postponed the project several years. On 11 June 1996, Parliament decided with 144 against 20 votes to build the Triangel Link. The original name proposal for the bridge was ; this was later changed to after input from the municipal councils and name committees.
Construction
Osterøy Bridge
Osterøy Bridge connects Kvisti on the island of Osterøy in Hordaland County with the mainland at Herland east from Bergen, Norway.Osterøy Bridge is a suspension bridge and has a main span of 595 meter. The towers are 121.5 meters high. The bridge was completed October 3, 1997 and cost about 308...
, which opened in 1997. The responsibility for the cables was given to Brown Beach Associates and Hordaland Mekaniske Verksted (HMV). Construction started on 25 March 1999. After the pylons were completed on 20 December 1999, two catwalks were erected between them, with the constructors choosing a continual catwalk instead of three separate ones. Extra stability to the catwalk was achieved by building connections between the two.
The cables were spun on-site using a reel
Reel
A reel is an object around which lengths of another material are wound for storage. Generally a reel has a cylindrical core and walls on the sides to retain the material wound around the core...
, based on the problems which had arisen using a bundle on the Great Belt Bridge. 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 place and with a crew with limited experience with spinning. This involved installing a cable car
Cable car
A cable car is any of a variety of transportation systems relying on cables to pull vehicles along or lower them at a steady rate, or a vehicle on these systems.-Aerial lift:Aerial lifts where the vehicle is suspended in the air from a cable:...
and connecting two double loops with a spinning wheel each, with one loop doing the outward spinning the other the inward spinning. The system has two reel racks, each with four reels, with two reels on one rack at any given time, allowing for minimum down-time when changing reels. Wires were connected using pressure casing. The balance in the system is kept in place using a counter-weight tower. Spinning of the main cable started on 24 May 2000 and was concluded on 13 July. In all 11600 kilometres (7,207.9 mi) of steel wire were used to create the cables for both bridges. It was the first time that on-site spinning was chosen in Norway, and it gave a cost saving of NOK 10 to 11 million.
The cables consist of seven bundles of cables, each consisting of 420 wires, each with a diameter of 5.35 millimetre (0.210629921259843 in). When compressed, this gives a diameter of 320 millimetres (12.6 in) and a quality of 1,570 megapascals. 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 helicoper, and the whole five week delay was eradicated. This allowed the deck sections to be installed as scheduled. There arose problems with small holes being created in the coating; as these had also been found on the Great Belt Bridge, it was decided that nothing would be done with the issue.
The deck sections were produced by HBG in Cimolais
Cimolais
Cimolais is a comune in the Province of Pordenone in the Italian region Friuli-Venezia Giulia, located about 130 km northwest of Trieste and about 40 km northwest of Pordenone.-External links:*...
, Italy, and transported first by truck from the plant to the port, and then by Barge to Stord. Each section is 48 metres (157.5 ft) long and consisted of subsections 6 by to allow for transport to the port. They were mounted using the crane ship Uglen, allowing an average of four sections to be installed per day. and completed in September 2000. Construction took 550,000 man-hours and cost NOK 342 million. The bridge was taken into use on 30 April 2001, after the E39-section of the Triangle Link had opened on 27 December 2000. The bridge allowed two ferry services to terminate.