Nordhordland Bridge
Encyclopedia
The Nordhordland Bridge is a combined cable-stayed
and pontoon
bridge
which crosses Salhusfjorden
between Klauvaneset
and Flatøy
in Hordaland
, Norway
. It is 1614 metres (5,295.3 ft) long, of which the pontoon section is 1246 metres (4,087.9 ft) long. The cable-stayed section consists of a single 99 metres (324.8 ft) tall H-pylon which has a length of 368 metres (1,207.3 ft) and a main span of 172 metres (564.3 ft). This allows for a clearance of 32 metres (105 ft).
The floating section is a steel box girder bridge
with ten pontoons, which because of the fjord's depth are not laterally anchored. The roadway sits on an orthotropic deck
. The pontoons and the cable-stayed bridge are built in concrete, with the main span being supported with 48 cables. The fjord end of the main span is supported by a 30 metres (98.4 ft) deep foundation, where the two bridges meet. From there and for 414 metres (1,358.3 ft), the roadwall has a 5.7 percent gradient on a viaduct anchored to the pontoon bridge.
The bridge carries two lanes of European Route E39
, also called the Coastal Highway, and one pedestrian and bicycle path, and connects the district of Nordhordland
to Bergen
. Plans for a bridge had existed since the 1960s, and after the decision to construct the bridge was passed by the Parliament of Norway in 1989, construction started in 1991. Total costs, including auxiliary roads, was NOK 910 million. Part of the contract payment was subject to a court case which the contractors lost. The bridge opened on 22 September 1994, and remained a toll road until 31 December 2005. In 2009, it had an average daily traffic of 14,698 vehicles. There are plans to reinstate a toll on the bridge from 2013 to finance other road projects. The bridge is the second-longest in Norway, and the second pontoon bridge in Norway.
which connects the two. The cable-stayed bridge consists of a 99.3 metres (325.8 ft) tall H-pylon with a foundation at Klauvaneset on the mainland of Bergen. It supports a 172 metres (564.3 ft) main span
, with the other end being fixed in a foundation 30 metres (98.4 ft) below mean sea level, which is anchored in the ridge Klauvaskallen. The whole cable-stayed bridge is 369 metres (1,210.6 ft) long, with a 190 metres (623.4 ft) long viaduct, supported by six pairs of pillars. The cable-stayed bridge allows for a sailing channel which is 32 metres (105 ft) tall and 50 metres (164 ft) wide. The main span is built in lightweight LC55 concrete
, while the viaduct and pylon is built with conventional C45 concrete. Inside the pylons is a 1.6 by hollow area.
The bridge has 48 cables, 12 on each side of the pylon on each side of the roadway. The distance between the cables is 12 metres (39.4 ft) on the main span, and 9.33 metres (30.6 ft) on the viaduct. Combined, the cables are 4432 metres (14,540.7 ft) long; each cable consists of 67 to 230 twined cables, each with a 7 millimetre (0.275590551181102 in) diameter. The cables have a weight of between 1.5 tonne each, and they have a capacity of between 1960 kilonewton. They can be tightened at the connection with the roadwall.
The floating section consists of a steel box girder placed on top of ten floating pontoons. The pontoon section is anchored only at both ends, on the underwater foundation at Kauvaskallen and on Flatøy. It is fastened using flexible plate connections fastened by bolts and cables under tension. These are flexible around the horizontal axis at right angles towards the axis of the bridge, allowing for deformation caused by the tide
. The fastening on Flatøy consists of a massive concrete block 22 by long and 14.5 metres (47.6 ft) tall which was poured into a blast-out foundation pit in bedrock. Vertical pretension rock anchors have also been installed, with 12 at Klauvaskallen and 14 at Flatøy, giving 42 and 44 MN (42,000,000 and 44,000,000 ) of support, although they were only built to increase the safety factor.
There are ten lightweight concrete pontoons, with 113.25 metres (371.6 ft) spans between them. The pontoons are between 7 metre in height. The draught
varies between 4.3 metre. Each pontoon consists of nine watertight cells which are partially filled with ballast for trim. The cells are dimensioned so two adjacent cells can fill with water without endangering the bridge.
The roadway lies on top of an orthotropic deck on a steel box girder, which is 15.9 metres (52.2 ft) wide, 5.5 metres (18 ft) tall and 1246 metres (4,087.9 ft) long. The steel box girder weighs 14150 tonnes (13,926.5 LT), of which 3000 tonnes (2,952.6 LT) is high-strength low-alloy steel. The girder has an octagonal shape and is made with 14 millimetre thick steel plates. They are longitudinally stiffened by trapezoidal stiffeners supported by cross frames at most every 4.5 metres (14.8 ft). Two full bulkhead
s have been used for every pontoon pilaster, made from welded steel plates 8 millimetre thick. External brackets built into the bulkheads transfer the support forces to the pontoons. The girder was built in sections of 21, 36, and 42 meters (69, 118, and 138 ft), which were subsequently welded together into 11 modules with a skew angle
of 1.2 to 1.3 degrees. The girder has a constant cross-section throughout the length, except at the anchoring points to the pontoons. The section from the land anchoring to the first pontoon is subject to the most stress, and is made with steel with a higher yield point. The inside of the girder has two dehumidifiers which ensure that it does not rust. The clearance under the girder is 5.5 metres (18 ft).
The two bridges are connected with a 414.5 metres (1,359.9 ft) long steel viaduct, which runs on top of the floating bridge, bringing the road from 11 metre above mean sea level. The viaduct weighs 1600 tonnes (1,574.7 LT) and has a gradient of 5.7 degrees. It consists of spans between 18 metre, with the roadway also built as an orthotropic deck with 12 millimetre (0.47244094488189 in) thick plates.
Overall, the construction of the bridge used 24000 tonnes (23,620.9 LT) of concrete, of which 10000 tonnes (9,842 LT) in the pontoons. The bridge was coated with 40000 litres (84,535.1 US pt) of paint.
The bridge is monitored by 132 sensors, including sensors on hatches to the pontoons, on doors to the steel box girder, for corrosion, strain gauges on the girder and on flexible elements, and weather information. On the cable-stayed section, the bridge is marked with navigation lights, as well as the center of the sailing area having a racon
. The bridge is the second-longest bridge in Norway, behind the Drammen Bridge
.
Ship services in Nordhordland started in 1866, and in 1923 the first car was purchased. A car ferry service between Isdalstø
in Lindås and Steinestø in Åsane
on the mainland was established on 7 July 1936. A plan was launched whereby all traffic from Nordhordland would be collected in one place and transported across Salhusfjorden to Åsane. By moving the ferry quay from Istadstø to Knarvik
, the length of the ferry service could be reduced. However, the fares would be kept the same and the extra revenue used to finance a bridge from Flatøy to Lindås. This allowed the Alversund Bridge
to open in 1958, and the ferry service from Flatøy and Meland to move to Knarvik. The proposal to cross Salhusfjorden was launched during the planning of the Alversund Bridge. Cost estimates were made based on the Golden Gate Bridge
in the United States, but it proved too expensive for a suspension bridge
crossing between Frekhaug
and Salhus.
In 1962, the issue was brought up again, this time as a pontoon bridge. The depth and steepness of the fjord would make it impossible to fasten the bridge to the sea bottom. However, a method without lateral anchorage had been developed for the Hobart Bridge
in Australia. Another alternative was launched in 1963, involving a submerged floating tunnel through the fjord. It was estimated to cost between NOK 19.5 and 26 million. Norwegian expatriate Leif J. Sverdrup
, co-founder of Sverdrup & Parcel
of the United States, inspected the fjord in 1965 and was later hired to plan the bridge in cooperation with Oslo-based civil engineering consultants Prosjektering. Municipal engineers started measuring currents in 1966. Prosjektering and Sverdrup & Parcel recommended a pontoon bridge with a movable
section to allow passage of ship traffic. In 1967, a new proposal was launched, in which a seaway tunnel would be blasted out in the rock on the Bergen side.
The Alversund Bridge was a toll bridge which was paying for the debt accumulated in its construction. By 1968, the debt would be paid off, but the Norwegian Public Roads Administration launched a plan whereby the tolls would continue to be collected and used to finance a bridge across Salhusfjorden. This was opposed by a group of locals, who brought the issue to the courts, claiming it to be illegal, as a bridge would never be built. Both Oslo District Court
and Eidsivating Court of Appeal
concluded that the tolls were legal, and the issue was rejected by the Supreme Court
. Protests were also raised against the use of a pontoon bridge, as it would limit the vessel size and thus the commercial development in the inner parts of the fjord.
In the 1970s, National Road 1 (today part of E39) was established through Knarvik towards Sognefjorden, resulting in upgrades to the roads in Nordhordland, and making the crossing one of the main routes from the north. At the same time, it was decided to establish a refinery
at Mongstad
in Lindås. In 1971, details about the suspension bridge were again discussed, with three different proposals with the main span of between 1090 metre with 160 metres (524.9 ft) tall pylons. There were protests from the Salhus area, as the suspension bridge would have resulted in the demolishing of part of the residential area.
In 1972, discussion started with the plans to connect Meland, Flatøy and Lindøy with bridges. This was passed by the Parliament of Norway in May 1975, and consisted of the Krossnessundet Bridge
between Flatøy and Meland, which opened in November 1978. The Hagelsund Bridge
opened on 1 April 1982 and connected Flatøy to Lindås and Knarvik, thus also connecting Meland and Lindås. Both bridges were partially financed with tolls. The plans for a pontoon bridge were presented to the Standing Committee on Transport and Communications
on 31 March 1981. They supported the choice of a pontoon bridge. The decision to construct the bridge was taken by parliament on 9 December 1987, but they demanded that a larger ship channel be constructed.
Detailed planning started in March 1990, and at first two technical methods for constructing the pontoon bridge were considered: a continuous concrete floating caisson between the abutments, and a steel version incorporating a truss bridge carrying concrete pontoons. However, they were both rejected in favor of a concrete or steel box section borne on concrete pontoons.
and Det Norske Veritas
, the former who also performed dynamic analysis and structural engineering
. Architects were Hindhammer–Sundt–Thomassen, Lund & Løvseth, and Lund & Slaatto. An H pylon was chosen instead of an A pylon both because it was more functional, and would be more aesthetic in conjunction with the other bridges in the area, particularly three suspension bridges.
The technology for the bridge was based on recent technology for pontoon bridges combined with Norwegian offshore technology. Among the technologies initially considered, but later ruled out, was that used in the Homer M. Hadley Memorial Bridge
and the Hood Canal Bridge
in the United States. Instead, an orthotropic deck was chosen, such as the Bergsøysund Bridge
had used. The choice of a box girder bridge and the orthotropic deck were chosen because it gave the lower material use. Conventional pontoon bridges have lateral anchorage systems which fasten the bridge to the seabed. The technique had previously been used down to 140 metres (459.3 ft), but Salhusfjorden is 500 metres (1,640.4 ft) deep, making the method prohibitively expensive. The choice of a cable-stayed section allowed reduced traffic hazards in storms, a reduction in corrosion on the bridge deck, and improved passage of water beneath the bridge in support of wildlife.
The contract for construction of the pontoon bridge was awarded in August 1991 to a consortium
, Arbeidsfellesskapet Salhus Bru, which consisted of Norwegian Contractors
, Aker Entreprenør, Veidekke
and Kværner Eureka. The components were built in Moss
and Fredrikstad
and then shipped to Lonevågen
, a branch of Osterfjorden
which was suitable to connect the parts. There were problems welding the high-strength low-alloy steel, which resulted in the work being halted for several days before an agreement was reached between the contractor and the Public Roads Administration. On 26 January 1994, the steel frame which would be used to fasten the pontoon bridge to the cable-stayed bridge, came adrift during transport in Skagerrak
, and was severely damaged, causing a delay in the project. As the bridge had the longest laterally unsupported span in the world, the construction was watched by many international delegations.
The construction of the tunnel also involved other investments in road infrastructure. This included 5.7 kilometres (3.5 mi) of new highways, 4.2 kilometres (2.6 mi) of local roads, and the 785 metres (2,575.5 ft) long Hordvik Tunnel just south of the bridge. A grade-separated crossing was built on both sides of the bridge. The intersection on Flatøy was also built as a bus interchange, and became the terminus of many bus routes in Nordhordland. Express buses would from there run directly to the city center of Bergen.
The bridge project cost NOK 910 million, of which NOK 513 was for the pontoon bridge, NOK 81 million was for the cable-stayed bridge, NOK 25 million was used for the waterway, NOK 115 million was used on planning, and NOK 176 million was used on auxiliary roads and the tunnel. The bridge was financed with NOK 41 million in state grants, NOK 139 million from tolls paid in advance, and NOK 730 million in debt which would be repaid by the tolls. Interest during construction cost NOK 138 million. The construction involved 1,150,000 man-hours.
supported the administration, but gave the plaintiff
partial support, claiming the administration should take part of the costs through improper choice of material. The Public Roads Administration was sentenced to pay NOK 34 million to Kværner. Both sides appealed to Gulating Court of Appeal
, which on 18 February 1998 refuted all of Kværner's claim regarding the steel boxes, and sentenced the administration to pay NOK 7.5 million. In addition, Kværner had to pay the administration NOK 19.5 million in penalties for overrunning the contract date. However, the court's decision was not unanimous. The plaintiff appealed to case to the Supreme Court, who unanimously confirmed the ruling of Gulating Court of Appeal. In addition, the plaintiff was sentenced to pay the defendants legal costs of NOK 910,000.
The bridge was officially opened by King Harald V
on 22 September 1994. It was the second pontoon bridge in Norway, after the Bergsøysund Bridge
which opened in 1992. The last tolls were collected on 31 December 2005. In 2008, there were 19,700 travelers on the bridge each day, 14 percent of which used public transport
. In 2009, the bridge had an average daily traffic (ADT) of 14,698 vehicles, up from 7975 in 2000. Following the removal of the tolls, the ADT increased from 9912 in 2005 to 12249 in 2006. In 2010, the bridge was one of twelve finalists in Teknisk Ukeblad
s competition for the most beautiful bridge in Norway. In December 2010, Bergen City Council approved the Nordhordland Package, which would result in NOK 3.8 billion being used on road investments in Åsane and Nordhordland. Two-thirds of the financing is to come from tolls, which will involve reinstalling a toll plaza on the bridge. The tolls will first be set to NOK 20 for five years, and then after the completion of the first stage, the toll will be NOK 40 for fifteen years. The toll plaza is scheduled to reopen in 2013. Among the projects is a new four-lane Nyborg Tunnel
which will shorten the distance of E39 from the bridge with the motorway at Nyborg in Bergen.
Cable-stayed bridge
A cable-stayed bridge is a bridge that consists of one or more columns , with cables supporting the bridge deck....
and pontoon
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...
bridge
Bridge
A bridge is a structure built to span physical obstacles such as a body of water, valley, or road, for the purpose of providing passage over the obstacle...
which crosses Salhusfjorden
Salhusfjorden
Salhusfjorden is a long fjord and sound between Bergen and Meland in Hordaland, Norway. To the west, it starts between Salhus and Frekhaug, where Byfjorden meets Herdlefjorden. To the east, the fjord ends between Knarvik and Hordvikneset, where Osterfjorden runs northeast, while Sørfjorden runs...
between Klauvaneset
Klauvaneset
Klauvaneset is a peninsula in the northern part of Åsane in Bergen, Norway. It is the site of the southern part of the Nordhordland Bridge....
and Flatøy
Flatøy
Flatøy is one of two smaller islands that together with the larger island Holsnøy make up the municipality Meland Kommune, in the district of Nordhordland, north of Bergen, in western Norway....
in Hordaland
Hordaland
is a county in Norway, bordering Sogn og Fjordane, Buskerud, Telemark and Rogaland. Hordaland is the third largest county after Akershus and Oslo by population. The county administration is located in Bergen...
, 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...
. It is 1614 metres (5,295.3 ft) long, of which the pontoon section is 1246 metres (4,087.9 ft) long. The cable-stayed section consists of a single 99 metres (324.8 ft) tall H-pylon which has a length of 368 metres (1,207.3 ft) and a main span of 172 metres (564.3 ft). This allows for a clearance of 32 metres (105 ft).
The floating section is a steel box girder bridge
Box girder bridge
A box girder bridge is a bridge in which the main beams comprise girders in the shape of a hollow box. The box girder normally comprises either prestressed concrete, structural steel, or a composite of steel and reinforced concrete. The box is typically rectangular or trapezoidal in cross-section...
with ten pontoons, which because of the fjord's depth are not laterally anchored. The roadway sits on an orthotropic deck
Orthotropic deck
An orthotropic bridge or orthotropic deck is one whose deck typically comprises a structural steel deck plate stiffened either longitudinally or transversely, or in both directions. This allows the deck both to directly bear vehicular loads and to contribute to the bridge structure's overall...
. The pontoons and the cable-stayed bridge are built in concrete, with the main span being supported with 48 cables. The fjord end of the main span is supported by a 30 metres (98.4 ft) deep foundation, where the two bridges meet. From there and for 414 metres (1,358.3 ft), the roadwall has a 5.7 percent gradient on a viaduct anchored to the pontoon bridge.
The bridge carries two lanes of European Route E39
European route E39
E 39 is the designation of a 1330 km long north-south road in Norway and Denmark, running from Klett just south of Trondheim to Aalborg, via Orkanger, Vinjeøra, Halsa ... Straumsnes, Krifast, Batnfjordsøra, Molde ... Vestnes, Skodje, Ålesund ... Volda ... Nordfjordeid ... Sandane, Førde,...
, also called the Coastal Highway, and one pedestrian and bicycle path, and connects the district of Nordhordland
Nordhordland
Nordhordland is a traditional district in the western part of Norway, consisting of the northern portion of the county of Hordaland. It includes the municipalities Austrheim, Fedje, Lindås, Masfjorden, Meland, Modalen, Osterøy, Radøy and Vaksdal....
to 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 , ....
. Plans for a bridge had existed since the 1960s, and after the decision to construct the bridge was passed by the Parliament of Norway in 1989, construction started in 1991. Total costs, including auxiliary roads, was NOK 910 million. Part of the contract payment was subject to a court case which the contractors lost. The bridge opened on 22 September 1994, and remained a toll road until 31 December 2005. In 2009, it had an average daily traffic of 14,698 vehicles. There are plans to reinstate a toll on the bridge from 2013 to finance other road projects. The bridge is the second-longest in Norway, and the second pontoon bridge in Norway.
Specifications
The bridge consists of three sections, a cable-stayed bridge, a pontoon bridge and a viaductViaduct
A viaduct is a bridge composed of several small spans. The term viaduct is derived from the Latin via for road and ducere to lead something. However, the Ancient Romans did not use that term per se; it is a modern derivation from an analogy with aqueduct. Like the Roman aqueducts, many early...
which connects the two. The cable-stayed bridge consists of a 99.3 metres (325.8 ft) tall H-pylon with a foundation at Klauvaneset on the mainland of Bergen. It supports a 172 metres (564.3 ft) 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...
, with the other end being fixed in a foundation 30 metres (98.4 ft) below mean sea level, which is anchored in the ridge Klauvaskallen. The whole cable-stayed bridge is 369 metres (1,210.6 ft) long, with a 190 metres (623.4 ft) long viaduct, supported by six pairs of pillars. The cable-stayed bridge allows for a sailing channel which is 32 metres (105 ft) tall and 50 metres (164 ft) wide. The main span is built in lightweight LC55 concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
, while the viaduct and pylon is built with conventional C45 concrete. Inside the pylons is a 1.6 by hollow area.
The bridge has 48 cables, 12 on each side of the pylon on each side of the roadway. The distance between the cables is 12 metres (39.4 ft) on the main span, and 9.33 metres (30.6 ft) on the viaduct. Combined, the cables are 4432 metres (14,540.7 ft) long; each cable consists of 67 to 230 twined cables, each with a 7 millimetre (0.275590551181102 in) diameter. The cables have a weight of between 1.5 tonne each, and they have a capacity of between 1960 kilonewton. They can be tightened at the connection with the roadwall.
The floating section consists of a steel box girder placed on top of ten floating pontoons. The pontoon section is anchored only at both ends, on the underwater foundation at Kauvaskallen and on Flatøy. It is fastened using flexible plate connections fastened by bolts and cables under tension. These are flexible around the horizontal axis at right angles towards the axis of the bridge, allowing for deformation caused by the tide
Tide
Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the moon and the sun and the rotation of the Earth....
. The fastening on Flatøy consists of a massive concrete block 22 by long and 14.5 metres (47.6 ft) tall which was poured into a blast-out foundation pit in bedrock. Vertical pretension rock anchors have also been installed, with 12 at Klauvaskallen and 14 at Flatøy, giving 42 and 44 MN (42,000,000 and 44,000,000 ) of support, although they were only built to increase the safety factor.
There are ten lightweight concrete pontoons, with 113.25 metres (371.6 ft) spans between them. The pontoons are between 7 metre in height. The draught
Draft (hull)
The draft of a ship's hull is the vertical distance between the waterline and the bottom of the hull , with the thickness of the hull included; in the case of not being included the draft outline would be obtained...
varies between 4.3 metre. Each pontoon consists of nine watertight cells which are partially filled with ballast for trim. The cells are dimensioned so two adjacent cells can fill with water without endangering the bridge.
The roadway lies on top of an orthotropic deck on a steel box girder, which is 15.9 metres (52.2 ft) wide, 5.5 metres (18 ft) tall and 1246 metres (4,087.9 ft) long. The steel box girder weighs 14150 tonnes (13,926.5 LT), of which 3000 tonnes (2,952.6 LT) is high-strength low-alloy steel. The girder has an octagonal shape and is made with 14 millimetre thick steel plates. They are longitudinally stiffened by trapezoidal stiffeners supported by cross frames at most every 4.5 metres (14.8 ft). Two full bulkhead
Bulkhead (partition)
A bulkhead is an upright wall within the hull of a ship or within the fuselage of an airplane. Other kinds of partition elements within a ship are decks and deckheads.-Etymology:...
s have been used for every pontoon pilaster, made from welded steel plates 8 millimetre thick. External brackets built into the bulkheads transfer the support forces to the pontoons. The girder was built in sections of 21, 36, and 42 meters (69, 118, and 138 ft), which were subsequently welded together into 11 modules with a skew angle
Skew lines
In solid geometry, skew lines are two lines that do not intersect and are not parallel. Equivalently, they are lines that are not coplanar. A simple example of a pair of skew lines is the pair of lines through opposite edges of a regular tetrahedron...
of 1.2 to 1.3 degrees. The girder has a constant cross-section throughout the length, except at the anchoring points to the pontoons. The section from the land anchoring to the first pontoon is subject to the most stress, and is made with steel with a higher yield point. The inside of the girder has two dehumidifiers which ensure that it does not rust. The clearance under the girder is 5.5 metres (18 ft).
The two bridges are connected with a 414.5 metres (1,359.9 ft) long steel viaduct, which runs on top of the floating bridge, bringing the road from 11 metre above mean sea level. The viaduct weighs 1600 tonnes (1,574.7 LT) and has a gradient of 5.7 degrees. It consists of spans between 18 metre, with the roadway also built as an orthotropic deck with 12 millimetre (0.47244094488189 in) thick plates.
Overall, the construction of the bridge used 24000 tonnes (23,620.9 LT) of concrete, of which 10000 tonnes (9,842 LT) in the pontoons. The bridge was coated with 40000 litres (84,535.1 US pt) of paint.
The bridge is monitored by 132 sensors, including sensors on hatches to the pontoons, on doors to the steel box girder, for corrosion, strain gauges on the girder and on flexible elements, and weather information. On the cable-stayed section, the bridge is marked with navigation lights, as well as the center of the sailing area having a racon
Racon
A racon is a radar transponder commonly used to mark maritime navigational hazards. The word is a portmanteau of RAdar and beaCON.When a racon receives a radar pulse, it responds with a signal on the same frequency which puts an image on the radar display...
. The bridge is the second-longest bridge in Norway, behind the Drammen Bridge
Drammen Bridge
Drammen Bridge is a motorway box girder bridge that crosses Drammenselva river in the town of Drammen in Norway. It is the longest bridge in Norway, 1892 metres long. The bridge has 41 spans; the longest span is 60 metres. The maximum clearance to the water is 11 metres.Drammen Bridge was opened...
.
Planning
Isdalstø
Isdalstø is a village in Lindås, Norway. Located north of Knarvik, it was a central hub for ferry traffic until the 1970s....
in Lindås and Steinestø in Åsane
Åsane
Åsane is a borough of the city of Bergen, Norway, making up the northwestern part of the city.It was a municipality in Hordaland county, from January 1, 1904, when it was separated from Hamre, until January 1, 1972 when it was merged with Bergen . The area was developed from mostly farmland to a...
on the mainland was established on 7 July 1936. A plan was launched whereby all traffic from Nordhordland would be collected in one place and transported across Salhusfjorden to Åsane. By moving the ferry quay from Istadstø to Knarvik
Knarvik
Knarvik is the administrative centre in the municipality of Lindås and the largest town in the region of Nordhordland, Norway. It had 4,265 inhabitants as of 2005....
, the length of the ferry service could be reduced. However, the fares would be kept the same and the extra revenue used to finance a bridge from Flatøy to Lindås. This allowed the Alversund Bridge
Alversund Bridge
Alversund Bridge is a suspension bridge spanning Alverstraumen, a narrow strait between the island of Radøy and Alversund, in Lindås municipality, Hordaland, Norway. The bridge was opened for traffic on June 29, 1958, and connected Radøy to the mainland. The Alversund bridge was the first toll...
to open in 1958, and the ferry service from Flatøy and Meland to move to Knarvik. The proposal to cross Salhusfjorden was launched during the planning of the Alversund Bridge. Cost estimates were made based on the Golden Gate Bridge
Golden Gate Bridge
The Golden Gate Bridge is a suspension bridge spanning the Golden Gate, the opening of the San Francisco Bay into the Pacific Ocean. As part of both U.S. Route 101 and California State Route 1, the structure links the city of San Francisco, on the northern tip of the San Francisco Peninsula, to...
in the United States, but it proved too expensive for a suspension bridge
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...
crossing between Frekhaug
Frekhaug
Frekhaug is the administrative centre of Meland municipality, Norway. The population of the urban area Frekhaug, which also encompasses Vikane, is 1,602 ....
and Salhus.
In 1962, the issue was brought up again, this time as a pontoon bridge. The depth and steepness of the fjord would make it impossible to fasten the bridge to the sea bottom. However, a method without lateral anchorage had been developed for the Hobart Bridge
Hobart Bridge
The Hobart Bridge was a pontoon bridge that crossed the River Derwent, connecting the eastern and western Shores of the City of Hobart, Tasmania, Australia.- History :...
in Australia. Another alternative was launched in 1963, involving a submerged floating tunnel through the fjord. It was estimated to cost between NOK 19.5 and 26 million. Norwegian expatriate Leif J. Sverdrup
Leif J. Sverdrup
Leif Johan Sverdrup was a Norwegian born, American civil engineer and general with the U.S. Army Corps of Engineers in the first half of the 20th century...
, co-founder of Sverdrup & Parcel
Sverdrup & Parcel
Sverdrup & Parcel was an American civil engineering company formed in 1928 by Leif J. Sverdrup and his college engineering professor John I. Parcel. The company worked primarily in a specialty field of bridges. Many of the company's projects were located in the St...
of the United States, inspected the fjord in 1965 and was later hired to plan the bridge in cooperation with Oslo-based civil engineering consultants Prosjektering. Municipal engineers started measuring currents in 1966. Prosjektering and Sverdrup & Parcel recommended a pontoon bridge with a movable
Moveable bridge
A moveable bridge is a bridge that moves to allow passage for boats or barges. An advantage of making bridges movable include lower price, due to the absence of high piers and long approaches. The principal disadvantage is that the traffic on the bridge must be halted when it is opened for passages...
section to allow passage of ship traffic. In 1967, a new proposal was launched, in which a seaway tunnel would be blasted out in the rock on the Bergen side.
The Alversund Bridge was a toll bridge which was paying for the debt accumulated in its construction. By 1968, the debt would be paid off, but the Norwegian Public Roads Administration launched a plan whereby the tolls would continue to be collected and used to finance a bridge across Salhusfjorden. This was opposed by a group of locals, who brought the issue to the courts, claiming it to be illegal, as a bridge would never be built. Both Oslo District Court
Oslo District Court
Oslo District Court is the district court serving Oslo, Norway. Cases may be appealed to Borgarting Court of Appeal. As the largest district court in Norway, it handles about 20% of all cases in the country...
and Eidsivating Court of Appeal
Borgarting Court of Appeal
Borgarting Court of Appeal is the court of appeal located in Oslo, Norway. It serves the counties of Oslo, Buskerud, Østfold and southern Akershus. The court has 62 judges and 45 administrative staff...
concluded that the tolls were legal, and the issue was rejected by the Supreme Court
Supreme Court of Norway
The Supreme Court of Norway was established in 1815 on the basis of the Constitution of Norway's §88, prescribing an independent judiciary. It is located in Oslo and is Norway's highest court...
. Protests were also raised against the use of a pontoon bridge, as it would limit the vessel size and thus the commercial development in the inner parts of the fjord.
In the 1970s, National Road 1 (today part of E39) was established through Knarvik towards Sognefjorden, resulting in upgrades to the roads in Nordhordland, and making the crossing one of the main routes from the north. At the same time, it was decided to establish a refinery
Refinery
A refinery is a production facility composed of a group of chemical engineering unit processes and unit operations refining certain materials or converting raw material into products of value.-Types of refineries:Different types of refineries are as follows:...
at Mongstad
Mongstad
Mongstad is an industrial site located in the municipalities of Lindås and Austrheim in Hordaland, Norway. The site features an oil refinery for Statoil and other oil companies, including Shell. At Mongstad, Statoil has a crude oil terminal with a capacity of . The port at Mongstad is the largest...
in Lindås. In 1971, details about the suspension bridge were again discussed, with three different proposals with the main span of between 1090 metre with 160 metres (524.9 ft) tall pylons. There were protests from the Salhus area, as the suspension bridge would have resulted in the demolishing of part of the residential area.
In 1972, discussion started with the plans to connect Meland, Flatøy and Lindøy with bridges. This was passed by the Parliament of Norway in May 1975, and consisted of the Krossnessundet Bridge
Krossnessundet Bridge
Krossnessundet Bridge is a cantilever bridge which connects Holsnøy with Flatøy in Meland, Norway. Opened in 1978, it is part of National Road 564. It is long and has a main span of ....
between Flatøy and Meland, which opened in November 1978. The Hagelsund Bridge
Hagelsund Bridge
The Hagelsund Bridge is a suspension bridge connecting the island of Flatøy with Knarvik, in Lindås municipality, Hordaland, Norway. The length of the bridge is 623 meters with the main span being 250 meters...
opened on 1 April 1982 and connected Flatøy to Lindås and Knarvik, thus also connecting Meland and Lindås. Both bridges were partially financed with tolls. The plans for a pontoon bridge were presented to the Standing Committee on Transport and Communications
Standing Committee on Transport and Communications
The Standing Committee on Transport and Communications is a standing committee of the Parliament of Norway. It is responsible for policies relating to transport, postal services, telecommunications, electronic communication and the responsibilities of the Norwegian National Coastal Administration...
on 31 March 1981. They supported the choice of a pontoon bridge. The decision to construct the bridge was taken by parliament on 9 December 1987, but they demanded that a larger ship channel be constructed.
Detailed planning started in March 1990, and at first two technical methods for constructing the pontoon bridge were considered: a continuous concrete floating caisson between the abutments, and a steel version incorporating a truss bridge carrying concrete pontoons. However, they were both rejected in favor of a concrete or steel box section borne on concrete pontoons.
Construction
Design of the bridge was awarded to Aas-JakobsenAas-Jakobsen
Dr. ing. A. Aas-Jakobsen AS, trading as Aas-Jakobsen, is a civil engineering consultant company specializing in structural engineering. The company is based in Oslo, Norway, and primarily works with bridges, roads, railways, offshore oil and buildings. The company has 250 employees. The company was...
and Det Norske Veritas
Det Norske Veritas
Stiftelsen Det Norske Veritas is a classification society organized as a foundation, with the objective of "Safeguarding life, property, and the environment". The organization's history goes back to 1864, when the foundation was established in Norway to inspect and evaluate the technical condition...
, the former who also performed dynamic analysis and structural engineering
Structural engineering
Structural engineering is a field of engineering dealing with the analysis and design of structures that support or resist loads. Structural engineering is usually considered a specialty within civil engineering, but it can also be studied in its own right....
. Architects were Hindhammer–Sundt–Thomassen, Lund & Løvseth, and Lund & Slaatto. An H pylon was chosen instead of an A pylon both because it was more functional, and would be more aesthetic in conjunction with the other bridges in the area, particularly three suspension bridges.
The technology for the bridge was based on recent technology for pontoon bridges combined with Norwegian offshore technology. Among the technologies initially considered, but later ruled out, was that used in the Homer M. Hadley Memorial Bridge
Homer M. Hadley Memorial Bridge
The Third Lake Washington Bridge, officially the Homer M. Hadley Memorial Bridge, is the fifth-longest floating bridge in the world, at 5,811 feet...
and the Hood Canal Bridge
Hood Canal Bridge
The Hood Canal Bridge is a floating bridge located in the U.S. state of Washington that carries Washington State Route 104 across Hood Canal and connects the Olympic and Kitsap Peninsulas. At long, The Hood Canal Bridge (officially William A. Bugge Bridge) is a floating bridge located in the U.S....
in the United States. Instead, an orthotropic deck was chosen, such as the Bergsøysund Bridge
Bergsøysund Bridge
Bergsøysund Bridge is a pontoon bridge that crosses the Bergsøysundet strait between the islands of Aspøya and Bergsøya in Møre og Romsdal county, Norway. The bridge is long, the longest span is , and the maximum clearance to the sea is . The bridge has 13 spans.Bergsøysund Bridge was opened in...
had used. The choice of a box girder bridge and the orthotropic deck were chosen because it gave the lower material use. Conventional pontoon bridges have lateral anchorage systems which fasten the bridge to the seabed. The technique had previously been used down to 140 metres (459.3 ft), but Salhusfjorden is 500 metres (1,640.4 ft) deep, making the method prohibitively expensive. The choice of a cable-stayed section allowed reduced traffic hazards in storms, a reduction in corrosion on the bridge deck, and improved passage of water beneath the bridge in support of wildlife.
The contract for construction of the pontoon bridge was awarded in August 1991 to a consortium
Consortium
A consortium is an association of two or more individuals, companies, organizations or governments with the objective of participating in a common activity or pooling their resources for achieving a common goal....
, Arbeidsfellesskapet Salhus Bru, which consisted of Norwegian Contractors
Norwegian Contractors
Norwegian Contractors AS was the world leading turnkey concrete gravity base structure supplierin the period of 1974 to 1994. Aker Marine Contractors AS was established in 1995 and is a continuance of the marine activities in Norwegian Contractors AS.Norwegian Contractors AS have worked on...
, Aker Entreprenør, Veidekke
Veidekke
Veidekke is the largest Norwegian construction company and the fourth largest in Scandinavia. Veidekke’s business involves a network of Scandinavian construction operations, rehabilitation work, major heavy construction contracts and development of dwellings for the company’s own account as well...
and Kværner Eureka. The components were built in Moss
Moss
Mosses are small, soft plants that are typically 1–10 cm tall, though some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems...
and Fredrikstad
Fredrikstad
is a city and municipality in Østfold county, Norway. The administrative centre of the municipality is the city of Fredrikstad....
and then shipped to Lonevågen
Lonevågen
Lonevågen is a bay of Osterfjorden, which is long and up to wide. Located in Osterøy, Norway, Lonevåg, the municipal center of Osterøy, is located at the end of the bay....
, a branch of Osterfjorden
Osterfjorden
Osterfjorden is one of three fjords surrounding the island Osterøy.The fiord runs between Lindås and Osterøy and is 27 km long, 1-3 km wide. The largest depth is 639 m....
which was suitable to connect the parts. There were problems welding the high-strength low-alloy steel, which resulted in the work being halted for several days before an agreement was reached between the contractor and the Public Roads Administration. On 26 January 1994, the steel frame which would be used to fasten the pontoon bridge to the cable-stayed bridge, came adrift during transport in Skagerrak
Skagerrak
The Skagerrak is a strait running between Norway and the southwest coast of Sweden and the Jutland peninsula of Denmark, connecting the North Sea and the Kattegat sea area, which leads to the Baltic Sea.-Name:...
, and was severely damaged, causing a delay in the project. As the bridge had the longest laterally unsupported span in the world, the construction was watched by many international delegations.
The construction of the tunnel also involved other investments in road infrastructure. This included 5.7 kilometres (3.5 mi) of new highways, 4.2 kilometres (2.6 mi) of local roads, and the 785 metres (2,575.5 ft) long Hordvik Tunnel just south of the bridge. A grade-separated crossing was built on both sides of the bridge. The intersection on Flatøy was also built as a bus interchange, and became the terminus of many bus routes in Nordhordland. Express buses would from there run directly to the city center of Bergen.
The bridge project cost NOK 910 million, of which NOK 513 was for the pontoon bridge, NOK 81 million was for the cable-stayed bridge, NOK 25 million was used for the waterway, NOK 115 million was used on planning, and NOK 176 million was used on auxiliary roads and the tunnel. The bridge was financed with NOK 41 million in state grants, NOK 139 million from tolls paid in advance, and NOK 730 million in debt which would be repaid by the tolls. Interest during construction cost NOK 138 million. The construction involved 1,150,000 man-hours.
Aftermath
The use of high-strength steel caused problems as it was necessary to heat the steel to 150 °C (302 °F) before and after welding, and Kværner had problems finding an adequate process during late 1992. In January 1993, an appropriate process had been found, although experimentation with various methods continued for another six months. Kværner felt that the Public Roads Administration should bear the extra costs, demanding NOK 108 million in compensation, but the administration denied this, resulting in a lawsuit. On 26 January 1996, Nordhordland District CourtNordhordland District Court
Nordhordland District Court is a district court serving Nordhordland and Midthordland , as well as Gulen in Norway. It is co-located with Bergen District Court in Bergen Courthouse. Cases can be appealed to Gulating Court of Appeal...
supported the administration, but gave the plaintiff
Plaintiff
A plaintiff , also known as a claimant or complainant, is the term used in some jurisdictions for the party who initiates a lawsuit before a court...
partial support, claiming the administration should take part of the costs through improper choice of material. The Public Roads Administration was sentenced to pay NOK 34 million to Kværner. Both sides appealed to Gulating Court of Appeal
Gulating Court of Appeal
Gulating Court of Appeal is a Norwegian Court of Appeal.-Jurisdiction:Gulating Court of Appeal is based in Bergen, Norway. Gulating Court of Appeal holding many hearings in Stavanger and also maintains permanent offices in the Stavanger Courthouse....
, which on 18 February 1998 refuted all of Kværner's claim regarding the steel boxes, and sentenced the administration to pay NOK 7.5 million. In addition, Kværner had to pay the administration NOK 19.5 million in penalties for overrunning the contract date. However, the court's decision was not unanimous. The plaintiff appealed to case to the Supreme Court, who unanimously confirmed the ruling of Gulating Court of Appeal. In addition, the plaintiff was sentenced to pay the defendants legal costs of NOK 910,000.
The bridge was officially opened by King Harald V
Harald V of Norway
Harald V is the king of Norway. He succeeded to the throne of Norway upon the death of his father Olav V on 17 January 1991...
on 22 September 1994. It was the second pontoon bridge in Norway, after the Bergsøysund Bridge
Bergsøysund Bridge
Bergsøysund Bridge is a pontoon bridge that crosses the Bergsøysundet strait between the islands of Aspøya and Bergsøya in Møre og Romsdal county, Norway. The bridge is long, the longest span is , and the maximum clearance to the sea is . The bridge has 13 spans.Bergsøysund Bridge was opened in...
which opened in 1992. The last tolls were collected on 31 December 2005. In 2008, there were 19,700 travelers on the bridge each day, 14 percent of which used public transport
Public transport
Public transport is a shared passenger transportation service which is available for use by the general public, as distinct from modes such as taxicab, car pooling or hired buses which are not shared by strangers without private arrangement.Public transport modes include buses, trolleybuses, trams...
. In 2009, the bridge had an average daily traffic (ADT) of 14,698 vehicles, up from 7975 in 2000. Following the removal of the tolls, the ADT increased from 9912 in 2005 to 12249 in 2006. In 2010, the bridge was one of twelve finalists in Teknisk Ukeblad
Teknisk Ukeblad
Teknisk Ukeblad is Norway's leading engineering journal.TU has appeared weekly since 13 April 1883 and is published by Ingeniørforlaget, jointly owned by three national professional associations of engineers and architects: the Norwegian Society of Engineers and Technologists , Tekna , and the...
s competition for the most beautiful bridge in Norway. In December 2010, Bergen City Council approved the Nordhordland Package, which would result in NOK 3.8 billion being used on road investments in Åsane and Nordhordland. Two-thirds of the financing is to come from tolls, which will involve reinstalling a toll plaza on the bridge. The tolls will first be set to NOK 20 for five years, and then after the completion of the first stage, the toll will be NOK 40 for fifteen years. The toll plaza is scheduled to reopen in 2013. Among the projects is a new four-lane Nyborg Tunnel
Nyborg Tunnel
The Nyborg Tunnel is a proposed road tunnel between Åsane and Klauvaneset in Bergen, Norway. If built, it would extend the four-lane motorway section of European Road 39 from Åsane to the Nordhordland Bridge. The tunnel is presumed financed with a five-year toll collection at the bridge while the...
which will shorten the distance of E39 from the bridge with the motorway at Nyborg in Bergen.