Georg Rotne/ASO Group - The Øresund Bridge

Georg Rotne/ASO Group
The Øresund Bridge
Denmark & Sweden

8000 Years ago, at the end of the Ice Age, Denmark and Sweden were separated by water. 348 years ago the southern part of Sweden, at that time under the Danish Crown, was conquered by King Karl Gustav X of Sweden and the Øresund Strait became the border between the two countries.
With the opening of the Øresund Bridge Denmark and Skåne are once again connected.
The Bridge was designed by architect Georg Rotne with the ASO Group Partnership.
Read an essay by Georg Rotne.

Photo courtesy ASO
The Øresund Bridge

The Competition
Towards the end of 1992, Øresundskonsortiet announced a competition for the design of the Øresund Link; an artificial peninsula, a tunnel, an artificial island, and a bridge between Denmark and Sweden. The Danish and Swedish Governments decided on the overall functional and technical requirements: The Link should be designed and constructed with due consideration of 'what is ecologically motivated, technically feasible, and economically reasonable in order to prevent any detrimental impact on the environment and within the budget that has been agreed by the two Governments.'
Six international groups were invited to take part in the competition, and the result was announced in July 1993: The winning design was proposed by the ASO Group, a joint venture team comprised of Ove Arup Partners, SETEC, Gimsing Madsen, and ISC, and with Georg Rotne as lead architect.

Design process
According to Ove Arup: "Engineering is not a science. Science studies particular events to find general laws. Engineering design makes use of these laws to solve particular problems. In this it is more closely related to art or craft-a creative activity, involving imagination, intuition, and deliberate choice".
It is often the relationship to the site that gives a bridge its unique character. The simple, rational, and straightforward design of the Øresund Bridge expresses function and structure with no unnecessary detail. The bridge stands in an open seascape with small, rolling hills and curving coastlines on either shore. The bridge rises gradually from the low artificial island in the middle of the sea. It is very long, and technical, functional, aesthetic, and economic issues were crucial. The structure appears as a whole and not a collection of parts. Given the huge scale of the project, the emphasis was put on developing a consistent and powerful design befitting the uniqueness of the site.

The Journey across the Øresund
The main attraction of the journey across the Øresund will be the unique views from the bridge: an ever changing sky and sea, and views towards the gently curved coastlines, the island of Saltholm, and the cities of Copenhagen and Malmö. The design team altered the original mandate from a straight to a curved alignment to create a safer and more interesting journey across the bridge.
The Link provides a dual two lane motorway and two tracks for high speed passenger and freight trains. For a two level bridge, the most economical structure is steel trusses with diagonals connecting the upper and lower decks. The deep girders naturally lead to longer approach spans, which has environmental advantages, and gives a lighter and more elegant appearance. With the motorway carried at the upper level and the railway below it, users are given ample comfort and security, and travelers can enjoy excellent views of the Øresund. To give railway passengers a clearer view, the trusses have been given a more open bracing than is usual. This in turn helps to make the bridge appear lighter and more transparent.
The Girder as a Unifying Element
The Øresund Bridge is not just a structure that extends from bank to bank with a distinct beginning and a distinct end. It is part of a much larger link to the road and railway networks in the two countries. In these circumstances, and given that the journey across the bridge will be made at the high speed, monumental end pieces seemed inappropriate. Unity and continuity are fundamental, so the approach bridges and the high bridge merge together rather than conflict with each other.
The bridge is continuous from Sweden to Pepperholm, the artificial island. The simple horizontal bridge girder is the principal element that unifies the design. The overall effect is a clear statement of structural purpose: the strong horizontal girder is supported on concrete piers in the approaches, and at the main span by cables which continue the line of the truss diagonals to the two high, free standing towers.
The stiffness of the truss deck was a factor in choosing the harp pattern for the cables. Straight towers together with outrigger brackets at the deck make it possible to arrange the cables in vertical planes. The centers of gravity at all cross sections of the towers are also on a vertical axis. Under certain light and weather conditions the cables will seem to vanish while the towers will always be a prominent.
The trusses are uniform throughout the bridge with the diagonals on a constant 20m module. The regular pattern in the approaches is modified at the cable stayed main span so that every other diagonal matches the cables. At the deck, the cables are anchored to large sloping outrigger brackets that transfer the cable forces from the anchorages to the bottom chords and through the upper deck.

Beacons in the Sea
The high and monumental towers stand out like beacons rising from the sea, aspiring towards the sky, and marking the summit of the journey and the border between Denmark and Sweden. All visible planes reduce in size from the sea towards the sky, expressing strength and stability. The towers are freestanding above the deck, and connected by a substantial crossbeam immediately below the deck and by their shared foundation below water level. Although they appear very slender, there are a number of factors that provide sufficient safety against buckling. The taper is effective in providing stability, the harp delivers only a small proportion of the load to the top, and the cables themselves provide some restoring forces to the column. Any incipient buckling displacement would move the cable tops out of the vertical plane and mobilize a horizontal restoring component in the cable force on the towers.
The strong design concept that interconnects the main components ultimately creates a harmonious and coherent whole.

Total length of link between Denmark and Sweden: 16 kilometers
Length of Øresund Bridge: 7.85 kilometers

Abridged text courtesy
The ASO Group

April 7, 2000

ASO arcspace features





				Features
		Georg Rotne/ASO Group The Øresund Bridge Denmark & Sweden 8000 Years ago, at the end of the Ice Age, Denmark and Sweden were separated by water. 348 years ago the southern part of Sweden, at that time under the Danish Crown, was conquered by King Karl Gustav X of Sweden and the Øresund Strait became the border between the two countries. With the opening of the Øresund Bridge Denmark and Skåne are once again connected. The Bridge was designed by architect Georg Rotne with the ASO Group Partnership. Read an essay by Georg Rotne. Photo courtesy ASO The Øresund Bridge The Competition Towards the end of 1992, Øresundskonsortiet announced a competition for the design of the Øresund Link; an artificial peninsula, a tunnel, an artificial island, and a bridge between Denmark and Sweden. The Danish and Swedish Governments decided on the overall functional and technical requirements: The Link should be designed and constructed with due consideration of 'what is ecologically motivated, technically feasible, and economically reasonable in order to prevent any detrimental impact on the environment and within the budget that has been agreed by the two Governments.' Six international groups were invited to take part in the competition, and the result was announced in July 1993: The winning design was proposed by the ASO Group, a joint venture team comprised of Ove Arup Partners, SETEC, Gimsing Madsen, and ISC, and with Georg Rotne as lead architect. Design process According to Ove Arup: "Engineering is not a science. Science studies particular events to find general laws. Engineering design makes use of these laws to solve particular problems. In this it is more closely related to art or craft-a creative activity, involving imagination, intuition, and deliberate choice". It is often the relationship to the site that gives a bridge its unique character. The simple, rational, and straightforward design of the Øresund Bridge expresses function and structure with no unnecessary detail. The bridge stands in an open seascape with small, rolling hills and curving coastlines on either shore. The bridge rises gradually from the low artificial island in the middle of the sea. It is very long, and technical, functional, aesthetic, and economic issues were crucial. The structure appears as a whole and not a collection of parts. Given the huge scale of the project, the emphasis was put on developing a consistent and powerful design befitting the uniqueness of the site. The Journey across the Øresund The main attraction of the journey across the Øresund will be the unique views from the bridge: an ever changing sky and sea, and views towards the gently curved coastlines, the island of Saltholm, and the cities of Copenhagen and Malmö. The design team altered the original mandate from a straight to a curved alignment to create a safer and more interesting journey across the bridge. The Link provides a dual two lane motorway and two tracks for high speed passenger and freight trains. For a two level bridge, the most economical structure is steel trusses with diagonals connecting the upper and lower decks. The deep girders naturally lead to longer approach spans, which has environmental advantages, and gives a lighter and more elegant appearance. With the motorway carried at the upper level and the railway below it, users are given ample comfort and security, and travelers can enjoy excellent views of the Øresund. To give railway passengers a clearer view, the trusses have been given a more open bracing than is usual. This in turn helps to make the bridge appear lighter and more transparent. The Girder as a Unifying Element The Øresund Bridge is not just a structure that extends from bank to bank with a distinct beginning and a distinct end. It is part of a much larger link to the road and railway networks in the two countries. In these circumstances, and given that the journey across the bridge will be made at the high speed, monumental end pieces seemed inappropriate. Unity and continuity are fundamental, so the approach bridges and the high bridge merge together rather than conflict with each other. The bridge is continuous from Sweden to Pepperholm, the artificial island. The simple horizontal bridge girder is the principal element that unifies the design. The overall effect is a clear statement of structural purpose: the strong horizontal girder is supported on concrete piers in the approaches, and at the main span by cables which continue the line of the truss diagonals to the two high, free standing towers. The stiffness of the truss deck was a factor in choosing the harp pattern for the cables. Straight towers together with outrigger brackets at the deck make it possible to arrange the cables in vertical planes. The centers of gravity at all cross sections of the towers are also on a vertical axis. Under certain light and weather conditions the cables will seem to vanish while the towers will always be a prominent. The trusses are uniform throughout the bridge with the diagonals on a constant 20m module. The regular pattern in the approaches is modified at the cable stayed main span so that every other diagonal matches the cables. At the deck, the cables are anchored to large sloping outrigger brackets that transfer the cable forces from the anchorages to the bottom chords and through the upper deck. Beacons in the Sea The high and monumental towers stand out like beacons rising from the sea, aspiring towards the sky, and marking the summit of the journey and the border between Denmark and Sweden. All visible planes reduce in size from the sea towards the sky, expressing strength and stability. The towers are freestanding above the deck, and connected by a substantial crossbeam immediately below the deck and by their shared foundation below water level. Although they appear very slender, there are a number of factors that provide sufficient safety against buckling. The taper is effective in providing stability, the harp delivers only a small proportion of the load to the top, and the cables themselves provide some restoring forces to the column. Any incipient buckling displacement would move the cable tops out of the vertical plane and mobilize a horizontal restoring component in the cable force on the towers. The strong design concept that interconnects the main components ultimately creates a harmonious and coherent whole. Total length of link between Denmark and Sweden: 16 kilometers Length of Øresund Bridge: 7.85 kilometers Abridged text courtesy The ASO Group April 7, 2000 ASO arcspace features