A symphony bridge or bridge symphony is a

bridge A bridge is a structure built to span a physical obstacle (such as a body of water, valley, road, or rail) without blocking the way underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually somethi ...

which combines the structural support systems of a

suspension bridge A suspension bridge is a type of bridge in which the deck (bridge), deck is hung below suspension wire rope, cables on vertical suspenders. The first modern examples of this type of bridge were built in the early 1800s. Simple suspension bridg ...

, a

cable-stayed bridge A cable-stayed bridge has one or more ''towers'' (or ''pylons''), from which cables support the bridge deck. A distinctive feature are the cables or stays, which run directly from the tower to the deck, normally forming a fan-like pattern o ...

and a

cantilever bridge A cantilever bridge is a bridge built using structures that project horizontally into space, supported on only one end (called cantilevers). For small footbridges, the cantilevers may be simple beam (structure), beams; however, large cantilever ...

. No such bridges have been built, nor are there any specific plans, although the method has been considered for several bridges in Norway. It was developed collaboratively by the

Norwegian Public Roads Administration The Norwegian Public Roads Administration ( no, Statens vegvesen) is a Norwegian government agency responsible for national and county public roads in Norway. This includes planning, construction and operation of the national and county road netw ...

and the civil engineering consulting company

Aas-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 buildi ...

as a means of building bridges with spans between . The design is based on two separate roadways which are connected by crossbeams. A symphony bridge would have two pylons, which would be circular in hollow cross-section. The center of the bridge would be supported by a central cable (unlike the conventional two side cables of a suspension bridge) connected to the deck via hangers connected to the crossbeams. The cross-beams and hangers are triangular in form. On both sides of the suspension section, the bridge would be built as a cable-stayed bridge with cables from the pylon. The areas closest to the pylons would be constructed with cantilever support. The designers have stated that the bridge would allow for greater wind stability, more drag, faster construction time, lower cost, and increased access for inspections and maintenance. For the

Hålogaland Bridge The Hålogaland Bridge ( no, Hålogalandsbrua) is a suspension bridge which crosses the Rombaksfjorden in Narvik Municipality in Nordland county, Norway. It is the second-longest bridge span in Norway. The bridge is part of the European Route E ...

, which is proposed to have a long main span, a symphony bridge was considered but was discarded after it was deemed too expensive at a projected cost of 2,380 million

Norwegian krone The krone (, abbreviation: kr (also NKr for distinction); code: NOK), plural ''kroner'', is currency of the Kingdom of Norway (including Svalbard). Traditionally known as the Norwegian crown in English. It is nominally subdivided into 100 ''� ...

r (NOK), compared to NOK 1,860 for a suspension bridge. The proposed

Storfjord Bridge The Storfjord Bridge ( no, Storfjordbrua) is a proposed suspension bridge that would span Storfjorden in Sunnmøre, Norway. If built, it would be long and have a main span of . This would make it the longest spanned bridge in the world, easily s ...

could be built as a symphony bridge.

References

{{reflist Bridges by structural type