Lidingöbron

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Aerial view of Eastern Stockholm looking south. Lidingöbron is in the foreground leading from Hjorthagen and Värtahamnen to the right over to Lidingö to the left.

View from the old Lindingöbron with a tram heading for Gåshaga and a man fishing from the bridge.

Lidingöbron (Swedish: "The Lidingö Bridge") is the name of two existing and two historical bridges across the strait of Lilla Värtan between Ropsten - a part of Stockholm - and the island of Lidingö.

1 History
2 References
3 See also
4 External links

[edit] History

[edit] First pontoon bridge

At a parish meeting in 1802, the inhabitants of Lidingö, at the time a mostly agricultural district, decided to open a venture to realize a pontoon bridge connecting the island to Stockholm. The 50 shares of the company had to be redeemed by contributing to the project with timber, work, or money and the bridge was completed in 1803; 750 metres long, 7 metres wide and financed by tolls. It had a hard time surviving the annual ice break-up, and a third of it was demolished in 1811, and most of it in 1858 - each time raising the price for milk in the capital, as most of it was produced on Lidingö at the time.^[1]

[edit] Second pontoon bridge

With the creation of the harbour of Värtan, the original bridge obstructed shipping in the strait, and it was therefore bought by the city of Stockholm in 1883 who replaced it with a new pontoon bridge - at the time one of the longest bridges in the world - 12 metres wide and with two moveable sections at each end for the passage of ships. The level of the roadway was only 10-15 cm over the water surface however, so even moderate winds made crossing the bridge a tough experience. The lateral stability of the bridge was ensured by means of logs attached to the bridge every 24 metres and anchored to the bottom. The use of logs instead of chains effectively increased the bridge's general buoyancy at the cost of its stability during low tide - the bridge often serpentined its way across the water while the inclination of the roadway at the two ends made use of extra horses necessary. Ice break-up destroyed a third of the bridge in 1918.^[1]

[edit] Old Lidingöbron

By the end of WW1, the increasing number of motor cars made a more able bridge necessary, and by 1926 a steel truss bridge, 9,1 metres wide with a 6,7 metres roadway, finally replaced the second pontoon bridge. To avoid foundation work at the maximum depth a 140 metres long truss arch was used, and to allow a horizontal clearance of 5,3 metres the bridge was provided with a simple flap.^[1]

[edit] New Lidingöbron

The population of Lidingö as well as the traffic continued to grow however, and by the 1950s the old bridge had become insufficient. The two municipalities met in 1961, and the following year it was settled a new bridge should be located south of the old, which should be used for the local tramway Lidingöbanan, pedestrians, and bicycles. The new bridge, inaugurated in 1971, is 997 metres long, 24 metres wide, and offers a horizontal clearance of 12,5 metres while the roadway passes 75 metres above the bottom of the strait. The part of the bridge passing over water, 724 metres long, is made of double box girders with a maximum span of 73,5 metres, the entire construction resting on steel poles filled with concrete. ^[1]

[edit] References

^ ^a ^b ^c ^d Dufwa, Arne (1985). "Broar och viadukter: Lidingöbron", Stockholms tekniska historia: Trafik, broar, tunnelbanor, gator. Uppsala: Stockholms gatukontor and Kommittén för Stockholmsforskning, 203-205. ISBN 91-37-08725-1.