Lidingöbron

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

History

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; almost 800 metres long, 7 metres wide and financed by tolls. It was one of the longest bridges in Europe. 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.cite book
last = Dufwa | first = Arne
title = Stockholms tekniska historia: Trafik, broar, tunnelbanor, gator
year = 1985
publisher = Stockholms gatukontor and Kommittén för Stockholmsforskning
location = Uppsala | id = ISBN 91-37-08725-1
pages = 203-205 | chapter = Broar och viadukter: Lidingöbron]

econd 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 1884 with a new pontoon bridge, 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.

Old Lidingöbron

By the end of WW1, the increasing number of motor cars made a more able bridge necessary, and by 1925 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 20 m long flap.

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.

Image gallery

ources

* [http://sv.wikipedia.org/wiki/Liding%C3%B6bron Lidingöbron in Swedish.]

Footnotes

ee also

* List of bridges in Stockholm
* [http://svt.se/svt/road/Classic/shared/mediacenter/index.jsp?a=511787&d=46016 SF-film sequence (SVT open archive) showing the old Lidingö bridge (built in 1925) and the preceding pontoon bridge (built in 1884) in rough weather conditions.]