Geography of Stockholm - Bridges and Viaducts

Bridges and Viaducts

The historical name for Stockholm Old Town was "The city between the bridges" (Staden mellan broarna), a name which is still used for the entire city which spans over numerous islands, islets, and hills. During the course of centuries, the city has seen many bridges relieve each other.

In a urban code dated 1350, King Magnus IV (1316-1377) prescribed the bridges leading over Norrström and Söderström to be built and maintained by the city of Stockholm together with six other cities surrounding Lake Mälaren, as they were the only land passage between the provinces Uppland and Södermanland, north and south of the city respectively. Apparently, in the view of the king, the city, a hundred years after its foundation, still couldn't afford to maintain its own bridges.

Still, these first bridges were in no sense technically complicated or physically impressive, but rather simple wooden bridges, either floating bridges or beam bridges resting on poles or stone caissons, in either case with spans of no more than a few metres. The width probably corresponded to the directions for public roads, eight ell or 4,8 metres, which was probably more than enough for many centuries. The long and narrow bridges were easily demolished in case of siege, which besides the drawbridges, also necessary for the passing of ships, was an important defensive strategy. As the accounts of the city tells, spring floods and ice break-ups resulted in the frequent destruction of the bridges.

By the mid 17th century, the population of the city had resulted in settlements north and south of Gamla stan, on Norrmalm and Södermalm, and the number of bridges had grown considerably, if not their dimensions or quality. In a map dated 1640, three bridges connects Stadsholmen to Norrmalm passing over Helgeandsholmen, at the time still a group of islets; while two bridges close to each other lead over to Riddarholmen. Several new bridges of considerable length connected Norrmalm to the islets west and east of it; Blasieholmen, at the time still an islet, was connected to the mainland by a bridge called Näckenströms bro, and northward to present day Strandvägen by Stora Ladugårdslandsbron, a 190 metres long bridge on poles; and to the west a bridge connected Norrmalm to Kungsholmen over Blekholmen, a now non-existent islet. By the end of the 17th century, population growth resulted in an additional bridge north of Stadsholmen.

One of the oldest bridges was located where today Stallbron is found, immediately south of the Parliament Building. The first stone bridge, Norrbro, was built in front of the Royal Palace under Gustav III.

Not until the 20th century, Stockholm was able to surpass the straits and bays surrounding the city. Half of the about 30 bridges in central Stockholm were built 1920–50, most of them during the 1930s. This development was due to increasing traffic loads caused by a fivefold increase of vehicles in the 1920s. At Slussen, passing ships caused stationary rows of trams several hundreds metres long. The situation was solved when a traffic committee in 1930 could present the so-called "clover-leaf solution" of engineer Gösta Lundborg and architect Tage William-Olsson inaugurated in 1935. The modernity of the solution put Stockholm in a state of rapture and impressed even Le Corbusier, who praised the scale of the construction and invited the world to follow the example of Stockholm.

Meanwhile, across the Riddarfjärden bay, construction works had started on Västerbron, the large bridge offering a north-south passage west of the historical city centre. Designed by architects David Dahl and Paul Hedqvist and engineered by Ernst Nilsson and Salomon Kasarnowski, Västerbron became the first large bridge designed by this quartet. Tranebergsbron was inaugurated in 1934, with its span of 200 m, for a few years the world's longest span. These large-scale bridges not only tied various parts of the city together, but their mere size changed the cityscape permanently. Considerably smaller but during the decade equally praised was the small Riksbron designed by Ragnar Östberg.