Report: Stößensee Bridge by Karl Bernhard
In 1899, the Berlin authorities decided to extend Bismarckstrasse to link the urban centre to the Grunewald, an extensive wooded area to the west referred to as the “heart and the lungs” of the city. The new road, Heerstrasse, was intended to relieve traffic from Kurfürstendamm and provide the capital with a boulevard modelled on those of Paris and London. The planned road had to cross the lakeland area in west Berlin, which would require two bridges. Karl Bernhard, one of the most influential master builders in Berlin at the start of the 20th century, was commissioned with the planning, design and construction. The 1909 Stößensee Bridge is consid ered one of his most beautiful and bestpreserved structures. In order to reduce the length and therefore the cost of the project, Bernhard crossed part of the lake with a 350 m long, 125 m wide embankment, which al lowed some of the marshland to be excavated, drained and put to good use. To ensure that the resulting beautiful, almost 100 m wide valley would not be marred by massive masonry piers, Bernhard chose to de sign a delicately proportioned steel truss girder superstructure with a simi larly slender and open single steel central support in the valley. A long span arch was ruled out because the horizontal forces could not be resist ed at reasonable costs by the em bankment fill.
