Stone-Ideas.com 
Solid construction with natural stone offers applications not only in building construction, but also for traffic routes. We show an example of a bridge with a roadway made entirely of granite in Berlin.
In the very north of the city, the Panke creek comes from the state of Brandenburg into the capital’s area. The Berlin-Usedom long-distance cycle route to the shores of the Baltic Sea currently runs a short distance along the banks of the Panke, and because the course of the water is to be redesigned to be as close to nature as possible in the near future, the route has already received two new bridges.
Their roadways are made of pre-stressed, or better: post-stressed, granite. The construction was chosen because it makes the bridges look very light and elegant and the material fits in with the environmentally friendly concept for the stream.
The roadways for the crossing are 18 and 15 m long, respectively, 3 m wide and 25 cm thick. They consist of individual granite slabs. They are held together by tension: steel cables are pulled through the natural stone slabs and tensioned mechanically after installation.
The technology is used in many places and is state of the art. This also applies to natural stone, even if tensioned constructions have not really become popular so far.
The leading company in Germany is Kusser Granitwerke.
In addition to the lightness of the bridges, Michael Herden from the press office of the Senate Department for Urban Mobility, Transport, Climate Action and the Environment, cites other arguments that convinced the planners of the construction: “In particular, the use of natural building materials, without special coating or coverings in a special natural area, was an important basis for the decision.“ In other words: the granite ensures that the bridge’s maintenance costs are minimal and that factors such as “slip resistance and resistance to abrasion and de-icing salt“ are guaranteed.
The “great durability of the natural building material“ also contributed to the decision, according to the press spokesman.
And because the bridges are so flat, there is a good chance that they will not offer any resistance to flooding and will simply let it pass through. After the redesign of the water, the planners hope that large amounts of water will be better distributed in a meandering riverbed, for example after heavy rain. The Kusser company shows examples of longer-span structures of the same type on its website and uses the slogan: “As massive as necessary, as thin as possible.”
The total cost of both bridges was €3.3 million.
Photos: Senatsverwaltung für Mobilität, Verkehr, Klimaschutz und Umwelt