The underlying idea of a bridge is to overcome boundaries. Post tensioned granite bridges from Kusser take that literally. Our sophisticated technology means the link between two shores can be more slender than ever before. But this lightweight appearance shouldn’t be the only benefit.
Essentially we just wanted to make an art professor‘s bold idea a reality. His vision was to install a 1:1,000,000 scale model of the Earth‘s axis at the entrance of Magdeburg central station. The idea was that the stone sculpture, measuring more than 12 meters long and weighing 10 tonnes, would rotate at the same angle and speed as the earth's axis. It took us almost a year to work out how to make it a reality. By the end, we hadn‘t just implemented the idea by Professor Timm Ulrichs, we had also developed a new technology: post tensioned granite.
Our aim in developing post tensioned granite was to imbue the stone with a stability which is not naturally inherent to it – at least not in the slender form we wanted. The solution we came up with was post tensioning. In the post tensioning of granite, steel tendons press the component together by a perfect combination of tensile and compressive stress. As a permanent anti-corrosion protection measure, the post tensioning elements are encased in grease-compressed plastic cladding tubes which are additionally protected by a second plastic pipe. The result is astounding resilience, with a floating effect.