Renovate Monuments Inexpensively And Professionally

The listed forest railway in Welzheim is one of the most beautiful railway lines in southern Germany. However, their viaducts are in need of renovation. The 100-year-old railway viaduct on the Laufenmühle has been damaged - cracks can be seen through the reinforced concrete. If one were to renovate the viaduct using today's standard methods, the effort and costs would be immense and the character of the monument endangered. The Karlsruhe Institute of Technology (KIT) Innovation Hub "Prevention in Construction" managed to bring the right partners together and to develop a tailor-made approach for the sustainable repair of the viaduct.

3D model

How 3D scans save a Czech work of art

Detailed data set enables individual repairs

"The construction of the Laufenmühle Viaduct a hundred years ago was a technical feat of civil engineering," explains Professor Andreas Gerdes, scientific director of the KIT Innovation Hub. "The engineers are also breaking new ground in the renovation of the damaged concrete pillars and arches." Based on today's regulations and the building data collected, a support structure under the viaduct arches made of 30 cm to 50 cm thick concrete arches was provided for the repair of this viaduct, but this was the historical one Appearance of the building would have changed significantly. "The effort and costs involved would have been immense," says Gerdes. "Instead, we used scientific methods and were able to improve the data situation sothat the repairs could be individually adapted to the Laufenmühle viaduct in a way that conserves substance.”The use of modern scientific methods in historical engineering buildings can open up tailored options for monument protection, especially in the case of early reinforced concrete structures.

"Using ultrasound and construction radar, every centimeter of the viaduct was examined, documented at a depth of 50 cm to 70 cm, and the damaged areas were identified and evaluated," reports Gerdes. The collaboration between Ionys AG, a KIT spin-off, and the engineering office Patitz provided a detailed picture of damage in the viaduct. With this data, the Rothenhöfer engineering firm was able to provide the static foundations for the repair based on a calculation approach. If the data is recorded and analyzed in detail, it can be easier for municipalities as building owners to plan sustainably, use resources optimally and implement a tailor-made repair concept.

Preserved monuments in their original appearance

For the Laufenmühle viaduct, this means that cement suspensions will soon be injected into the damaged areas of the arch bridge. "This makes it possible to preserve the Laufenmühle viaduct in its original appearance," explains Gerdes. "And the renovation is much cheaper." So the city of Welzheim only has to pay a sum of 2.2 million euros - instead of the 3.5 million euros for the originally planned renovation. At the same time, the enjoyment of a train journey on the historic train can also be ensured for tourists by maintaining rail operations. The renovation is scheduled to be completed by summer 2017 in parallel with ongoing operations.

The Swabian Forest Railway runs between Rudersberg and Welzheim and consists of three viaducts: Laufenmühle Viaduct, Strümpfelbach Viaduct and Igelsbach Viaduct. The almost 23 km long route is a listed building as a whole. The Laufenmühle Viaduct in particular is considered a striking bridge structure of early railway construction and has become a landmark. The tourist train has been in operation since 2010 and has developed into an important infrastructure factor for the climatic health resort of Welzheim. (kj)