For research purposes, the ETH Institute had acquired a required centrifuge second-hand in Germany. The centrifuge, which is one of the largest in the world with a diameter of nine metres and a capacity of up to 250g, had also been used there for this area of research since the 1980s. "The large centrifuge had not been used for years and was delivered to a steel fabricator in Switzerland after being purchased. He carried out the first inspection. This revealed that all of the roller bearings needed to be replaced," recalls Patrick Iten, Drive Technology Supervisor at Montalpina AG. It was also necessary to check whether the gears installed in the centrifuge could withstand further loads or needed to be replaced.
Montalpina AG was called in as a specialist due to its many years of expertise. After an on-site assessment, the team decided to design and manufacture various devices to dismantle and assemble the large bearings. A number of challenges awaited Iten and his colleagues. "The bearing had a tight fit on the outer ring, which made disassembly complicated. In addition, we didn't have the right tools for the job, which was also due to the size of the bearing. Unsuccessful inspection work in the past had also damaged the bearing seat," summarises Iten. Furthermore, large bearings generally have long delivery times. Montalpina therefore had to improvise and find new solutions. "Due to the size of the centrifuge, the bearings were ultimately dismantled in a car park of a steel construction company," recalls Iten. "It was necessary to rework and assemble the fits of the slewing bearings. However, we were unable to carry out this work on site, as a larger oven and presses were required for precise assembly," says Iten.
Now that the work has been completed, the earthquake centrifuge enables realistic model tests to simulate ground movements. This in turn allows conclusions to be drawn about infrastructure damage and stability influences. This information can prove to be crucial, particularly in the implementation of construction projects, as it can be used to optimise the foundations of buildings. It is also possible to minimise relevant risks using the recorded data.
