The 161.53 m high main tower of Ulm Minster is known as the highest church spire in the world – equally as impressive is the 29 m long, 15 m wide and 26 m high choir. PERI systems are currently assisting with the extensive renovation work on the vaulted ceiling and the choir stalls as part of the restoration of the main tower and the north-east, 86 m high choir tower.
The ongoing, time-intensive renovation work on the largest evangelical church in Germany started in 2015. In parallel to the main tower restoration to the exterior of the Minster, the internal choir was also worked on in 2019. In 2021, a new construction site will be set up at the north-east choir tower.
The modular PERI UP scaffold system was the key element to the success of the main tower’s renovation: The secure work and safety scaffold is designed for a massive live load of 15 kN/m². A 7 m high heavy-duty platform was also erected on the façade to allow for the professional, temporary storage of heavy stones of up to 1.5 t. However, it was not only stability, but also the regional origin of the scaffold that played a major part in the selection decision of the Minster’s head mason, Michael Hilbert and master craftsman, Andreas Böhm. The central location of the rental park for system units at PERI’s head office in Weißenhorn offered short transport routes – and on-schedule supply of materials without any downtimes.
The PERI engineers’ on-site support ranged from 3D planning to tests for structural integrity, working hand-in-hand with the Ulm Minster builders, the scaffolding workers from Mack GmbH, also locally-based, and the surveying service provider, Moselcopter GmbH. This smooth collaboration was supplemented by the option of hiring flexibly-combined PERI systems at short notice.
The missing as-built plans for the interior was an obstacle that the PERI engineers were able to overcome with complex 3D scaffold planning using the BIM methodology (BIM = Building Information Modelling). It was possible in the early planning phase to avoid possible collisions with historic construction materials by using 3D laser scanning and then transferring this into a 3D building model. The complicated, three-dimensional geometry of the choir’s interior was worked on using the free-standing, metric system grid PERI UP Flex, in 25-cm and 50-cm chunks with a total size of 13,000 m³.
The flexible PERI UP adaptation for the weight and geometry in the 25 cm grid also played a very important part in the main tower’s renovation: The manageable, modular ULS Flex lattice girder allowed for 3 to 9 m bridgings of up to 30 m high without any pipe coupling connections. In comparison: The bulky dimensions of one-piece lattice girders would complicate or even prevent the installation. Due to the light weight of the individual system parts, these could be transported using small-goods vehicles – an important factor in the historic building’s renovation.
The internal scaffold in the choir of Ulm Minster is currently being dismantled – the renovation work has already been concluded. From 2020 it will be open to visitors again. The 86 m high, north-east choir tower, which has already been surveyed using a drone from the Rheinland-Palatinate company Moselcopter GmbH, will be renovated next.