The tower of the old Mannheim Town Hall will disappear behind module scaffolding and not reappear until 2012. The challenge posed by the complex architecture was met by using a flexible and easy-to-erect system.
The restoration of Mannheim’s oldest building, the Town Hall with its parish church St. Sebastian built in 1713, will cost a seven-digit sum. After a planned construction time of about two years, work to renovate the historic town hall tower is to be completed in time for the 2012 Catholic Day and the steeple with its double facade, also known as the Mannheim Symmetry, will shine in new splendour.
Litterer Gerüstbau GmbH has been awarded the contract for the extensive scaffolding work and employed Gerüstbau Dostmann GmbH as its subcontractor. “Dostmann specialises in extraordinary projects, mainly steeple scaffolding, and the company is renowned for its expert and reliable work”, said Volker Wegner, the plant manager and authorised signatory of the Mannheim-based scaffolding company Litterer Gerüstbau GmbH. “We have a long-standing partnership with Dostmann. In view of a lack of time and an equipment bottleneck, it was easy to decide to pass the contract on to the steeple specialists”, the authorised signatory told us.
Dostmann Gerüstbau GmbH has its origins in the year 1645 and is Germany’s oldest crafts enterprise. In 1962, the initially small carpenter’s shop changed its company name to Gerüstbau Dostmann GmbH. Already in the fourth generation, the present managing director, Frank Dostmann, took over the business from his father in 1994 at the age of just 24 and at the moment employs 15 full-time workers.
Highest possible flexibility
The system used is the MJ COMBI module scaffold. Its module disk makes the system a real allrounder. With up to eight connections per knot – freely selectable in heights of 0.50 m intervals – the system offers the highest possible variability in constructing a modular scaffold. The small notches of the perforated disk are used to connect the ledgers and enforce a 90 degree angle, which is required for many forms of application. In connection with the larger notches arranged in between, the system also offers variable assembly options for angles outside the 90-degree grid. The decisive benefit of the module scaffold is – besides freely definable angles of knots – in the individual selection of bay lengths, widths and level heights. This enables flexible adjustment to virtually any type of building or construction. Various building supervision approvals have been issued for the system by Deutsches Institut für Bautechnik which, among other things, also regulate joint use with compatible systems made by other manufacturers.
Project with obstacles
Since the start of the work in August 2010, the erection of the scaffolding for Baden-Württemberg’s beautiful cultural monument made slow progress as work had to be stopped on market days for safety reasons. This meant that active work on the scaffold with three scaffolders was possible only on three days per week. A total of some 31 tons of the module scaffolding system, three tons of steel tube coupling scaffold and 16 tons of steel scaffold decks and as many steel beams were inserted into the tower’s stonework to apply the load. Moreover, tailor-made brackets had to be installed at the tower sides to further stabilise the scaffold structure.
The system was well suited for the technically demanding project. It is flexible, easy to erect and thus very cost-effective and efficient. “The manufacturer’s high quality standard also enabled us to take account of all safety aspects”, says the managing director, Frank Dostmann. Gang leader Ahmet Metin agrees: “We are really delighted! The system’s high bearing capacity makes it almost perfectly suitable and its comprehensive range of parts allows flexible adjustment to the challenging architecture.”
Free standing at a height above 25 m
As the dilapidated and centuries-old sandstone steeple facade cannot provide sufficient support, a steel structure had to be erected all around for stabilisation and to guarantee free standing at a height of more than 25 metres above the ground. All lattice beam structures, consisting of 75-size steel lattice beams, are partly installed in lying position to transmit horizontal forces into the steel structure. To shelter workers and the building from the weather during the approaching wintertime, a protective shell will be installed using shrinking foil or the MJ tarpaulin system with piping edges.
Upon completion of the renovation work, the former royal seat of the historic Electoral Palatinate that once was the economic and cultural centre of Europe’s metropolitan Rhine-Neckar region will be able to present itself in a handsome outfit to its believing visitors from all over the world due to the efficient and unbureaucratic cooperation based on partnership.