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struts. Despite the size of the elements, it was possible for five or six workers to assemble them quite simply and without an additional supporting construction. The repetition of the prefabrication process and the optimal working conditions allowed errors to be avoided in the manufacturing process and a quality control to be carried out prior to erection. The training school operates so successfully that in the meantime it has been extended by a further student project from the University of Augsburg under Prof. Susanne Gampfer, and the roof construction of the school has since served as a model for a new school and assembly building in nearby Malaa (also to be erected in bamboo), where the workers who
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13 –17 B uschkrankenhaus in Ngaoubela, Kamerun, 2013 13 Raumaufteilung und Ringanker 14 Mock-up Fenster- und Lüftungselemente 15 Montage Holzbalkendecke 16 Operationssaal 17 Ansicht Süd
13 –17 B ush hospital in Ngaoubela, Cameroon, 2013 Internal spatial divisions and peripheral tie beam 13 14 Mock-up of window and ventilation elements 15 Assembly of timber-beam roof 16 Operating theatre 17 South elevation
Stefan Krötsch ist Architekt in München und war von 2008 bis 2014 wissenschaftlicher Mitarbeiter von Prof. Hermann Kaufmann am Fachgebiet Holzbau der TU München. Er leitete die Projekte Handwerksschule Nairobi zusammen mit Susanne Gampfer, Buschkrankenhaus Ngaoubela zusammen mit Matthias Kestel, Prototyp-Schule für Sambia zusammen mit Wolfgang Huss, Matthias Kestel, Jörn von Grabe und Martin Gräfe und Schulaula in Kibwigwa zusammen mit Christian Schühle, Martin Kühfuss und Matthias Kestel. Seit Juli 2014 ist er Professor für »Tektonik im Holzbau« an der TU Kaiserslautern.
Stefan Krötsch is an architect in Munich. From 2008 to 2014, he was a research assistant to Prof. Hermann Kaufmann for timber construction at the University of Technology, Munich, where he was in charge of various projects: the craft training school in Nairobi (with Susanne Gampfer), the bush hospital in Ngaoubela (with Matthias Kestel), the prototype school for Zambia (with Wolfgang Huss, Matthias Kestel, Jörn von Grabe and Martin Gräfe) and the school hall in Kibwigwa (with Christian Schühle, Martin Kühfuss and Matthias Kestel). Since July 2014, he has been professor for the Tectonics of Timber Construction at the University of Technology, Kaiserslautern.
have learned to use this material are to be employed as chargehands and foremen. The hall of the village school in Kibwigwa, western Tanzania, which is currently under construction, is the hitherto largest structure among the African projects (ills. 5 – 8). It will provide a dining hall for 500 pupils and will also serve as a space for various functions for both the school and the village. To keep it column free and to obtain an economical span, the students adapted the historical timber lattice-shell construction developed by Friedrich Zollinger, which offers an appropriate solution for regions in Africa with a weak infrastructure. It is extremely economical in terms of material use, allowing a saving of up to
40 per cent in comparison with linear loadbearing structures; it consists of small elements that can be transported by hand if ne cessary; and it can be erected by untrained workers without site equipment. In Kibwigwa, timber boards cut to an identical length of less than two metres form a vaulted roof with a span of 13.5 m, a length of roughly 40 m and a rise of 5 m. The uniform nodes have connections consisting simply of a threaded rod with two nuts and washers. The implementation, however, confronted the design team with a number of challenges. Firstly, there were no closed gable areas to provide bracing, as in the Zollinger structure. Secondly, the relatively heavy roof tiling on German halls of