Experimental techniques for suspended structures: the construction of Chauderon hanging building in Lausanne (R. Willomet, P. Dumartheray and J. Prouvé, 1970-1974)

The lecture, starting from a synoptic analysis of the European situation and Belgian realizations of suspended buildings in the years 1960 - 1980, will mainly deal with the construction history of the Administrative Buildings of the Place Chauderon in Lausanne, designed between 1970 and 1974 by the Swiss architects Willomet and Dumartheray, with the expertise of Jean Prouvé. The building represents in many ways the apex in suspended building construction. Here can be found, thanks to a mixed steel and concrete structure, a real optimization in the use of materials, with compressed elements all made of concrete and all tensioned elements made in steel. The facade is cleverly designed by Jean Prouvé with prefabricated modular panels, adopting the CIMT system, directly derived from the railway industry and applied to the construction industry. Thanks to its flexibility and the sliding possibility of the neoprene panels’ joint, the system is capable of supporting vertical deformations up to 50 cm and more, overcoming one of the most challenging constraints, due to the presence of steel hangers. At the same time the sandwich panels, filled with polyurethane foam, assure acoustic and thermal insulation, providing the first link to sustainability themes. According to Roland Willoment, the presence of Jean Prouvé was essential to answer the numerous technological issues of the project, otherwise not manageable in their complexity by any other Swiss architect or engineer. So, the lecture will be focused on the building construction techniques, adopted for the structure and its facade; on the materiality of the complex and its actual condition; on the industrial process conceived for the panels’ fabrication. Particular attention will be also given to construction details, with the analysis of the original technical drawings at the scales 1:10 / 1:5, coming from the EPFL Archives de la Construction Moderne.