Moving Weights: Nervis Prefabricated Wave Ashlar Roofs and the Artisanal Cantiere

Among Nervis best known works are long span vaults and domes that exploit the folded-plate principle to achieve unprecedented spans. While the structural performance of these undulating roofs was remarkable, their construction processoften alluded to but rarely documentedwas equally radical. Nervi was not only a structural designer, he was also a builder; Nervi & Bartoli was renowned for their experimental process and their ability to build to budgets and schedules that others found impossible. But in many ways they were a typical Italian contracting firm in that they were family-owned and artisanal in scale. Their ability to construct on a scale that matched that of the worlds largest contractors in the 1950s and 1960s rested on principles of prefabrication and modularity. Nervi & Bartoli built some of the most sophisticated concrete structures of the postwar era, but they did so almost entirely by hand, by breaking down giant spans into elements that could be fabricated and moved by just a few workers, and that could be lifted into place by small jobsite equipment.This paper examines the construction processes behind these prefabricated vaults, using component, construction, and scaffolding drawings in the Nervi Archives at MAXXI in Rome and in the Centro Studi e Archivio della Comunicazione collection at the Universita degli Studi di Parma to show how Nervis structural daring was matched by ingenious jobsite and fabrication techniques. It will focus on the processes involved in the Salone B, but will show how these evolved for later projects. In conclusion, the paper focuses on the short-lived, ambitious project for Reynolds, using previously unpublished correspondence and digital reconstructions to explore the limits of the folded plate structural type and of the System Nervi.