The Structural Behaviour and Design of Free-Standing Barrel Vaults of Eladio Dieste Remo Pedreschi INTRODUCTION The period from the late nineteenth through to the twentieth century was a time of great innovation and experimentation in structural form and the expression of structural form in architecture. Engineers such as Gustav Eiffel (1832 – 1923), Eugene Freyssinet (1879 – 1962) and Robert Maillart (1872-1940) worked with new materials and techniques to produce structures and buildings that were elegant, economic and structurally efficient. More than this they showed a great care for the expressive qualities of structures. David Billington describes this combination of structural efficiency and expression as “structural art” (Billington 1985). Later on in the twentieth century the work of engineers and architects such as Nervi, Torroja and Candela became rightly recognised for their “structural art”. Common to most is the strong relationship that they had with the process of construction, learning and developing technique with successive projects. Many of them concentrated on one material. The engineer Eladio Dieste (1917-2000) without doubt deserves to be part of this company. Throughout a long career Dieste developed many new techniques and forms, almost entirely in brick that are only now becoming recognised as masterpieces of structure and architecture. His company Dieste y Montañez constructed over 1.5 million square metres of building in South America, The bulk of these were thin brick vaults in either single or double curvature used in buildings such as warehouses, factories, gymnasia and workshops. The paper considers in particular one form of vault, developed by Dieste, the Free-standing Barrel Vault. These highly expressive vaults were developed as economic solutions for the construction of industrial buildings. The evolution and design of the vaults is explained including the innovative construction techniques, such as looped pre-stressing that Dieste developed to optimise both the expressive qualities and efficiency of the vaults. Examples are presented and finite element techniques are used to gain further insight into the behaviour of the vaults. Background to the life and career of Eladio Dieste Dieste was born in Artigas, a small town in the northern part of Uruguay. He studied engineering at the University of the Republic in the capital city, Montevideo, graduating in 1943. Montevideo at this time was growing culturally and economically. It was a period of great optimism. According to Lucio Cáceres a former student of Dieste and Minister of Public Works and Construction for Uruguay “He (Dieste) played an active role in a generation that exalted duty towards oneself and toward’s ones fellow man as a way to elevate the soul and to promote private and public virtues” 2451