Eduardo Torroja's thin concrete shells stand among the best examples of structural engineering work of the 20th century. At a time when computers did not exist, Torroja's imagination and creativity were not constrained by the limits of the analytical methods available for structural design, and he was able to design and build economically innovative structures of the highest aesthetic quality. One of his major creations was the roof of the Frontón Recoletos, a unique two lobe thin shell that was destroyed during the Spanish Civil War. This paper reviews briefly the history of the Frontón, shows the results of a structural analysis of its roof by several Finite Element (FE) models of different complexity and precision, and compares FE results to those obtained by Torroja. FE results confirm the validity of Torroja's conceptual design, although he seems to have underestimated the internal forces and stresses in the roof. In addition, the paper analyses in detail the influence on the behaviour of the roof from its support conditions and from the stiffening ribs that Torroja designed but that never were built. As a result, the paper enables a better understanding of one of the masterpieces of Structural Art, and of simplified and complex shell analysis models, which is useful for the education of engineers as well as for future designs. © 2010 Elsevier Ltd.

Funding for this research has been provided to Mr. Paya-Zaforteza by the Spanish Ministry of Education through its program for postdoctoral stays (Contract No. EX-2008-0669) and to Mr. Lozano-Galant by the Junta de Comunidades de Castilla La Mancha, Spain (Research Project PII2I09-0129-4085). The authors are also grateful to Prof. J. Antuna and J.A. Torroja of the Universidad Politecnica de Madrid, Professors C. Lazar and J.M. Adam of the Universidad Politecnica de Valencia and Professors H. Sundquist and C. Pacoste of the Royal Institute of Technology of Stockholm for their assistance and support. The authors also want to thank the Archivo Torroja and its librarian, Isabel Garcia, for all the information and support provided. Finally, the authors express their gratitude to CEng W. Plunket who carefully reviewed the English of the manuscript and to M.Sc. C. Llopis who lent the authors his original copy of Ref. [23].