Some Notes on Gothic Building Processes: the Expertises of Segovia Cathedral
Santiago Huerta and Antonio Ruiz
Paper given: The Second International Congress on Consrtuction History (2006)
Gothic architecture has aroused the interest of architects, engineers and historians for centuries (Frankl 1960). The technical point of view has also received attention; in particular, there is an abundant literature on gothic vault construction and structural behaviour. The rational approach of Viollet-le-Duc (1854), followed by Choisy (1899) and many others, was subsequently criticized, mainly by Pol Abraham in the 1930s (for an excellent résumé of the debate, see Kubler 1944, pp. 135-7; see also Mark, 1977). From a structural point of view the discussion focused on the actual functioning of the different elements of the vault (the ribs, webs and bosses) and the debate was actually closed by Heyman (1966, 1968) with the application of the ideas of modern limit analysis to masonry structures. However, the deep meaning and the practical consequences of Heyman’s discoveries have not yet been fully understood by many architects and engineers, who are still using sophisticated computer programs to try and obtain the actual state of internal stresses in masonry.
There is another aspect that has been rarely considered: the cathedral must also have been in equilibrium during the building process. In any of the intermediates phases, the sequence of the operations, the dispositions of scaffoldings, materials, etc., must have assured a safe state of equilibrium. This consideration implies some order in the erection procedures. The only author who has tried to answer these kinds of questions is Fitchen in his book The construction of Gothic Cathedrals: A Study of Medieval Vault Erection (1961). After four decades, Fitchen’s book is still the main reference on gothic building processes and is a mine of scholarly information. However, in his discussion of these matters, Fitchen uses a building commonsense approach, trying to deduce the possible gothic processes from the nature of the problems involved, which he studied thoroughly. He assumed explicitly that the scarce gothic original sources could give no information about building processes. In fact, this is not the case. Since the 1960s, the work of Shelby (1977, 1979), Müller (1990), Coenen (1990), Binding (1993), etc., has unearthed a remarkable amount of gothic technical literature on building.