Salisbury Cathedral and Its Diversity of Flying Buttresses
By Johanna Mähner
Proceedings of the Third International Congress on Construction History, Cottbus, May 2009
Abstract: The flying buttresses of Salisbury Cathedral are unique in their number of diverse types and in the irregular layout of these types in the Cathedral plan. Yet research on this topic has been neglected both from the fields of art history and construction history. Now the various types of flying buttresses were surveyed each as part of the complete section of the building and have been examined with the means of building archaeology within the research project presented here.
The section drawings form the basis for the ongoing research which aims at gaining a realistic understanding of the structural function of the flying buttress types. In this paper the analysis of the structural behaviour of a selected number of flyers is presented. The flying buttresses are examined as isolated structures under minimum thrust conditions in order to exemplify their strengths and weaknesses. The examination of the behaviour of the flying buttresses in the context of the overall system of the cathedral will follow.
Introduction: The structural function of flying buttresses aroused interest since the beginning of the gothic revival. Besides the
ribbed vault they played a role in the discussions on the relation of form and construction in Gothic building. The essential structural role attributed to flying buttresses by Eugène Viollet-le-Duc is expressed in his comparison of a gothic cathedral without flying buttresses with a ship without keel.
Georg Ungewitter and Karl Mohrmann dedicated a substantial part of the “Lehrbuch der Gotischen Konstruktionen” to the buttressing system and the flying buttress. Their analyses using graphic statics have been the basis for many later investigations. Jacques Heyman (1966) contributed a further step in methodology by applying plastic design principles on masonry and employing this limit state analysis to flying buttresses. The structural behaviour of flying buttresses was discussed in the overall system of cathedrals both by Helmut Weber (1957) and Jürgen Segger (1969), a new approach in this line of investigations was the photoelastic modelling by Robert Mark (1982) providing advanced insight. Recently Maria Katerina Nikolinakou, Andrew Tallon and John Ochsendorf (2005, 2006) presented investigations on early Gothic flying buttresses that will be referred to in detail below.