Computer analysis of a Gothic Cathedral Pere Roca 1 , Climent Molins 2 Universitat Politècnica de Catalunya, Departament d’Enginyeria de la Construcció Jordi Girona 1-3, 08034 Barcelona, Spain ABSTRACT This paper presents the studies carried out on the structure of a Gothic construction using a numerical technique of analysis specifically developed for the assessment of masonry skeletal structures. This technique consists of a generalisation of conventional matrix calculation for frames to non-linear analysis of structural systems composed of straight or curved members with variable cross section. In spite of its relative simplicity and limited computer needs, the technique provides satisfactory engineering results. The application of this technique in the study of the structure of the nave and cimborio of Barcelona Cathedral is here presented in order to illustrate its actual applicability to the assessment of masonry ancient constructions. 1 INTRODUCTION The study of large masonry ancient structures requires the use of techniques of analysis endowed with powerful procedures for the modelling of the geometry, the simulation of the mechanical response of the various materials (including ashlar blocks and masonry, backings and fills) and the simulation of the possible agents (gravity, wind, earthquake, settlements) which may affect the structure or may have affected it through history. Very powerful and realistic tools have been recently proposed by Oñate et al. (1997), Lourenço et al. (1998), and other researchers for the analysis of masonry structures, based on state-of-the-art concepts and numerical developments. A detailed report of the today available approaches for this kind of analysis can be find in Molins (1997) and Lourenço (1998). However, simpler and more conventional tools of analysis are also needed for first approach calculations or to undertake the analysis of large and complex structures which, otherwise, might require unaffordable computer effort. The generalised matrix formulation (GMF) here presented is intended for this purpose. The actual applicability of the used generalised matrix formulation is illustrated through the description of the analysis of the structure of Barcelona Cathedral. This study includes two different aspects: first, the analysis of the structure of the typical bay of the nave; second, the study of the structure sustaining the cimborio, built centuries after the construction of the nave. 1 Professor, corresponding author (pedro.roca@upc.es) 2 Assistant Professor, Dr. Número 9, 2000 Engenharia Civil • UM 29