Layout of the Gothic octagonal dome of Tortosa Cathedral

Identifier:  PC:2010

Handle: https://hdl.handle.net/20.500.11797/PC2010

Authors:  LLUÍS GINOVART, JOSEP; COLL-PLA, SERGIO; COSTA-JOVER, AGUSTI

Abstract:
The Cathedral of Tortosa (1345–1757) is one of the most important Gothic buildings of Catalonia (Spain). Its relevance is partly due to the great amount of documents from the beginning of the construction. Between them, stands out the Guarc’s parchment (c.1345–80), which contains the draw of the plan view of a cathedral.The basilica floor plan with three naves, a dome, and a polygonal apse was never built The study of the Gothic layout of Guarc through its imprints allows the determination of the methodology of its outline. The outline of the octagon dome is determined by the geometric method of design. At the same time, the proportional theory that exists behind the parchment allows the transport of the project to the site using simple metrological arithmetic operations. The methodology used for the study of the document is based on the analysis of its auxiliary layout and the lines and compass points on which the final plan is drawn. An analysis of the preceding imprints to the final plans allows us to establish an interpretive methodology of the possible graphical construction. After, this documentation will be compared with the built cathedral. The measure of study is the cana, the pattern, appear into Llibres d’Obra (ACTo). The cana have 8 spans, and the span of 12 fingers.