Methodologic Evolution Assessment of Large Deformations on Romanesque Masonry in Val d‘Aran (XII-XIII centuries), Spain

Abstract

There is a set of Romanesque churches at Val d'Aran that were built between the eleventh and thirteenth centuries. One of the main features of these buildings is the presence of large deformations and geometrical displacements in their masonry. One of the most deformed buildings is the church of Santa Maria de Arties (XII), which arches' and vaults' have antifunicular shapes. The assessment is based on a three-dimensional model obtained with a terrestrial laser scanner (TLS). The scanner used is a Leica ScanStation P20. In the study of built heritage, the use of direct measurement techniques for architectural surveying requires a large number of resources. These deformations have caused, in some cases, turn centerlines of the vaults into convex shapes, which have the inverted shape of an arch. Joints appeared because of active and passive thrusts that were performed to keep the structures in equilibrium. Geometrical assessment of the least rigid elements, the pillars, makes it possible to analyze the displacements, which have been the cause of anti-funicular shapes on some vaults. It is possible to deduce the regression plane of the displacements of the pillars of the central nave and to define the deformation vectors over it. Thus, these data all for the directions of the deformations of the vaults to be determined.The methodology of this study focuses on the assessment of the geometrical characteristics of the pillars, with the objective of studying the displacements that they have suffered. The point cloud is processed with the software; Cyclone, and the program 3DReshaper (2016), and Google SketchUp (2019). The study allows to analyze the evolution of the treatment of points, concluding that deformations of the pillars are not perpendicular to the axis of the central vault. The methodology used and its results let to understand the nature of the displacements in order to preserve these masonry structures.