Non-destructive analysis in cultural heritage buildings: Evaluating the Mallorca cathedral supporting structures

Geophysical prospecting surveys are being increasingly used in non-destructive evaluations of structures, and several methods can be applied in the evaluation of cultural heritage buildings. However, accurate studies of cultural heritage structures usually need the application of combined techniques, historic and structural knowledge also being necessary. The present paper describes the application of two non-destructive testing techniques: ground-penetrating radar and seismic tomography, in the analysis of some structural elements' inner geometries and physical properties. This job is part of a more complete project developed to define the Mallorca Cathedral structural behaviour. Both geophysical methods are used in a complementary way. GPR allows the detection of small anomalies (changes of about centimetres), and the results are used to select the most appropriate seismic tomography initial model. The aim of the study is to define the internal structural configuration as well as the stone quality. Results reveal the internal structure of columns, walls and buttresses, showing different structural elements. Even when the visual inspection points to external damages, the detailed NDT evaluation indicates that the inner structure is in good condition and the ashlars are of good quality.