Non-destructive testing techniques applied for diagnostic investigation: Syracuse Cathedral in Sicily, Italy

The long-term research experience of the authors has enlightened the importance of the knowledge of the building through experimental investigation. Recently, the authors intensively studied the Syracuse Cathedral in order to evaluate the structural state of preservation of the pillars. The Cathedral of Syracuse was built in different phases on an ancient Greek temple from the 5th cent b.C. and modified along the centuries. The pillars of the central nave, obtained cutting the temple cell walls, show a complex situation of damage and repairs. An investigation program (including sonic, radar, ultrasonic tests, etc.) has been recently planned, aimed to design the preservation and restoration actions. An accurate geometrical survey of the surface problems and defects allowed the localisation of the most damaged area, suggesting the further control by non destructive testing (NDT). The results obtained from the survey were compared to the results of the other type of tests and the elaborated data will implement an analytical model for the study of the seismic vulnerability. The preliminary results of the experimental investigation carried out by the authors are presented.