La prova resistografica per l’analisi e la diagnostica di strutture lignee in opera: letteratura, normativa, applicazioni sul costruito storico

The resistograph drilling test is a quiet non-destructive evaluation method for the in situ analysis and the diagnosis of wooden structures. This paper presents the results of several applications on wooden structures in historical contexts where its features of non-destructivity are very useful. Nowadays the employment of the resistograph is recommended during the inspection of wooden roof and floor structures, beside the direct visual inspection and the employment of other simple evaluation methods to survey the general conditions of decay. After a brief bibliographical digression, we discuss the results obtained in a couple of in situ campaigns in the North of Italy, at the Palazzo del Podestà (Mantova) and Rocca Rangoni of Spilamberto (Mo), and during a wider-scale application of the resistograph method in the South of Italy, at Borgo Laino Castello (Cs). The results suggest a few possible improvements of survey procedures and the resistograph itself and claim the necessity of an international survey protocol.