In situ assessment of structural timber using the resistance drilling method - Evaluation of usefulness

The paper presents a survey of the state-of-the-art of the application of drilling resistance methods as quasi non-destructive (semi-destructive) diagnostic techniques for testing timber structures, with examples of their application. The method is based on correlating drilling resistance and hardness - density of materials. Resistance drilling tests are quasi non-destructive as the openings arising from drilling do not affect the mechanical and aesthetic properties of the material being tested. The average diameter of an opening remaining after testing does not exceed 3 mm. The method enables assessment of the extent of wood damage of the tested elements and a preliminary assessment of the mechanical properties based on an appraisal of internal defects (e.g. wood decay) in the material. The paper presents also research using a mobile drilling resistance device carried out by the authors to investigate the technical state of buildings, including those of high historical value.