Review article

One of the promising methods for evaluating the internal condition and the physical and mechanical properties of wood during inspection of wooden structures is the method based on measurements the resistance to drilling, but no unified methodology and general rules and recommendations are available in this respect. The investigations were carried out on wooden beams of inter-flooring covering slabs made of twin four-beam timber from pine wood ( Pinus sylvestris L. ). The IML-RESI PowerDrill 400 drilling tool and standard boring drill bits (IML System GmbH, Wiesloch, Germany) were used to evaluate internal condition of wood in timber joist at the rotation frequency of 2500 rpm and feed rates of 0.5 and 1 m/min. The paper presents typical drilling and feeding resistance (DR and FR) profiles of the thin drill bit, including the use of blunted drill bits. The average values of the drilling resistance and feed resistance profiles of the thin drill bit were analyzed, as well as the influence of wood moisture degree on the measurement results. Further research is going to focus on the development of a comprehensive methodology for instrumental inspection of wooden structures using the drilling resistance measurement method.