Association of nondestructive testing to inspect timber structures

Abstract

Wood is a building material recognized during the human history and, currently, also considered among the most sustainable because of its low incorporated energy, its storage carbon and because it is a renewable material. But, like all materials, the wood degrades and loses its strength capacity over time. Thus periodic inspections are required to maintain the integrity of the structure in service. Many nondestructive or semi destructive methods are being proposed to applying in timber inspections and all of them have positive aspects. Contrasting, none are enough complete to guarantee, as unique methodology, adequate results of the inspections, either because of the methodology or because of results limitations. Therefore, the combination of NDT methods has been the focus of discussions, particularly in scientific events. The fact of that such discussions have not yet generated consistent number of scientific articles published in journals, may be related to the lack of conclusive results, guided by theoretical bases of the techniques. So, the objective of this project is to evaluate the association of two nondestructive technologies: the wave propagation and drilling resistance. In the case of the wave propagation the equipment will be the Ultrasound and in the case of the drilling resistance the Resistograph. The study will be conducted considering the theoretical methods in order to propose appropriate methodology for these bases, limiting the scope of each technique. As specific objectives intended to evaluate the accuracy of each of the techniques for detecting the levels, dimensions and location of deterioration using as isolate method as well as correlation models with physical properties (density and moisture) and mechanical (residual strength) involved in inspections of wooden structures. Considering that the two methods to be analyzed are both easy to use and with moderate cost, proving the efficiency of the joint application will contribute to a proposition of an alternative methodology for inspection in Brazil. (AU)