Abstract:
Strength and stiffness assessment of timber members in-service is a crucial task in the
rehabilitation of a timber structure. Unsatisfactory results given by traditional procedures
applied for appraisal of in-service structural timber members are a strong motivation for
research on non-destructive techniques (NDT). For assessing strength and stiffness of clear
wood zones of structural members an indirect ultrasonic method is proposed, given the
advantage of requiring the access to only one surface of the element.
This paper presents results of a study comprising three different wood species (oak,
maritime pine and european spruce) with two different cross-sections and 150kHz
transducers. Different arrangements of the transducers on the same surface were tested and
the results compared with the ones obtained with a direct method (transducers placed at
opposite ends of the specimens). The results obtained are discussed having in mind the ones
already obtained in almost clear structural timber elements as well as in small size clear wood
specimens.
