Comparison between experimental results and design equations of artificially degraded single step joints

Abstract

In the case of interventions in existing buildings, the assessment of timber elements and joints, such as the Single Step Joint, is a challenge for engineers, especially when timber presents signs of biological degradation. In this context, many roof structures are subject to unnecessary substitutions due to the lack of knowledge about the behaviour of these types of joints, and specially the consequences of eventual biological attacks. This study aims to evaluate the residual shear strength of Single Step Joints artificially degraded by wood boring insects from the Anobiidae family (e.g. Anobium punctatum). To achieve the established objectives, destructive tests were carried out on undamaged (reference level) and artificially degraded Single Step Joint specimens, varying the level of degradation. The results were analysed in terms of degradation level and compared with the results obtained with design equations for this type of joint found in the literature. From the analysis of the results, it was possible to observe the tendency of reduction of the shear strength with the increase of the degradation level.