Load carrying capacity of halved and tabled tenoned timber scarf joint

The stress distribution of timber tenoned scarf joint subjected to tension force was analysed by means of finite element method. This analysis was compared and validated with results from an experimental work on 42 specimens of Scots pine wood ( Pinus sylvestris L.) with 48 × 148 mm in cross-section and 1932 mm, in length, manufactured with a tenoned scarf joint in the middle of its length. Specimens were divided in eight groups corresponding to different joint geometries. A plane finite element analysis using ANSYS software was made considering the elasticity moduli, Poisson ratios and friction coefficients obtained in previous research works for the same material. Three different failure modes were analysed: compression parallel to the grain in the notch area, shear parallel to the grain in the heel surface, and the combination of tension and bending moment in the effective cross-section of the piece, which is limited by the crack initiation due to tension perpendicular to the grain. Equations for the verification of this joint are proposed as a practical conclusion.