Load Bearing Behavior of Stop Bladed Scarf Joint With Cog and Peg

The main issue in constructing timber structures has always been the design of joints, which were to ensure the proper transfer of loads and tied the structure together. This study is focused to understand the performance of Stop Bladed Scarf Joint with Cog and Peg to different loading and compare the capacity of joint with that of solid beam. The tensile strength test and three-point flexure test were conducted to obtain the tensile strength and modulus of elasticity of the material. Numerical modeling for tensile and bending has been performed whereas physical modeling of joint has been done for bending test only. Upon testing of the joints after classification, gives the structural performance, effective joint length and orientation. For the purpose, all three joint types are tested in reduced scale for bending in directions perpendicular to axis of element. Joint was classified into 3 types, Type A, B and C, based on joint lapping length. Failure patterns in joint types A and C were similar under all loading. Tensile failure occurred due to combined tension and internal bending in joint A (140.47 kN) and C (193.57 kN), whereas joint B (76.78 kN) failed primarily in shear. Bending tests showed that joint C achieved the ultimate moments—21.88 kN.m in direction 2 and 43.69 kN.m in direction 3—followed by joint A (14.14 kN.m and 36.42 kN.m) and joint B (8.20 kN.m and 20.15 kN.m). While the joint was originally designed to resist bending in the standard loading orientation, testing revealed that its moment capacity in the perpendicular orientation was approximately twice as large. Overall, joint type C achieved approximately 11–18% of the solid beam’s tensile and flexural capacity, whereas joint type B developed only about 4–9% of the corresponding solid beam strength.