Effect of shear performance by the duration of load in parallel to the grain direction of wood

High-strength joints are increasingly used in timber structures to exploit the shear properties of wood. Therefore, understanding the long-term shear performance is essential. In this study, the long-term shear behavior of timber was evaluated using the tensile-shear test method. A duration of load (DOL) test was conducted to assess shear performance parallel to the grain under sustained loading. The test was carried out at loading levels ranging from 70–90%, and strength modification factors as well as duration of load coefficients were calculated to ensure conservative values relative to current design standards. The results indicate that the deformation at failure tends to converge at approximately 0.3 mm. A correlation was observed between deformation and environmental conditions, with the specimens loaded in April demonstrating greater deformation than the loaded in October. The strength modification factor was determined to be 0.67, which is considered a safe value compared to the current standard of 0.55. This result is consistent with values reported in the previous study involving creep limit test study.