Size effect on shear strength measured by the ASTM method

This note contains a description of the experimental process and results of an investigation to evaluate the effect of decreasing sheared area (size effect) on the shear strength of solid wood parallel to the grain. The dimensions of the sheared plane, including width (perpendicular to the applied force) and length (parallel to the applied force), of standard block shear specimens were gradually decreased while other parameters were kept constant. Statistical analyses of the obtained shear strength data by the standard ASTM method demonstrated slight positive correlation between the magnitude of the sheared area and strength. These variables tend to increase together. Similarly, decreasing width demonstrated decreasing strength values. No significant relationship was observed between length and strength. Results indicate that the size effect may be negligible within the examined area range.