Size effect tests of different notch depth specimens with support rotation measurements

Test results from a Type I & II size effect experimental study on notched and un-notched beams are presented in this paper. The test specimens were geometrically similar but had different scale ratios and different notch length ratios of 0, 0.02, 0.075, 0.15 and 0.3. The specimens had rectangular cross sections with constant thickness of 40 mm and the depth varied from 40 mm to 500 mm corresponding to a scale ratio of 1:12.5. Rotations measured at support locations for each specimen are presented to reinforce the experimental findings. It was observed that all specimens with different notch-to-length ratios exhibited size effect, in which the stress at maximum load (failure load divided by cross-sectional area) decreased as the size was increased. The results indicate that the failure is governed by fracture mechanics principles. This phenomenon is not addressed in current design codes, which do not account for such size effect. The test results showed that beams with shallow notch exhibit Type I, beams with deep notch exhibit Type II size effect law. The test results compared favorably with several widely accepted size effect models.