The distance d between the notch simulating a defect and the load application was fixed in all tests at 75 mm. The relation between the test load FP and the maximum bending stress σbc at the location of application was determined by the specimen’s section modulus Zx2. The corresponding nominal bending stress σb at d (place of notch) can be obtained from the ratio equation using the effective lever arm, so equation (1) gives the relation between test load FP and bending stress σb at d