A simplified extreme method for determining double‐K fracture parameters of concrete using experimental peak load

Abstract A simplified approach to obtain the double‐K fracture parameters of concrete for three‐point bending beams was proposed based on the extreme method. With the proposed method, the double‐K parameters can be easily obtained by the experimental peak load. This method requires fewer parameters or tests than the double‐K method and the peak load method. It also avoids complicated numerical integral compared with the traditional extreme method. The double‐K parameters obtained by the proposed method are slightly smaller than those by the double‐K method, and they do not seem to be influenced by the initial crack length to depth ratio.