Simulating the Crack Propagation Mechanism of Pre-Cracked Concrete Specimens Under Shear Loading Conditions

Abstract

The mechanism of crack propagation in concrete specimens containing cracks under shear loading conditions is studied. The shear box test of pre-cracked (double edge cracks) concrete specimens is carried out under laboratory conditions. The higher order displacement discontinuity formulation and the special crack tip elements for the treatment of crack ends is used to numerically simulate the crack propagation mechanism of brittle solids under direct shear loading. A special modeling technique is also proposed to take into account the effect of crack overlapping on the fracturing process of the bridge area in between the two parallel cracks. In this study, the wing cracks are produced at the first stage of loading and continued their propagation paths toward the shear loading direction. The crack propagation path of the double edge cracked specimens in the bridge area is mostly affected by ligament angles and crack length whereas the shear strength is closely related to the failure pattern. The coalescence mechanism of cracks indicated that the pre-cracked concrete failure occurs in mixed mode in case of non-overlapping cracks configuration and in tensile mode for the overlapping cracks. Finally, comparing the numerical and experimental results validated the crack propagation modeling and verified the accuracy and efficiency of the proposed numerical method.