Crack Shear in Concrete: Crack Band Microflane Model

Abstract

The crack band model is applied to the problem of crack shear in concrete. The constitutive law for concrete within the crack band is provided by the microplane model, in which the microstrains on weak planes of various orientations (the microplanes) are assumed to conform to the same macroscopic strain tensor, and the microstresses from all the microplanes are superimposed. Due to the neglect of shear stiffness on individual microplanes, the material behavior is completely characterized by the relation between the normal stress and strain for each microplane. To simulate crack shear, the law for unloading contribution on the microplanes after previous tensile strain‐softening is important, since the shear stresses resisting crack shear, as well as the normal confining stresses and crack dilatancy, result from compression along lines inclined with regard to the crack plane. A satisfactory agreement with the existing results from shearing tests of cracked concrete blocks (i.e., aggregate interlock tests) i...