Shear Response of Reinforced Concrete Deep Beam: Validating Fracture Mechanics Based Numerical Modelling With Experiments

摘要

This article presents a computational fracture mechanics analysis of reinforced concrete deep beams using nonlinear fracture mechanics to study load deflections, cracking patterns and size effects observed in experiments of normal and high-strength concrete deep beams with and without stirrup reinforcement. The article describes the development of a numerical model that includes the nonlinear processes that contributes to the strength of any concrete beam such as compression and tension softening of concrete, bond slip between concrete and reinforcement, and the yielding of the longitudinal steel reinforcement. Because the complexities that are present during the meshing when multiple cracks are in the system, the development also incorporates the Delaunay refinement algorithm to create a triangular topology that is then transformed into a quadrilateral mesh by the quad-morphing algorithm. These two techniques allow automatic remeshing using the discrete crack approach. Nonlinear fracture mechanics is incorporated using the fictitious crack model and the principal tensile strength for crack initiation and propagation. The model has been successful in reproducing the load deflections, cracking patterns and size effects observed in experiments of normal and high-strength concrete deep beams with and without stirrup reinforcement.