Analytical Modeling of Reinforced Concrete in Tension
Abstract:
A smeared crack approach to fracture of concrete in mode I was implemented in the finite element program ADINA. Nonlinear concrete elements with tensile cracking were modified to include tensile strain softening. When an element at an integration point cracks, the stiffness perpendicular to the crack is reduced to zero and the tensile stress across it is set as a function of the crack opening. Equilibrium iterations were implemented to redistribute stress. Two- and three-dimensional models of a single edge notched beam in three-point bending were analyzed and compared to experimental results with good agreement. The analytical representation of mixed mode fracture was also addressed. The mechanisms of shear transfer across a crack were detailed, and the rough crack model, relating shear stress to crack opening, is presented with discussions on orientation of successive crack planes, tensorial invariance, and snap-back phenomena. Problems are identified with modeling bond at the concrete reinforcement interface and its effect on crack patterns. Keywords Fracture mechanisms Crack propagation Mixed mode Shear Bond tension Softening Fracture energy ADINA computer programs.