Post-cracking analysis of reinforced concrete panels including tension stiffening

Abstract

In finite element analysis of reinforced concrete structures, the effect of bond forces between concrete and reinforcement, referred to as tension stiffening, is discussed. To account for this phenomenon, the post-cracking constitutive model for concrete is modified by assigning a linear strain softening branch to its stress–strain curve in the tensile stress direction. For analyzing orthogonally reinforced concrete panels, a simple procedure for determining the termination strain on the softening branch is then developed. Appropriate constitutive models for steel and uncracked concrete along with the post-cracking model to simulate the behavior of cracked reinforced concrete are implemented in a finite element program. Three orthogonally reinforced concrete test panels subjected to pure shear loadings causing inclined cracking are analyzed. It is shown that the adopted numerical procedures are capable of predicting the post-cracking responses, ultimate capacities, and modes of failure for the analyzed panels with good accuracy. The capabilities of the employed post-cracking model to simulate the crack shifting behavior observed during testing of a highly anisotropically reinforced panel is also demonstrated. Key words: reinforced concrete panels, finite element, post-cracking, tension stiffening, crack shifting, ultimate load.