Effect of Various Structural Factors on Shear Strength Degradation after Yielding of RC Members under Cyclic Loads

Shear failure after flexural yielding is a typical failure mode for a reinforced concrete (RC) member subject to cyclic load, and it is caused by the phenomenon that the initial shear strength is decreased with the increasing plastic ductility until the shear capacity degrades to be lower than the flexural strength. In this study, the flexure-shear behaviors of a number of RC columns with a relatively wide range of crucial structural factors involving tensile reinforcement ratio, shear reinforcement ratio, shear span-depth ratio (covering deep and slender columns) and axial compression load were simulated by the Three Dimensional Rigid-Body-Spring-Method, and the degradation behaviors of shear strength of all specimens were quantitatively evaluated to comprehend the effect of the structural factors. Moreover, the degradation behaviors of shear strength were decoupled into the degradation behaviors of shear resistance components (beam action, arch action, truss action, concrete contribution for beam action) to clarify the mechanism of shear failure after flexural yielding for the RC columns at various crucial structural factors. Consequently, the effect of crucial structural factors on the degradation behaviors of shear strength and shear resistance components were understood and it was concluded that the stepwise degradation of arch action was the dominant mechanism for the investigated structural factors for the shear failure after flexural yielding of RC column. This paper is an extended version in English from the authors' previous publication