Extent of Plasticity in Reinforced Concrete Columns

This paper discusses a method to determine the extent of plasticity at the ends of laterally loaded ductile reinforced concrete columns where plastic hinges form, and where transverse reinforcement is detailed to ensure ductility. Current code formulations are shown to generally underestimate the extent of this region. An analytical method is derived, which combines flexural analysis of the column with flexure-shear interaction considerations. The analytical method is compared to the experimental results from tests on reinforced concrete columns conducted over the last 30 years, showing good agreement. The paper concludes with simple recommendations for use in design