Local Buckling Analysis of Longitudinal Reinforcing Bars

Abstract

The local buckling behavior of longitudinal reinforcing steel, which occurs between two transverse hoops, is examined using rational mechanics, taking into account the full plastic behavior of the steel and the effects of true stress and strain. A computational fiber element analysis is used to compute the coupled effect of axial compression and lateral buckling. The results of the computational analysis are then used to develop a simple model for the compressive behavior of longitudinal reinforcing steel in engineering stress-strain coordinates. Although several models exist that are capable of predicting compressive behavior with a moderate degree of precision, these models are generally computationally intensive and therefore of little practical use to structural designers. Other existing simple models either have a high degree of built-in empiricism or are based on overly simplified assumptions about the plastic behavior of the steel. The minimalist model developed in this study is compared with available experimental results. A statistical study shows favorable correlation between the proposed analytical model and experimental results.