Modelling uncertainty induced by plastic hinge length in lumped-plasticity analysis of RC columns

Abstract

This study quantifies the influence of various plastic hinge length assumptions on the uncertainty in the response of reinforced concrete (RC) columns simulated using lumped plasticity models. Although several expressions have been proposed in the literature to estimate the plastic hinge lengths of RC members, the plastic hinge length values computed using these equations vary considerably and only a limited number of studies have attempted to quantify the effect of using different plastic hinge lengths on the simulated response of RC members. In this study, concentrated plasticity models of RC columns tests reported in literature are developed using Opensees. Different equations proposed in the literature to estimate plastic hinge length are used in conjunction with section (moment-curvature) analysis to generate the inelastic moment-rotation backbone of the plastic hinges. The uncertainty associated with plastic hinge length estimation on the simulated member response is quantified by conducting nonlinear static analyses. Further, fibre-element modelling of the selected RC columns is carried out and the results are compared with the results from plastic-hinge models to understand where the distributed plasticity prediction sits within the range of lumped-plasticity predictions.