Modelling steel-strip-confined reinforced-concrete columns

Confinement introduces deformability in reinforced-concrete columns. The stress–strain relationship of confined concrete is significantly influenced by the yield strength, configuration and spacing of the confining reinforcement. These also influence estimation of compressive strength of confined concrete. Performance of confined columns can be studied through the hysteresis response. The backbone curves of the hysteresis are of significant importance. Parameters such as yield, peak load, ultimate displacement, stiffness degradation and ductility can all be measured and evaluated from these curves. In this paper, the behaviour of steel-strip-confined columns is presented in the form of hysteresis curves along with their backbone curves. The experimentally achieved backbone curves are modelled in Drain-3DX through simple calibration. The hysteresis of standard stirrup columns is also modelled and compared with that of steel-strip-confined columns. The comparison indicates improvement in the response of columns confined with steel strip transverse reinforcement. The study will be helpful in understanding the modelling of the hysteresis response in Drain-3DX. The calibrated models will be available for further application in evaluation of the performance of building structures containing steel-strip-confined or standard stirrup columns.