08-10-2014, 04:31 PM
Ductile flexural behaviour of large reinforced concrete hollow sections is investigated. Effect of confinement in enhancing the strength and ductility of concrete sections is studied. For this, an existing confinement model applicable for both circular and rectangular solid sections is extended and modified to analyze large hollow sections of both shapes. An analytical method is proposed to quantify the effect of confinement in a hollow circular section where inner and outer hoops are connected by radial links. A number of sections are analysed to obtain the influence of axial load as well as various sectional parameters on the curvature ductility of the section. From the analysis, links are found to have large effect on the ductility of a circular section, but the effectiveness varies with the wall thickness. For circular sections, lower wall thickness provides higher ductility, while for rectangular sections wall thickness has no bearing on the ductility as long as transverse spacing of cross-ties is kept same. Also, rectangular sections can achieve much higher streng