Effect of cover upon the stress-strain properties of concrete confined in steel binders

Abstract

Cover to the stirrups in reinforced concrete struc- tures is one of the important parameters in the theory of confined concrete. On the basis of experimental results, a new term 'ejj4ective confinement index' is introduced. The expressions for increase in maximum stress and the corresponding strain in terms of effective confinement index are given. Theory is developed to obtain the stress-strain curve of total concrete with confined core and unconfined cover. The experimental and analytical stress-strain curves are compared. Also the maximum stresses and the corresponding strains of shell concrete are compared with the results obtained by the theory of Sargin et al.