Influence of Different Confinement Patterns on the Axial Behavior of R/CColumns

摘要

This paper studies the axial behavior of reinforced concrete columns using a newrnconfinement technique that the first author has developed. Two opposing spiralsrn(cross spirals) are used to confine reinforced concrete circular columns in order tornenhance their strength and ductility or to increase the spiral spacing (pitch) tornfacilitate the flow of concrete during construction. The influence of the newrnconfinement technique on the axial strength and ductility of reinforced concreterncircular columns is experimentally investigated and compared to columns confinedrnwith conventional single spiral. Ten small-scale reinforced concrete circular columnsrnconfined with different spiral patterns were constructed and tested subjected tornconcentric axial compressive loading. The axial force, axial displacement and strainsrnin the concrete and confining and longitudinal reinforcement were measured duringrnthe testing. This study showed that columns confined with two opposing spiralsrnbehaved almost similar to columns confined with single spiral when same amount ofrnconfining reinforcement is used. The study also showed that the new confinementrntechnique could significantly improve the axial strength and ductility of circularrncolumns without hindering the flow of concrete during construction.