Experimental Study on Concrete Cylinders Confined with Various FRP under Uniaxial Compression

Abstract

External confinement of concrete by means of FRP composites can significantly enhance its strength and ductility as well as result in large energy absorption capacity. The present paper focuses on studying the behavior of concrete cylinders confined with hybrid FRP composites. A total of thirty 150 mm by 300 mm cylinders were tested, which included 3 plain concrete specimens, 12 concrete cylinders confined with one kind of FRP, and 20 specimens confined with hybrid FRP sheets. Experimental parameters included the different types of FRP sheets, different hybrid ratio of FRP. The relationships of axial stress-axial strain of FRP-confined concrete are studied, as well as the variation of Poisson's ratio of FRP confined concrete. Behaviors of concrete cylinders confined with hybrid FRP and counterpart specimens confined with one kind of FRP sheet are compared. Finally, some equations are proposed to evaluate the ultimate strength and strain of concrete cylinders confined with hybrid FRP. This paper provides a framework for better understanding of confining effects of concrete cylinders confined with different FRP composites.