Behavior of high performance concrete externally confined by composite shells

摘要

This paper presents an experimental study about the compressive behavior of concrete columns externally confined by carbon and glass FRP shell. The influences of different parameters were studied such as the confinement level, the shell characteristics and the compressive strength of the concrete core. The results show that external confinement permits to significantly enhance the ultimate strength and ductility of the specimens. The stress-strain curves of confined concrete are bilinear: in the first part, the behavior is similar to that of unconfined concrete whereas the second part, plastic, mainly depends on shell mechanical properties. The shell stiffness determines the curvature of the transition zone and the slope of the plastic branch while its ultimate strength determines the ultimate strengths and strains of confined concrete. Also, is shown an important increase of the confinement efficiency with the compressive strength of the concrete core.