Compressive behavior of FRP-confined steel-reinforced high strength concrete columns

摘要

Few studies have prospectively examined the axial compressive behavior of FRP-confined steel-reinforced concrete (FCSRC) columns employing high strength concrete (HSC) with a compressive cylinder strength up to 120 MPa. In FCSRC columns, the encased steel sections would ensure a ductile response under the large axial deformation and provide additionally axial and shear load-carrying capacities. Therefore, the FCSRC column with HSC is a promising type of hybrid structural element that enables effective utilization of both HSC and high-performance FRP. In this study, a comprehensive experimental study has been conducted to evaluate the compressive performance of FCSRC columns with HSC, considering the effects of steel section shape and thickness of FRP tube. For comparison purpose, the compressive behaviors of FCSRC columns using normal strength concrete (NSC), concrete-filled FRP tubes (CFFTs), and steel-reinforced concrete (SRC) columns were also investigated. The load and deformation capacities, dilation behaviors, failure modes and failure mechanism, composite effect between constituent materials, and enhancement effect of FRP confinement on SRC columns were discussed in this paper. This study revealed that the use of HSC produced higher axial stiffness as well as higher axial compressive capacity for the FCSRC columns, although the deformation capacity was reduced as compared to the use of NSC.