Experimental and Numerical Investigation on the Cyclic Behavior of SRC Columns considering Unsymmetrical Confinement Effect

Abstract

Experimental and numerical studies were conducted on the cyclic behavior of steel reinforced concrete (SRC) columns with T-shaped and L-shaped steel section. A total of 8 SRC columns were tested under axial compression and lateral cyclic loading. The design details, loading procedure and main results, including the failure modes, hysteretic characteristics and ductility were reported. Four failure modes as flexural failure, shear bond failure, shear compression failure and shear compound failure were observed. By considering various unsymmetrical confinement and plastic hinge region, the experimental study was supplemented by numerical analysis to study the influence of axial compression ratio, shear-span ratio and concrete strength. The results revealed that the FEA is in good agreement with the experimental results. The ultimate loading of specimen with confinement effect has been improved by 21.4%–33.8%. The failure modes is dominated by the shear-span ratio and type of cross section. The specimens with smaller shear-span ratio are prone to shear failure, while the unsymmetrical steel arrangement causes shear compound failure which is combined with shear bond failure and shear compression failure. Moreover, the specimens with larger shear-span ratio and stirrup ratio present greater deformation capacity and ductility. In practical engineering, the confinement degree of SRC columns with unsymmetrical steel section can be enhanced by increasing the stirrup ratio and arranging the cross ties.