Experimental study on seismic performance of RC beam- CFST column joint combination using ECC

This paper experimentally investigates the effects of engineered cementitious composite (ECC) replacing normal concrete (NC), stirrup ratio and shear span ratio on the seismic performance of exterior beam-column combination specimens. In this study, six beam-column combinations were designed and fabricated, and the concrete-filled steel tube (CFST)column and RC beam were connected by the bar sleeve-corbel method. While ECC replaced the NC at the beam ends and joint core zone to improve the seismic performance of the specimens. The damage process, hysteresis behavior, intensity attenuation, stiffness degradation, energy dissipation capacity, and deformation capacity were all considered while analyzing the seismic performance of the test specimens. The experiments show that the sleeve-corbel connection is safe and reliable, and the failure position of the six specimens are all located on the beam, realising the outward movement of plastic hinge region, which satisfies the "strong column but weak beam" and "strong connection but weak component" design criteria. After the peak load, compared with the NC specimen, the ECC specimens showed a slower decline in bearing capacity, higher ductility and energy dissipation capacity, and a higher percentage of beam bending deformation, indicating that ECC replacing NC can significantly improve the seismic performance of the specimens. Furthermore, the specimens with lower stirrup ratios and smaller shear span ratios demonstrate good deformation and energy dissipation capacity when using ECC.