Research on Seismic Performance of Eccentric Beam–Column Joint Retrofitted with CFRP–Steel Plate

Abstract

A new retrofitting technique of CFRP–steel plate was proposed to retrofit the eccentric beam–column joint without sufficient transverse stirrups in the joint panel zone. Four specimens were fabricated with different retrofit techniques. The seismic performance of aforementioned specimens was studied through low-frequency reciprocating cycle load tests. Research shows that the yielding carrying capacity is increased by 24.35–47.65%, while the maximum carrying capacity is increased by 30.65–55.37% for the retrofitted specimen. Besides, the ultimate carrying capacity of the specimen retrofitted with CFRP, steel plate and CFRP–steel plate is increased by 32.26%, 41.08% and 58.41%, respectively. The displacement ductility coefficient of the retrofitted specimen is increased by 12.09–33.02%. The cumulative energy-dissipation capacity of the specimens is sequentially determined by specimen retrofitted with CFRP–steel plate, specimen retrofitted with steel plate, specimen retrofitted with CFRP sheet and specimen without retrofitting. The stiffness of the retrofitted specimen is greater than that of the specimen without retrofitting. The stiffness degradation rate of the specimen without retrofitting is greater than that of the retrofitted specimen. In general, the retrofit effect of steel plate on the eccentric beam–column joint is better than that of CFRP sheet, while the retrofit effect of CFRP–steel plate on the eccentric beam–column joint is most obvious. The calculation method of the shear carrying capacity of retrofitted eccentric beam–column joint was proposed. Comparison results show that the proposed calculation method can effectively predict the shear carrying capacity of retrofitted eccentric beam–column joint.