Seismic performance of end plate connection joint between I-beam and square steel tube column reinforced by casing tube

In this paper, the end plate connection joint between the I-beam and square steel tube column reinforced by the casing tube was designed. The failure mode, energy dissipation capacity, initial rotational stiffness, stiffness degradation, strength degradation, ductility index, and shearing deformation of the specimen were obtained. The results show that the seismic performance of T-shaped joints is better than that of cross-shaped joints. The failure modes of T-shaped joints are buckling of web and flange, while the column flange of cross-shaped joints is concave, and the end plate is warped. The weld quality between the casing and column directly affects the performance of the joint. All specimens in this paper are semi-rigid joints. The end plate thickness has a significant impact on the seismic performance of the joint. With the increase of the end plate thickness, the energy dissipation capacity of the joint increases. The initial rotational stiffness of the specimen is not only related to the end plate thickness, but also affected by the bolt diameter. The initial rotational stiffness of the joint can be significantly improved by increasing the end plate thickness and the bolt diameter. The finite element analysis shows that the seismic performance of the joint is affected by the end plate thickness and the bolt diameter, but it is less affected by the bolt diameter. The increase of end plate thickness can improve the seismic performance of the joint, but the continuous increase has little effect on the performance. The seismic performance of the joint increases with the increase of casing thickness. When the wall thickness exceeds 5 mm, the casing thickness has little influence on the joint performance.