Numerical study on the seismic performance of H-beam to built-in CFRP circular tube CFST column joint with replaceable energy dissipation angle steel

Based on the idea of failure mode control and earthquake resilience, a H-beam to built-in CFRP circular tube CFST column joint with replaceable energy dissipation angle steel was proposed in this paper. The finite element models of the joint were established by ABAQUS software to reveal its working mechanism and seismic performance under low cycle reciprocating load. Based on the analysis of the working mechanism, the effects of angle steel thickness, assembled energy-dissipation beam free deformable length, outer diaphragm thickness, and the number of CFRP layers on the seismic performance of the joint were analyzed. The simulation results indicate that the hysteretic curves of the joint are plump with an equivalent viscous damping coefficient of 0.283-0.362, and the ductility factor of the joint is 3.43-7.17, which proves good seismic performance and deformability. The plastic hinges are also effectively transferred to the assembled energy-dissipation beam. When the joint is damaged, the main structural members are basically in the elastic state except for assembled energy-dissipation beams. This means that the proposed joint can accomplish recoverable seismic performance and controllable failure mode. Furthermore, based on the optimal seismic performance of the joint, it is recommended that the angle steel thickness be taken as 0.8-0.9 times the H-beam flange thickness, the outer diaphragm thickness be taken as 1.5 times the angle steel thickness, the assembled energy-dissipation beam free deformable length be taken as 0.8-1.3 times of the H-beam flange width. The CFRP configuration rate can be designed by the strength and stiffness requirements of the frame column in the structural system.