| Concrete filled steel tubular column-steel beam structure system has many advantages,such as high bearing capacity,good seismic performance,easy standardization of components and convenient construction.It has been widely used in prefabricated structures.The existing beam-column joints are mainly welded and stud-welded hybrid connections,such as internal diaphragm joints,diaphragm through joints,end-plate joints,etc.Based on the existing research,this paper proposes an assembled blind joint.In order to clarify the influence of axial compression ratio,concrete strength,the number of blind bolts,sleeve thickness and sleeve height on the bearing capacity and seismic performance of the joint,the three-dimensional nonlinear finite element model of the joint was established by using ABAQUS finite element software,the static performance and seismic performance of the joint were simulated and analyzed,and the results were compared with those of the recommended joint in the specification.The results show that:（1）The static performance analysis of the joint shows that the bearing capacity and ductility of the joint decrease with the increase of axial compression ratio.Filling concrete in steel tube can effectively improve the stiffness of joints,but the change of concrete strength in steel tube has little effect on the bearing capacity and ductility of joints.The increase in the number of blind hole bolts and the height of sleeve has little effect on the bearing capacity of joints,but the ductility of joints decreases with the increase in the number of blind hole bolts,and the increase in the height of sleeve increases the ductility of joints.The thickness of sleeve has little effect on bearing capacity and ductility.（2）It can be seen from the seismic performance analysis of joints that under seismic action,the ductility of joints decreases with the increase of axial compression ratio.The elastic limit inter-story drift angle and elastic-plastic limit inter-story drift angle of the joint meet the specification requirements,and the joint has good deformation ability and seismic performance.The parametric analysis shows that the bearing capacity,ductility and seismic energy dissipation capacity of joints gradually decrease with the increase of axial compression ratio.Concrete filled steel tube effectively increases the stiffness of joints,but the change of concrete strength in steel tube has little effect on the seismic performance of joints.The increase in the number of bolt connections between the column and the sleeve blind hole makes the stiffness degradation rate of the joint faster and the ductility of the joint reduced.The increase of sleeve height has little effect on the bearing capacity and seismic energy dissipation capacity of the joint,but the ductility of the joint is significantly improved,and the stiffness degradation rate of the joint is significantly slowed down.The increase of sleeve thickness has little effect on seismic performance.（3）Compared with the seismic performance of the fabricated blind bolted joint and the《Technical specification for joint in rectangular concrete-filled steel tubular structures》recommended joint,the results show that the fabricated blind bolted joint has good bearing capacity.Comparative analysis of seismic indicators such as energy dissipation capacity,ductility and stiffness degradation between the proposed joint and the standard recommended joint shows that the proposed joint has good seismic performance. |
