| The tubed steel reinforced concrete structure has high bearing capacity,superior ductility,convenient construction,good deformation resistance and seismic energy dissipation.However,the research focusses more on the mechanical performance of the column and pays little attention to frame joint.The seismic performance of two circular tubed steel RC column to steel beam joint with RC ring beam was carried out in the previous experiments.To popularize this joint,this paper considers the influence of RC slab on seismic performance of this joint and proposes a new type of joint: circular tubed steel RC column steel beam with RC ring beam and RC slab.The main work is as follows:(1)The software ABAQUS was used to simulate and analyze the previous experiment joints,including a circular tubed steel RC column to steel beam joint with RC ring beam and a circular concrete-filled tubular column to steel be am joint with RC slab.The calculation results are compared with experiments to verify the accuracy and reliability of the modeling method.The numerical analysis of the new joint was carried out,and the comparison with the joint without RC slab was made to analyze the influence of the existence of RC slab on the seismic performance of the joint.(2)The parameters of the new joint to explore the influence of the parameters on seismic performance of the new joint were analyzed,the parameters consist of RC slab structural parameters(thickness,width and reinforcement ratio),beam-column stiffness ratio,ring beam width,column axial compression ratio and steel beam flange weakening.The results show that axial pressure ratio,RC slab thickness,ring beam width and beam-column stiffness ratio and have significant effects on the seismic behavior of the joint,while the RC slab reinforcement ratio mainly influences the failure mode of the joint.According to the analysis,the suggested values of each parameter are given in this paper.(3)According to the calculation results.the restoring force model of the joint was established which can accurately reflect the hysteretic behavior of the joint,and provide a reference for the subsequent analysis of the joint.(4)Fit the relational expressions of various parameters on horizontal bearing capacity and flexural bearing capacity,and integrate these relational expressions to obtain the mathematical formulas for the horizontal and flexural bearing capacity of the joint.The formulas are applicable and the difference between the calculation results of the formulas and the results calculated by ABAQUS is less than 5%.The formulas provide a reference for the joint design and engineering practical application. |
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