| The application and promotion of prefabricated buildings is an important measure to achieve the goal of " double carbon " in the construction field.The research and development focus of prefabricated construction technology is to propose safe and reliable beam-column connection technology.In the building structure,the beam-column joint is not only the connection hub between the beam and the column,but also the most vulnerable part of the structure.Under the action of earthquake,the failure of joints may lead to the overall instability of the whole frame.Therefore,domestic and foreign scholars have carried out a lot of research on different forms of beam-column assembly construction technology.Among them,the concrete-filled steel tube composite structure has the advantages of both steel structure and concrete structure,and is favored in the assembled building structure.According to the construction requirements of the new talent housing project of Chengdu Habitat Xiangcheng Real Estate,this paper proposes a rectangular steel tube self-compacting concrete column-H-shaped steel beam fabricated joint.The location of plastic hinge under seismic load is transferred by structural measures to protect the joint area from premature failure.Under different axial compression ratios,low-cycle reciprocating tests were carried out on the new assembled joints of rectangular concrete-filled steel tubular columns-Hshaped steel beams to study the failure characteristics and seismic performance of the joints.The main work is as follows:(1)Research on construction technology of assembled joints of rectangular steel tube selfcompacting concrete column-H steel beamBased on the existing research results,the existing construction technology of concrete-filled steel tubular beam-column joints is statistically analyzed,and the structural characteristics,application scope,advantages and disadvantages of concrete-filled steel tubular beamcolumn rigid joints,semi-rigid joints and hinged joints are summarized.According to the design idea of ’ strong joints,weak components ’,combined with the stress analysis of beamcolumn joints and the characteristics of field construction,the assembled joints suitable for rectangular concrete-filled steel tubular columns and H-shaped steel beams are designed by using the measures of inner diaphragm,outer diaphragm,outer rib ring plate and diaphragm penetration,and the assembly and construction methods of the joints are given.(2)Experimental study on seismic performance of rectangular steel tube self-compacting concrete column-H steel beam jointsIn order to study the seismic performance of rectangular steel tube self-compacting concrete column-H-shaped steel beam joints,the quasi-static test of six beam-column joints was carried out with the axial compression ratio,the form of joint welds and whether the reinforcing plate was set locally in the core area of the joints as variables.The failure characteristics of each joint under low cyclic loading under different axial compression ratios were observed,and the seismic parameters such as hysteresis curve,skeleton curve,stiffness degradation,ductility and energy dissipation capacity of each joint were obtained.The results show that the failure does not occur in the joint area,which indicates that the plastic hinge is transferred,thus protecting the joint area.In the case of no cracking of the weld,the weld form has little effect on the seismic performance of the joint.The stiffness and maximum bearing capacity of the joint can be effectively improved by setting the strengthening plate in the core area of the joint.The joint has high ductility,and the difference between the energy dissipation capacity and the steel reinforced concrete joint is very small,which indicates that the seismic performance of the joint is good.(3)Numerical calculation of seismic performance of rectangular steel tube self-compacting concrete column-H steel beam jointsBased on the experimental data,the finite element analysis software ABAQUS was used to simulate the finite element analysis of each node,and the numerical calculation results were compared with the experimental results.It is found that the phenomenon of node failure in the numerical calculation process is basically consistent with the experimental observation results,and the calculated hysteresis curve is in good agreement with the test hysteresis curve.Therefore,the deformation and stress of the joint area under different working conditions are analyzed in detail by numerical calculation. |
