| RCS composite structure is a new type of structure system,which is composed of reinforced concrete columns and steel beams.It can give full play to the material advantages of concrete and steel,which has the characteristics of high economy and fast construction efficiency,and at the same time,is a kind of low cost and high efficiency structure.At present,scholars at home and abroad have done some research on RCS composite frames and joints,which indicates that the structure has good seismic performance and is suitable for high intensity fortification areas and high-rise buildings.However,there is no systematic normative provisions based on the current research status.Therefore,it is necessary to further study the mechanical and seismic properties of RCS composite structures.In order to study the seismic performance of RCS composite joints,this paper takes the steel girders plug-in RCS composite joints as the prototype in the "Meizhou World Merchants and Culture Center" project.And the low frequency cyclic loading has been studied by designing a similar form of side joint specimen.At the same time,the hysteretic curve,skeleton curve,plasticity,energy consumption,stiffness,bearing capacity degradation and other seismic performance indexes are studied.Combined with ABAQUS finite element software,the variables of six parameters are analyzed,and the influence of these factors on the seismic performance of joints is also researched.The main results of this paper are as follows:(1)The plastic joint failure of steel beam occurs under the frequency cyclic loading on RCS composite joint specimen.According to the seismic conceptual design principle of "strong column and weak beam",the hysteretic curve of the specimen is full,and the equivalent viscous damping coefficient is higher than that of the general reinforced concrete joint,which shows good plasticity and energy dissipation capacity.The other analysis indexes also reflect the good seismic performance of the joint.(2)The ABAQUS finite element analysis model of RCS composite joints under the low frequency cyclic loading is established.The model takes into account the nonlinear material and the contact between steel beams and concrete.The numerical simulation is carried out by using the parameters consistent with the experimental conditions.After comparing the calculated results with the experimental results,it is verified that the finite element model has better reliability.(3)Six parameters affecting the seismic performance of joints are studied and compared by using the verified finite element model,including the insertion length of steel beam,the width of end plate of steel beam,the height of steel beam,the axial compression ratio,the hoop ratio of joint and the structure of bearing plate.The hysteretic curves,joint ductility and stress changes of different models are compared and analyzed,and the optimal value of each parameter is provided,which offers a reference for joint design. |
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