Seismic Performance Research On 3D Joints Of Composite CFST Column And Steel Beam

With the continuous development of high-rise and long-span architecture,the ordinary reinforced concrete structure already cannot satisfy the development of construction market.The appearance of concrete filled steel tube structure can improve the bearing capacity of the component.When the structure have higher request for load bearing,blindly increase the thickness of steel tube will bring the inequality problem of steel radial stress distribution.Composite concrete filled steel tube(CFST)column is placed steel in steel tube,which can reduce the area of column and improve the bearing components.At present,the domestic research on joint of CFST is based on the plane joint and the study of space joint which is rarely reported in abroad was rare.In practical engineering,according to the joint of different position can be divided into interior joint,exterior joint and corner joint.The ground motion and structural dynamic response is multi-dimensional.The beam-column joints are affected by the two directions of beam of bending moment,shear force and torque.Space joint showed more complex mechanical properties.In this paper,the software ABAQUS was used to establish the 29 joints space model and a plane joint,which were used to analysis the seismic performance of spatial joints.The main content of this paper includes the following several aspects:This paper expounds the research status of CFST column.The concrete beam and steel beam of 3D joint researches are reviewed.The CFST column and steel beam space joint was put forward.On the basis of related literature material and specification,the reasonable size and model simulation load amplitude tables needed for the seismic effect were designed.The finite element simulation software ABAQUS was used to establish the 3D joints to analysis.Reasonable choice material constitutive relationship,setting the contact relationship and mesh etc.,were used to ensure the validity and rationality of the modeling.The author studied the axial compression ratio,reinforcement ring size,steel beam web thickness,load system,and so on to analysis the seismic performance of spatial joints.The results show that the CFST column and steel beam space joint has a good seismic performance.The highest capacity when the axial compression ratio is 0.3.But the bearing capacity of the joint under axial compression ratio is not very big difference,which showed that the node can shaft under high pressure and had plastic good performance.With the increase of axial compression ratio,the node energy efficiency and accumulation showed a trend of decrease after the first increase energy consumption.The bigger the ring width and beam web thickness,the higher bearing capacity of the joints,when the stiffness degradation was slow.The thicker the steel tube walls the higher of the bearing capacity.But the bearing capacity of the joints will into the steady stage instead of rising after reaching the effective thickness.Edge joint has poor seismic performance which caused by loading the Asymmetric load.Compared with the plane loading system,the bearing capacity of the joint under space loading system has fallen by 23.36%,when seismic performance and accumulated energy dissipation are significantly reduced.The last,on the basis of numerical simulation and theoretical analysis,a space joint three line skeleton model was established,on which the shear restoring force model and hysteresis rule of the 3D joint of CFST column and steel beam were put forward.