Study On Seismic Behavior Of Corrugated Steel Web-encased Concrete Composite Beam To Corrugated Plate-square Concrete

Corrugated steel plate has the advantages of strong shear resistance,high lateral stiffness and low steel consumption.The research group proposed a new type of encased corrugated steel-concrete composite beam and corrugated STEEL-CONCRETE-FILLED steel tubular column,but the joint connection form between this type of composite beam and this type of column has not been studied.Therefore,this paper proposes a new type of encased corrugated steel-concrete composite beam and corrugated STEEL-CONCRETE-FILLED steel tubular column joint（CSW joint for short）.The CSW node is studied through three methods:experimental research,finite element analysis and theoretical analysis.The main research contents are as follows:（1）Design CSW side joints and conduct low-cycle reciprocating tests to analyze the seismic performance of CSW side joints such as failure mode,hysteretic curve,skeleton curve,ductility,energy consumption,steel strain,etc.The results show that: the CSW side joint is bending failure of the plastic hinge area at the beam end,the hysteretic curve is full,and the seismic performance is good,which satisfies the design requirements of "strong column,weak beam,strong joint and weak member".The results show that the interlayer displacement of the joints is mainly caused by the elastic deformation of the beams,the plastic deformation of the beams,the elastic deformation of the columns and the shear deformation of the joints,among them,the interlayer displacement caused by the plastic deformation of the beams accounts for a relatively large proportion.and that caused by the shear deformation of joints accounts for a relatively small proportion;（2）The finite element software ABAQUS is used to simulate the CSW side joint,and the finite element results fit well with the test results.On this basis,the bearing capacity,stiffness and other seismic performance of CSW side joint are analyzed with the parameters of axial compression ratio,thickness of lower flange plate,thickness of corrugated steel plate and stiffness ratio of beam to column.The results show that the thickness of the lower flange of the beam have a greater influence on the bearing capacity and stiffness of the joint,the thickness of the corrugated steel plate of the beam have a limited influence on the bearing capacity and stiffness of the joint,the axial compression ratio has a little influence on the bearing capacity and stiffness of the joint.The beam-to-column linear stiffness ratio increases from 0.75 to 0.81,the load-bearing capacity and energy dissipation capacity of the joint are improved,and the failure mode of the specimen gradually changes from the bending failure of the beam end to the shear failure of the joint;（3）Design the CSW mid-joint and conduct low-cycle reciprocating test to study the failure mode,hysteretic curve,skeleton curve,ductility,energy consumption,stiffness degradation,strength degradation and steel strain of the CSW mid-joint.The results show that the mode of CSW mid-joint is bending failure in the plastic hinge area of the beam end,the joint hysteresis curve is full and the seismic performance is good;（4）ABAQUS is used to simulate the CSW mid-joint,the inite element results fit well with the test.By changing the beam-column linear stiffness ratio,a model based on the shear failure of the core area of the joint is established,and the factors affecting the the bearing capacity of the simplified model are analyzed.The results show that the strength grade of the steel,the wall thickness of the steel pipe and the axial compression ratio have a greater influence on the bearing capacity of the simplified model.When the strength grade of large cavity concrete and the thickness of the steel pipe are small,the thickness of the tension plate in the core area of the joint has a limited effect on the bearing capacity of the;the strength grade of small cavity concrete has almost no impacton the bearing capacity of the simplified model;（5）In this paper,through in-depth analysis of the stress and strain of steel and concrete in the core area of the joint in CSW the force transmission path and force mechanism of each component in the core area of the joint are clarified,the shear mechanics model of the core area of the joint is proposed.The formula of shear bearing capacity of the core area of the joint is put forward.The formula calculation results are in good agreement with the finite element calculation results.