Research On Seismic Performance Of New Prefabricated Steel-reinforced Concrete Composite Columns

Prefabricated steel reinforcement concrete frame structure has been widely used due to advantages such as easy quality control,high assembly efficiency,reduced labor cost and sustainable development.As an important part of the whole structure,to study the seismic behavior of prefabricated SRC composite columns under pseudo-static load is necessary.In order to improve the connection structure of precast SRC column connection area,a new column-to-column dry connection method for precast SRC column was proposed in this paper,and three new precast SRC composite columns were tested by pseudo-static loading.The failure modes,hysteresis curves,skeleton curves,stiffness degradation,ductility and energy dissipation properties of the specimens were obtained.Based on the experimental results,the test specimens were analyzed and calculated by the ABAQUS nonlinear finite element software,and the results of the finite element simulation were compared with the experimental results for verification.On this basis,the finite element model with 13 different parameter variables was established by ABAQUS,and the influence laws of axial compression ratio,position and height of connecting module,thickness of cover plate and stiffening plate on the seismic performance were studied.The main research results as follows:(1)New prefabricated steel reinforced concrete composite column specimens under low cycle reciprocating horizontal loading failure pattern is mainly by the stiffening plate buckling deformation,the connection at the end of the plate and the cover plate of the buckling deformation,the connection at the end of the board and the joint surface between the concrete cracking,square steel tube at the bottom of the corner of the weld crack,at the bottom of the stiffening plate and cover plate connection weld fracture cause;The hysteresis curves of all specimens are relatively full,and the stiffness degradation is gentle.When the specimen finally fails,the ultimate displacement Angle is between 1/18～1/11,the displacement ductility coefficient is between 3.04～4.11,and the equivalent viscous damping coefficient is between0.19～0.23,showing excellent plastic deformation ability and energy dissipation ability.(2)Through nonlinear finite element software ABAQUS to establish a new type of prefabricated steel reinforced concrete composite column refinement model,the calculated under low cycle reciprocating horizontal load of the final failure pattern,hysteresis curve,skeleton curve and stiffness degradation curve largely consistent with the test experimental data and verify the elaborating the feasibility and the rationality of the finite element model is built in this paper,Furthermore,that can lay a foundation for the finite element parameter analysis of the new precast SRC composite column under low cyclic horizontal load.(3)The seismic performance of a new precast SRC composite column was analyzed by ABAQUS.The results show that with the increase of axial compression ratio,the horizontal bearing capacity,stiffness and energy dissipation capacity of the model all increase correspondingly,but the ductility becomes worse,and the stiffness degrades relatively quickly in the late loading period.When the height of the connecting module is increased,the horizontal bearing capacity,stiffness and energy dissipation capacity of the model are greatly increased,but the plastic deformation capacity decreases,and the stiffness degradation is more obvious in the later loading process.With the increase of cover plate thickness,the horizontal bearing capacity,stiffness,ductility and energy dissipation capacity of the model increase,while the stiffness degradation rate is basically the same.With the stiffening plate thickness increasing,the horizontal bearing capacity and stiffness of the models are improved,and the energy dissipation capacity and stiffness degradation rate among the models have no significant difference,but the ductility decreases.