Study On Seismic Behavior Of New Type Of Plug-in Assembly Concrete Beam-to-column Connection

In building industrialization,prefabricated concrete structures have been focused at home and abroad owing to economic,efficient,environmental and other advantages.Among them,fabricated concrete frame system is one of the most widely used in prefabricated structural system,which has high prefabrication rate and flexible layout of building space.The prefabrication of components is the main feature of prefabricated concrete frame system.The connection modes of the nodes greatly affect the overall performance and construction efficiency of the frame structure.Therefore,it is the key of large-scale popularization of prefabricated concrete frame structure to develop a joint form with good performance and easy assembly.This paper proposes a new type of plug-in assembly concrete beam-column connection based on the combined steel and concrete structure.The use of embedded steel members and high-strength screws to achieve the connection of precast beams and columns.First,a pseudo-static test study was performed to compare this new type of joint with the cast-in-place concrete joint.The low-cycle reciprocating load was used to study the failure form,hysteresis performance,skeleton curve,energy consumption capacity,Response characteristics such as stiffness degradation and strain.The test results showed that the mechanical properties of the plug-in joint were related to the embedded depth of the steel in the beam,which was mainly affected by the bond slip between the steel and the concrete.In the case of good bonding,the bearing capacity of the joint was significantly improved compared to the cast-in-place joint.Due to the limited combination effect of the splicing area,the energy consumption capacity and initial stiffness of this type of assembly node were slightly lower than the cast-in-place node.Then through ABAQUS finite element analysis software,the numerical simulation analysis of the plug-in assembly connection was performed.The difference between the response characteristics of the nodes obtained by numerical simulation and the test results was compared,and the stress variation law of the embedded members in the prefabricated beam and column was described in detail.Finally,static push-over analysis was performed on the cast-in-place frame and fabricated frame using SAP2000 software.The base shear-vertex displacement curves of the two frame structures under different loading modes were compared and analyzed,and the performance points of the two frames under different seismic levels were obtained.The results showed that the performance points of the fabricated frame were within the target performance range,and the failure of the frame belongs to the beam hinge failure mechanism,which meets the performance requirements of "strong nodes".It was proved that this type of assembly frame can basically meet the requirements of seismic performance.The research results of this paper provide a certain reference for the development of prefabricated concrete frame joints and the research on the mechanical properties of steel-concrete composite joints.