Experimental Study On Seismic Behavior Of Prefabricated Steel Reinforced Concrete Joint Combined By Steel Sleeve

In recent years,China's urbanization construction process has been speeding up,the country has vigorously promoted the industrialization of construction,and realized the transformation and upgrading of the construction industry.Fabricated concrete structures have begun to be widely used in housing structures.In this context,many scholars have carried out in-depth research on fabricated concrete structures,and the seismic performance of beam-column joints in fabricated frame structures has become a research hot spot for scholars.Based on the existing research results,a new type of Prefabricated Steel Reinforced Concrete joint combined by Steel Sleeve is proposed in this paper.The core area module of this joint is a cross-shaped joint steel sleeve welded by steel plates,and external steel sleeves are set at the beam end and column end of the box-type node domain,respectively.The prefabricated beam and column modules are connected to the external steel sleeve of the joint by welding embedded parts and grouting,which realizes the seismic design concept of 'strong joints,weak members'.In this paper,the seismic performance of Prefabricated Steel Reinforced Concrete joint combined by Steel Sleeve is studied.The main work and research results obtained in this paper are as follows:(1)In this paper,five test specimens are designed and subjected to low reversed cyclic loading test.The test parameters include the reinforcement ratio of the precast beam and the length of the steel sleeve at the end of the beam.This paper observes the test process and failure mode,analyzes the seismic performance indicators including bearing capacity,stiffness degradation,energy dissipation capacity,and ductility of each joint under low reversed cyclic load,and studies the influence of each parameter on the seismic performance of the joint.The results show that the plastic hinge is located at the edge of the steel sleeve extension at the end of the beam.This joint has higher bearing capacity and better energy consumption capacity,its strength and stiffness are steadily degraded,and its ductility is average.Properly increasing the reinforcement ratio of the prefabricated beam can increase the bearing capacity of the joint and improve the seismic resistance of the joint.Within the range of test,increasing the length of the steel sleeve at the end of the joint beam,the bearing capacity of the joint is slightly increased,the energy consumption performance is improved,the ductility coefficient has decreased;(2)In this paper,the ABAQUS finite element software is used to simulate the mechanical properties of the joint.On the basis of determining the element type,mesh accuracy,material constitutive and boundary conditions,it has established a finite element model.The simulated ultimate load and skeleton curve are consistent with the test results.This paper combines the finite element analysis and experimental results to clarify the failure modes of the joints.(3)On the basis of verifying the accuracy of the test results,this paper expands and analyzes the parameters of the joints.The results show that increasing the reinforcement ratio of prefabricated beams and concrete strength can significantly improve the bearing capacity of the joints,while strengthening the strength of the joint steel plate has almost no effect on the mechanical properties of the joint;(4)This paper uses ABAQUS finite element software to establish a finite element model of a reinforced concrete frame structure,and studies its failure morphology and mechanical properties.The simulation results show that the plastic hinge of the new type composite frame is located at the edge of the steel sleeve extension at the end of the beam and the bottom of the lowest column,which has higher bearing capacity and better bearing capacity retention performance.