Research On Shear Behavior Of Exterior-Diaphragm Connection Between Concrete-Filled Rectangular Tubular Column And H-Shaped Steel Beam

Exterior-diaphragm connection between Concrete-Filled Rectangular Tubular(CFRT)Column and H-shaped Steel Beam has been recommended in technical specification for structures with concrete-filled rectangular steel tube members and has been widely used in practical engineering.The failure mode of most relevant researches is plastic hinges on the beam ends or failure of weld,while there is only a few of experimental study of shear failure mode in the panel zone.This paper summarizes the research status of the exterior-diaphragm connection at home and abroad,and clarifies the existing problems about the exterior-diaphragm connection.A combination of experimental and theoretical analysis has been used to study the shear behavior of the panel zone of the connection in shear failure mode.Four exterior-diaphragm connections are studied by low frequency cyclic loading test.According to the test results,the failure characteristics of each specimen are introduced.The influence of the thickness of the steel tube of the panel zone,the width of the external stiffening ring and the axial compression ratio on the bearing capacity of the connection have been analyzed.According to the load-displacement curve of the test,the seismic performance of the connection is analyzed.Through the concrete cutting test,the width of compression area of core concrete is determined.The mechanical mechanism of panel zone has been analyzed in this paper.The existing calculation methods for shear bearing capacity of panel zone are introduced and its deficiency is mentioned as well.Based on experimental results,the computing model of the steel tube webs of the panel zone,the steel tube flange of the panel zone,the concrete of the panel zone and the external stiffening ring are established for shear bearing capacity calculating.A new calculation method for shear bearing capacity of panel zone based on superposition theory was presented.Comparison analysis indicates that calculating results agree well with experimental results.Combined with experimental research and finite element analysis,the deformation mechanism of the joint is investigated.Then,the rotation model of the connection with external stiffening ring is established and the calculation method of the elastic rotation stiffness in the panel zone is proposed.In this paper,the calculation method of shear strength and elastic rotation stiffness of exterior-diaphragm connection can provide a reference for its design in engineering application.