| At present,the steel-concrete composite structure is widely used in high-rise and super high-rise buildings in China due to its unique advantages.The steel tube constrained steel concrete column combines the characteristics of steel reinforced concrete columns and concrete filled steel tube columns.It has been widely studied and applied due to its superior seismic performance,good fire resistance and convenient construction.However,the research on axial compression performance of steel tubular confined steel concrete column mainly focused on the mechanical behavior of the columns,while the influence of joints on the axial compression performance of specimens is not studied systematically.Based on the research results of the steel-reinforced concrete and the concrete-filled steel tubular beam-column joints,In this paper,two kinds of space cross-shaped steel beam-circular tubed steel reinforced concrete beam-columns joints are designed.Axial compression tests of two kinds of joint specimens were carried out.On the basis of the test,the axial compression performance is analyzed by using finite element method.The specific work contents are as follows:(1)According to relevant building and construction codes,one steel beam RC ring beam joint specimen,two steel beam ring plate joint specimen and one comparison short column specimen were designed and processed,and the axial compression test was carried out.The test preparation,test process and test phenomenon,failure characteristics,load-axial displacement curve,load-lateral displacement curve,load-strain curve and other test results were analyzed and explained in detail.(2)On the basis of the test,the finite element analysis software ABAQUS was used to simulate the test specimens,and compared the load-axial displacement curve,failure mode and others with the test results.Based on the comparative analysis,the model and relevant parameters were determined.The influences of steel pipe diameter-thickness ratio,steel ratio of section steel,concrete strength,width of ring beam,ratio of ring beam reinforcement,width of ring plate,thickness of ring plate and spacing of ring plate on axial compression performance of specimens were analyzed by using finite element software.(3)The calculation formula of existing axial bearing capacity of confined concrete filled steel tube is summarized.The variation law of circumferential stress of steel tube is analyzed combining the results of finite element calculation.Some design and construction requirements are suggested according to the finite element results and relevant specifications,and the axial bearing capacity calculation formula of steel beam-circular tubed steel reinforcedconcrete columns joint are proposed.The calculated results are in good agreement with the finite element and test results and can be used in subsequent studies. |
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