Research On Restoring Force Model And Shear Bearing Capacity Of SRC Column-Steel Beam Composite Joints

Steel Reinforced Concrete(SRC)is an overall structure formed by using steel as the basic skeleton,arranging steel bars around the steel and pouring concrete on the outside.It has the advantages of short construction period,strong bearing capacity,large stiffness and significant economic benefits.The SRC column-steel beam frame structure is a common form of high-rise composite frame structure formed on the basis of SRC components.And Now it has been widely used in high-rise and super-high-rise structures due to its convenient construction performance and good seismic capability.In this paper,through the research on the restoring force model of the SRC column-steel beam composite joints and the finite element analysis software ABAQUS,the shear bearing capacity of the SRC column-steel beam composite joints and the SRC column-steel beam composite joints with floor is studied.And the following work is completed.(1)Based on the completed low-cycle repeated loading experiment of SRC column-steel beam composite joints and SRC column-steel beam composite joints with floor,finite element models of the SRC column-steel beam composite joints are established using finite element analysis software ABAQUS.The numerical simulation of the finite element models under low-cycle repeated load is carried out and compared with the completed test results.The test results are consistent with the simulation results.(2)The skeleton curve is extracted from the hysteresis curve obtained from the low-cycle repeated loading test of the 4 SRC column-steel beam composite joints and the 2 SRC column-steel beam composite joints with floor.On this basis,dimensionless and fitting into a trilinear model are carried out to determine the stiffness degradation law of each stage of loading and unloading.Finally,the calculated skeleton curve is obtained according to the established restoring force model,and compared with the experimental results.The results show that the simulated skeleton curve can better reflect the hysteretic behavior of the specimen,and the established restoring force model can be used as a reference for the elastoplastic seismic response analysis of the steel reinforced concrete column-steel beam joints.(3)Through the low-cycle repeated loading test of 4 SRC column-steel beam composite joints and 2 SRC column-steel beam composite joints with floor,the corresponding calculation model is obtained,and the shear bearing capacity test value is obtained through calculation.Then the corresponding calculated values of shear bearing capacity are obtained through the shear bearing capacity formulas in different regulations at home and abroad.Finally,the test values are compared with the calculated values.The calculation formulas of shear bearing capacity in various regulations at home and abroad are analyzed on the basis of the results.According to the results of the comparison,the floor influence coefficient is proposed.Through the finite element software ABAQUS,30 SRC column-steel beam composite joint models considering different floor thicknesses and widths are established,and their shear bearing capacity calculation values are obtained.Through the linear fitting of SPSS software,the relationship between the floor influence coefficient and the floor width and thickness is obtained.Finally,the shear bearing capacity formula proposed by the JGJ regulations is improved and verified.