Research On Seismic Performance Of Special-Shaped Concrete-Filled Stell Tubular Column Frame Structure With Two-Yielding Bucking-Restrained Barces

Since the country began to promote the industrialisation of construction,with the increasing rise of steel-assembled buildings,the steel pipe and concrete shaped column combination structural system has been widely used in village buildings,however,the lateral stiffness of this structural system is small,and the horizontal displacement and inter-storey shear force generated under the action of earthquake loads in high intensity zones is large,so adding bracing to the structure can improve its lateral stiffness resistance,but the traditional anti-buckling restrained bracing has the problem of non-dissipation under multiple encounters with earthquakes.In order to further promote the future use of shaped steel tube concrete column structural systems in village housing projects in high intensity zones in Yunnan,this paper provides an in-depth study of the energy dissipation performance of the new anti-buckling restrained bracing in the combined steel tube concrete shaped column structural system,and proposes a reasonable design method for improving the energy dissipation of anti-buckling restrained bracing.The main contents are as follows.(1)In this paper,a new type of anti-buckling brace with two-stage energy dissipation characteristics is designed,and theoretical analysis and ABAQUS finite element parametric analysis are carried out for it.In addition,the key factors affecting the hysteresis performance of the TYBRB are analysed and reasonable suggested values for the preliminary design of the TYBRB are given.The results of the numerical analysis show that the theoretical equations derived in this paper are highly accurate,fit well with the theoretical model results and have a full hysteresis curve,high ductility and good seismic performance.(2)Based on the above analysis results,a finite element model of a 3-storey,2-span,3-open frame with steel pipe and concrete shaped columns was established using SAP2000 finite element software.The seismic performance of the two structural systems under multiple and rare earthquakes was compared.The TYBRB system has a significant reduction in inter-storey displacements and inter-storey shear forces compared with the normal steel tubular concrete shaped column system.Under the action of rare earthquakes,TYBRB in the TYBRB-pipe and concrete shaped column system plays the role of second-stage yielding energy dissipation,and the energy consumed accounts for a larger proportion of the seismic input energy,and plays a good energy dissipation performance,compared with the ordinary steel pipe and concrete shaped column structure,this structural system has a large degree of reduction in inter-storey displacement and inter-storey shear,and the plastic hinge only appears in some beam ends This shows that the seismic performance of the new buckling-proof braced steel pipe and concrete composite frame structure is significantly better than that of the original structure.The performance points of the two structural systems under rare earthquakes were obtained by pushover analysis,and the distribution of plastic hinges in the two structural systems was clarified and compared to obtain the seismic performance of the two structural solutions under rare earthquakes.The elastoplastic analysis reveals that a large number of plastic hinges appear in the beams and columns of the steel tube concrete shaped column frame structure,and the overall structural damage is more serious.In contrast to the TYBRB-steel and concrete shaped column system,only some of the beam ends show plastic hinges under rare earthquakes,and the overall structure is in a safe condition.