Study On Seismic Performance Of Prefabricated Concrete-filled Steel Tubular Frames With Infill Walls

The prefabricated building structure has the advantages of good quality,short production cycle,high construction efficiency,energy saving and environmental protection,and low labor intensity,which meets the development needs of construction industrialization 4.0 under my country’s "double carbon" target policy.The concretefilled steel tubular frame-shear wall structure system composed of concrete-filled steel tubular columns(CFST),steel beams and reinforced concrete shear walls has high bearing capacity,high lateral stiffness,good ductility and strong energy dissipation capacity,widely used in engineering.However,the current construction method of CFST frame-shear wall structure mainly adopts the form of cast-in-place structure,and the assembly design of the combined shear wall structure system is conducive to the wider application of this type of structure and promotes the transformation of the industrialization of the construction industry upgrade.The key to the cooperative work of prefabricated shear walls and concrete-filled steel tube frames lies in a reasonable connection structure.Based on the dry connection method of prefabricated structures,this paper designs a CFST frame-shear wall structure system with reliable connections and easy assembly,and develops carried out the following research work:(1)In order to realize the frame-shear wall structure assembly,the CFST frameshear wall structure is designed.The CFST frame and the shear wall are connected by high-strength bolts through pre-embedded connectors.Based on the finite element ABAQUS software,reasonable materials are selected constitutive model,contact mode between components,loading method and boundary conditions,establish refined numerical models of cast-in-place shear walls,prefabricated shear walls and CFST frame composite shear walls with frame,and conduct low-cycle reciprocating load analysis.The rationality of the modeling method is verified by comparative analysis with the results and phenomena of the existing test pieces,and the refined numerical modeling process of CFST frame-shear wall is introduced in detail.(2)Based on the CFST frame-shear wall refinement model,compare and analyze the hysteretic performance of the prefabricated structure and the cast-in-place structure,and study the failure state,hysteretic curve,skeleton curve,ductility and energy dissipation performance of the prefabricated structure.Comprehensive evaluation of the mechanical performance of the assembled structure.The results show that the failure mode of the prefabricated structure and the cast-in-place structure is shear baroclinic failure,the load-displacement hysteresis curve is "full without pinching",and the displacement ductility coefficient is greater than 5;compared with the prefabricated structure,the cast-in-place structure has The initial stiffness is increased by 18.76%,the ultimate bearing capacity is increased by 19.67%,and it has stronger energy dissipation capacity.(3)Parameter expansion analyzes the effects of frame column axial compression ratio,prefabricated wall horizontally distributed reinforcement ratio,floor thickness,steel strength,and the number of vertical joint T-shaped steel connectors on the hysteretic performance of prefabricated CFST frame-shear wall structures Influence law,compare and analyze the load-displacement hysteretic curve,skeleton curve and seismic performance index of the structure under different parameters,and give a reasonable range of parameter values.(4)Based on the calculation formula of the shear capacity of the cast-in-place CFST frame-shear wall structure,considering the positive impact of the seam steel connectors on the shear capacity of the structure,a correction factor β is introduced to give a new type of fabricated CFST frame-shear wall.The simplified calculation formula for the shear bearing capacity of the force wall structure,the theoretical calculation and the finite element results are in good agreement,and the error is within10%,and the design method and construction requirements for the connection between the frame column and the prefabricated shear wall are proposed.