Seismic Performance And Design Method Of Self-centering Concrete-filled Steel Tube Column Hybrid Frame

With the rapid development of prefabricated buildings in our country,the prefabricated steel pipe irregular column structure has received increasing attention as one of the technical routes.However,this structure generally faces problems such as difficulty in post-earthquake repairs,which seriously restricts its widespread application.Therefore,this paper proposes a Self-centering Concrete-Filled Steel Tube Column Hybrid Frame structure to improve its seismic performance and reduce beamcolumn damage.The self-centering steel pipe irregular column hybrid frame structure mainly includes three parts: self-centering steel pipe irregular column frame,wooden shear wall,and variable friction damper.The self-centering steel pipe irregular column frame is composed of prefabricated steel pipe irregular columns and steel beams,which are connected by post-tensioned high-strength steel strands,providing overall structural resetting ability.The variable friction damper is responsible for system energy dissipation and serves as a connecting component between the frame and the wall.The lightweight wooden shear wall and the self-centering frame work together to resist lateral forces.Through reasonable design,the proposed self-centering steel pipe irregular column hybrid frame in this paper can achieve multi-stage performance advantages after an earthquake and has a wide range of engineering application backgrounds.This paper conducts a systematic study of the seismic performance of the selfcentering steel tube-shaped column frame structure system through theoretical derivation and finite element analysis,with the main content as follows:(1)By conducting a rational analysis of the deformation mechanism and stress performance of the self-centering steel tube-shaped column hybrid frame,the ideal response of the hybrid frame was studied and a simplified moment-rotation hysteretic model of the node was established.Based on the aforementioned stress analysis model,the calculation formulas for axial force and shear force under two stress states of the connection interface were proposed,laying the foundation for subsequent numerical simulation and design methods.(2)Based on the Open SEES platform,a numerical analysis model of the selfcentering steel tube-shaped column hybrid frame was first established.The friction dampers in the hybrid frame were redeveloped using C++ language and their accuracy was verified in the software.Then,the seismic performance of the hybrid frame was analyzed through low-cycle reciprocating loading,and the hysteretic curve,skeleton curve,residual deformation curve,cumulative energy dissipation curve,and stress change curve of the prestressed steel strands were analyzed.Based on this,the effects of changing the initial stress level of the prestressed steel strands,the sliding distance of the friction device,and its starting sliding force on the seismic performance of the hybrid frame were analyzed.At the same time,through a comparative analysis of the calculation results of the self-centering steel tube-shaped column hybrid frame and the traditional steel frame model,the advantages of the hybrid frame structure in seismic performance were further verified.(3)Based on the analysis of finite element calculation results,a performancebased seismic design method for the self-centering steel tube-shaped column hybrid frame structure was proposed.Firstly,the performance-based design objectives of the hybrid frame structure under different seismic fortification requirements were put forward.Then,a performance-based seismic design method to achieve the objectives was established,mainly including node bearing capacity design,internal beam prestressed steel design,friction device design,and lightweight wood shear wall.Finally,design suggestions and construction measures for the self-centering steel tubeshaped column hybrid frame structure were proposed.