Seismic Performance Of Steel Frame Of Partial Self-centering Energy Dissipation Bays

To reduce the residual deformation of the traditional steel frame structure under ground motions,implementing energy dissipation bays in the frame structure becomes a feasible design idea.However,the steel frames equipped with perfectly self-centering energy dissipation bays exhibit typical bilinear flag-shaped hysteretic responses,which may be appreciably affected by acceleration.Thus,this paper proposes introducing the super-elastic SMA hybrid self-centering connections into the energy dissipation bays,at the same time a number of normal steel energy dissipation beams are added in energy dissipation bays to enhance the energy dissipation capacity.Therefore,the steel frame structure with partial self-centering energy dissipation bays is developed.Based on the existing experimental results,this paper uses finite element numerical analysis and programming calculation to explore the seismic behavior of the proposed frame structure,and corresponding design recommendations are put forward.The main research contents of this paper are as follows:(1)A simplified modeling method is proposed.The numerical analysis based on the simplified model of the SMA hybrid self-centering connections is carried out by exploring the mechanical behavior of the connections,and the feasibility of the proposed modeling method is confirmed by comparing the calculated results with experimental data.At the same time,compared with the refined modeling results,it is found that the simplified modeling can not only improve the computational efficiency,but also do not reduce the computational accuracy,which is convenient for the structural nonlinear analysis.A simplified calculation model is also proposed for an innovative beam-column self-centering connection with buckling constraints of steel-SMA plate elements.(2)The steel frame structure equipped with partial self-centering energy dissipation bays including SMA hybrid self-centering connections and original steel beam connections is studied by finite element numerical analysis.In order to study frame structures’ seismic performance,based on the Code for Seismic Design of Buildings(GB50011-2010),a steel frame which equipped with partial self-centering energy dissipation bays and a steel frame equipped with perfectly self-centering energy dissipation bays are designed.The corresponding finite element models are set up in ABAQUS.The model analysis,static elastic-plastic analysis and nonlinear dynamic analysis of the frame structure are carried out.The inter-storey drift ratio,residual inter-storey drift ratio and peak acceleration of the structure are examined.The results show that the steel frame equipped with partial self-centering energy dissipation bays have satisfactory self-centering ability and seismic performance.(3)In order to reflect the general rule of the seismic performance of the steel frame structure equipped with partial self-centering energy dissipation bays,the system of equivalent single-degree-of-freedom(SDOF)is used as a tool to calculate the nonlinear responses quantities under 320 ground motions,including maximum displacement,residual deformation and strength reduction factor.The effects of different parameters on the seismic performance of the structure are discussed.The research parameters include: post-yield stiffness ratio(α),energy ratio(β),the fundamental natural period of vibration(T)and ductility coefficient(μ).Derived from the calculation results of the SDOF systems,a set of suitable functional forms for the strength reduction factor are proposed,and the results indicate that the proposed empirical expressions have good accuracy.