Seisimic Performence Analysys Of Steel Frame Based On Simplified Therotical Model Of Dutile Connections

Plastic hinge of ductile and energy-dissipated connection can move away from weld zone of beam-column connections under strong earthquake,ductile and energy-dissipated connections have good seismic performance and they are gradually used in engineering field.Ductile connection structures are more complex than traditional connection structures,steel frame entity model with ductile connection is carried out finite element numerical analysis,it will be time-consuming,to improve calculation efficiency and save cost,it is necessary to simplify steel frame model with ductile connection reasonably.To analyze whether it is feasible that simplified model is used to dynamic calculation,simplification of steel frame models are carried out modal analysis and dynamic time-history analysis.Main contents and conclusions are as follows:Firstly,the domestic and foreign relevant norms were chosen as reference,six-layer and twelve-layer steel frames with ductile connections were designed,the ductile connections include reduced beam section connection,cover-plate reinforced connection and arc-type expansion wing connection,the steel frames with common connection were also designed in the same size.Secondly,on the basis of simplified theoretical model of common connection,according to the structure and force factors of ductile connection,simplified theoretical model of ductile connection is designed by introducing spring element,the stiffness formula of spring element in simplified model of ductile connection is derived theoretically,then entity models of interior column connection and exterior column connection in frames are calculated by finite element method,to analyze constitutive relation of connections,to obtain stiffness curve of spring element in panel zone and two flanks,which provide technical support for establishing simplified models subsequently.Thirdly,by using simplified theoretical model of ductile connection to simplify three steel frames with ductile connection,the simplified frame models are carried out modal analysis and elastic-plastic dynamic time-history analysis,for comparison,the actual frame models with ductile connections and actual frame models with common connections are carried out modal analysis and elastic-plastic dynamic time-history analysis,to verify the calculation result of actual frame models with ductile connections,firstly,fundamental period of structures,time-history curve of top column displacement,time-history curve of column bottom shearing force and time-history curve of top column accelerometer are calculated by actual frame models with ductile connections and compared with numerical results of actual frame models with common connections,then numerical calculation results of simplified frame models with ductile connections are compared with actual frame models with ductile connections.Fourthly,the research shows that: based on theory formula of spring stiffness,it can obtain connection spring stiffness accurately and simplified numerical frame models which is consistent with actual stress by using finite element to analyze connection entity models.The results of modal analysis and elastic-plastic dynamic time-history analysis show that the calculation results of simplified numerical frame models with ductile connections and actual numerical frame models with ductile connections are in good agreement,the design of simplified model with ductile connection is reasonable.It has higher computational accuracy when simplified model of ductile connections are applied to dynamic calculation of plane steel frames,it can effectively and rapidly analyze the seismic performance of steel frame structures with ductile connections,and the research results can afford reliable technical service for engineering.