Research On Seismic Performance Of Steel Frame Considering The Performance Of The Joint

As a new joint,the joint which links the circle hollow section column and H steel beam is widely used in multistory and high-raised steel buildings and special steel structures.The type of joint is welded and the structure is comparatively complex.So series of problems seriously affect the seismic behavior in the region of the joint,and then threaten the seismic behavior of steel frame structures,such as stress concentration,asymmetric distribution of stress,and so on.Extensive studies show that the behaviors of beam-column connection have great effects on the seismic performance of steel frames during the earthquake,which indicates that it is of great significance and engineering benefit to investigate the seismic performance of steel frame structures that are affected by the behaviors of the joints that connecting the beam and the column.The influence of the behaviors of beam-column connection on the seismic performance of steel frame structures is primarily studied in this thesis,which provides theoretical basis and reference for the seismic design of steel frame structures.Main contents are as following:Through the finite element nonlinear analysis for the mechanical behaviors of the circle hollow section column and H-beam with exterior diaphragms,the influence of different parameters on flexural capacity and shear capacity of the connection can be obtained,and the parameters includes:the thickness of the steel tubular column,the width and the thickness of beam flange,the thickness and height of beam web,the width of outer ring,the axial compression ratio of tube column.The data were analyzed by the regression analysis,consequently the bearing capacity evaluation formula and the rigidity evaluation formula of beam-column connection can be obtained.The test selected the joints connecting the circular hollow section column and the H-beam with exterior diaphragms as the specimen.The simulating models of the joints are founded by OpenSees including rigid joint,Joint2D-1SPR element based on the joint shear deformation,Joint2D-5SPR element based on the joint shear deformation and semi-rigid connections,the model of the joint is analyzed by finite element software.The numerical results show that,the hysteretic curves of numerical simulation are in good agreement with experimental results,the validity and the rationality of the bearing capacity formulas can be verified,the results of Joint2D-5SPR fit the experimental results well in shape.The static pushover analysis and dynamic time-history analysis were carried out on a six-floor plane steel frame with three spans.Reactions of steel frames with three joint models under the rare earthquake were respectively compared.It can be concluded that,the assumption not considering the behaviors of joints will overestimate the structural lateral displacement capacity when the whole structure is studied through the elastic plastic analysis.To make the results more reasonable,it is necessary to take the joint model into consideration.