| Concrete filled steel tube(CFST)has the advantages of high bearing capacity,strong fire resistance,easy construction and cost saving,so it is more and more used in practical construction engineering.Because of the vast area,complex terrain and more frequent earthquakes in China,it is necessary to popularize the composite structure of concrete filled steel tube,so it needs to have deep seismic performance.Yes,but there are still many shortcomings in the study of its seismic performance.Therefore,studying its overall seismic performance is of great theoretical significance and engineering application value.In this paper,a 24 story L shaped plane irregular square steel tube concrete composite frame structure is selected as the engineering background.The project is derived from an engineering example of a commercial center building in Xi'an,and the three-dimensional finite element analysis model of the structure is established based on the finite element software SAP2000.At the same time,the composite frame structure of the square steel tube concrete column type steel beam is established according to the equivalent stiffness principle.The three-dimensional finite element analysis model of the corresponding circular concrete-filled steel tube composite frame structure is made,and the aseismic performance of the concrete filled steel tube composite structure is investigated by the analysis of the seismic performance of the two structures.In the future,the use of cross section can be more reasonable for the use of space,and it has a reference value for the seismic design of irregular plane concrete filled steel tube structure.The innovation of this paper is to analyze the elastoplastic analysis on the basis of the previous study cases combined with the actual engineering background.Two,by taking the actual project as a case,through the finite element analysis software SAP2000,two simplified models of steel pipe cross sections are created respectively,and then they are compared and analyzed.And the model of this paper is L shaped irregular plane,supplemented to the steel pipe mixing.The frame form of the study of the seismic performance of the soil.In this paper,the present situation,results and application of a series of research on concrete filled steel tube composite structure system at home and abroad are summarized.Then,the constitutive relation of steel and concrete in concrete filled steel tube is introduced.Then,the two kind of concrete filled steel tube mixed structure model of the finite element software SAP2000 is used to analyze the two model structures first and obtain their periodic and vibration modes.Then,on the basis of modal analysis,the displacement and shear of the twostructures are investigated by the mode decomposition response spectrum analysis,and the two structures are compared and compared with the results of the modal analysis.Then the displacement and shear of the two structures under multiple earthquakes are investigated by the elastic time history analysis,and the comparative analysis is made.After seismic response analysis,elastic-plastic time history analysis of two structures under rare earthquakes is carried out,and their seismic performance under large earthquakes is compared.Through the analysis of the two models in this paper,we can see that the seismic responses of the two different cross section models have little difference in the multiple and rare earthquake.Compared with the reinforced concrete side stiffness,the seismic performance of the two structures is better. |
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