| Earthquake is an extremely common disaster which poses a serious threat to human beings.Steel,as a green material,is increasingly used in construction.Under the requirement of urbanization,irregular steel structure buildings are emerging.Due to the characteristics of irregular steel structures themselves,their seismic response is often very complex.Therefore,it is necessary to study the seismic performance of irregular steel structures.In this paper,we focus on the seismic response of an irregular steel structure,and apply SAP2000 finite element software to establish models,which are Model I(original structure without additional bracing),Model II(structure with additional X-shaped bracing),Model III(structure with additional inverted V-shaped bracing)and Model IV(structure with additional single diagonal rod-shaped bracing).The seismic performance of these four model structures was analyzed to derive the effects of different bracing types and arrangement locations on the stability of the structures.The main research contents and conclusions are as follows.(1)This paper first introduces the concepts related to earthquake damage and causes,irregular structures,and steel structures,followed by an overview of the seismic theory of structures,and then three methods commonly used in seismic analysis.(2)Through modal analysis,the period and vibration data of the structure can be obtained.Compared with model one of the original structure,the X-shaped brace,inverted V-shaped brace,and single diagonal rod brace reduce the period by 38.06%,35.13%,and28.00%,respectively.After the addition of supports,the period of the original structure decreased,and the X-shaped supports reduced the period most significantly.The two-way response spectrum analysis shows that the floor displacements and interstory displacement angles in both X-direction and Y-direction have been reduced,and the values of displacements and displacement angles are minimized in both directions with the X-shaped bracing.It indicates that the bracing can improve the seismic performance,and the X-shaped bracing is the best among the three kinds of bracing.(3)The linear time analysis shows that the displacements and displacement angles of the original structure are significantly reduced after the additional bracing,and the seismic performance of the original structure model is the worst among the four models.In the ElCentro wave,the additional X-shaped bracing has the best effect on the reduction of the displacement and displacement angle of the original structure,which significantly improves the seismic performance of the structure.Under the action of Taft and Tangshan waves,the X-shaped brace is the best in the X-direction;the single diagonal rod-shaped brace is the best in the Y-direction.Then the nonlinear time-time analysis was performed for each of the four structural models,and the results were basically consistent with the linear time-time analysis.(4)To investigate the influence of the arrangement position of the brace on the seismic performance of the structure,the brace position was changed from being arranged at both ends to being arranged in the middle.SAP2000 software was applied to establish the structural models,which were model V(structure with X-shaped brace in the middle arrangement),model VI(structure with inverted V-shaped brace in the middle arrangement)and model VII(structure with single diagonal rod-shaped brace in the middle arrangement).The analysis results are compared with models II,III and IV.Under El-Centro wave,the Xshaped brace has the most significant seismic enhancement to the structure and is better arranged in the middle.Under Taft wave,the best arrangement is to arrange X-shaped brace in X-direction(middle arrangement)and single diagonal bar-shaped brace in Y-direction(both ends arrangement).Under Tangshan wave,the best arrangement in X direction and Y direction is to arrange X-shaped support and inverted V-shaped support respectively,and the best position in both directions is in the middle.The different types of bracing and the location of bracing arrangement have an impact on the seismic performance,and the degree of impact is different.In the actual project,the type and location of bracing should be selected reasonably,so as to increase the seismic capacity of the structure more effectively and reduce the damage to the building structure caused by the earthquake.Figure: [64] table:[56] reference:[47]... |
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