Elasto-plastic Earthquake Response Analysis Of Frame-bent Structure

Because of the need of production technology,some factories are composed of frame and bent frame to form frame-bent system.This kind of structure system is complicated,and it has many shortcomings,such as uneven distribution of mass and stiffness,more weak parts and lower safety reserve.In order to better understand the force and deformation performance of frame-bent system,it is of great theoretical significance and engineering application value to study the seismic behavior of frame-bent.According to the requirements of the code for seismic design of our country,the elastic-plastic seismic response analysis of a frame-bent structure is carried out.The dynamic characteristics of the structure,the mechanical behavior of the structure under earthquake and the loading mode of the pushover analysis are studied.The following four research results have been obtained:1)The three-dimensional numerical model of the frame-bent frame was established by SAP2000 program.The modal analysis of the structure shows that it is difficult to reflect the true stress of the structure by using the traditional modal analysis method,and the flat and torsional coupling of the structure or the time-history analysis method should be considered.A reasonable lateral loading mode should be considered.2)Under the action of EL-Centro,Lanzhou 1 and synthetic wave,the elastic-plastic time-history analysis of the frame-bent model is carried out.The results of the deformation ability and interstory displacement angle of the model under the rare earthquake of 8 degrees are studied.the interlayer shear force and plastic hinge distribution show that the deformation curve of the frame-bent structure is neither bending nor shearing.The two-story frame beam and the top column are the weak links of the structure and should be strengthened in design.3)The pushover analysis of frame-bent structures is carried out under two lateral loading conditions:uniform acceleration and mode loading.The results of the model are obtained,such as relationship between base shear force and vertex displacement,floor displacement and interstory displacement angle,etc.The seismic performance of the structure is evaluated by capacity spectrum method.4)By comparing the elasto-plastic time-history and the pushover analysis results,it is shown that the uniform lateral loading mode is not suitable for this kind of frame-bent structure,and can choose the mode of vibration load loading.The results of the deformation and internal force obtained by the pushover method are most enveloped in the time-history analysis,and the average value of dynamic analysis is greater than that of the pushover method.As a result,when selecting the pushover method,it is suggested that a certain coefficient be selected to enlarge the target displacement.