Seismic Analysis Of Irregular Structures

With the development of society, the building of the irregular structure is increasing day by day, this often gives engineers a design problem. Previous earthquakes shows that, the irregular structure is especially serious in the earthquake action, therefore, it is necessary to analyze the seismic analysis of irregular structure.Body shape is irregular, including vertical irregular and irregular plane, in the irregular plane, designers generally through establishing seismic joints divide the irregular structure into the plane combination of relative rules. In this paper, the model based on the planar irregular annular teaching building, through the establishment of seismic joints, three modeling schemes are obtained, the three analysis models of the three schemes are circular, L- shaped and one- shaped, three models are used to analyze the vibration mode decomposition response spectrum analysis under small earthquake, the elastic dynamic analysis and the static elastic-plastic analysis under rare earthquake, and the calculation of each model are compared, the aim is to have a deeper understanding of this kind of building structure and provides theoretical basis for further design work.This paper first introduces the relevant provisions of the irregular structure,then introduces the theory and method of structural seismic analysis, in this paper, the method of static elastic plastic analysis is emphatically introduced. In the contents of the third chapter, the YJK software is used to analyze the vibration mode decomposition response spectrum and elastic dynamic analysis of three models.Specific to the cycle ratio, the layer displacement angle, layer shear and structural member internal forces of the structural model were compared, it is concluded that the torsion effect is more significant for the ring building with the division of the seismic joints.Under the action of rare earthquake, using push-over of Midas/Gen analysis performance points, base shear- peak displacement curve, inter layer drift angle,shear layer and distribution of plastic hinges, for the circular building, with the division of the seismic joints, the lateral stiffness of the structure is gradually reduced.It is also concluded that the bottom column and the beam on the inside of the modelneed to be strengthened; for the model two and the model three with the seismic joints,end of components in structure and bottom column need to be strengthened and other conclusion.