Analysis On The Effect Of Vertical Earthquake Action On Mega Column Frame-Core Tube Structure

In recent years, a large number of super tall buildings are constructed with the rapid development of Chinese economy and the improvement of national comprehensive strength. The structure of mega column frame-core tube with outrigger truss is widely used by existing super tall buildings, which has favorable applicability,economy and seismic performance. But there are still many problems to be further studied for the seismic performance. There is little information of researching on the effect of vertical earthquake on the mega column frame-core tube structure. So this thesis mainly research on this area to provide a theoretical basis for that structural system in the seismic design.In this thesis, the mega column frame-core tube structure is studied, that structure model is built by using SAP2000 software. The structure is researched by analysis of natural vibration characteristics, response spectrum analysis and elastic time history analysis. The responses of the structure subjected to horizontal(bi-directional) earthquake action, horizontal and vertical(three-directional)earthquake action and vertical earthquake action are obtained by response spectrum analysis and elastic time history analysis. The bi-directional earthquake response and three-directional earthquake response are compared and analyzed. The changes of base shear, story displacement, axial force of mega column, midspan moment of girder in the frame, axial force of belt truss, axial force of outrigger truss are obtained when there is vertical earthquake acting on the structure. The vertical earthquake response and bi-directional horizontal earthquake response were compared, and getting the proportion of internal force of the structure under vertical earthquake action to the horizontal earthquake action.The effect of internal force and deformation of the mega column frame-core tube structure due to vertical earthquake action was summarized by comparing the results obtained from the response spectrum analysis and the elastic time history analysis.Based on the overall analysis of the structure, the finite element model of mega column was established by ABAQUS software, and the nonlinear analysis was carried out. The load-deformation curve, stress distribution and failure modes of the mega column under axial load are studied. And the stress state of the mega column is analyzed under the rare earthquake action.