| Diagrid tube structure,which is composed of the level of ring beam and oblique inclined column,is a new structural system.It has many advantages,for example,big lateral stiffness.Now this kind of structures have been used in practice successfully in some part of the place at home and abroad.As a new structural system,compared with the conventional system structure,the outer cylinder structure,the stress mechanism and force transmission path are obviously different.The research on the basic mechanical properties of this type of structure is not mature.Based on the existing research results of the diagrid structure,the shear lag effect and lateral stiffness and the seismic performance of structures were studied.The main research work and results are as follows:(1)By using SAP2000,different geometric parameter diagrid tube structure models were built,and elastic analysis was carried out on these models under the horizontal wind loads.The phenomena and basic characteristics of the shear lag effect of the high-rise diagrid tube structure were introduced.The emergence mechanism of the shear lag effect of the high-rise diagrid tube structure under horizontal loads was studied and the effect was compared with that of a framed tube structure.The influences of angle of inclined column,span-height ratio of ring beam,aspect ratio of the structure,length to width ratio of the structure and existence of corner columns on shear lag effect of the high-rise diagrid tube structure were studied.The results show that the shear lag effect of diagrid tube structure is smaller than that of the framed tube structure.The shear lag ratio at lower layers increases with the increase of the angle of inclined column in optimal lateral stiffness space.When the inclined angle of column is more than about 80°,the shear lag ratio at lower layers increases rapidly with the increase of the angle of inclined column.The shear lag ratio at lower layers increases with the increase of the aspect ratio of the structure,which shows an obvious shear lag effect.(2)The simplified calculation formula of the shear angle and the bending angle of the sub-module of the diagrid tube is derived.The calculating formula of the deformed angle is established.The lateral stiffness and deformation capacity of the structures in the elastic stage are controlled by controlling the deformed angle of the sub-module of the diagrid tube.The influence factors of the lateral stiffness of the diagrid tube structure are analyzed,and the key factors that affect the lateral stiffness of the diagrid tube structure are defined.The results show that both the shear stiffness and the bending stiffness decrease with the increase of the angle of the inclined column.The influence of the change of the angle of the inclined column on deformed angle is obvious.The angle of inclined column is the key factor to affect the lateral stiffness of diagrid tube structure.(3)By using SAP2000,the models of diagrid tube structure with different angles of inclined columns were analyzed with elastic analysis and Pushover analysis methods.The development process of lateral stiffness of the diagrid tube structure was discussed.The plastic development process and the component yield order of the diagrid tube structure were summarized.The yield path of diagrid tube structure was clear.The influence of the span-height ratio of main ring beam on the structure stiffness and plastic development process of the diagrid tube structure was analyzed.Meanwhile,the influence of the compression performance of inclined column on the ductility of diagrid tube structure was analyzed.The results show that the ductility of high-rise diagrid tube structure is poor and the degradations of stiffness and strength are not obvious.Enhancing the compression performance of the section of inclined column can improve the ductility of the structure obviously.And the span-height ratio of main ring beam has little effect on the development process of the lateral stiffness for the diagrid tube structure. |
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