The Theoretical Analysis,Experimental Researches And Applications Of Membrane Effect Of Steel And Stayed Column

With the development of modern Science and Technology, steel structure with large span and exceedingly thin roof is turning into possibility, in the field of civil engineering. In this dissertation, two new steel structure technologies in the aspects of membrane effect of steel and stayed column is researched and discussed.Membrane effect of steel is evolved from the technology of stressed skin in steel structure, of which the characteristic is the sufficient utilization of the effect of tensility-resistance and shear-resistance in the plane. With reliable connections, the steel with membrane effect can be used in an actual structure, and when it is concerned with the structure to bear the load jointly, the capability of the structure can be improved. As one kind of modern prestressed steel structure, stayed column has its own work feature: with the second spring supports provided by several tensional cables through the stay bars or brace, it can enhance its own carrying capacity of stability. Based on those previous research results, the theoretical analysis, experimental researches and application practice are carried out in this dissertation. The contents include as follows:The author put forward the conception of membrane effect of steel, so that the meaning of the technology of stressed skin in steel structure is expanded.On the basis of elastic mechanics theory of membrane, with the theory of finite element, the analyses theory of the structure involved membrane effect of steel is constituted; the displacement, internal force and self-vibration periods of the structure involved membrane effect of steel are contrasted those ones of the primary structure. And the calculating formula on the connections of the membrane and the structure is also proposed.As to stayed column, its two conformation shapes——inside staying and outside staying are proposed, and their definitions and conformation details are respectively expounded. Starting off with the idea of two-phase-action analysis, the author gives the calculation theory and method on stayed column which bears self-prestress and load at different phases, deduces the formula of initial tension of the cable and the formula of carrying capacity of stability of stayed column, on these bases furthermore, proposes the design method and steps on stayed column. In addition, the details design on some vital nodes on stayed column is showed in sequence.From the model experiments, the displacement and internal force of the structure can be reduced because of the membrane effect of steel, and in the case of slender column, the carrying capacity of stability and the mechanics performance of which put up their more advantages when compared with the column without special measures and the CFT column in the same section, when the modern technology of stayed column is applied on it.The above theories are used to complete the theoretical analyses and design researches on the steel structure of the practice of Nanjing New Library, in which square-steel-tube truss at exceeding span- height ratio and slender column at exceeding slenderness ratio are involved, as well as the validity of these results is demonstrated through model experiments.