The Whole Stability Research Of The Mid-hollow Steel-Tube Structure With Stiffening Ring

The mid-hollow steel-tube structure is different with the common tube structure. The structure is composed of many columns connected by members, which form circle-shape, to resist the level and the vertical load. It has a big clear space in its lower structure. The structure has the characteristics of the high height-diameter ratio, the same diameter from bottom to top, large space in its lower part and the equipments on the upper part of the structure. It is widely used in the field of Civil Engineering and the most typical example is the prilling tower structure. Because its lower structure has a big clearance request, the normal rigidity of the tower is weak. Setting the lateral bracing, like tabula, is not suited to the lower structure, so stability becomes the key problem of the calculation in this construction . Stiffening rings are adopted to improve the stability of the structure in this thesis.Although the stiffening ring has been used in some projects in China and abroad, as well as in the astronautics, the steamboat, the machinery and so on, it is different with the stiffening ring which is used in the mid-hollow steel-tube structure. It is essential to understand correctly the performance of the structure and the optimum position of the stiffening ring, there is few literature about it at present .Thus, it is very significant to study the quantity and the position of the stiffening ring for saving investment and enhancing economic benfit and have the theoretical significance to the analysis of similar structures.This thesis takes the actual project as the background and the three-dimensional model is established by ANSYS. It is studied the influence of the stiffening ring to the overall performance in the mid-hollow steel-tube structure, and develops following investigation:First, the thesis proposes the principles and the methods about the position of the stiffening ring, then analyzes the structural bearing, considered invariable loads and wind loads, and egien buckling. The contrastive analysis is carried out through establishing the stiffening ring or not, different the stiffening rings' setting about the position, quantity and rigidity. The influence to dynamic property, the displacement of the top floor, and buckling load are studied. At last, the rational suggestion values are proposed.Second, nonlinear buckling analysis of the whole mid-hollow steel-tube structure that sets up the stiffening rings or not is carried out. The influence of the quantity and position of stiffening rings to the ultimate bearing capacity is anlysized.Third, based on the research achievent, the author puts forward the problems to further study.