The Analytical Analysis Of Internal Forces Of The Steel Helix Stair

The staircase is one of the most functional elements in modern building, is the most common and most closely building components contacting with the man. The structure of the steel helix stair is light; its section is distinctly less than that of the concrete helix stair; it is light and beautiful seen in the appearance. Those good characters are attached importance to people.The steel helix stair has been applied in structural engineering, but its theoretical analysis and design method were less studied. And there are not the design methods and corresponding regulations in the design criterions. So the theoretical analysis and design method of the steel helix stair are of great significance.The steel helix stair fixed at both ends has been studied, according to the theory of the thin-walled structures and the basic theory of the force method in structural mechanics, and making some reasonable assumptions, the theorety analytical model of the steel helix stairs is built, the calculation formulas of the internal force are derived, and then the program is compiled to calculate the internal forces of arbitrary cross section. This method's results, with the calculation results of the same model built in ANSYS finite element software, are compared to demonstrate that the datas of the internal forces have a high degree of accuracy. By the way of adjusting the height, width, inner radius, thickness of ring beam of the steel helix stairs, the variation of the internal forces is studied systemically, and the factors that infect the force performance of the steel helix stairs are analyzed. Basing on the large amount of the calculated datas, the recursive analysis is done, and the relationships between the maximum of vertical shear and torque with the various factors are gained, at the same time, the formulas of the various geometric parameters on the maximum of the internal forces are given. These afford academic warrant and design method to engineers.