Elastic Stability Analysis Of Two Layers Of Different Cross Section Column

Steel structure building is a new kind of energy conservation and environmental protection building system, it was hailed as the new "green building" of the century. With the development of China’s economy and science and technology, more and more steel structure building began to appear in our country. In the design of steel structure, stable design is very important, the steel structure before buckling deformation usually is very small, almost imperceptible, are very dangerous. Therefore, the stability of the steel structure calculation should cause enough attention.Most countries including China have adopted calculation length coefficient method in calculating the stability problems of steel structure, China’s "code for design of steel structure" in the form D-l and D-2do not apply to all situations encountered in engineering, such as the two layers column structure system, methods are given by "standard" was not considering the interaction between the upper and the lower column. So this paper studied and deduced the calculation length coefficient deeply without side sway two layers of different cross section column, And calculated the drawing chart which can quickly determine the effective length. Use this diagram can not only quickly and accurately determine the two layers column effective length, but also can see the change trend of effective length.In order to verify the correctness of the method in this paper, citing actual examples, this paper also uses the finite element analysis software ANSYS as a further verification. In order to test and verify the correctness of this chart method. According to the method of this paper compared with the calculated by using ANSYS to calculate the results.In this paper, considering the mutual influence between the up column and down, also consider the influence of other factors on the effective length. In a sense can be said to be Added to the "standard". In this paper, calculation method and chart is an effective and convenient method to solve the effective length.