The Study Of Analytical Methods On Static Force And Dynamic Characteristic Of Polygonal Section High-Rise Steel Tower Structure

Based on mathematical model with continuous technique in this paper, the polygonal section high-rise steel tower is simplified as a cantilever beam with variable stiffness, and each floor's equivalent bending and shearing stiffness are derived. In structural static force analysis, three analytical methods are introduced. They are Galerkin method, decomposed rigidities energy variational method and floor element method. The former two methods all make use of continuous function of structural equivalent bending and shearing stiffness that varies with height. The lateral displacement of cantilever beam is composed of lateral displacement aroused by bending deformation and lateral displacement aroused by shearing deformation. These two methods have the advantage of computational simplicity. The third method is that the structure is regarded as a cantilever beam with variable stiffness, too. Then each floor that is divided by traverse bracing is regarded as beam element with two nodes and four degrees of freedom in view of beam-action shear. The element rigidity matrix is derived by making use of spline function and solved equivalent stiffness. The method makes highly less degrees of freedom of structure than of general finite element method. Therefore, it is simple, effective and accurate. In structural dynamic characteristic analysis, centralized mass method and floor element method are proposed, and its computational process is simple. Finally,the present methods in the paper and ANSYS software are used to calculate the concrete example of high-rise steel tower structure and these results are compared and analyzed. It is shown that the present methods are simple and meet engineering precision. Hence, those methods that are put forward in the paper are economical and effective.