Non-Linear Analysis And Design Application Of The Asymmetric Steel Tower Structure

The asymmetric steel tower structure is in common use recently. This structure has large height-to-width ratio and little lateral-resist rigidity, so it will undertake large non-linear effects under the lateral load. However research was mainly focus on guyed mast structure and truss tower which is usually used in TV tower. The asymmetric spatial member steel tower structure is analyzed without more information to use for reference. The paper studied this structure of its nonlinear response and design application as well. A new model is formulated for geometric nonlinear analysis: EEP element on the basis of PEP element. The model can describe the effect of two-direction bend and torsion. Compared with the other model, the EEP element is identified to be more accurate. Many nonlinear factors will influence the limit carrying capacity of a structure. In this paper, the two factors: semi-rigid connection and initial imperfection of the structure are stressed. The stiffness formula that can consider semi-rigid connection and geometric non-linearity is got. An imperfect EEP element model is formulated by using the principle of stationary total potential energy, for simulating directly the effects of imperfection on structures and stiffness. The prescripts and demands for non-linear analysis of many countries are also summarized in this paper. The paper provided typical examples to explain the disadvantage effects when the high-rise steel tower structures are asymmetric. The results make clear that asymmetry brings more nonlinear effects to the structures. Some design advice is provided due to the asymmetric steel tower structures. Brace system is one of the important methods to improve the lateral-resist ability of structures. The effects of the brace are also clarified by examples. The brace design suggestions are offered. In the end, the nonlinear analysis program: NIDA is used to research the nonlinear effect of the Nanjing Olympic View tower. The result testified the design.