中文摘要：

输电铁塔通常被简化成桁架结构并采用线弹性和小变形分析方法进行设计，而特高压输电铁塔结构柔度大、负载高、杆件连接复杂，若仍按线弹性分析不能准确反映其真实的受力情况。采用有限元分析方法建立铁塔空间梁杆混合模型，单元模型中考虑几何非线性和材料非线性的双重影响，并与在设计荷载下的真型塔试验对比验证了模型的正确性。分析结果表明，按线弹性和小变形法设计的特高压输电铁塔安全裕度过大、浪费材料，应考虑几何非线性、材料非线性及端弯矩对结构受力性能的影响。最后对铁塔主材的应力计算及次应力分布特点进行分析，为评估特高压输电塔的承载力提供参考设计建议。

英文摘要：

Transmission towers are traditionally idealized for space truss whose members are assumed to be axially loaded and stress calculations are obtained from a linear elastic and small-displacement analysis. In practice, such conditions do not exist, especially for UHV transmission tower whose structure is flexible, high-loaded and connection is complex. A beam-line model based on finite element theory is built, with both geometrical nonlinearity and material nonlinearity considered in the model. The method has been calibrated with results from full-scale tower tests with good accuracy in terms of the design load. The results show that UHV transmission tower designed according to the current theory has large safety margin, and geometrical nonlinearity material nonlinearity and bending moment should also be considered in analysis. So the, stress calculation method and secondary stress distribution of primary member is studied, and the method can be employed to assess the strength of UHV transmission tower and strengthen the existing towers.