中文摘要：

选用实际工程中常用的2种不同类型的输电铁塔，首先计算它们的动力特性，分析了影响动力特性的主要因素。根据简化抗震计算方法．分别研究了硬、中硬和软弱3类场地土条件下它们在侧向、纵向振动情形时的塑性极限状态，其中每类场地土选用2条地震波，每条地震波都通过调整加速度峰值的方法探讨输电铁塔的非线性行为以及塑性极限状态。分析结果表明，作为高耸结构的输电铁塔，塔架的主材和附材抗弯线刚度比值，塔架的根开尺寸对动力特性有较大影响，产生塑性应变的杆件集中于塔架的下部，且作为悬臂部分的横担在地震作用下也发生了塑性变形。

英文摘要：

The dynamic characters of two different kinds of towers were calculated. The influencing factors of their dynamic characters were discussed subsequently. Based on the simplified method of aseismic calculation, for the sock, medium, solid site, tow transmission towers were calculated with two different pieces of seismic records. In order to ascertain the plastic limit under in-plane and out-of-plane vibration, the peak values of the seismic records were scaled up and down until solution was not converged. In the end, the nonlinear behaviors and plastic limit of transmission towers in different vibration directions subjected to earthquake action were summarized. And the results show that the flexural rigidity ratio between the main leg and bracing component has a great influence on the dynamic characters of the tower. The study reveals that a lot of components, which located in the lower of the transmission tower, have plastic deformations when the tower reaches in critical state.