覆冰导线静张力对输电塔横担的作用特征

为了研究输电塔横担在覆冰导线作用下的受力变形特征,以在冰灾发生时横担严重破坏的某转角耐张塔为对象,按照模型相似理论制作大比例节段模型,进行模拟导线重覆冰状态下的静力加载试验.考虑连接偏心、节点板厚度和螺栓长度等因素对构件传力路径的影响,建立中横担精细化有限元模型,对试验全程进行模拟并与试验对比.在此基础上通过非线性屈曲计算,获得覆冰导线静张力作用下横担的失效模式及薄弱位置.研究表明：横担主材两端螺栓分别连接在角钢的水平肢和竖直肢上会造成构件各个截面应力状态相差很大并使受压构件在局部位置产生受拉区域.对于斜材,连接偏心引起的弯矩和二阶效应不可忽略,且受压斜材是横担的薄弱环节,斜材稳定承载力的不足会导致横担的整体失效．

Study on mechanical features of transmission tower cross arm under static tension of iced conductor

In order to study deformation mechanics and characteristics of cross arm of transmission tower under iced conductor, strain resistant corner tower segmental model with scale of 1∶4 was established on the basis of a typical tower whose cross arm was severely damaged during the ice disaster, and static experiment under tension of iced transmission line was conducted. The finite element model of middle cross arm was founded precisely taking into account the effects of connection eccentric, joint plate and the length of bolts on the force-transfer characteristic of members, then the whole test process was simulated and the results showed good agreements with the experimental value. Based on that, failure mode of cross arm was obtained by using the method of nonlinear bulking analysis. It is found that: at two ends of main member, the connection way of bolts installed in different legs results in the stress of each cross-section varying greatly, and make compression member produce tensile stress in partial location. To diagonal member, the bending moments caused by connection eccentric and second-order effects cant be neglected. Furthermore, the shortage of stable bearing capacity for compression diagonal member is the main reason for failure of cross arm．