【作者】 刘雪松；

【导师】 武振宇；

【作者基本信息】 哈尔滨工业大学 ， 土木工程， 2020， 硕士

【摘要】 输电铁塔的可靠性关系到整个电网的安全,近年来自然灾害频发,输电塔倒塌的事故时有发生,加上部分输电线路改造,一些老旧输电塔已无法满足承载力要求,而将这部分铁塔拆除重建代价高昂,因此寻找行之有效的输电塔加固方法具有重要的意义。在这样的背景下,本课题组提出了一种输电塔原位加固方法,该方法采用套箍箍紧的方式在原杆件上并联一根加固角钢来实现对输电塔的加固,已有研究表明,该加固方法具有显著的加固效果。但与此同时,该方法中原角钢与加固角钢构成的是闭口截面,加固角钢位于原角钢的肢内侧,而原角钢的肢内侧连有较多支撑杆件,为了使加固角钢顺利安装在铁塔上,就需要对加固角钢作开孔处理,这样就会降低该方案的加固效果,因此有必要对开孔后的加固后构件进行研究,以进一步完善这种方案。另外,以往在设计输电塔主杆时,每个节间均按铰支处理,没有考虑相邻节间的影响,实际上主杆破坏时每个节间并不能同时达到极限状态,未达到极限状态的节间就会对达到极限状态的节间提供有利的约束作用,所以规范中的设计方法是偏于安全的,当节间之间的这种约束作用较强时,就应该考虑这种有利的约束作用,以充分利用材料。本文具体研究内容如下:(1)根据已有的试验数据,验证了有限元模型的准确性,并在此基础上分析了输电塔主杆初始荷载对加固效果的影响。(2)根据实际输电塔中可能存在的情况,分析了开孔形状、主杆长细比、荷载偏心距、开孔大小等因素对构件开孔后承载力的影响,在此基础上本文共提出了五种开孔后的补强方案,分析并比较了这五种方案的补强效果,随后针对不同开孔形式和开孔尺寸探究了较为合适的补强方法,最后进行了补强方法的适用性验证。(3)研究了加固前输电塔主杆中的节间相互影响,通过三弯矩方程求解了考虑节间相互影响后的主杆计算长度系数,然后将其拟合成了较为实用的计算公式。(4)在加固前主杆节间相互影响的基础上,分析了加固后的节间相互影响,为输电塔加固的设计与施工提供了一些建议。更多还原

【Abstract】 The reliability of the transmission tower is related to the safety of the power grid.In recent years,natural disasters have occurred frequently,and accidents such as the collapse of transmission towers have occurred from time to time.Coupled with the transformation of some transmission lines,some old transmission tower has been unable to meet the requirements of bearing capacity.However,The dismantling and reconstruction of the tower is costly,so it is of great significance to find an effective method for strengthening the transmission tower.In this context,our research group proposed an in-situ reinforcement method for the transmission tower,which uses a hoop tightening method to connect a reinforcing angle steel in parallel to the original pole.Our studies have shown that the reinforcement method has a significant reinforcement effect.But at the same time,in this method,the original angle steel and the angle steel for reinforcement constitute a closed section.The angle steel for reinforcement is located on the inner side of the leg of the original angle steel,and the inner side of the leg of the original angle steel is connected with many supporting rods.In order to make the angle steel for reinforcement installed on the tower,it is necessary to open a hole on the angle steel,which will reduce the reinforcement effect of the method.So it is necessary to study the reinforcement members after the opening to improve this plan.In addition,in the past,when designing the main pole of a transmission tower,each section was hinged,and the influence of adjacent sections was not considered.In fact,when the main pole is damaged,each section cannot reach the limit state at the same time.The sections that do not reach the limit state will provide favorable restraints for the section that reach the limit state.Therefore,the design method in the standard is biased towards safety.When the restraint between the inter-nodes is strong,this kind of restraint should be considered to make full use of materials.The specific research content of this paper is as follows:(1)Based on the existing test data,the accuracy of the finite element model is verified,and the influence of the initial load of the main pole of the transmission tower on the reinforcement effect is analyzed on this basis.(2)According to the possible conditions in the actual transmission tower,the influence of factors such as the shape of the opening,the slenderness ratio of the main pole,the load eccentricity,and the size of the opening on the bearing capacity of the reinforcement member after the opening is analyzed.On this basis,this paper proposes five strengthening methods after the opening,analyses and compares the strengthening effects of these five methods,and then explores the most suitable strengthening method for different opening forms and opening sizes,and finally verifies the applicability of the strengthening method.(3)The interaction of the sections in the main pole of the transmission tower before reinforcement is studied.The calculated length coefficient after considering the interaction of the sections is obtained through the three-bending moment equation,and then it is fitted into a more practical calculation formula.(4)On the basis of the mutual influence between the main poles before reinforcement,the mutual influence after the reinforcement is analyzed,and suggestions are provided for the design and construction of the transmission tower reinforcement.更多还原