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前燃料工业部电业管理总局东北设计分局于1952—1953年曾设计了东北某地22万伏高压送电线路。在苏联专家维金尼科夫的指导下,由于设计分局和东北电业局同志们的努力.该线路于1954年1月27日胜利地全部建成。由于初次从事这项工作,设计部门缺乏经验,为了验证设计方法是否正确,铁塔工作是否可靠,特于1953年6月间进行了线路中为数最多的直线铁塔的真形实验。铁塔结构是参考苏联酒杯形铁塔型式进行设计的,高25.3公尺。由于该线路所在地区的地形对结构的要求,以及受当时施工条件的限制,因而采用螺栓结构,材料为钢3,四脚分别置于混凝土预制基础上。为了消除试验时基础可能产生位移而影响铁塔的试验结果起见,将基础特别加强。试验按照各种设计的受力情况进行,包括正常情况、事故情况及超荷情况;并将作用于导线及塔身的全部风力以当值风压代替,集中作用于横梁上。用经纬仪在塔的四面测定塔在受外荷作用时的挠曲情况,用千分表(因受当时设备条件的限制)测定主要构件的变形,再由变形推出构件中的应力大小。由于用千分表在高空观测构件的变形极为困难,同时实验前的准备工作亦不足,因而测定主要构件的应力极不准确,只能从塔身的变化结果来判断铁塔的工作。根据测得的塔形变化结果可得下列结论:1)结构受重复荷重时,变形与荷重关系曲线中的剩余变形随荷重次数之增加而减少,即全结构的弹性模数随荷重次数之增加而提高,最后形成封闭环形;2)由变形荷重曲线可见第三点以下的变形稳定较早,可见膈材对结构的变形性质有良好影响。3)由各种实验的变形曲线的规律来看,结构中并无特别弱的局部缺陷部分;4)实测挠度皆比计算值大,特别是初次加荷的情况。因而铁塔结构的强度是安全可靠的,不过挠度和理论计算值相差过大,为了确定原因起见,继续在实验室内进行了螺栓接头的实验研究工作,并得出了螺栓接头的平均弹性模数值。最后建议在进行螺栓结构的挠度计算时,应将各焊件分成接头部分和非接头部分来计算,而整个结构则按照平均折算模数计算。根据螺栓接头的试验结果,按平均折算模数求得的铁塔挠度为:初次受荷时实测值小于计算值,重复受荷时实测值约和计算值相等。据此,足以证明铁塔设计是正确的,结构工作完全安全而可靠。
Former Ministry of Fuel Industry Electric Administration Northeast Design Branch in 1952-1953 had designed a 220,000-volt high-voltage transmission lines in a certain northeast. Under the direction of Soviet expert Vikinnikov, thanks to the efforts of the Design Branch and Comrades of Northeastern Electricity Administration, the line was successfully completed on January 27, 1954. As a result of this work for the first time, the design department lacks experience. In order to verify that the design method is correct and whether the work of the tower is reliable, the true experiment of the most straight line tower was carried out in June 1953. Tower structure is based on the design of the Soviet-style wine glass tower, 25.3 meters high. Due to the structural requirements of the terrain in the area where the line is located and the restrictions imposed by the construction conditions at that time, the bolt structure was adopted and the material was steel 3 and the four legs were respectively placed on the prefabricated concrete foundation. In order to eliminate the test base may produce displacement affect the test results of the tower, the foundation will be particularly strengthened. The test shall be carried out according to the stress conditions of various designs, including the normal conditions, accident conditions and overloading conditions. The entire wind force acting on the conductor and the tower shall be replaced by the on-site wind pressure to concentrate on the beam. The theodolite was used to measure the deflection of the tower under the action of the external load on the four sides of the tower. The deformation of the main component was measured with a dial gauge (limited by the equipment conditions at that time), and then the stress in the component was deduced from the deformation. Because it is very difficult to observe the deformation of the component at high altitudes with the dial gauge and the preparation work before the experiment is insufficient, the stress of the main component is extremely inaccurate. The tower’s operation can only be judged from the change of the tower. The following conclusions can be drawn from the measured tower-shaped changes: 1) When the structure is subjected to repeated loading, the residual deformation in the curve of the deformation and load decreases with the increase of the number of loadings, that is, the elastic modulus of the whole structure increases with the number of loadings And finally form a closed ring. 2) The deformation below the third point shows a stable deformation earlier by the deformation load curve. It can be seen that the diaphragms have a good effect on the deformation properties of the structure. 3) From the laws of the deformation curves of various experiments, there is no particularly weak partial defect in the structure; 4) The measured deflections are all larger than the calculated values, especially the initial loading. Therefore, the strength of the tower structure is safe and reliable, but the deflection and the theoretical difference between the calculated value is too large, in order to determine the reason, continue to experiment in the laboratory bolted joints and obtained the average elastic modulus of the bolt joints value. Finally, it is recommended to calculate the deflection of the bolt structure by dividing each weldment into a joint part and a non-joint part, and the whole structure is calculated according to the average conversion modulus. According to the test results of the bolted joints, the deflection of the tower obtained from the average conversion modulus is: the measured value under the initial load is less than the calculated value, and the measured value is approximately equal to the calculated value under the repeated load. Accordingly, enough to prove that the tower design is correct, structural work completely safe and reliable.