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一、问题提出在预应力电杆的生产过程中,为克服预应力值的不均匀性,本省大多在梢端采用芯棒式张拉头靠外锥形螺帽在张拉时定位。此工艺均能达到设计要求而沿用多年。然而,此工艺在张拉时,芯棒式张拉头靠模体内圆主正而必须进入杆模内,造成电杆长度不足,缩短90～120毫米,而整根锥形杆的长度与变截面有关,故又涉及到金具尺寸的使用与配合。特别是预备孔有相当部分是由梢端起步定位,因而造成的误差更大。因此,尽管被缩短的长度还不至于影响到电杆力学检验时的有效力臂,且GB 4623 84
First, the problem is put forward in the production process of the prestressed pole, in order to overcome the non-uniformity of the prestress value, most of the province adopts the mandrel type pull head to locate the outer conical nut when it is stretched. This process can be used for many years to meet design requirements. However, when the process is being tensioned, the mandrel type pull head must be inserted into the rod mold by the inside of the mold body, causing the length of the electric pole to be insufficient, shortening by 90 to 120 mm, and the length and the change of the entire tapered shaft. Cross-section related, it is also related to the use of fittings and fittings. In particular, a considerable part of the preparation hole is positioned from the tip end, resulting in greater error. Therefore, although the shortened length does not affect the effective arm of the pole during the mechanical inspection, and GB 4623 84