当电杆受力弯曲时，杆柱的截面一侧受压另一侧受拉，虽然拉力主要由钢筋承受，混凝土同钢筋一起伸长，但混凝土因受拉而可能出现裂缝，裂缝较宽时会进水而使钢筋锈蚀，防止裂缝的最好方法是在杆柱浇注前将钢筋预拉，使混凝土在承载前就承受"预压应力”，当电杆承载受拉时受拉区的混凝土由于有“预压应力”而不致裂缝，这种电杆称为 预应力钢筋混凝土电杆。
When the electric pole is subjected to bending force, one side of the cross-section of the pole is under pressure and the other side is under tension. Although the tension is mainly borne by the steel bars, the concrete and the steel bars elongate together. However, cracks may appear in the concrete due to tension. When the cracks are wide, water will enter and cause the steel bars to rust. The best way to prevent cracks is to pre tension the steel bars before pouring the pole, The concrete is subjected to "pre compression stress" before bearing, and when the pole bears tension, the concrete in the tension zone does not crack due to the "pre compression stress". This type of pole is called a prestressed reinforced concrete pole.
这样的电杆比普通钢筋混凝土杆可节约钢材40%左右，同时水泥用量也减少，电杆质量减轻，壁厚也相应减少，抗裂性能好，能延长电杆的使用寿命。
This type of electric pole can save about 40% of steel compared to ordinary reinforced concrete poles, and at the same time, the amount of cement used is reduced, the weight of the electric pole is reduced, the wall thickness is correspondingly reduced, and the crack resistance performance is good, which can extend the service life of the electric pole.