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预应力混凝土电杆(下称预应力电杆)是靠预应力钢筋与混凝土之间的握裹力来传递应力的。在纵向应力传递长度范围内,应力分布近似呈三角形。应力传递长度与混凝土的脱模强度、预应力钢筋的直径、表面形状以及张拉控制应力有关。目前,在我厂的生产条件下,直径5.5毫米的高强钢丝(R_Y~b=11000公斤/厘米~2)的应力传递长度约为90d(d——预应力钢筋的直径)。因骤然放松预应力钢筋,距电杆端部约有0.25L_c(L_c——应力传递长度)的长度范围内电杆纵向基本处于无应力
Prestressed concrete poles (hereinafter referred to as prestressed poles) rely on the gripping force between prestressed steel bars and concrete to transfer stress. In the longitudinal stress transmission length range, the stress distribution is approximately triangular. The length of the stress transfer is related to the demoulding strength of the concrete, the diameter of the prestressed steel bar, the shape of the surface, and the tensile stress. At present, under the production conditions of our factory, the stress transmission length of a high-strength steel wire with a diameter of 5.5 mm (R_Y~b=11000 kg/cm~2) is about 90d (d—the diameter of the pre-stressed steel bar). Due to the sudden relaxation of the prestressed steel bars, the length of the poles is basically in a stress-free range over a length of approximately 0.25L_c (L_c - the length of the stress transmission) from the ends of the poles.