离心成型预应力钢纤维混凝土电杆设计试验研究

对研制的呼称高27m离心成型预应力钢纤维混凝土电杆进行了受力性能试验研究。结果表明,在断线工况荷载作用下,电杆的受力表现出良好的整体性,各项性能均满足设计要求;杆身采用预应力和钢纤维双重增强作用,使电杆的抗裂能力提高,变形减小;一旦发生超载运行出现裂缝,裂缝细短且非贯通,卸载后变形回复能力强,残余变形很小;在极限承载时,整杆变形明显,具有良好的延性破坏预兆。同时,预应力钢纤维混凝土电杆在预应力筋放张和杆段对焊组装过程中,避免了普通预应力混凝土电杆在预应力筋挂板和杆段连接钢圈附近混凝土起皮爆裂现象。根据试验结果对比分析,建立了预应力钢纤维混凝土电杆抗裂度、裂缝宽度、挠度和正截面承载力设计计算方法。研究成果为河南省漯河~淮阳220kV线路工程建设提供了重要科研依据,为钢纤维混凝土在预应力电杆中的应用提供了重要参考。

DESIGN AND EXPERIMENTAL STUDY OF PRESTRESSED SFRC POLE FABRICATED BY CENTRIFUGAL SHAPING METHOD

Experimental study has been carried out on the prestressed Steel Fiber Reinforced Concrete (SFRC) pole fabricated by centrifugal shaping method with cross arm 27m above ground. It is proved that under the line-break status, the prestressed SFRC pole has good integrity and the behaviors meet with design requirements. With the pole body reinforced by both prestress and steel fiber, the cracking-strength is improved, the deflection is decreased. The cracks are short,thin, and unlinked up in the case of overload. The performance of deformation recovery is good and the residual deformation is small after unload. The ductile failure property is enhanced. Meanwhile, it has been found that the decortications of concrete surface near the hanging plate of prestressing steel bars and the steel link ring of poles in the normal prestressed concrete pole are avoided. Based on the analysis of the test results, method are proposed for calculating the cracking-strength, the crack width, the deflection and the ultimate bearing capacity of the pole. The results have provided the important research basis for the construction of Luohe~Huaiyang 220kV transmission line project in Henan, and the important reference for the application of steel fiber reinforced concrete to prestressed poles.