Studies of spun concrete poles for electric power transmission line supports reinforced with Au1000P rebars

Introduction. In connection with the present volumes of electrification in central Russia, the need for the construction of new electric power transmission lines (EPTLs) has decreased considerably. At the same time, the natural degradation of EPTL supports in time, as well as the prospects for developing the vast expanses of the northern, Siberian and Far Eastern regions, caused by the reorientation of Russia’s economic relations from the West to the East, make it urgent to increase production volumes and technical and economic efficiency of using spun reinforced concrete poles for EPTL supports.

Aim. Industrial implementation of spun reinforced concrete poles with the high-strength innovation profile reinforcement by replacing A800 rebars with four-row-profile Au1000P rebars.

Materials and methods. The article provides data on the full-scale tests of spun reinforced concrete poles for EPTL supports according to the GOST 22687.1-85 “Centrifugal cylinder reinforced concrete posts for high-voltage transmission lines. Structure and dimensions” [1]. Three pole samples with a length of 26 m were prepared and tested. One sample consisted of prestressed A800 rebars according to GOST 22687.1-85, while the other two prototypes include the prestressed Au1000P rebars with the four-row profile. In the second sample, the reinforcement scheme (diameters and rebar quantity) repeats the standard option, increasing the bearing capacity of the pole. Having the same bearing capacity as the pole, manufactured according to the GOST, the third sample promoted for the reduction in the quantity of non-stressed rebars.

Results. A new scheme for reinforcing the pole sample using Au1000P rebars was developed. The results of the sample testing are presented; a comparative evaluation of the pole strength and deformation characteristics is given; technical and economic indicators, as well as the recommendations regarding the reinforcement of the prestressed spun concrete poles with Au1000P rebars are provided.

Conclusion. According to the results of the performed study, an economic effect was established due to a reduction in the quantity of non-stressed rebars by 28 %. Poles with Au1000P prestressed rebars have an increased corrosion resistance and durability due to the closing of cracks formed during the impact of short-term dynamic loads from wind gusts, wire breaks, etc. In terms of a recommendation, it is proposed to update the GOST 22687.1-85 in order to use new types of high-strength reinforcement rolled products and higher strength concrete.

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