Аңдатпа
The article is devoted to the optimization of the reinforcing string package of a reinforced concrete sleeper. Standard sleepers of the Sh1 and ShS types of small height in the middle section are characterized by an uneven distribution of sole pressure on the ballast. The purpose of this study was to improve reinforced concrete sleepers and determine their parameters to ensure better stress distribution in the sleeper during its operation under trains, in particular, to increase the “effective” area of the sleeper foot. Several variants of reinforced concrete sleepers were modeled in software systems for calculation by finite element methods. The design cases were determined, the most unfavorable for the bending of the sleeper – the support of the sole of the sleeper on the weakly compacted crushed stone ballast and the bending of the sleeper on the test factory stand when checking it for crack resistance. An analysis of calculation results with a change in the tension force of the wires showed that crack resistance is provided with a total tension of 38 strings with a force of 300 to 310 kN for a modified sleeper reinforced with 38 strings with a diameter of 3 mm. As a result of testing reinforced concrete sleepers from an experimental batch with a string package height of 90 mm and a number of strings equal to 40 pieces, it was shown that the concrete is destroyed, and the reinforcement is not torn. Therefore, this modification allows more efficient use of reinforcing wire. In addition, it provides a better distribution of sleeper pressure on the ballast. For the production of reinforced concrete sleepers, it was proposed to increase the height of the string package to 105 mm with a decrease in the number of strings of high-strength wire to 40 pcs. This will reduce the maximum pressure of the sleeper on the ballast to 8 % and reduce the rate of accumulation of residual deformations of the ballast under the modified sleeper by 25 % in comparison with a typical sleeper Sh1 with a string package of 44 strings 75 mm high. The results of an experimental verification of the strength and crack resistance of reinforced concrete sleepers with 38–40 reinforcing strings at the sleeper plant LLP “Magnetik” showed that with an increase in the height of the string package to 90–105 mm, the required crack resistance of reinforced concrete sleepers is provided.