PHYSICAL AND MECHANICAL PROPERTIES OF COMBINED WOODEN SLEEPERS
Wooden sleepers and bars are still widely used due to a number of their advantages over others on the railways. Using of wood products and structures in place of reinforced concrete can significantly reduce the global emissions of CO<sub>2</sub>. The main problems in the production of wooden sleepers are the difficulty of drying the thick material to pre-impregnation moisture and its deep uniform impregnation with the wood preservative. However, the most acute problem is the need to use scarce high-quality wood raw materials of large diameters (over 26 cm). In this paper, we consider alternative solutions for solid sleepers - combined sleepers. Calculations were made to evaluate the designs. The model takes into account the anisot-ropy of the wood, shrinkage, swelling and applied load using the finite element method. The stress-strain state of the wooden sleepers was estimated from the relative strains of Hill. The performed calculations showed the purposeful application of combined sleepers in the railway industry. In confirmation of the calculated data, full-scale tests of the obtained wooden structures were made. They determined the ultimate strength at static bending and the strength of the adhesive joint. The breaking load of the glued sleepers was 144.5 kN, the composite - 142.8 kN, the whole - 135.1 kN. The average value of the strength of the adhesive bond was 5.9 MPa. These figures are higher than the required values.