LOAD-BEARING CAPACITY OF THE CONTACT NETWORK POLE OF RAILWAYS MADE OF CONCRETE REINFORCED WITH COMPOSITE REINFORCEMENT

Purpose. During operation on electrified direct current railways, reinforced concrete contact network pole of railways are damaged by electrical corrosion. Therefore, the development of alternative support structures, in particular, concrete with composite reinforcement, and the assessment of their bearing capacity is an urgent task. The purpose of the study is to compare the bearing capacity of conical centrifuged poles of the contact network of railways made of concrete reinforced with steel and composite reinforcement. Methodology. The comparison of the load-bearing capacity of the pole of the contact network of railways made of concrete reinforced with composite and steel reinforcement was carried out by means of a calculation experiment with the analysis of the stress-strain state of the risers using the finite element method and the LIRA-SAPR software complex. Findings. A finite-element model of poles with steel and composite reinforcement with the same cross-section and prestress was constructed. Their load during the calculation experiment was carried out until destruction, the calculation was performed in a non-linear setting. As a result of the calculated experiment, the isofield of deformations, stresses in concrete, forces in longitudinal and transverse reinforcement was obtained. It has been established that poles with both steel and composite reinforcement are destroyed due to the development of the working reinforcement. In the stretched zone of the pole with steel reinforcement, cracks do not form before failure, the pole with composite reinforcement works with cracks in the stretched zone. In a pole with steel reinforcement, the distribution of stretched and compressed zones along the cross section is uniform, in a pole with composite reinforcement, a wide stretched zone is observed, precisely in which cracks form, and a minimal compressed zone. The design of the reinforced concrete pole provides the necessary load-bearing capacity of the pole - normative bending moment, the pole with composite reinforcement - does not provide it by 21% due to the 5.4 times smaller modulus of elasticity of the composite reinforcement compared to steel. The deformation of the pole with composite reinforcement exceeds the deformation of the pole with steel reinforcement by 64%. Ensuring the required load-bearing capacity is possible by increasing the cross-section of the reinforcement and the tension of its package. Originality. For the first time, a finite-element model of a conical ring cross-section of a structure made of concrete reinforced with pre-stressed composite reinforcement and the regularity of the distribution of deformations and stresses during bending was obtained. Practical value lies in the creation of an opportunity to design poles of the contact network of railways that are resistant to electrocorrosive influences.