Investigation of the bearing capacity, crack resistance and endurance of reinforced concrete sleepers SH3-D 4×10 and SH3-DPG 4×10

Abstract

   The article presents the results of research on the bearing capacity, crack resistance and endurance of reinforced concrete sleepers with rod reinforcement, which are manufactured using the Italian automated OLMI technology. Two types of sleepers are calculated SH3-D 4×10 and SH3-DPG 4×10. SH3-DPG 4×10 sleepers differ from SH3-D 4×10 sleepers by additional indirect reinforcement in the end section in the form of spirals at the ends of the reinforcement and end holes minted with concrete mortar. At the same time, the concrete compressive strength class for SH3-D 4×10 sleepers is assumed to be at least B55, and for SH3-DPG 4×10 sleepers it is assumed to be at least B60.
   The load-bearing capacity calculation is performed according to the method of calculating bent elements of any shape of cross-sections, directions of action of the external moment and any reinforcement in the general case of calculating normal sections of bent elements. The specifics of the operation of iron-concrete sleepers under load require mandatory calculation of crack resistance and endurance, since the impact of multiple repetitive loads on the sleeper causes a significant stress drop in concrete or in stretched reinforcement with a large number of cycles during the operating period.
   Based on the results of the calculations, it was found that an increase in the concrete class in compressive strength from B55 to B60 has practically no effect on crack resistance and bearing capacity, which means it will not lead to a decrease in the defects of reinforced concrete sleepers with core reinforcement on load-stressed sections of the Central Siberian Railway.