In this article, numerical and experimental studies of the strength of compressed steel-reinforced concrete elements made using high-strength concrete and square steel pipes of class C345 are considered in order to determine the bearing capacity. The main issue in the calculation of pipe-concrete structures is the question of the design strengths of materials working as part of a pipe-concrete section. These strengths differ from the strengths of materials in a uniaxial stressed state and depend on a number of parameters. Concrete with small eccentricities of longitudinal force is in a state of triaxial compression, and its strength increases compared to uniaxial compression. The steel of the pipe is in a flat stressed state. When the eccentricity of the longitudinal force application increases, the strengths of materials approach to the strength under uniaxial compression. The issue of changing the strength of materials with a change in the eccentricity of the longitudinal force has been studied quite well. Therefore, the main issue is the strength of materials in the central compression of the pipe-concrete structure. The work of materials in the composition of a square tube-concrete section is fundamentally different from the work of materials in the composition of a round tube-concrete section. The main difference lies in the uneven lateral compression of concrete in a square pipe.