No abstract

Bar reinforced concrete structures, which include piles, in real working conditions perceive a whole range of internal force factors. Axial tension-compression forces, bending moments and shear forces are the most commonly perceived internal force factors. Of particular interest is the effect on the cross section of the shear force. If a complex curly shape is replaced by elementary form, then the calculation is not difficult. However, when calculating the composite cross section, there is no unambiguous solution. In accordance with the adopted regulatory documentation, it is necessary to accept only a main part, while discarding the surrounding areas. It is important to study the configuration of the shape of a complex section for the perception of a shear force. The purpose of the work was to refine the account of the entire complex section using numerical simulation by the finite element method, analytical calculations and small-scale experiments. Determination of further practical application of the obtained results on real structures was also the goal of the study. The parameters of the distribution of shear force between the main rib and flanges were obtained by numerical analysis and small-scale experiments. Numerical models of rectangular and tee cross sections beams have been developed. Analytical dependences were studied and full-scale tests of reinforced concrete beams of various sections were carried out. It has been established that when taking into account the work of the entire cross-section, the bearing capacity of concrete for the action of a shear force is 20% greater than when calculating only the main section without taking into account the shelves.

The article proposes resolving equations for eccentrically compressed reinforced concrete short columns obtained on the viscoelastic model basis. Comparison of the results obtained according to the theory of heredity, theory of hardening, aging, flow, kinetic theory, as well as the nonlinear theory of concrete creep by Yu.A. Gurieva is presented.

The article discusses a method for calculating three-layer plates, in which a lightweight viscoelastic material acts as a middle layer. The technical theory of three-layer structures is used. The derivation of the resolving equation, the numerical and analytical solution of the problem, as well as comparison with the solution in the LIRA software package are presented.