Determination of the Load-Bearing Capacity of Physically Nonlinear Concrete Columns and Beams of a Multistory Building

This paper considers a multistory reinforced concrete building. A braced structural frame with transversely arranged frames is adopted as a structural scheme. Columns and beams are considered as multilayer composite reinforced concrete structures. The calculations take into account the physical nonlinearity of the deformation diagrams and the difference in strain limits under tension and compression of the constituent phase materials of the rods, including their self-weight loads. The deformation of the rod implies that the classical Kirchhoff-Love kinematic hypotheses are valid, and a uniaxial stress state is in the rods. The deformation law is adopted as the second-order polynomial approximation for each layer of the rod. The analytical relations are provided for the limit load values, at which the strain does not exceed the corresponding limit values under tension and compression in each phase material of the columns and beams. The relations are presented for determining the forces, moments, strains, and deflections in the considered rod structures.