Учет физической нелинейности при расчете плоской железобетонной рамы с использованием вычислительного комплекса SCAD

Abstract

The aim of the paper is to analyze the results of the determination of forces and motions in a flat slab under static load, obtained considering the physically nonlinear operation of reinforced concrete. The deformation theories used for composite materials were compared. A linear analysis was carried out, along with a nonlinear automated analysis of forces and motions in a slab in the SCAD Office software (version 21.1.9.7) based on various deformation theories. An automatic calculation of a slab was conducted in accordance with the guidelines of the SP 52-103-2007 “Concrete monolithic building structures”, according to which the nonlinear operation of reinforced concrete structural elements should be considered by introducing reducing coefficients. A comparative analysis of the obtained forces and motions in a flat reinforced concrete slab was carried out. An inconsistency was found between the values calculated based on the theory of physical nonlinearity and those calculated according to the recommendations of SP 52-103-2007. In comparison with the nonlinear analysis based on SP 52-103-2007, the maximum error comprised 55.8%. The obtained values of motions, according to the recommendations of SP 52-103-2007, were also inconsistent. The largest discrepancy in the results of the nonlinear analysis was 49.4%, while the largest discrepancy in the linear analysis was 69%. Thus, the study showed inconsistency between the results obtained using the guidelines and the results of linear and non-linear analysis. The difference in the results demands additional verification when using non-linear analysis in calculations for strength and stiffness as a means of clarifying the stress-strain state of the studied structure.