Verification of Scad Models of Reinforced Concrete Coffered Floor Based on an Analytical Calculation Method That Takes Into Account Spans and Structural Rigidity

Abstract

In accordance with the modern requirements of urban planning legislation, the design of building structures without the use of BIM technologies is impossible. Strength calculation on an electronic computer is carried out in software complexes implementing the finite element method, in which the forces or stresses calculated in the elements may turn out to be unreliable. There is a number of reasons for this. Analysis of the data of analytical and computer calculations of reinforced concrete coffered structures shows that the forces in the beams may differ significantly depending on the created finite element model and the geometry of the overlap. The work is aimed to find out the most accurate finite element model when calculating reinforced concrete coffered floor. The numerical experiment is based on the work of verification calculations performed in the computing system SCAD of a rectangular overlap with rectangular coffers, modeled by four finite element models. It is concluded that the model consisting of shell finite elements is the most accurate. It addition, the stress obtained is compared with the data of the well-known analytical method for calculating coffered ceilings, which is based on the beam analogy and takes into takes into account only the spans of the structure. In this paper, the analytical calculation of the caisson overlap is carried out both taking into account the spans of the structure and its orthogonal rigidity. The calculation is also performed in the computing system SCAD on a model consisting of rod finite elements of a T-section. The results allow to conclude that the most accurate finite elements models is the bar models. Shell finite element models in the example under consideration show understated results. When performing verification calculations on a computer by the finite element method, in order to confirm the reliability of the stress –strain state obtained, it is necessary to compare with the data of full-scale or model tests of structures. For complex, repeatedly statically indeterminate systems for which there is no an analytical solutions, other methods of studying the convergence of the obtained FEM results have an error.