SIMULATION OF THE STRESS-STRAIN STATE OF LIGHTWEIGHT MULTILAYER OVERLAP

Abstract

In order to establish the main lines of research, we have made a review of existing scientific research and modern needs of the construction industry in the part of reinforced concrete structures, namely, overlapping disks. The current issue is the problem of increasing the energy efficiency and sound resistance of inter-floor structures that can be provided with various materials in the ceiling. Taking into account the complexity of the stress-strain state of multilayer overlappings and analyzing the problem thereafter, the task was to develop finite-element models of three-layer overlappings with two support options. The first option represents the example of support of the rectangular that was carried out on two sides by the beam scheme, and in the second one, the square plate pillrs were fixed in the corners behind the non-backtronic scheme.

Construction of 3D calculation models was performed with the help of CE-241 and CE-231. The rigidity of the outer layers of concrete was set using the CE-241, which characterizes the rectangular layers of the shell. The middle lightweight concrete layer was made of CE-231, which works as volumetric finite elements and is intended to solve spatial problems of the theory of elasticity, as well as for determination of the stress-strain state of spatial structures.

To calculate the nonlinear problem, when describing the stiffness of the plate element, the exponential dependence between stresses and deformations was used to take into account the real physical and mechanical characteristics of both heavy and light concrete, as well as the broken line law like "deformation-stress" for the working armature of the lower layer of the test plate.

On the basis of calculations, the maximum stresses Nx compression and tension in the sections of three-layer plates (beam and beamfree) are located in the upper and lower shelves, respectively. As a result, the thickness of the upper layer of heavy concrete is sufficient for the perception of the compressive forces, and the strength of the middle layer of light concrete is sufficient for the work of the multilayer bending element as a solid reinforced concrete one.

The compressed concrete zone in those two investigated overlap structures before the stage of destruction was in the upper compressed layer of heavy concrete, so that ensured the joint work of the ball structure as a solid reinforced concrete one, and also made the phenomenon of displacement impossible.