CALCULATION OF THE NORMAL SECTION OF A PASSIVE COMBINATION OF REINFORCED WOOD BEAMS TAKING INTO ACCOUNT THE CRITERIA OF DEFORMATION FAILURE

Abstract

The use of wood is one of the most effective mechanisms reduction of carbon emissions into the air during the construction of buildings and structures. Along with this, there is wood the only material that is constantly renewed in nature. However, wood - it is an anisotropic natural material that has significant disadvantages. One of the main ones are the different degree of stress state of the wood in equidistant layers of wood from the neutral line in compressed and stretched zones of the normal cross-section of the element during work on transverse bending. This leads to a shift of the force neutral line in the direction of a stronger one stretched zone. This fact does not make it possible to determine the moment of resistance cross section W y at all stages of perception of external loads from for being tied to the center of gravity of the area of ​​this flexural section wooden element. In addition, the calculation of any reinforcement bending elements made of wood due to combined  reinforcement is not provided for by the norms. To eliminate these shortcomings, the article developed a calculation method passively combined reinforced wooden elements (in the compressed zone steel reinforcement, and stretched composite tape), which are located in the conditions of direct transverse bending using the deformation model, which takes into account the uneven distribution of stresses in compressed and stretched zones of the estimated normal cross-section. For consideration well-known laws are applied to this in the accepted calculation section distribution of deformations along the height, both in the compressed and in the stretched zones and an apparatus of infinitesimally small values ​​is used under the condition of non-discontinuity functions in the vicinity of the intersection point, which is determined by the hypothesis of continuity and homogeneity of the material.

Taking into account the theoretical prerequisites for calculating the stress-strain state of an element, a block diagram was created for the structural calculation of a wooden passively combined reinforced beam containing composite plastic reinforcement in the stretched zone and steel reinforcement in the compressed zone.