Methods for determining the critical deformations of wood with various moisture content

Abstract

During construction of bridges, the possibility of flooding periods should be considered. Therefore, it is necessary to understand the degree of possible deformation of wooden structures and calculate the limit of their plasticity and elasticity at different values of moisture content. Thus, the purpose of study is to find the method for determining the relative critical deformations of wood with different moisture content and analyse the dynamics of their change. Problems of a deformable solid material were investigated by the analysis of a model of complete deformation diagram “stress σс – deformation uс ”, methods of mathematical statistics, and systematic analysis of experimental results. This study allowed formulating the method for determining the relative critical deformations of solid wood at different moisture levels by axial compression along the fibres of experimental samples. Based on the experiment results, the formula for determining the relative critical deformations of solid wood with different moisture was proposed. The dynamics of changes in critical relative deformations at different moisture, and its elastic and plastic components were presented. It was found that in case of drying wood from 30 to 12%, the plastic component of relative critical deformations decreases and the elastic one, on the contrary, increases. The findings can be used in the deformation calculation methodology for wooden elements and structures of bridges, hydraulic structures, buildings, taking into account the changes in the moisture content of the material