Numerical Study of the Stress-Strain State of a Modified Wooden Beam

Preservation of wooden architecture monuments requires special attention since during their operation for 100 years and more wooden structures are exposed to environmental influences resulting in weakening their bearing capacity. The use of external reinforcement systems for buildings of historical value leads to a loss of architectural look. The proposed method of restoring the bearing capacity of the destructed wooden beams in the support zones is based on modification with a polymer composition. We have considered 3 types of pine beams: destructed, modified in the support zones; wooden, weakened by destruction; “healthy”. Numerical calculation of beams with a length of 6 m and a cross-section of 100×200 mm is performed in the Lira software package. The calculation model of the beams considered was created by adapting the initial data for the working environment of the software package used. The computational model is set as a three-dimensional body obtained by triangulation and “extrusion” of beam projection section. Shear stresses in the supporting zone, as well as vertical movements of the beams have been determined according to the developed method of calculation of wooden beams. The parameters of the modified beam and the reference “healthy” structure were compared. Shear stresses in the strengthened beam are 15–17 % higher than in the “healthy” beam. It was found that the strength of the destructed beam modified on supports increased by 16–18 % compared to the destructed beam. The boundary conditions for the modification of destructed wooden beams in the support zones to restore their bearing capacity have been determined on the basis of the obtained results. If the loss of bearing capacity is more than 35 %, then this method is not recommended due to the expediency of replacing such structures.