TO DETERMINATION OF DEFORMATION CHARACTERISTICS OF GLUE-LAIMED PINE AND SPRUCE WOOD AT DIFFERENT HUMIDITIES IN THE PRECRITICAL AND POSTCRITICAL STAGES OF WORK: EXPERIMENTAL STAGE

Abstract

Solid and glued wood is often operated in environments with different humidity levels. Current regulatory documents limit such operation to the Kmod coefficient. In some cases, it is unclear how to determine certain mechanical characteristics with increased moisture content, including deformable ones. For example, the operation of elements in bridge structures, hydraulic structures, sea piers, shore protection structures, and others. Very often, materials, elements, and structures based on wood operate in a post-critical stage of operation (seismic vibrations, dynamic loads, progressive destruction, floods, changes in water levels, and others).
The purpose of our research is to conduct experimental studies of structural glued laminated wood of pine and spruce with different moisture content under a strict regime of axial compression tests along the fibers during operation in river and marine aquatic environments. As well as to establish the main deformation parameters in the pre-critical and post-critical stages of operation under such operating conditions.
Experimental studies of structural glued pine and spruce wood of different humidity after immersion in river and sea water environments by axial compression along the fibers under a rigid test regime were carried out. The main mechanical characteristics of glued pine and spruce wood in the pre-critical and post-critical stages of operation were experimentally established, including the temporary ultimate strength of wood, the modulus of elasticity, relative critical, limiting and residual deformations, under such operating conditions. Formulas were proposed for determining the relative limiting deformations of structural glued wood at different humidity. The main deformation characteristics of glued pine and spruce wood, both in river and sea water environments, relative critical, limiting and residual deformations were established. At humidity levels of 21% and 30%, they increase in comparison with the characteristics determined at a standard humidity of 12%.