INFLUENCE OF TEMPERATURE-HUMIDITY REGIME ON THE DEFORMABILITY OF BENDING ELEMENTS AFTER LONG-TERM OPERATION

Abstract

uences for timber as a building material is moisture exposure. There are many causes of failure in timber structures of buildings and сооружений. In most cases, failure results from a combination of specific factors and influences acting on structural elements. An analysis of the conducted studies indicates that such factors include, among others, an increase in timber moisture content and the aging of materials.
The results of experimental tests of solid timber beams under different service conditions are presented. Within the framework of the tests, these conditions were simulated by varying the moisture content of the specimens from 12% to 15% and by considering different service lives. In total, twelve experimental beams with service lives of 25, 50, and 75 years were tested. The test specimens were divided into three series with different moisture contents and service lives.
As a result of the conducted tests, the values of the relative deformations of the beams were determined from the beginning of loading until failure. The load-bearing capacity of the beams was established. The failure mode of the beams was identified, occurring in the pure bending zone. The maximum values of relative deformations in the compressed and tension zones were determined. It was established that an increase in timber moisture content leads to an increase in the relative deformations of the compressed zone of the beam by up to 12%, and of the tension zone by up to 7%. No consistent patterns regarding the influence of timber age on the development of deformations in the tested beams were identified. However, it should be noted that no clear generalized correlation can be established regarding the influence of service life on deformability. The deformation behavior and load-bearing capacity of beams depend on their service conditions and the presence of external adverse effects on timber as a building material.