The Reasons of Performance Impairment of Wooden Structures During Operationin an Environment with Cyclically Changing Temperature and Humidity Conditions
The article presents an overview of the main characteristics of wooden structures of buildings and facilities formed during their operation in an environment withcyclically changing values of temperature and humidity. These characteristics have a significant effect on the operation of structures after their intended use. Inthis context the aim of this article is to determine the main reasons of decrease of wooden structures operation capacity during exploitation. To achieve the aim theinfluence of constructive system, type of connections, quality of performance, quality of materials, and magnitude of load on the stage of wooden structures and itswork in the process of exploitation is studied. It is revealed that in addition to these factors, parameters of the environment surrounding the structures, temperatureand relative air humidity namely, are important. Criteria for selecting the type of the structure depending on operational conditions have been determined. It isestablished that one of the reasons for decay of wooden elements is condensation processes, more complicated than the processes of drop-liquid humidification.Differences between differential condensation, systematic condensation and cyclic process of condensation have been revealed. The effect of the temperaturehysteresis on the process of moisture penetration in the wood has been determined. The aim of the further studies is to determine the effect of temperaturehumidityparameters of the external environment on the strength of wooden structures in various buildings with due regard for improving their durability.