Mechanical performance of timber structures in tropical climate

Timber construction is increasingly utilized in tropical regions; however, the influence of tropical climates on their mechanical performance remains not fully understood, characterized by high humidity and temperature, significant daily relative humidity (RH) fluctuations, and limited seasonal RH variations. This study investigates the mechanical performance of timber structures in tropical climates, focusing specifically on the effects of short-term ambient RH variations. Experimental studies were conducted to measure real-time strain variations in response to changes in the ambient environment, using a digital image correlation (DIC) system. The experimental results were used to validate a numerical model that accounts for the transient moisture transfer process. This model was subsequently employed for a systematic numerical parametric study based on actual climate data, with a focus on tropical cities. The model calculated moisture content variations for timber members of varying sizes and investigated the effects of different coatings. The impact on the mechanical performance of these timber members, including eigen-stress and mechano-sorptive creep, was evaluated. The findings indicate that, despite significant daily RH variations, the tropical climate leads to relatively less severe eigen-stress and mechano-sorptive creep compared to climates with a significantly seasonal RH variation.