Strength degradation and service life prediction of timber in ancient Tibetan building

Abstract

Tibetan heritage building has attracted much attention recently for its historical and cultural value. Many of these buildings have different degree of damage after hundreds of years of service. A multivariate cumulative damage (CD) model and prediction model of strength degradation of timber in the ancient Tibetan building are proposed in this study. Experimental tests on old and new timber are conducted and a correction factor considering the effects of different influencing factors on the timber properties is introduced to modify the strength prediction model. Two failure criteria based on the ultimate strength capacity and allowable deformation are proposed to predict the service life of timber component. Finally, reliability-based analysis is conducted for the residual strength and service life prediction of timber component with consideration of the statistical uncertainty of different influencing factors. The analysed results show that the rate of residual strength degradation increases with time with consideration of different influencing factors. An ancient timber component with a longer history associates with a lower reliability.