ABSTRACT
The seismic performance of post-tensioned cross-laminated timber (CLT) shear walls during long-term service is dependent on the time-varying prestressing force. The prestressing force in the steel strand may change over time because of creep and environmental deformation of timber. In this study, three different post-tensioned CLT shear walls were monitored to investigate the prestressing force variation under uncontrolled environment. The environmental temperature, relative humidity, timber moisture content and prestressing force were recorded. Attention was paid on the effect of stress level on prestressing force losses. It was found that the prestressing force variation of the post-tensioned CLT shear walls was closely relative to the ambient relative humidity and stress level. A numerical model was developed to analyze the moisture content variation in CLT walls with respect to relative humidity. Fick’s second law was applied in the model to simulate the process of moisture diffusion in timber. It was shown that the simulated results had a good agreement with the experimental results.
