Long-term loading effect on vibration performance of CLT floors: An 896-day monitoring study

Timber, a viscoelastic material, undergoes deformation over time when exposed to sustained loads, a process known as creep. Its rising popularity as a construction material, especially for timber floors, is notable. However, the influence of creep on the dynamic characteristics of timber floors, such as their natural frequency and vibration response, is not well studied. This research focused on how long-term loading (creep) affects the vibration behaviours of a cross-laminated timber (CLT) floor. A full-scale CLT floor was constructed in a lab and subjected to long-term loading using sandbags. Over 896 days, the centroid point deflection and environmental conditions (temperature and relative humidity) were monitored. Human-induced vibration tests were carried out at the beginning, throughout, and at the end of this period. The vibration response, measured in terms of the Vibration Dose Value (VDV), was assessed at various stages of long-term loading. The findings showed a moderate positive correlation between the creep deflection and environmental conditions. The fundamental frequency slightly increased over time due to creep, and a general decrease in VDV was observed as the creep advanced.