As the construction industry increasingly adopts timber for high-rise applications to meet sustainability goals, understanding the dynamic behavior of these lightweight structures is critical for ensuring serviceability and occupant comfort. This thesis investigates the dynamic behaviour of a nine-storey timber building through a combined experimental and numerical approach. Ambient vibration measurements were carried out using Operational Modal Analysis (OMA) to extract the structure’s natural frequencies, mode shapes, and damping ratios under real operating conditions. The measured modal parameters were then used to calibrate and update a finite element (FE) model developed in RFEM. A systematic model-updating procedure was implemented, including mass adjustment, external wall bracing, and internal stabilising walls, to improve correlation between experimental and numerical results. Multiple validation metrics were employed, including frequency comparison and Modal Assurance Criterion (MAC). The updated FE model demonstrated strong agreement with OMA results, achieving high cross-MAC values for the primary global modes, confirming accurate mode pairing and reliable stiffness representation. The study also explored the influence of structural system choice on dynamic performance by comparing the updated model of the existing GLULAM post-and-beam structure to an equivalent-height CLT shear-wall building. The results showed that the GLULAM frame exhibits higher natural frequencies and stiffer lateral behaviour, while the CLT system demonstrates stronger torsional coupling and greater flexibility due to its shear-dominated load path. Overall, this work provides a validated numerical model suitable for performance evaluation and future design studies. The findings highlight key differences in vibration characteristics between GLULAM and CLT high-rise typologies and emphasize the importance of connection stiffness, mass distribution, and stabilising systems in the dynamic response of modern timber buildings. The research contributes to improved prediction reliability for timber structures and supports ongoing development of sustainable tall-timber engineering solutions.
Nesga et al. (Wed,) studied this question.