Fyrtornet, a pioneering 51-meter-tall mass timber office tower in Malmö, Sweden, is thefirst and tallest building of the Embassy of Sharing project. Fyrtornet’s lightweight naturemade wind-induced accelerations for occupant comfort a critical design factor. The designincorporated analytical assessments validated by wind tunnel testing, with mass distribu-tion and CLT core wall shear connections identified as key factors. Iterations led to the finaldesign with an optimised brazing system and added mass in the concrete roof slab so thatcomfort criteria were met.

Extensive ambient vibration testing at seven construction stages in combination with FE-model updating revealed that non-structural elements (screed and internal walls) signifi-cantly decreased natural frequencies, as the added mass outweighed the stiffness in-creases. The foundation exhibited rigid behaviour, and GLT connection stiffness ap-proached rigidity in the final stages, likely due to screed and partition walls. A permanentmonitoring system is now installed to track dynamic performance and environmental ef-fects. With this, Fyrtornet serves as an essential case study for the dynamics of tall timberbuildings