A Framework for the Estimation of Damping Ratio of Glued-Laminated Buildings by Use of Analysis in the Time Domain.

Abstract

The increased interest in tall timber buildings has led to the need for more accurate prediction models. With inherently low mass and stiffness properties, multi-story buildings made of timber are susceptible to wind-induced vibrations, which can result in discomfort for the occupants. Multiple experimental and numerical studies investigating natural frequencies and mode shapes of timber buildings can be found in the literature. However, modeling the damping properties in timber buildings has not been studied fully yet. This study presents a framework for the estimation of the global damping ratio of glue-laminated-frame buildings by use of linear-elastic finite element modeling. Using stiffness-dependent Rayleigh damping and the dynamic analysis in the time domain, it was demonstrated that the predictions of the FE model for the damping ratio were within the range of the results obtained by on-site measurements. The case study of the tallest all-timber building in the world (Mjøstårnet, Norway) was used to demonstrate the framework using extensive small- and large-scale experimental data. The parametric study identified the damping ratio in the diagonals and material damping ratio in the glue-laminated timber as the key parameters influencing the damping ratio of the whole building.