System Identification of Tall Mass Timber Structures Employing Ambient Vibration Test and Fe Modelling

Abstract

Despite the recent rapid development in dynamic characteristics identification of structures, lack of knowledge in dynamic properties of tall mass timber buildings is still an open issue for researchers and designers. There are ongoing international efforts to develop a comprehensive database for predicting the vibration performance of timber structures for serviceability and seismic design. This paper discusses an ambient vibration test (AVT) that was conducted on a six-storey mass timber building known as Wood Innovation and Design Centre (WIDC) located in Prince George, Canada. The test results including the experimental natural frequencies and damping ratios were compared with a threephase test program undertaken in 2014, 2015, and 2017 by FPInnovations. In addition, a numerical modal analysis was conducted on the same building, using both simplified and complex finite element (FE) models. A sensitivity analysis was carried out considering various assumptions of connection types to investigate its effect on the natural frequencies of the structure. The results of current AVT showed minor changes in frequencies over the service time in comparison to previous tests. According to the numerical results, the simplified FE model poorly matched with the results from AVT, while the complex model showed a better agreement with the measured fundamental frequency; however, significant discrepancies were observed in the second and third modes. The sensitivity analysis indicated low impact of different connection type assumptions on the natural frequencies of the case building obtained from the FE models.