Investigation of modal parameters of a 600-m-tall skyscraper based on two-year-long structural health monitoring data and five typhoons measurements

Abstract

On the basis of two-year-long structural health monitoring data, this paper investigates the structural dynamic properties of a 600-m-high supertall building installed with an active tuned mass damper (ATMD) system. The long-term modal parameters such as natural frequencies and damping ratios of the monitored skyscraper are first determined by the stochastic subspace identification approach, and the results generally agree well with those obtained by the finite element method and forced vibration tests. The statistical analysis of the modal parameters indicates that the natural frequencies follow the normal distribution, while the damping ratios fit well with the Gumbel distribution. In addition, the two-year-long variations of the modal parameters with ambient environmental factors are investigated and it is found that both the ambient temperature and humidity have limited effects on the modal parameters of the skyscraper. Moreover, the impacts of the ATMD system on the modal parameters are explored based on the field measurements during five typhoons. The analyzed results demonstrate that the active damper system had significant effects on the modal parameters of the fundamental sway modes, while it had marginal influences on these of higher modes. This study aims to enhance the understanding of structural dynamic properties of supertall buildings and provide useful information for their wind-resistant design.