Monitoring dynamic characteristics of 600 m+ Shanghai Tower during two consecutive typhoons

Though the dynamic performance of high-rise buildings under wind has been widely investigated, there have been relatively limited studies focusing on the wind effects on 600 m+ super high-rise buildings based on real measured data during typhoons. This paper presents the field measurement results of structural dynamic characteristics and wind-induced responses of the Shanghai Tower with a height of 632 m during two successive typhoons, from August 12 to 18, 2018. Additionally, based on the analytical mode decomposition method, a modified discrete-time Fourier transformation method combined with moving window technology in time domain is developed to analyze the time-varying characteristics of natural frequencies. The relationship between the mean wind speed and acceleration amplitudes is investigated as well. A numerical experiment is carried out to verify the effectiveness of the random decrement technique, by using which the time-varying average damping ratios of the first mode associated with the Shanghai Tower are identified. In addition, the damping ratios do not exhibit an increasing trend with the increase of vibration amplitudes without the contribution of the tuned mass damper. It recommends that the critical damping ratios under high vibration amplitude are 2.5%–3.0% when the damper is active and 0.5%–1.0% when the damper is inactive. The analytical results can provide useful information for the dynamic characteristics as well as the wind-resistant design for 600 m+ super high-rise buildings.