Investigation of time-varying structural dynamic properties of high-rise buildings under typhoon conditions

This paper investigates the time-varying structural dynamic properties of high-rise buildings under typhoon conditions via the covariance-driven stochastic subspace identification (SSI–COV) method. Firstly, a numerical simulation study on a three-degree-of-freedom model is conducted, and the results prove that the SSI–COV method can provide accurate identification of the time-varying structural dynamic properties. Then, based on field measurements on a 420-m-tall high-rise building during Super Typhoon Mangkhut (No. 1822), the time-varying structural dynamic properties of the skyscraper are presented and discussed. The results indicate that the structural natural frequencies exhibited a trend of first decreasing and then increasing, while the damping ratios and modal directions basically remained unchanged during the typhoon process. Moreover, the variation of structural dynamic properties of the fundamental sway modes of the monitored building during 16 typhoons is investigated. The results show that the degree of variation in structural natural frequencies generally increased with the peak acceleration response of the building or the maximum 10-min-mean wind speed atop the building during a typhoon. While the damping ratios of the fundamental sway modes did not vary significantly during these 16 typhoons, which were around 0.64%. This paper aims to further the understanding of structural dynamic properties of high-rise buildings during typhoons.