Modal Identification of 38 Supertall Buildings and Establishment of Predictive Models

Abstract

Information on natural frequencies and damping ratios is essential for structural dynamic analysis. To develop predictive models of modal parameters applicable for modern high-rise buildings with increasing heights, an advanced interferometric radar system was employed to measure the displacement responses of 38 supertall buildings with heights ranging from 200 to 600 m under ambient excitations. Then, a combined approach of the stochastic subspace method and an uncertainty bound estimation method are adopted for modal identification, and its accuracy is validated by a numerical simulation study. By applying the modal identification method to the field measurements, modal parameters of the 38 supertall buildings are identified. Based on these results, predictive models for fundamental natural frequency and damping ratio of supertall buildings are accordingly proposed, which are more applicable for the wind-resistant serviceability assessment or design of high-rise buildings with heights over 200 m than existing empirical models.