Field measurement and validation of structural dynamic parameters of skyscrapers under super typhoon excitation

Abstract

This paper analyzes the field measurement data of wind-excited vibration responses of two skyscrapers (393 and 432 m in height) during Super Typhoon Mangkhut (1822), and utilizes such measurement data to validate the design parameters adopted in both buildings. In this paper, the structural accelerations of the two monitored skyscrapers measured during Mangkhut are presented. Based on the measured acceleration data, building modal parameters, including natural frequencies and damping ratio, are identified and they generally agree with the predicted values by the finite element modelling (FEM) or are within the expectation of their assumed values at the design stage. Furthermore, the amplitude dependencies of the parameters are estimated by the random decrement technique, and the results show that the fundamental frequencies slightly decrease with the vibration amplitude, which may be attributed to the P-Delta effect according to the similar trend revealed by the FEM results, whereas no evident varying trend of damping ratios is demonstrated. The study also identifies the beating effect existing in the monitored building response signals, investigates its impact on modal parameter identification and discusses the correlation between the beating effect and the structural modal characteristics. Finally, the root-mean-square structural accelerations of one of the two buildings are re-calculated based on the wind tunnel test data and the measured building modal parameters, and their comparison with the in situ measurements demonstrates a reasonable agreement.