Experimental investigation of vortex-induced vibration of a thousand-meter-scale mega-tall building

To ensure acceptable performance for survivability, serviceability and habitability of the mega-tall buildings, it is necessary to study their wind-induced response characteristics and vortex-induced resonance mechanism. In this study, the wind-induced responses of a thousand-meter-scale four-tower-connected mega-tall building are investigated using the aeroelastic model test in a boundary layer wind tunnel. The results show that the root mean square across-wind tip displacement increases dramatically within a certain wind velocity range at 60°wind direction, which indicates that the vortex-induced resonance occurs. Accordingly, the relation between the aerodynamic damping ratio and reduced wind velocity is further studied at this wind direction. Furthermore, the underlying mechanism of vortex-induced vibration (VIV) is comprehensively discussed based on the amplitude spectra of the across-wind tip displacements, which facilitates the identification of corresponding lock-in region. The identified critical reduced wind velocity for vortex-induced resonance for the mega-tall building is 10.19, with a lock-in region from 10.19 to 11.70. In addition, the VIV-like phenomenon occurred in the along-wind direction for this complex mega-tall building, associated with VIV in the across-wind direction. This observation indicates that there is aerodynamically coupled vortex shedding of the mega-tall building in the two directions. This study contributes to a detailed insight of the VIV phenomenon for the thousand-meter-scale four-tower-connected mega-tall building, and hence facilitates the wind-resistance design of this type of flexible structures.