Investigation on aeroelastic effects of high-rise buildings based on three-dimensional forced vibration wind tunnel tests

Most of conventional forced vibration systems consider only one-dimensional (1D) structural vibration of highrise buildings and do not account for aeroelastic coupling effects when determining aeroelastic parameters. In the present study, the motivation-feedback mechanism is introduced to account for aeroelastic coupling effects. In addition, synchronous three-dimensional (3D) vibrations of the building model are achieved by employing a 3D forced vibration system. Aeroelastic parameters including aerodynamic damping and aerodynamic stiffness ratios are determined using the wind pressure and structural displacement responses measured from wind tunnel tests. The two aeroelastic parameters obtained from 3D forced vibration wind tunnel test are then compared with those from 1D forced vibration wind tunnel test, to indicate the meaning of synchronous 3D vibrations. Effects of aeroelastic coupling on the aeroelastic parameters are investigated systematically. In addition, effects of structural vibration frequency and amplitude on the two aeroelastic parameters are examined, and an expression for the aerodynamic damping ratio is proposed based on regression analysis. Results show that alongwind aeroelastic parameters are barely influenced by vibrations in the crosswind and torsional directions. However, either crosswind or torsional aeroelastic parameters are significantly affected by vibrations in both crosswind and torsional directions, demonstrating the considerable aeroelastic coupling between these two directions. Within the range of vortex lock-in wind speeds, the absolute value of the minimum of both aeroelastic stiffness and damping ratios gradually decreases with the increase of structural vibration amplitude; whereas the absolute value of the minimum of both aeroelastic stiffness and damping ratios increases with the structural vibration frequency.