This paper presents characteristics of motion-induced wind forces acting on a rectangular high-rise building with a side ratio of 2 during across-wind and torsional vibration. The motion-induced wind forces afe measured by a forced-vibration method in a wind tunnel. Main results are as follows: 1. The characteristics of motion-induced modal wind force acting on high-rise buildings with a side ratio of 2 during turbulent flows are different from those during a uniform smooth flow in the case of reduced wind speeds of 7 or more. 2. The wind speed in which the out-of-phase components of motion-induced across wind force shows a positive value during turbulent flows is limited to the vicinity of 5 for the reduced wind speed in the case of across-wind vibrations. In the case of the motion-induced torsional moment, the positive value of out-of-phase components is shown in the wind speed area where the reduced wind speed is 5 or more. 3. The aerodynamic damping ratios and response displacements obtained from the spectral-modal analysis using the out-of-phase components of motion-induced wind forces almost agree with the results of multi-degree-of-freedom aeroelastic model tests.
