Wind Induced Self-Excited Vibration of Tall Buildings and Its suppression

对于300m以上的高层建筑，可能会发生涡激振动、驰振和颤振等气动弹性失稳，从而导致结构失效。本文主要通过风洞试验研究了建筑物体型、结构阻尼、接近流特性和弯扭振固有频率比对气动弹性失稳的影响。研究结果表明：1)对于较浅截面的建筑物，涡激振动发生在城市地形上的强湍流中。2)对于任何形状和流动类型的建筑物，气动弹性不稳定性都被限制在0-15ﾟ的攻角范围内。3)弯曲振动受扭转振动的影响不大。另一方面，扭转振动受弯曲振动的影响较大。当扭转振动的固有频率与弯曲振动的固有频率接近时，扭转颤振通过能量传递到弯曲振动而被抑制。4)建筑物角部的切割、圆角对于减小气动弹性失稳是非常有效的。特别是在转角处向后退一小步，对涡激振动有很大的抑制作用。

For tall buildings with more than 300m, the aero-elastic instability like vortex induced vibration, galloping and flutter could be occurred to lead their structural failure. In this research, effects of building shape, structural damping, approaching flow characteristics and natural frequency ratio of bending and torsional vibration on the aero-elastic instability were investigated mainly by wind tunnel tests. From the investigation, the following results are obtained.1) The vortex induced vibration occur in strong turbulent flow like flow over urban terrain for a building with a shallow section.2) The aero-elastic instability is limited within the angle attack of 0 - 15ﾟ for any building shapes and types of flow.3) The bending vibration is not so much affected by the torsional vibration. On the other hand, the torsional vibration is greatly influenced by the bending vibration. When the natural frequency of the torsional vibration is close to that of the bending vibration, the torsional flutter suppressed by the energy transfer to the bending vibration.4) The cutting, rounding of a building corner is very effective to reduce the aeroelastic instability. Particularly, a very small step back at the corner has a great effect to suppress the vortex induced vibration.