修角对方形超高层建筑横风向气动阻尼的影响

EFFECT OF CORNER-CUT AND TAPERING ON ACROSS-WIND AERODYNAMIC DAMPING OF SQUARE HIGH-RISE BUILDINGS

为了研究横截面削角、凹角及沿高收缩处理三种气动修正措施对作用在建筑上的横风向气动阻尼比的影响，对10个超高层建筑气动弹性模型进行了风洞试验。利用随机减量法识别了横风向气动阻尼比，通过与前人相关研究成果的比较，验证了识别结果的正确性。研究结果表明：角沿处理及截面沿高收缩对抑制超高层建筑的气动弹性效应并非总是有效，较小的削角率（5％~20％）、凹角率（5％和10％）及沿高收缩率（1％）可以有效的减小各折减风速下气动阻尼比绝对值的大小，而当这些气动修正措施相对尺寸较大（凹角率20％、3％及5％的沿高收缩率）时，气动阻尼比的改变将增大结构风致振动响应。基于这些研究，拟合了适用于低折减风速下相应工况的横风向气动阻尼比的经验参数，供工程设计人员参考。

In order to study the effects of chamfered, slotted, and tapered cross-sections on across-wind aerodynamic damping ratio of super-high-rise building, 10 aeroelastic model tests were conducted in the TJ-1 wind tunnel at Tongji University. The random decrement technique was used to evaluate across-wind aerodynamic damping ratios. The accuracy of the evaluated results was verified through comparison with previous research achievements. Results indicated that modifications of cross-sections are not always effective in suppressing the aerodynamic effects of tall buildings. Chamfer ratios from 5% to 20%, slot ratios from 5% to 10%, and taper ratio of 1% significantly decrease the magnitudes of absolute aerodynamic damping ratios. Slot ratio of 20%, and taper ratios from 3% to 5% increase wind-induced responses through changing the aerodynamic damping ratios. Based on the findings, empirical aerodynamic damping function parameters are fitted for aerodynamic damping ratios of high-rise buildings reduced wind velocities. with aerodynamically modified square cross-sections at low