风场类型对高层建筑风致响应的影响研究

风荷载是影响高层建筑安全性的重要因素之一,而不同的风环境会对高层建筑的风致响应存在不同程度的影响,基于此背景,本文通过高层建筑多自由度气动弹性模型风洞试验,获得了结构原始加速度时程曲线,采用随机减量法对其气动阻尼进行识别,分析了风场类型对高层建筑气动阻尼比和风致加速度响应的影响。结果表明:横风向气动阻尼比随折减风速的变化起伏较大,顺风向气动阻尼比随折减风速的增大而增大;折减风速小于特定值时,地貌类型对气动阻尼影响较小;随着风场类型从A类变化为D类,结构横、顺风向的气动阻尼比的变化趋势趋于平缓,气动阻尼比的正峰值减小,正峰值风速增大。高层建筑横风向的加速度响应大于顺风向;风场类型从A类变化为D类的过程中,横、顺风向的加速度响应均减小。风向角对气动阻尼比和加速度响应均存在较明显的影响。

Effect of geomorphologic terrian categories on wind-induced response of a tall building

Wind load is one of the important factors affecting the safety of high-rise buildings,and different wind environments will have varying degrees of impact on the wind-induced response of high-rise buildings.According to this background,the aerodynamic damping ration were identified by random decrement technique based on multi-degree-of-freedom aeroelastic model wind tunnel test,the effect of geomorphologic terrian categories on the aerodynamic damping and wind-induced response of the tall building was investigated.The results show that:Cross-wind aerodynamic damping ration fluctuates greatly with the change of the reduced wind velocity,alone-wind aerodynamic damping ration increases with increasing wind velocity;when the reduced wind velocity was below a certain value,roughness exposure had less influence on the alone-wind aerodynamic damping ration.As terrian categories change from A to D,the trend of aerodynamic damping’s change tend to be steady,the positive peaks of aerodynamic damping ration was reduced,and so does the corresponding reduced wind velocity.The acceleration response of cross-wind is greater than that of the alone-wind.As terrian categories change from A to D,acceleration response of cross-wind and alone-wind was decreased.The wind direction has obvious influence on aerodynamic damping ratio and acceleration response.