某超高层建筑刚性模型测力试验研究

在4m×3m边界层风洞中对某高295m的超高层建筑分别进行了有、无周边建筑的刚性模型测力天平试验,得到建筑3个主轴方向基底力矩均值和均方根值随风向角的变化情况,通过比较表明周边超高层建筑对其具有较严重的干扰影响;分析了功率谱和相干函数所表现出的力矩频域特性,横-扭方向基底弯矩相关性明显较顺-横、顺-扭两向大;通过敲击试验得到基底弯矩的自由衰减信号,采用HHT变换方法,识别了模型-天平系统在两个主轴方向的一阶频率和阻尼比,并根据频率和阻尼比消除了基底弯矩信号中由于模型非绝对刚性引起的共振响应分量,由此修正得到较为精确的基底力谱和各角度均方根值,为计算风振响应提供了依据。

Research on a super high-rise building based on the rigid model force measurement testing

Rigid model testing of a super high-rise building,with and without surrounding buildings,are performed respectively in a 4m×3m boundary layer wind tunnel based on the force balance.The changes of mean and rms moments in three body axes with the wind direction angle are obtained,which shows that surrounding super high-rise buildings act notable interference on it.The frequency domain property of power spectral density and coherence are analyzed.The results show that coherence of bottom moment between across-wind and torsion direction is obviously bigger than that between along-wind and across-wind direction,along-wind and torsion direction.According to the free attenuation of bottom moment by means of a knock testing,the frequency and damping ratio of the model-balance system,are recognized by HHT method,which are further utilized to eliminate the resonant response raised by lack of stiffness.In this way,modified power spectral density of the base moment and the root mean square can be obtained and be used to calculate the wind induced response.