基于实测数据的某高层建筑结构动力参数和气动阻尼识别  

Structural dynamic and aerodynamic parameters identification for a tall building with full-scale measurements

作　　者：黄铭枫[1] 吴承卉 徐卿[1] 张凤亮[2] 楼文娟[1] 

机构地区：[1]浙江大学建筑工程学院结构工程研究所,杭州310058 [2]同济大学土木工程学院结构与防灾研究所,上海200092

出　　处：《振动与冲击》2017年第10期31-37,83,共8页Journal of Vibration and Shock

基　　金：国家自然科学基金资助(51578504);浙江省公益性技术应用研究计划资助项目(2012C21059)

摘　　要：根据在北冕台风及汶川远震作用下某270 m高大楼顶层实测得到的加速度响应数据,对该高楼的结构动力参数和气动阻尼进行了识别。采用两种方法识别得到了该大楼的模态振动频率和阻尼比参数。一是经验模态分解(EMD)结合随机减量法(RDT)及希尔伯特黄变换法(简称EMD+RDT),另外采用了基于贝叶斯理论和快速傅里叶变换的识别方法。利用EMD+RDT法,还得到了阻尼比随加速度幅值的变化规律。两种方法识别得到了非常一致的模态振动频率结果。然而,在台风作用和地震作用下所识别的大楼阻尼比特性却表现出明显不同的特性和规律,这种不同主要是由于在台风作用下的建筑物阻尼包含了气动阻尼成分。如果把地震作用下识别得到的该高楼阻尼比作为结构阻尼比,台风条件下识别得出的阻尼比为总阻尼比,则二者相减可以作为该楼气动阻尼比的估计。Based on the two sets of acceleration response data,full-scale measured on a 270 m tall building in Hong Kong during Typhone Kammuri and 512 Wenchuan earthquake in 2008,the dynamic modal properties of the tall building were identified by two methods.One is the traditional method of empirical mode decomposition(EMD) combined with the random decrement technique(RDT),the other is the recently proposed fast Bayesian method using the fast Fourier transform(FFT).The natural frequency of each mode identified by these two different methods is very close to each other,while noticeable difference is observed between the damping ratio results corresponding to each mode.The identified results under the two excitation events were also compared.As expected,the wind-induced acceleration data suggest almost the same natural frequency values as those identified from the acceleration data under the long-distance earthquake.However,the damping ratios of the tall building corresponding to Wenchuan earthquake are found to be larger than those under typhoon excitation.The subtraction results between these two sets of damping ratios might be considered as the estimation values of aerodynamic damping ratios.

关 键 词：高层建筑 现场实测 加速度响应 自振频率 阻尼比 气动阻尼比 

分 类 号：TU311[建筑科学—结构工程]