台风作用下超高层建筑模态参数识别的短时贝叶斯谱密度法及应用  

Application of short-time Bayesian spectral density approach for modal parameter identification ofsupertall buildings under typhoon effects

作　　者：李飞强 谢壮宁[1] LI Feiqiang;XIE Zhuangning(State Key Laboratory of Subtropical Building and Urban Science,South China University of Technology,Guangzhou 510640,China)

机构地区：[1]华南理工大学亚热带建筑与城市科学全国重点实验室,广东广州510640

出　　处：《建筑结构学报》2024年第9期181-190,共10页Journal of Building Structures

基　　金：国家自然科学基金项目(52378513)。

摘　　要：为更加准确地提取台风作用期间超高层建筑结构模态参数的时变特性,基于贝叶斯谱密度模态识别方法,引入短时傅里叶变换时频分析方法,在贝叶斯识别过程中考虑加窗效应影响,提出适用于非平稳激励下结构模态参数识别方法--短时贝叶斯谱密度法(ST-BSDA)。在采用数值模拟验证了该方法可靠性和准确性的基础上,将ST-BSDA用于台风“海高斯”过境期间高度210 m超高层建筑实测数据的模态参数识别,并对风场和结构模态参数取值的不确定性对结构风振响应的影响进行了研究。结果表明:利用ST-BSDA方法识别结果的平均值可以较好地表征结构模态频率、阻尼比的时变特征,其识别精度对荷载激励形式不敏感;台风过境期间,实测建筑结构前两阶自振频率变化率最大可达7.3%,与设计阶段有限元模型计算结果相对误差最大可达20%,阻尼比小于现行规范所建议的2%;相较于2阶模态响应,结构1阶模态响应对风速、风向、自振周期(频率)以及阻尼比的变化更为敏感;根据实测的模态参数结果对结构的风致响应进行重分析,得到的结构峰值加速度和实测结果吻合较好。To accurately extract the time-varying characteristics of modal parameters for super-tall buildings during typhoon period,a Bayesian spectral density modal identification method is employed.This study introduces the short-time Fourier transform analysis method and considers the influence of the windowing effect on the Bayesian identification process.The short-time Bayesian spectral density approach(ST-BSDA)is proposed as a suitable method for identifying structural modal parameters under non-stationary excitations.After being validated by numerical simulation to demonstrate its reliability and accuracy,the ST-BSDA method is applied to identify the modal parameters of a 210 m supertall building during Typhoon Higos.The study also investigates the effect of uncertainties in wind field and structural modal parameters on wind-induced vibrations in structures.The results show that the ST-BSDA method accurately captures the time-varying characteristics of structural modal frequencies and damping ratios.In particular,the identification accuracy of this method is not affected by the form of excitation.During Typhoon Higos,the measured building experiences a maximum rate of change of 7.3%in its first two natural frequencies.Compared with finite element models,the natural frequencies have a maximum relative error of 20%,and the damping ratios are lower than the recommended value in current standards(2%).In comparison to the second-order modal response,the first-order modal response of the structure is more sensitive to variations in wind speed,wind direction,natural period(frequency),and damping ratio.Based on the measured modal parameters,the wind-induced response of the building has been reanalyzed.The calculated peak acceleration of the structure is in good agreement with the measured results.

关 键 词：超高层建筑 模态识别 短时贝叶斯谱密度法 现场实测 风洞试验 风致响应 

分 类 号：TU973.213[建筑科学—结构工程]