Application of short-time Bayesian spectral density approach for modal parameter identification of supertall buildings under typhoon effects
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.
super tall buildingmodal identificationshort-time Bayesian spectral density approachfield measurementwind tunnel testwind-induced response
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